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Message started by DragBikeMike on 09/24/23 at 21:54:57

Title: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 21:54:57

IMO, the Savage lubrication system is woefully inadequate. You can’t even let the thing idle without fear of wrecking the top end. When idling in traffic, my oil pressure gage routinely read “zero”. It doesn’t get super-hot over here. Imagine what the pressure is in Phoenix (can it be less than “zero”?).

Many of us think extended idling results in cam lobes that look like this.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 21:55:50

I suspect these rocker arms are a victim of ZPS (zero pressure syndrome).

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 21:56:32

Start makin some serious power, and you may end up with pitted gears. The five-speed gears can’t handle big power. A four-speed gearset is more robust, but a little more oil wouldn’t hurt.

This is a picture of 5th gear after a few thousand miles behind a powerful engine.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 21:57:04

How’s this bearing look? It was a self-inflicted wound. Who would have thought that a main bearing gets its lubrication from the cam lobes.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 21:57:41

Did this piston get too hot? Granted, the clearance was on the tight side (Wiseco specification .0019”), but a little more oil might have prevented this mess, or at least minimized the damage.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 21:58:23

Have any of you seen bronze deposits on your clutch spacer? I’ve had trouble with a grabby clutch that squeals. I have since corrected those problems by restoring the wave washer assembly, but while figuring out the problem I noted that my push piece o-ring seemed to affect the squealing problem. When the o-ring wore out, the problem got worse. Something tells me that the clutch could use a little more oil too.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 21:58:57

If you’ve been seeing this on your magnetic drain plug, it’s time to look inside that motor. You might need a new main bearing. As previously mentioned, I failed to see the significance of the oil holes in the cam lobes. Unfortunately, that main bearing doesn’t give you much warning. By the time you see this on your magnetic plug, the bearing is in the toilet.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:00:02

My engine had reached the point where the power was just too much for the stock lubrication system to keep up with. What the heck, the stock oil system can’t even keep up with a stock engine, why did I expect it to provide sufficient lubrication for a modified engine? I also managed to shoot myself in the foot by installing a DR cam without drilling holes in the cam lobes. Obviously, I did not fully understand the system. It was time to take a hard look and see what I could figure out.

With engine oil at normal operating temperature (about 200°F), my oil pressure was always “zero” at 1300 rpm (idle), and about 6 to 7 psi at 4000 rpm (freeway cruise). That’s with 20W–50 Mobil 1. If you run 10W-40, you can expect less pressure (how do you get less than “zero”?). As you can see, the stock oil system doesn’t develop a lot of oil pressure.

This is a schematic of the stock system. There are three main circuits: bottom end, top end, and transmission. Note that the main bearings are not pressure fed, they get the leftovers.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:00:56

The oil pump is a typical gerotor pump. It’s a positive displacement pump, so it moves the same amount of oil each revolution of the rotor, there’s no slip. The oil system has fixed clearances and oil passages. The only variable is the oil filter bypass relief. There is no pressure control (no unloader valve, no pressure regulating valve). It’s crude.

Oil pressure is dependent on the speed of the pump, internal clearances, and the viscosity of the oil. Speed up the pump and oil pressure will increase. Slow down the pump and pressure will decrease. As the plain bearings wear, pressure will decrease (ball & roller bearings don’t affect the pressure). Higher viscosity oil will result in higher pressure. Lower viscosity, lower pressure. Heat up the oil and pressure will decrease. Cool down the oil and pressure will increase.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:01:32

The pump is driven by a set of gears. The pump gear is rotated by a drive gear attached to the clutch basket. As the clutch basket rotates it turns the oil pump. The diameter of the gear on the clutch basket (30 teeth) is smaller than the diameter of the gear on the pump (35 teeth), so the pump turns slower than the clutch (0.86:1).

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:02:21

The pump is located on the inside of the right-hand engine case. The crescent shaped discharge port on the pump aligns with a crescent shaped pocket in the case. The main oil passage in the case intersects the crescent shaped pocket. Oil flows from the pump into the pocket and through the main passage in the case (yellow arrows).

There is a windage partition (circled in green) that is intended to keep the oil from sloshing over the rotating crankshaft. Normal oil level (red line) is just below the windage partition.

The transmission bearings (circled in white) are situated well above the oil level. That tells you that the transmission gears do not dip into the oil. The gear mesh is lubricated by oil that is thrown off the rod bearing. Not all the gears line up nicely with the rod. Top gear is not in line with the rod. That’s important since you spend almost all your time in top gear.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:04:13

A view from the outside of the engine case shows the location of the various oil circuits. I grabbed this photo from someone else’s old post. Can’t remember who posted it, but they did a nice job. Whoever you are, thanks very much.

You can see from this excellent markup, that the stock system has three flow circuits, bottom end, top end, and transmission. Don’t be fooled by the description “to tranny”. Yes, the oil in this circuit goes to the transmission (also to the clutch), but it doesn’t lubricate the gear mesh. It lubricates the idler bearings inside the gears.

The filter is housed in the clutch cover, so the oil supply to the filter runs directly into the clutch cover. The oil supply out of the filter is directed into the end of the crankshaft to supply oil to the bottom end, and into the channel that runs fore & aft along the top of the engine case, where it connects to passages that supply the top end and the transmission. There is a .071” orifice in the transmission supply.

It has this cool plug (green arrow) at the end of the main oil passage. That plug presents all sorts of possibilities for measuring pressure, hooking up a cooler, supplying oil to specific components, etc. I like that plug. But remember, this is a crude lubrication system. If you take oil from that passage, you will be robbing oil from the other circuits. Oil pressure will diminish rapidly because you will be adding a 4th circuit.

The .071” orifice in the transmission oil circuit looks inviting too. Make the orifice bigger and maybe you can help the gears. Same problem. If you start messing around with that orifice, oil pressure will change. Make the orifice bigger and pressure will go up in the transmission, but down at the bottom end & the top end.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:04:46

This shows the flow path through the clutch cover. The green arrow shows where the oil from the pump enters the clutch cover. It flows into the filter housing where it goes through the filter. From the filter, the oil flows to the crankshaft (yellow arrow) and the supply channel that feeds the top end and transmission (red arrow).

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:05:24

Oil enters the filter housing and surrounds the pleated filter cartridge. The port circled in red is where the oil comes into the filter cavity. The port circled in green is where the oil exits the filter and branches out into the three separate circuits. The small hole circled in yellow is not an oil passage. It is a threaded hole used to mount an oil seal retaining plate on the inside of the clutch cover.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:05:56

The filter element is a typical pleated paper filter.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:06:32

This shows the bypass relief disk. It doesn’t regulate pressure. It simply opens when the differential pressure is too high. When the relief opens, it allows oil to bypass the filter. The seating area is 11mm.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:07:07

This shows the internal components of the bypass relief.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:08:06

At installed height, the spring exerts about 3.7 lbs of force. It’s simple to calculate how much differential pressure is required to open the bypass. It should take about 25 psid. The keyword here is “differential”. Remember there is pressure both upstream and downstream of the disk. The pressure downstream of the disk is working to keep the disk on its seat, the pressure upstream of the disk is trying to lift (open) the disk. So, if I am reading system pressure downstream of the filter, the lift point for the bypass will be system pressure plus 25. For instance, if the system pressure is 10 psi, then the pressure at the pump discharge would have to reach 35 psi before the bypass lifts.

58.6 ounces is 3.7 lbs. An 11mm diameter seating area is 0.15 square inches. So, 3.7 lbs over 0.15 square inches works out to 24.7 psi.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:08:40

Oil is fed through the right side of the crankshaft to lubricate the bottom end (connecting rod, transmission gear-teeth & bearings, and the cylinder & piston). The oil seal in the clutch cover mates with the end of the crankshaft.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:09:17

The seal journal on the right side of the crankshaft is critical. It must be in perfect condition to ensure there are no leaks. The journal spins upward of 6000 rpm, so the surface finish must be smooth and free of nicks. I’ve seen a lot of these seal journals damaged from inexperienced mechanics beating on them with a hammer or punch. Never strike the end of a crankshaft. It wrecks the crank.

This journal is damaged, but I think it can be salvaged.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:10:02

The oil gets pumped through the crankshaft and into the rod bearing. There are drain notches in the sides of the rod that permit the oil to escape. That oil gets thrown all over inside the bottom end, wetting down the cylinder, underside of the piston, wrist pin, and the transmission gear teeth.

This picture shows a five-speed trans. See how 4th gear (circled in yellow) & 5th gear (circled in red) do not align with the rod drains. Ride this thing on the freeway and you spend a lot of time in top gear. The gear will get hot. It would be nice to have a steady supply of cool oil rather than the random few droplets that find their way into the mesh. If you make decent power, both of these gears start to pit.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:10:38

The top end circuit runs up through drilled passages in the cylinder, cylinder head, and head cover. At the very top, you can see my pressure tap for the oil pressure gage.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:11:16

The oil enters the cylinder at the bottom. This is the drilled passage. It is located in the right-rear corner of the cylinder.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:12:04

At the top of the cylinder, there is an unusual keyhole shaped passage that allows the oil to flow sideways until it lines up with the drilled passage in the head. Note there is a threaded hole at the end of the keyhole shaped passage. That threaded hole is for the long 130mm bolt that secures the head cover. The bolt runs all the way through the head cover and head. It runs directly through the oil feed passages. Those internal threads in the cylinder routinely strip.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:12:50

The top end oil continues upward through the cylinder head. The green arrow shows the hole in the cylinder head that mates with the unique keyhole passage in the cylinder. You can see the keyhole impression from the embossed steel head gasket.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:13:30

The oil travels straight up through the cylinder head and exits here. It hasn’t lubricated anything yet.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:14:11

Then the oil enters the head cover. There is a network of drilled passages in the head cover. Those passages direct oil to the upper half of the cam bearings.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:14:53

The upper halves of the cam bearings are incorporated into the head cover. These are the first items to receive lubrication.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:15:51

Right at the horizontal split, each cam bearing has heavy chamfers. These chamfers are important parts of the lubrication flow path. You don’t want the chamfers filled in with sealant or debris.

The chamfers on the left-side (yellow) direct oil into a cavity adjacent to the camshaft. This cavity is pressurized which forces the oil to run through the hollow camshaft.

The chamfers on the right-side (green) direct oil into a reservoir below the cam lobes. I call it the trough. The trough (or reservoir) fills with oil. As the cam rotates, the lobes dip into the trough (like a paddlewheel), pick up oil, and continue around to the cam followers. The oil coating the cam lobe lubricates the cam followers and cam lobes. The followers & lobes are subjected to heavy load as the cam actuates the rocker arm and opens the valves. Each valve spring requires about 130 lbs of force to fully open, so the rocker arm must overcome about 260 lbs of force. The rocker arms are about 1.4:1 ratio, so the required force is now increased to about 364 lbs. Torture.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:16:40

This is the trough (or reservoir). You can see that the cam lobe is well coated with oil. This is a picture of a 1995 DR650 cam. I made the mistake of installing it without drilling holes in the lobes. More on that later. I just want to give you an idea of exactly how the oil trough lubricates the cam lobes.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:17:19

This picture shows how the oil flows through the chamfers into the left side cavity and into the oil trough. From the left side cavity, the pressurized oil fills the hollow camshaft and exits through holes in the cam lobes. There is also a hole in the right end of the cam. The oil exiting the right end of the cam lubricates the outboard cam bearing.

Although the holes provide some lubrication for the lobes, I personally believe that their primary function is to spray oil forward into the cavity that surrounds the exhaust valve springs.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:18:02

As the lobe dips into the trough, it picks up oil. Then, as the lobe continues rotation most of that oil is thrown aft onto the intake valves (paddlewheel effect). Then, the lobe encounters the cam follower. The pad on the cam follower wipes any remaining oil off the lobe. By the time the lobe clears the cam follower, there simply isn’t any more oil left on the lobe. So, IMO, the exhaust valves get their lubrication from the holes in the cam lobes. That’s a very important point since the left-hand main bearing and balancer bearing are lubricated by drain oil from (you guessed it) the exhaust valve spring pocket.

This picture should drive the idea home. See how the cam follower wipes off the lobe and squeezes the oil out the back side. The only way for oil to go forward into the exhaust valve pocket is via the holes in the lobes. Since it’s pressurized oil, it will spray out of the holes.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:18:37

To add insult to injury, the oil trough has a drain that looks like it is intended to maintain the oil level in the reservoir. That drain is in the rear of the trough, so it exits into the intake valve pocket. There isn’t a similar drain in the forward portion of the reservoir. Without the holes in the cam lobes, little or no oil goes into the froward valve pocket. I’m shocked and amazed, the holes in the cam lobes are critical to the left-hand main bearing.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:19:09

This is the all-important drain hole. It supplies the oil to the left-hand bearings.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:19:59

The drain moves at an angle until it intersects the cylinder head stud hole. So, the left-front stud hole serves as a drain.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:20:33

At the base of the cylinder, the drain enters a keyhole shaped cavity.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:21:10

The mating surface on the case has a hole (green arrow) that directs drain oil to the balancer bearing, and a notch (yellow arrow) that directs oil to the main bearing.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:21:44

Fill the exhaust spring pocket with oil and you can watch the oil cascade over the left-hand bearings.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:22:17

What a pathetic way to lube main bearings. But hey, it’s all we’ve got. The good old drip lubricator, been around since 1872. The real McCoy.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:22:52

The right-hand side has a similar system. Instead of a drain hole, the oil simply spills over the edge of the intake valve spring pocket (like Niagra Falls).

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:23:24

Then the oil dribbles down the side of the chain well and runs over the main bearing.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:23:59

The right-hand balancer bearing has this contraption that gathers up stray oil and directs it to the edge of the bearing. Reminds me of a coal chute.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:24:39

The right-hand bearings also get oil off the primary drive. You can see from this picture that the clutch basket dips into the oil (the yellow line shows the oil level). That must sling a whole bunch of oil around inside the clutch cover.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:25:23

The transmission shafts and clutch are fed oil through this .071” orifice. The orifice restricts the flow, so the pressure inside the transmission shafts is somewhat less than the pressure in the rest of the system.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:25:57

The orifice is removable. It is sealed to the case with a small o-ring. It’s tempting to enlarge this orifice, or to remove it altogether. I don’t recommend it. If you enlarge or remove the orifice, you will steal oil from other parts of the engine.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:26:46

From the orifice, oil travels to the left side of the transmission via a drilled passage in the top of the case. There is an o-ring in the case joint to prevent the pressurized oil from leaking out. The area circled in red is where the drilled passage resides. The plugs circled in green and yellow seal off the ends of intersecting vertical passages that carry oil to the transmission bearings on the left side. I don’t think that oil is intended to lubricate the trans bearings because they are sealed. The oil running through this circuit is intended for the internal idler bearings in some of the transmission gears, and for the clutch bushing.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:27:29

This shows how oil enters the cavity between the output shaft bearing and the output shaft seal. The passage is circled in yellow. Note that the outboard side of the bearing is sealed. Since the oil is trapped between the bearing seal and the shaft seal, it is forced to travel into the output shaft. The input shaft has a similar arrangement. The green arrow shows the passage to the input shaft.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:28:08

Oil enters the end of the input shaft and provides lubrication for the idler bearings in 4th & 5th gears. The oil continues to flow through the shaft to the right side of the engine where it lubricates the clutch bushing.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:28:48

This hole in the input shaft provides lubrication for the clutch sleeve and bronze bushing.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:29:41

Both sides of the input shaft are open. Oil enters the left side of the shaft so the left side must remain open. The right side of the input shaft must be sealed off to prevent the oil from just running out of the shaft.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:30:26

The push piece in the clutch release mechanism has an o-ring. The function of this o-ring is to seal off the right side of the input shaft. Keep the o-ring in good condition so that you don’t degrade oil pressure to the transmission shafts and clutch. The first indicator of a problem might be those bronze deposits I kept seeing on my clutch sleeve.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:30:59

Oil enters the output shaft through this small hole. Never obstruct this hole by installing the pulley spacer backwards. The notches in the pulley spacer must touch the inner race of the output shaft bearing, not the pulley. The oil in the output shaft lubricates the idler bearings in 2nd, 3rd & 4th gears.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:31:34

These are the notches in question. These notches provide a flow path for the oil to enter the output shaft. The notches must face the bearing, not the pulley.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:32:07

I was curious how much pressure to expect downstream of the transmission supply orifice, so I made a test connection to replace the pulley and spacer.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:32:51

I couldn’t drive the thing around with that test fitting in place, but at least I could get a feel for the relationship between pressure at the cylinder head and pressure at the transmission. I was mostly concerned with too much oil pressure blowing out the output shaft seal. A wimpy sheetmetal retainer is all that’s preventing the seal from blowing out and oiling down the rear tire. Pressure is highest when the oil is cold, so I figured a test with cold oil would be appropriate.

With cold oil (77°F) and the engine running 2100 rpm, the pump discharge was about 45 psi, the oil pressure at the head was about 13 psi, and the transmission pressure was about 5 psi. I’m thinkin that filter bypass is open under these conditions.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:33:36

So, under low-speed cold conditions the trans pressure is about 5 psi. Looks like it might be safe to assume that with a .071” orifice the trans pressure should be about 38% of head pressure.

I know, this is a crude gage installation, but what the heck, it’s temporary. At least the test fitting was pretty.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:38:01

What a pickle. I was pitting gear teeth, spalling main bearings, seizing pistons, wearing out my clutch bushing, and who knows what else.

I thought I had figured out the main bearing spalling. Drilling holes in the cam lobes would restore oil flow to the main bearings. Who would have thought that those holes in the cam lobes were crucial for main bearing longevity.

Seized pistons could be mitigated with a bit more running clearance. I never felt comfy with .0019” clearance to begin with. The 94mm Wiseco has a recommended clearance of .0025”, why should the 97mm be less. My wrist pin was always on the dry side when I opened it up for inspection. I don’t think it would be a good idea to add more clearance there, so more oil seemed like it would be beneficial.

But those pitted gear teeth. How was I gonna fix those? I am running a 4-speed gear set because it is beefier, but more oil would help too. Any increase in oil flow to the transmission would require more oil from the source. I needed a bigger pump, or a faster pump. If I could provide more oil flow, I could increase flow to all three circuits, or enlarge the transmission orifice. Maybe some of the extra oil would find it’s way to the gear teeth. I didn’t think it would hurt to have more oil flowing everywhere.

If I could increase oil flow enough, I could possibly add a fourth oil circuit to provide direct lubrication to the gear mesh, and still maintain adequate pressure and flow to the original three circuits.

I came up with two options, a High-Volume Oil Pump and a High-Speed Pump Drive. This old report provides the details on those pump mods.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1680140612

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:39:53

I decided to use the high-speed pump drive because I could restore the system to stock configuration without completely disassembling the engine. Let’s face it, I was exploring virgin territory. The increased flow would allow an additional oil circuit with a dedicated spray for top gear (in my case 4th).

To utilize the high-speed pump, I would need a way to control flow to the various circuits and bleed off excess pressure. That could be accomplished with jets placed in strategic locations.

The primary objective was to provide lots of cool oil to top gear, and the secondary objective was to increase pressure to the cylinder head. If I could maintain at least 7 psi at the head, I knew that the original oil circuits would still be receiving the as-designed volume of oil at the as-designed pressure. But if I could increase pressure at the cylinder head, every component in the engine would benefit from additional oil. Any pressure over 7 psi would be gravy.

To achieve the “cool oil” objective, I would use an oil cooler. I don’t think the Savage needs an oil cooler. My oil temperature has always been a bit cooler than desired (about 200°F here in Hawaii). But I wanted that gear running cool. So, if I restricted the flow of oil through the cooler, maybe I could achieve the goal of cooling the gear without reducing sump temp too much. Running the pump at higher speed was gonna heat up the oil a bit too. Maybe one would offset the other.

The DR cam would get the requisite oil holes in the cam lobes.

This is a diagram of the modified system. The 4th oil circuit (in red) runs from the main oil passage, through a jet to control flow, through the oil cooler, and through a spray tube directly into the gear mesh. A bleed jet is installed in the oil filter housing to dump excess oil if necessary.

This oil system upgrade wouldn’t prove much unless I installed it on an engine with some yank, so I simply moved the entire top end and 4-speed trans off my Big Bore 4-Speed project over to the oil system test mule. Up to this point, the Big Bore 4-speed had proved that it was up to the job. It had overwhelmed the clutch, destroyed a main bearing, and seized a piston. This thing makes great power. It will be a good test for the modified lube oil system.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:40:31

The heart of the system is the high-speed pump drive. The 4th oil circuit would not be possible without the increased volume that the high-speed drive provides. Now, the drive gear has 35 teeth, and the driven gear has 30 teeth. That changes the ratio from 0.86:1 to 1.17:1, an increase of 36%. It converts the drive from a reduction gear to a speed increaser.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:41:03

A special fitting taps off the main oil passage where the plug used to go. The fitting has a provision for a thermo bulb. It has an integral 3/8” hose barb that is drilled & tapped to accept a standard Mikuni main jet. The jet will allow me to control how much oil goes through the 4th circuit. I use the jet as a primary control for oil pressure, and to prevent over cooling the oil. I want to try and maintain oil temperature about 200°F. If the cooler gets good and hot, I know that there is significant flow through the cooler (more than enough to lubricate and cool the gears).

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:41:40

The special fitting fits just right.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:42:17

The oil cooler is an old Jagg unit that I had in my junk bin. I used to run it on my Harley Softail. This thing is intended to be installed in the return line from the scavenge pump back to the oil tank. I don’t think it was intended to be used in a pressurized system, so I must be careful with it. With a flow control jet upstream, and an open-ended spray tube downstream, I think the cooler will be OK.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:42:55

The cooler almost looks like it was made for the Savage. I just attached it to the frame with Adel clamps. Hose routing was a breeze. I used Derale trans cooler hose rated for 100 psi @ 300°F.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:43:32

The cooler and associated hoses hold a significant amount of oil. That oil drains back to the sump when you shut the engine down. So, when the engine is running, the oil level in the sump will be below the desired range. To compensate, you must fill the engine to the normal level, and then add an additional amount of oil. That additional amount should be whatever the cooler holds when the engine is running. In my case, the Jagg cooler holds 8 ounces of oil.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:44:14

As an additional precaution, I installed a special bleed jet in my oil filter housing. The jet is situated on the upstream side of the filter element. I used Mikuni air bleeds. They come in sizes ranging from 0.5mm up to 2.0mm. If the additional bleed is not needed, just install a 4mm set screw.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:45:13

To set up the additional bleed, I drilled & tapped the existing 6mm threaded hole for the crankshaft seal. That hole goes directly through the clutch cover and penetrates the filter cavity. I tapped the hole for a 5/16-24 UNF screw, then made a special fastener to hold the seal retainer in place.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:46:59

This shows the seal retainer with the special fastener installed.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:47:40

The gear-spray was the hardest part of the job. It required a special penetration block for the rear of the engine case. The special penetration was a set of aluminum discs with a 90° hose fitting on the inlet side and 1/8” copper tubing on the spray side. The tubing runs over the top of the transmission gears and is fastened to the case with small aluminum clips. I drilled holes through the case to permit the use of small screws to secure the clips to the case.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:48:25

This shows how the 1/8” tubing is installed in the disc. The assembly is secured to the rear of the case with small stainless-steel screws, and it is sealed with JB Weld. The phongraphic grooves are intended to prevent the epoxy layer from becoming too thin when the screws are tightened.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:48:59

The spray tubing is aligned so that oil is discharged directly into the gear mesh. Since the input gear is rotating counterclockwise, and the output gear is rotating clockwise, the cool oil is pulled right through the mesh. I can’t get much better than that.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:49:36

Since there was a chance that the oil pressure might end up significantly higher than stock, I was concerned about the o-ring in the case joint where the transmission feed passes through the centerline. That o-ring prep is simply a spot face, it doesn’t have an actual “groove”. If oil leaks past the o-ring, it can force the o-ring to collapse and enter the passage, so I made a special piece to establish a bona fide o-ring groove. The o-ring is captured. The worst that can happen is a small leak develops.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:50:13

This is the case with the special piece epoxied in place. It requires an o-ring that is the same OD as stock, but the cross section is thinner.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:50:51

The DR camshaft got the hole treatment. Leaving these holes out was a big mistake. Never put one of these bumpsticks in your engine without drilling the holes.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:52:16

So, how did all this work?

With a #120 flow control jet to the cooler, the oil pressure is now about 5 psi at idle, and 10 to 11 psi at 4000 rpm. So, about double.

No problems with the pump drive gears. No unusual noise or vibration. No fluctuating oil pressure at high rpm. You can run it up to 7K and the gage shows no signs of cavitation or loss of suction.

Oil temperature remained at 200°F. I know the gear spray has adequate flow because the cooler gets hot. If there was no flow, or low flow, the cooler would not get hot. It clearly has a lot of oil flowing through the cooler, but not so much that the sump temperature drops below what it was before. So, flow through the cooler seems pretty close with the #120 jet.

I did not have to use the special oil bleed in the filter housing. It is plugged with a set screw. But I haven’t done any tests to see if the filter bypass is lifting. The filter shows no signs of distress, no evidence of tearing, deformation, or collapse. I need to get a gage in between the #120 jet and the pump. It’s on my to-do list.

The transmission supply passage is dry at the case joint. No leaks.

The transmission output shaft is dry. No leaks.

The special fitting I installed on the rear of the case is dry. No leaks.

The clutch works perfectly. Repeated inspections show no evidence of bronze deposits on the sleeve. No slipping, no grabbing, no squealing. I suspect most of this improvement is due to the wave washer installation, but I’m sure the extra oil is helping too.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:53:02

I’ve put a little over 11,000 miles on the engine with the improved oil system. Repeated inspections show no evidence of any sort of failure. I’ve been changing oil about every 3000 miles, and have been inspecting the magnetic drain plug about every 300 to 600 miles. I took the following photos at the 10,000 mile inspection.

No more chips on the magnetic drain plug. No indication of a failing bearing or gear teeth. This drain plug has a special neodymium magnet. It’s Big Time strong, so it grabs chips like crazy. I don’t consider it to be any sort of cleaning device, it’s a tool to monitor the engine. Like a chip detector on a jet turbine.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:53:44

See what I mean about that magnet having some pull. That’s a 12-inch crescent wrench.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:54:30

So far, all I have observed is magnetic sludge typical of a motorcycle engine with an integrated crash box. I wipe the plug off on a clean paper towel and examine at 5X magnification to make sure there are no chunks. Going forward, I’ll only be doing this at an oil change. No more interim drain plug checks.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:55:13

The oil filter always looks fine. Every now and then I find a small flake of metal, almost always non-ferrous.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:55:50

Top gear looks great. I have inspected it at each oil change, and it remains unchanged. No pits or spalling. This picture was taken at the 10,000 mile mark. The gear looks like this all the way around. I have no idea how many miles are actually on this gear set. I bought it used off eBay. I personally have logged about 16,000 miles on it (6000 prior to this oil system upgrade).

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:56:28

The cam lobes look great too. No significant pits or scoring. The valves have not needed any adjustments either.

This is the nose of the exhaust lobe. It has some very tiny pits, but they are too small to see in the photo. I’ve been monitoring these pits for a very long time, and they never seem to change. I lost track of the exact mileage on the cam. I’ve used it on a bunch of projects. If my records are correct, it should have about 43,000 miles on it.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:57:15

This is the intake cam lobe. You can see the oil hole. I wanted to give you a better idea of how much detail you can expect from one of these cheap endoscopes. A little blurry, but good enough for my purposes.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:57:53

The cylinder looks fine. No excessive carbon accumulation. No evidence of seizing. A few vertical scratches but they appear superficial.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:58:25

Compression has remained about the same for the full 10,000 miles. It’s always about 200 to 210 psi.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:59:14

The breather catch can never has much oil accumulation, maybe a teaspoon every oil change. The additional oil flow does not overwhelm the drains or the breather system.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 22:59:51

The clutch bushing looks great. Seems to be getting lots of oil.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 23:00:25

There are no more bronze deposits on the clutch sleeve, and the squealing and grabbiness have not occurred over the entire 10,000 mile test.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 23:01:00

The oil pump drive gears work great. There is no unusual noise. The wear pattern looks fine. No pitting, scoring or spalling. All is well with the pump drive.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 23:01:41

This one looks good too.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 09/24/23 at 23:05:12

The engine is running well. With this new oil system, every component in the engine gets more oil, all the time, and my problem gear is continuously bathed in cool oil. I’m very pleased.

My plan is to set up a test gage in the pump discharge and try to figure out if the bypass relief is continuously open. If the pump discharge pressure approaches 35 psi when the oil is at normal temp (200°F) and the engine speed is at cruise (3500-4000 rpm), then I can enlarge the jet to the cooler, install an aux bleed jet, or switch to 10W-40 oil. Just depends on how high the pressure is. If it’s borderline, maybe all I have to do is switch to the lighter oil. I’m not concerned if the bypass lifts occasionally, I’m just not fond of it being open all the time.

Now that I have good confidence in the engine and transmission, I can forge ahead with some carburetor testing. Can’t wait to fool around with that PWK with the emulsion tube.

I hope some of you find this report informative. Maybe it will help you with your project. As always, I invite your questions and comments. I spent a lot of time on this project. I am humbled. I learned a lot of new things. I thought I understood this oil system and I didn’t have a clue. If you think I got some of this wrong, please speak up. I don’t wanna find my drain plug covered in chips again.
:o

Best regards,

Mike

Title: Re: Oil System Evaluation & Upgrade
Post by zevenenergie on 09/25/23 at 03:27:27

Wow,

That's an extensive study, and ditto report.

I now see that it is really necessary to do something about the lubrication when I tune the engine. The lubrication system is now not optimal.

I thought that simply increasing the yield would be the solution, but that is an underestimate.
This is not only a good guideline, but actually the way it should be done.

I am grateful to you for sharing this information. And impressed by the thoroughness with which you approached this.

Tanks.

In my eyes you are the David Vizard of the Savage.

Things get done through dedication. And that is something you certainly understand.

Title: Re: Oil System Evaluation & Upgrade
Post by Armen on 09/25/23 at 12:23:09

Awesome work DBM!
Thanks for sharing!

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 11/13/23 at 20:03:39

So, I recently rolled over 60K miles. It was time to look at a few things. While I was racking up the mileage, I managed to do a test to see if the oil filter differential pressure (DP) approached the point where the filter bypass would lift (25 psid).

To measure the filter DP, all I needed was a simple test rig that allowed me to get a gage on the pump discharge pressure. This contraption was easy to make and worked well. Not something I want to go riding around with, but for a short test it served the purpose.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 11/13/23 at 20:07:40

With the oil up to temperature and the engine running at 4K, pump discharge pressure was about 20 psi and system pressure was about 11 psi. So, we're lookin at about 9 psid. Well below 25 so I think it's good just where it's at.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 11/13/23 at 20:18:56

All the important stuff was inspected. It's all good.

-No chips or chunks on the magnetic drain plug

-No pits in the gear teeth

-Compression 200 psi

-Clutch bushing & sleeve ace

-Clutch action ace

-Pump drive gears ace

-Valve lash unchanged (.004 - .005)

-Cam lobes unchanged, still some superficial pitting

So, at the 14K mark it's holdin its own. So far, I am very satisfied with this system. It seems to have resolved my gear pitting and bearing spalling issues. It also seems to have helped the clutch engagement issue. While I believe the wave-washer deserves the lion's share of the credit for clutch engagement, the improved oil system has to be at least partially responsible for the absence of bronze deposits on the sleeve.

I will keep you posted on my progress.

Best regards,

Mike

Title: Re: Oil System Evaluation & Upgrade
Post by Dave on 12/08/23 at 04:20:07

Mike:

That is an impressive amount of work and the results are hopefully going to keep you engine healthy while you push the limits of power.

For most of us the HP and wear is not as severe as it has been while you explore the limits of the Savage.

Doing the modifications to the oil pump drive gears might be within my ability with my lathe - my previous experience cutting hardened steel was a bit ugly. Oil pump drive gears for the Savage are cheap on eBay....I can get a set and play with them to see how successful I am with that part of the modification.

However - I am not likely to do anything to split the center cases and install the oil feed to the gear set, or modify the seal at the center of the engine case. I ride my modified engine at a fun pace - but I seldom use all the power that is available. My rides generally keep the engine between 3,000-4,000rpm, half throttle or less - the big benefit to me from the modified engine is the amount of torque that is available as I exit the corner and roll on the throttle a bit.....I rarely do any full throttle run through the gears to 80mph.

What would us mortals do to the oil passages to prevent over pressurization if we did the overdrive oil pump gears? Is there a way we could install a pressure relief valve that would open when the amount of oil flow from the overdriven pump is excessive?

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 12/08/23 at 16:16:55

Dave, regardless of the way you ride your bike, you would certainly benefit from a bit more oil flow and the resulting increase in pressure. If you installed an oil pressure gage on your head cover, you would routinely see zero pressure at idle, extremely low pressure when stuck in congested traffic, and a paltry 6 to 8 psi when cruising at 4K.

Managing the extra oil can be done in several ways.

-Install the oil cooler and gear lube circuit like I did.

-Install the special fitting with hose barb and control jet. Route the bleed oil directly back to the filler cap, or route the bleed oil through a cooler back to the filler cap. I personally don’t think the cooler is necessary, but someone in Phoenix or Las Vegas might like it.

-Dump the excess back into the primary drive via the existing hole in the filter cavity. This is the easiest and least invasive way, and I have already figured out a jet size that should be very close to any riders’ situation.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 12/08/23 at 16:18:38

Let’s look at the quick & dirty solution. As I mentioned in reply 64 thru 66, there is a drilled & tapped hole in the clutch cover that is used to attach the oil seal retainer for the crankshaft oil feed. That hole is a M5 x 0.8 thread, and it goes all the way through the cover into the oil filter cavity. I drilled that hole out, made a special bolt with provision for a jet, and installed the special bolt so that I could install the jet by simply removing the oil filter cover. That way, I could fiddle with the jet or simply plug the hole with a set screw. Turns out, the jet wasn’t needed for my system, so I am running with the hole plugged with a setscrew. That means that the #120 main jet (1.2mm) I am running in the 4th circuit to the cooler and gear spray is just about right to maintain reasonable oil pressure (about 4 to 5 psi at idle, about 10 to 11 psi at cruise). I’m very happy with that.

Since we now know that a 1.2mm bleed (#120 main jet) will get the system pressure just about right when the high-speed gears are used, you could simply install a 1.2mm bleed in the oil seal retainer hole. The Mikuni main jets are M5 x 1.75, the tapped hole is M5 x 1.8. No big deal, the jet screws right in. It’s snug, sort of like a fiber self-locking nut, but totally OK. That 1.2mm bleed jet will spray the excess oil right back into the primary drive. Might help the drive gears a bit, but IMO could be put to better use. This bleed satisfies your concern regarding over pressurization.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 12/08/23 at 16:19:48

I guess you could install the high-speed gears without installing an oil pressure gage, but IMO you really need the gage to verify that things are working correctly.

I install the pressure tap in the head cover since it’s the most remote location. There is a drilled passage that runs across the top of the head cover to feed oil into the cam bearings. It’s perfect for the gage connection. You want to do this with the head cover removed. The wall is thin, so I drill the hole a bit oversize (like 23/64 or 3/8) so that the tap doesn’t split the casting when I cut the threads. I use JB weld to seal the threads. It doesn’t leak and it ain’t commin out either. It goes without sayin that ya gotta clean all this up before you reinstall the head cover.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 12/08/23 at 16:20:30

Once I have drilled and tapped the passage for 1/8 NPT, I install a 1/8NPT x 1/8 tube 90° fitting. It has plenty of clearance with the fuel tank. The gage tubing is Nylon rated at 625 psi. It’s Parker Parflex NR-2-026, 1/8 OD x .026 wall, 625WP, 200F, 6605729822. It’s available from Nitrous Oxide Systems. You can get it from Pingle, Jeggs, Summit Racing, etc. Been runnin this same tubing for about 5 years, never had a problem.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 12/08/23 at 16:24:52

It’s very comforting to have this oil pressure gage. For the stock oil system, you need a 0-15 psi gage. For the high-speed gear set you need a 0-30 psi gage. If you decide to measure pressure right off the pump, you need a 0-60 psi gage. Marshall 1.5” liquid filled gages work great.

This picture shows the 0-60 gage, but the range was too wide for my system. I’m runnin the 0-30 with the high-speed gears and it’s just right. The Marshall part number is CF00030.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 12/08/23 at 16:25:36

I feel that this high-speed gear set is the best mod I have done to the Savage. It doesn’t make it run faster or smoother. It doesn’t sound better. It doesn’t start easier. If I didn’t have the gage, I wouldn’t know the high-speed gears are there. It gives me a lot of satisfaction knowing that the engine is getting plenty of lubrication. Now, when I’m stuck in gridlock I don’t have to pull off and let the thing cool off, or grit my teeth and hope I don’t get stuck. No more ZERO pressure situations. The extra volume of oil flow gives me the latitude to direct additional oil to components that need it, like top gear.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 12/08/23 at 16:27:09

Regarding the gear machining, there is only one critical step. That would be cutting the fit on the larger gear, the one that was originally installed on the oil pump. It has a small hole in the center and spokes that connect the center hub to the tire. That fit will be your reference and must be machined before the spokes are severed. You need to use carbide tool bits and adequate cutting oil. It’s a very small cut, just enough to establish a true circular fit that is concentric to the gear tooth pitch diameter.

I achieve that by using a spud. I machine an aluminum spud using my three-jaw chuck. That spud has a machined diameter just about .0005” smaller than the center hole in the gear. I also drill and tap the center of the spud for a pinch bolt. Once I have machined the OD of the spud and drill & tap the hole, I do not take the spud out of the chuck. That way, the fit on the spud will be running exactly true. Then I place the gear onto the spud and clamp it to the spud with the pinch bolt and washers. Since the spud runs true the gear will run true.

With the gear running true, I take very light cuts with a small carbide boring bit (must be a boring bit). Remove just enough material to clean out the radius and establish a circular fit for the new aluminum hub. Make sure to accurately measure the diameter of your new machined-fit before you cut through any spokes.

When you cut through the spokes to remove the center hub of the gear, it will go out-of-round. Not a problem. The new hub you make will have an OD the same size as the fit bore. When you install the new hub in the gear tire it will make the gear round again.

I believe FinnHammer made a special holding clamp so he could keep the gear round for machining operations etc. I’m too lazy to do that, I just use the new hub to make the gear round again. When I cut the spokes, I left about .015” clearance with the shoulder on the new hub. I just use the spokes to provide a place to secure the gear to the hub, they don’t accurately locate anything.

This is a picture of the gear mounted in a four-jaw chuck. The dial indicator is reading on the new fit for the new aluminum hub. I was trying to see if I would be able to clean up a bore in the spokes once I severed the spokes. The aluminum spud is still in the gear. Sorry, I guess I never took a pic of the gear and spud mounted in the three-jaw. Hope you get the idea. The spud gets mounted in the three-jaw and machined to suit the center bore in the gear. Then, without removing the spud from the chuck, the gear gets clamped to the spud. Now the gear is running true. Then the fit is cut. Then the spokes are severed. Once severed, you don’t need to machine a bore in the spokes. You can simply grind them with a die grinder to provide adequate clearance with the new hub.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 12/08/23 at 16:28:12

The new aluminum hub is made to the same dimensions as the original hole in the smaller gear that ran on the clutch basket. You make the thickness and fit to suit the original axial position and special fit you cut in the gear. You can see from this picture that there is a bit of clearance between the aluminum hub and the spokes. The spoke in line with the keyway is hand ground to suit the drive pin. You want it to capture the pin. You only use the remainder of the spokes to provide a place to install the button head screws.

Title: Re: Oil System Evaluation & Upgrade
Post by Dave on 12/09/23 at 03:26:23

Thanks Mike......that is all very straightforward and even at 5AM I can understand it!

I would likely just use the jet screwed into the seal retainer.....seems too easy!

:)

Title: Re: Oil System Evaluation & Upgrade
Post by Dave on 12/09/23 at 18:57:03

Well I learned how to machine hardened steel today.....felt a bit like trying to cut porcelain!

Lot of shallow cuts and I sharpened the carbide bit 4 times!

Making the aluminum center is going to be refreshing after this event!

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 12/09/23 at 19:02:04

Well look at you. Nice. Very nice indeed.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 07/09/24 at 00:49:28

On this lube oil system project, I had initially intended to do a complete tear down at 10,000 miles, but it was running so well I decided to keep going. Then in November of 2023 I did an endoscope inspection at 14,000 miles; all was good. It was running great, so I kept going. In May of 2024 I had logged 20,000 miles. It was still running great, but it seemed prudent to take a look. It was time to tear it down and get my eyeballs on the parts in question.

Up to this point, I had been doing regular services at 3500-mile intervals. I was not finding any chips on the magnetic drain plug. Each time I did an oil change, I pulled the clutch cover and did an endoscope inspection of the gears. No pitting was observed.

The engine was still making great power. The compression was down a bit (from about 220 to 200), but the motor was still plenty healthy. To refresh your memory, these oil system mods were done on my Big Bore 4-Speed engine. It used a 97mm Pop-Top Wiseco in a shortened cylinder; compression ratio was 10.8:1. The cylinder head was ported with 34mm intakes, 1.79” exhaust port, and a 55cc combustion chamber. The cam was the trusty DR650. Breathing chores were handled by a PWK40, a Mac Header, and a HiFlow Muffler. It was makin good power. More than enough to test the gears and main bearings.

I’m pretty sure the reduction in compression was related to my compression gage. It simply ran too good to have lost that much compression. If anything, it felt like it made more power than when I started. The gage didn’t seem to hold pressure. The needle would swing way up, but then drop off quickly.

I think this might have something to do with the reduced compression readings. Don’t know why it took me so long to notice this. Obviously, a new gage is in order.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 07/09/24 at 00:50:31

I needed to get a good look at the transmission gears. Although the endoscope inspections had been good, I felt it would be much better to do a visual inspection through the opening in the case. That way, I could be 100% positive that no pits were developing in the gear teeth. With the cylinder removed, I had good visual access to the input gears. The gears looked great.

The magnetic drain plug was better than ever. Over the entire 20,000-mile test, it never picked up even a single chip. I was confident that no main bearing fretting was taking place.

So, the high-speed pump and gear spray combined with the beefier 4-speed gear set seems to have solved the gear tooth pitting issue, and the oil holes in the cam lobes seem to have solved the main bearing fretting issue. I think 20,000 miles is more than enough to confirm that those problems are behind us.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 07/09/24 at 00:51:59

Like all things HotRod, there’s always a catch. Since it was all torn apart, I had to take a look at the other stuff. I noticed several things that are concerning. These issues don’t seem to be related to lubrication, so I will not elaborate in this post. I’m just going to bring them to your attention. I will do additional posts to discuss each problem.

The 97mm pop-top piston had an unusual dull grey area just above the top ring. This dull grey area was only on the intake side of the piston. Closer examination revealed that the small grooves machined into the outside diameter of the piston had been eroded. These grooves are referred to as “detonation suppression bands”. Further research revealed that this is a typical result of detonation. If any of you have observed this condition (I refer to it as “sand blasted”) please share your experience.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 07/09/24 at 00:52:43

The cylinder head had a circumferential groove eroded into the quench area on the intake side. It was perfectly aligned with the circumference of the cylinder bore. Again, if any of you have prior experience with this condition please share.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 07/09/24 at 00:53:28

The exhaust valves had significant linear indications around the stems. These indications, when viewed at 5X, looked like the beginnings of a crack. The valves appeared to be on the verge of failure, so I replaced them. I don’t think this is related to lube oil, but I thought it would be important to bring to your attention. I will elaborate in another post. For now, I suggest that if you have the exhaust valves out, take a good look in this area. Use at least 5X magnification and make sure none of this stuff is goin on.

Title: Re: Oil System Evaluation & Upgrade
Post by Michael Moore on 07/09/24 at 09:54:27

Mike, I think the erosion on the piston and the slight groove on the head have the same cause since they are both in the same area.

I'd expect detonation to not be localized like that, but instead taking place all around the edge of the chamber. But there might be some very slight differences in the piston/chamber that aren't readily visible that caused the detonation to be limited to those areas. Maybe detonation starts there but is extinguished before it travels to the rest of the bore?

Title: Re: Oil System Evaluation & Upgrade
Post by zevenenergie on 07/09/24 at 12:49:18

I'm no expert, but when droplets of gasoline are deposited on the cylinder wall, they are collected in the space above the upper piston ring.
This can cause corrosion above the piston ring and in the squis area of [ch8203][ch8203]the head, just like you show.
A squis that is too small increases this effect because the gasoline evaporates more poorly during compression.

It doesn't have much to do with the compression ratio.

This effect can be caused by the mist from the carburetor being incorrect.
You may have an optimal mixture adjustment, but the mist may have too large droplets.

Also the valve seats of the inlet valve can be too fluid in shape, which prevents further atomization. They must always have sharp corners for both a 3 corner and a 5 corner valve job.

The exhaust valve seats can, be rounded.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 07/12/24 at 00:30:58

Michael Moore, thanks for your comment. I also was surprised that the damage is confined to the intake side. I assumed that would be the cooler area and less prone to detonation. But I guess detonation must occur where the fuel is, and fuel certainly will be on the intake side. The ignition source will be the rapid rise in pressure, and that pressure will be uniform throughout the combustion chamber. I was able to find some YouTube vids of a Ducati that had almost exactly the same condition as mine. I have no idea if the fellow that made the vid is an authority, but what he said made sense.

Zevengerie, I am confident that this is detonation rather than corrosion. The ring land is deformed across the back side of the piston. You make a good point about fuel droplets and fuel hiding out in the crevice above the top ring. Smokey Yunik recommended reducing that crevice as much as possible without bringing the ring too close to the top of the piston. He felt that the fuel trapped in the crevice could be good for something on the order of 5% more power. Otherwise, it's simply wasted. I may be aggravating the condition with my port configuration. I increased the short side radius to improve flow on the bottom of the port. That in turn results in more charge being directed at the area in question. But I don't want to give up on the improved flow, so I'm gonna rely on the tried and proven recommendation to keep the quench as tight as possible, and reduce CR to a more appropriate level (as close to 10.5 as reasonably achievable).

I don't take any extra effort to blend in my seat angles. I cut them and leave the corners as they are cut. I do use four angles (75, 60, 46, & 30). Thankyou for your comments. They are very helpful and give me more to ponder.

See my most recent post on this detonation issue.

Title: Re: Oil System Evaluation & Upgrade
Post by zevenenergie on 07/12/24 at 02:44:44

Tanks Mike, I feel compelled to share a little more.
(Life is all about sharing)
I don't want to sound too decisive, like this is how it should be, but you can also think about this:

There is also some power to be gained if you round off the squis edge, so that the flam front can enter the squis and crevice more easily when the piston descends.

http://https://i.imgur.com/O12AJdYm.jpg

Detonation in the squis cleft is a bit strange. If the squis is not larger than 1mm, the piston and head cool the mixture sufficiently so that it does not self-ignite.
When you increase compression you have to look at the squish space and optimize it to prevent detonation.

You cannot make the gap too small because the connecting rod stretches.
And you also have to pay attention to the speed of the gases that are squished because they can blow the plasma away from the spark. Sometimes a tapered squis slit is therefore better.

Title: Re: Oil System Evaluation & Upgrade
Post by DragBikeMike on 07/12/24 at 23:36:03

I'm gonna copy and paste these replies into the new post that deals directly with the detonation issue. That way, this post will be about oil system mods, and the other post will be about detonation problems.

Post where these comments are going:

https://suzukisavage.com/cgi-bin/YaBB.pl?num=1720767228

Title: Re: Oil System Evaluation & Upgrade
Post by Ruttly on 07/13/24 at 07:36:59

What I learned from several builders is that a combustion chamber should not have any sharp edges regardless of compression , of course it becomes more critical as compression ratio goes up. It’s as simple as rounding the sharp edges before assembly. Freshly machined surfaces look so clean & perfect you would never know. I do it on every build.