ThumperPaul wrote on 04/11/26 at 06:38:06:


It is hard to find a good place to mount the temperature sensor that is a good representative of what is going on.  My sensor was intended to be mounted under the spark plug - however it is impossible to get it there as there is no room for it in that tiny hole.

The Savage has ball and roller bearings in most places, and it doesn't require much pressure to get oil "flow" into the bearings.  I believe the head is also designed in a way that the cam bearings have sufficient flow without needing much pressure to get the oil in the places needed....the slots and cutouts in the surfaces allow oil to flow without much force.  Unfortunately this isn't a very friendly design for those who let their bike idle on the sidestand or have their idle speed excessively low.

It is wonderful to have this bike running without leaks again.  The bike was wonderfully reliable, efficient and a joy to ride prior to using that aftermarket head gasket that created the leak.  The bike regularly got 63mpg.....except when I was chasing MMRanch around in the mountains!  

Today I went on what would be a "normal" ride for me.  It was in the lower 80's and I rode over to a friends house for a visit.  The ride was on the rural roads where I live - 6 STOP signs and 2 traffic lights in the 15 miles it takes to get to his house.

The cylinder head temperature stabilized right at 220 degrees for the entire trip there and back.  I only got stuck at one traffic light for a red light cycle...it is a somewhat long wait as there are left turn lanes/arrows that get to go separate from the main light.  While I was waiting for my turn the cylinder head temperature slowly climbed to 265 - then within a mile had dropped back down to 222.....and a bit farther down the road it was back at 220.

I believe the temperature at the front of the cylinder is very similar to what I was reading at the left rear cylinder stud at steady cruising - however the temperature does fluctuate more with the sensor under the exhaust port.

I am waiting for one more clutch thrust washer to arrive.  It was supposed to arrive somewhere between May 10-16 - but the eBay seller didn't get it to the Post Office until the 13th....so it likely won't be here until Saturday the 18th (or perhaps Monday the 20th).

Thanks for keeping us updated on your progress.  Your head temp numbers are interesting.

So, now that the oil leak is a thing of the past, do you think you know conclusively what was causing the leak?  Are you pretty confident that the aftermarket head gasket was the problem?  Where on the gasket do you think the oil was actually coming out.  You were pretty diligent in your inspection of that joint.  As I recall, you were even giving it the foot powder inspection.  How do you think the oil was getting out of that joint and eluding your visual checks?

I had a rainy day yesterday - so I took the clutch side apart and put in the new washers and put in the overdrive pump gears.

Today I ran the bypass hose for bleeding off the excess oil to the head cover, and I checked the valve clearance.  The valve clearances all checked and no adjustments were necessary.

I also wondered if perhaps the fuel mixture might be a bit too rich, and that is why my cylinder head temperatures are significantly lower than DragBikeMikes.  The exhaust port had a very light coating of dry and sooty carbon - nothing heavy or wet.  The spark plug looked just fine, and this is a very old spark plug and it likely is time to consider getting a new one!  Once I get the overdrive oil system working properly I will put the Oxygen Sensor system back on and check the fuel/air mixture and see if any jetting changes are necessary.  I believe jetting is pretty close as the fires up instantly if you use the choke - but will not fire if you don't use the choke (indicates to me that the low speed jetting is close).  The engine runs very well and gets great fuel mileage.

We are having a cold spell here for a couple of days with overnight temps in the 30's and daytime highs in the 50's....I may not get out and do a long ride test on the oil pump overdrive gears for a few days - however I am likely to get it fired up and see what things looks like with cold oil.

Today I was able to go for a 20 minute ride in 56 degree weather....the engine temp was 76 degrees from being in the shop when I pushed it outside into the "cold".

The pressure is a bit scary when the engine is cold - I could not open the valves on the gauges as the pressure was more than the gauges could handle (15psi on head cover and 30psi on filter cover).

After the engine warmed up to 180 degrees I opened up the valves and the pressure was about double what it was stock.

The engine never got over 200 degrees as a result of the cold weather and my slow riding as the oil warmed up.

At 3,000 rpm I was getting 15psi at the filter and a bit over 7psi at the head cover.  Idle showed 6psi at the filter and around 3psi at the cylinder head cover.

The new oil bypass line only felt slightly warm - so there is likely not a huge amount of oil flowing through the #130 jet sized orifice.  

I will put a 0-60psi gauge on the filter cover - however I believe when the engine is cold that may not be big enough!

I may try a slightly larger bypass...I would be happy with 1-2psi at the cylinder head cover at idle.  

I went for a pretty good ride today and got things good and warmed up.

There is a new 15psi pressure gauge for the head cover....and it is showing a bit less pressure in comparison to what the previous 30psi gauge shows at the oil filter.  (I replaced the 30 psi gauge as it was starting to hang up when pressure dropped below 5psi and it required a tap with my finger to drop below 5 psi).

On this ride at 3,000 rpm I was right at 15psi at the filter and about 5.5psi at the head cover.  At 4,000 rpm I had around 18 psi at the filter and around 7psi at the head.  At idle I had a bit more than 5psi at the filter and around 1psi at the head cover.

The numbers at the filter have gone up - but the numbers I have at the head have gone down about 1 psi...and it could be the new gauge.  It could also be that this oil filter is getting a bit clogged....it may have gathered up particles that came off the piston skirt coating.  (I have changed the oil twice while breaking in the piston skirt - but not the filter yet).

I will get a new filter installed and see what things look like....and it that doesn't bring the number up a bit then I guess I will try a #120 size jet.  (My target goal was DragBikeMike's numbers at 4,000 rpm of 20psi at the filter and 11psi at the head).

The numbers when you start up the bike and attempt to ride away are intimidating - over 60psi at the filter and over 20psi at the head cover.  I am sure they are like this when the bike is stock - but without gauges you never see what is happening with a cold engine.  I wonder what kind of pressures happen for those folks who start up bikes that have been sitting outside in freezing weather??!!!!!

I think you are getting too hung up on the pressure upstream of the filter.  I measured that pressure so I could determine what the differential was across the filter element.  The filter bypass should lift at about 25 psid, so I wanted to make sure that the differential was well below 25psid when the oil was up to normal operating temp.  I don't care if the bypass lifts when the oil is cold, but I want the bypass closed when the oil is up to normal temperature.

I suggest you quit paying attention to the gage upstream of your filter element. Base the size of your bleed orifice solely on the pressure at the head cover.  I don't see any technical issue with the current location of your bleed.  Make it bigger and pressure is reduced at all locations downstream of the filter, make it smaller and pressure is increased at all locations downstream of the filter.

I am having great success with my modified system, and my pressure is about 4-6 psi at idle and 10-12 psi at 4000 rpm.  Those values are observed with 20W-50 oil at 200 degrees.  With 10W-40 yours will be slightly less.  So, I think you should adjust your bleed orifice to achieve numbers around 3-5 psi at idle and 9-11 psi at 4000 rpm (oil at 200 degrees).  You will need a 0-30 psi gage to accommodate the cold oil.  When cold, the pressure will over-range the gage, but it only takes a minute or two before the pressure drops to a point where you can ride normally without fear of killing the gage.

Your pressure in the filter housing is going to be quite high when the oil is cold, but the bypass will lift.  It's not gonna hurt anything.  It probably lifts with the stock pump drive too.

Please refresh my memory, how are you measuring oil temperature.  If you don't have an installed instrument with the sensing unit immersed in the oil flow, the only option you have is to ride that motorcycle a very long time to get the oil up to max temp.  Mine takes a good 30 minutes to get all the way up to temp, and I'm riding in a very warm climate.  The temp makes a huge difference in observed oil pressure.  

The important parameter is oil pressure at your most remote bearing.  That's the left-hand cam bearing and that is where you have your instrument installed.  Get that pressure at the values I suggested, and you will have a sweet lube oil system.  If the pressure at the most remote bearing is higher the pressures at the crankshaft feed and the transmission will also be higher.  What's not to like?  I've racked up a whole bunch of miles on this system and it has completely eliminated problems with cam lobe pitting, main bearing spalling, and gear pitting.  In addition, I never have loose valves.  There's no valve train wear.

Regarding your CHT.  You have your sensing lug installed in the exact location I have mine installed.  But you are observing values way lower than mine.  The location represents sort of a mix between CHT and EGT.  The stud runs straight up into the exhaust port, and the sensing lug is actually in contact with the cylinder, not the cylinder head.  That's perfectly fine since what we are looking for is a value to evaluate trends and identify anomaly.  We run the engine and correlate what we see on the instrument to the current conditions and then store that value in our memory.  Then if we see a value that seems out of the ordinary, we investigate.  It's simply our personal reference.  There isn't any factory specification.  

As I recall, you have your exhaust port lined with Cerakote.  Two things jump out at me here.  The first is the Cerakote.  If it works as advertised, then it will certainly reduce temperature at the location of your sensing lug.  The second is my copper head gasket.  The copper gasket transfers heat mush better that the steel MLS gasket.  So, my copper gasket would result in a higher reading in the location where the sensing lug is installed.  Do you have any thoughts on that?  Seems like a feasible explanation for the difference in our readings.

This is quite a project.  You really went the extra mile.  I can't wait to hear more.