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/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Big Bore Engine - Part 4 - Crankcase /cgi-bin/YaBB.pl?num=1597910972 Message started by DragBikeMike on 08/20/20 at 01:09:32 |
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Title: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:09:32 This is the fourth in a series of reports outlining my big bore engine project. Part 1 covered the cylinder. Part 2 covered the cylinder head. Part 3 covered the head cover. If you haven’t read Parts 1, 2 or 3 you can find them here. [http]://suzukisavage.com/cgi-bin/YaBB.pl?num=1593567475[/url] http://suzukisavage.com/cgi-bin/YaBB.pl?num=1595224521/0 http://suzukisavage.com/cgi-bin/YaBB.pl?num=1596951230 Part 4 covers the crankcase. About eight-months ago, I purchased a 1997 crankcase assembly on eBay. I wanted to build new engine combinations without putting my bike out-of-commission. Then it’s plug & play, pop out the old engine and plug in the new one, rock & roll. I didn’t do any modifications to the lower end, but I did open it up to fix a leak and inspect a few things. Let’s get started. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:10:29 The new crankcase assembly looked fairly good. Nothing got damaged in shipment. The seller removed the alternator rotor, drive pulley, and cylinder studs and sent those items in a separate box. I temporarily installed the parts for this photo. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:11:09 It didn’t come with a clutch, but I already have one of those. I had a junk cylinder all freshly bored out, and my original cylinder head that was modified to Stage III specs. All the major stuff necessary to build the 97mm was in-hand. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:11:56 I threw on a shift lever and ran it through all five gears. Seemed to be working fine. No problem finding neutral. The transmission seemed OK. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:12:42 Visual inspection of the accessible gears didn’t reveal any ugly stuff. The crank and connecting rod looked OK, and there wasn’t any noticeable play. Things seemed clean enough on the inside. There were a few chunks of soft crud, but I could flush those out. I was tempted to leave it as-is and slap on the cylinder & head. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:13:45 I had seen several posts about the case joint leaking, so I decided to test it. I put on a clutch cover and alternator cover, filled it up with three quarts of cheap SuperTech oil from Walmart, and let it sit overnight. I checked on it several times. No leaks. Dry as a bone. Then, after about 30 hours, I went to move the crankcase on my bench and noticed a small puddle of oil. Yep, she’s leakin. Oil was coming out of a mount-bolt hole. Should I fix it or see if I can stop the leak by installing an engine mount-bolt? I dwelled on that for a while. Then an interesting post showed up on the forum. BlakeEM had a slight problem with balancer shaft timing. The pin in the drive gear had backed out and resulted in a catastrophic failure. Now it seemed prudent that I peek inside. I didn’t know the history on this engine, so I decided to inspect the balancer drive and fix the leak at the same time. Ooooooooo! That’s ugly. See the pin hangin out there? Blake didn’t even need to tear the engine apart to get a look-see. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:14:37 Start by popping off the alternator rotor. More on the special tool in my next post. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:15:21 The key for the alternator rotor prevents removal of the starter drive gear. That little sucker (the key) is tight. If you start prying on it, you run a good risk of marring the critical taper on the crankshaft. I found a good way to remove the key is to tap it straight in toward the drive gear using a drift punch. You don’t have to tap it very hard, just straight toward the gear and it scoots right out of the keyway. Wrap the key with tape so you don’t lose it. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:16:05 If you don’t tape the key it will fly off and you could lose it, or worse yet, it could drop out and find its way into the engine. Be safe, tape it off. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:16:45 For the inspection and repair I was planning, the flywheel did not have to come off, but I wanted a 3” flywheel for my monster motor. To remove the flywheel nut, you need an extra deep 46mm socket. Those are hard to come by. I have a special 1-7/8” socket that I fabricated for removing Harley Davidson drive pulley nuts. It is just a bit too big. To dial it into the Suzuki flywheel nut I made a .030” sheet metal insert that slips into the socket. It fits just right. Also note that the end of the socket has been machined to remove the internal chamfer on the hex. That’s to improve the amount of overlap on the ultra-thin nut. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:17:23 The insert was easy to make, so if you can find a deep 1-7/8” six-point socket all you need is some .030” steel sheet metal. I suspect a 1-13/16” deep socket will work without the shim stock. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:18:00 Hold the flywheel with a fixture like this. It’s just a couple of steel bars, two spacers, and two M8 x 1.25mm bolts. While this tool is in place, it’s a good time to remove the primary drive nut on the right side of the crankshaft. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:18:40 That flywheel nut is tight. The torque spec is 115 ft-lbs. I use a pipe wrench on the socket to preload the system and then blast it with a rattle-wrench. It takes a lot of force to break it loose. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:19:21 After the flywheel was off, I threw it in the lathe and turned it down from 6.528” OD to 3.000” OD. That takes a long time and makes a big mess. The mod reduces the weight from 6 lbs. 0.2 ozs to 14.8 ozs. It’s a lot of weight, all rotating mass. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:23:05 While the flywheel holder is in place, you should remove the primary drive gear nut (left hand threads) and the balancer shaft bolt (right hand threads). Be careful, the primary drive gear nut has left hand threads. Don’t turn it the wrong way. To loosen, turn the nut clockwise. The balancer shaft bolt is regular right hand threads. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:23:56 It’s probably not necessary but I figured it would be a good idea to remove the speedometer drive. It is held in place by one special bolt. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:24:38 Once the bolt has been removed the speedo drive pulls right out. As I mentioned, the bolt is special. Don’t lose it or the special aluminum sealing washer. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:28:29 There are 15 bolts that secure the two case halves together. On the right side there are 11 bolts, and on the left side there are 4 bolts. Of these 15 bolts, three are well hidden. Don’t miss these two bolts on the right side. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:29:14 On the left side, don’t miss this one. It’s down inside a void; hard to see. Leave any of these bolts in and you will have a tough time splitting the case halves. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:30:12 Since I was only going to inspect the balancer drive and re-seal the case joint, I left the shifter mechanism alone. I wasn’t planning on removing the gear set. Leaving it in place did not present a problem. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:30:50 I needed some simple tools to crack the case halves. A plate with two strategically placed notches and a 3/8” hole, three 8mm bolts, a flat bar, and some continuously threaded 6mm bolts with nuts. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:31:56 The plate with the notches and hole is used as a jack to push the crankshaft through the inner race of the right-hand main bearing. When you back off the primary drive gear nut it pushes on the plate, which is equivalent to pushing on the crankshaft. You also must take measures to keep the shaft from turning with the nut. I discuss that later in this report. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:32:46 And the flat bar is used to jack the transmission input shaft through the inner race of the right-side input shaft bearing. As you tighten down the 6mm nut it causes the bar to push on the input shaft. You have to use the two jack assemblies (crank & input shaft) simultaneously, back & forth, slowly jacking each shaft through its bearing. You must keep the case halves parallel. Very simple tools. Way better than beating on the shafts. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:34:21 I did not remove the crankshaft or gear set. I only wanted to fix the leak and check out the balancer shaft drive. Fixing the leak was simply a matter of cleaning up the sealing surfaces, checking for defects, and applying a fresh coat of Permatex Optimum Grey. The three items I wanted to inspect on the balancer drive were: -The drive key on the balancer shaft -The drive pin in the drive gear -The cam chain drive sprocket. The key & keway looked fine. No evidence of any wear or deformation. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:35:12 The pin looked OK. I don’t have any bonafide inspection criteria other than it should be tight and not show any signs of migrating out of the hole in the gear. It was definitely tight. I compared it to another assembly I had on-hand. Both pins stuck out of their respective gear .395”. I guess that means I have two good pins or two pins failing exactly the same amount. The gear was burnished on the face that contacts the inner race of the bearing. That could be an indication of movement. The gear on the right is the gear I intend to use. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:36:12 Based on the photos that BlakeEM posted, I believe his failure was the result of overtightening the nut that secures the primary drive gear and cam chain sprocket. The overtightening cracked the cam chain drive sprocket. That relaxed the pinch on the left side of the crankshaft, allowing the balancer drive gear to rotate back & forth as the crankshaft went through its normal acceleration and deceleration. The constant back & forth rotation pounded the drive pin loose. This is just my opinion, but I think it’s based on compelling evidence from his post. I examined the cam chain drive sprocket at 5X magnification. I wanted to make sure there were no cracks in the fillet. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:36:49 I also examined the face that bears against the inner race of the main bearing. It looked fine. No cracks. Just a nice witness mark 360°around the face indicating uniform contact with the bearing race. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:37:34 I toyed with the idea of making a stepped pin for the drive gear. The step would capture the pin between the gear and crankshaft. Maybe I could make one from a grade-8 bolt. Checked the pin with a machinist’s scribe. That sucker is hard as a diamond. The scribe wouldn’t even mark the pin. I can’t fabricate a pin of equal hardness. Guess I will have to live with the factory setup for now. It will become one of my routine inspection items. Reinstalled the gears and made sure they were properly timed. All three dots have to line up. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:38:08 I made this special tool to check the drive pin in the future. Any time I have the cylinder removed I intend to check the pin to verify that it’s not migrating. The aluminum sleeve is exactly .500” long. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:38:45 There should be about 1mm gap between the tool and the crank when the pin is in the correct position. If the gap is any significant amount larger or smaller than 1mm, the pin may be moving. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:39:43 I cleaned all the old sealant off the sealing surfaces, wiped out any crud, and verified all the accessible bearings turned free. The oil pump turned smooth and there wasn’t any junk in the suction strainer. Everything seemed fine. Time to reassemble. Make sure that the special o-ring in the trans bearing oil feed is in the left-hand case. Sorry, I didn’t get a proper photo of the o-ring placement. It seals this oil passage. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:40:40 I will be using the clutch nut to jack the input shaft bearing onto the input shaft, and the primary drive gear nut to jack the right-hand main bearing onto the crankshaft. To keep the input shaft from turning while I turn the clutch nut, I place the transmission in 5th gear and clamp a vice-grip onto the output shaft. Strips of soft-roll copper tubing protect the splines on the output shaft. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:41:24 A similar problem exists on the crankshaft. As you tighten the nut to jack the bearing over the shaft, the crank will try to rotate. You can hold back the crank with a small wooden block and the wrist pin. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:42:58 Apply a nice uniform coat of sealant (I like Permatex Optimum Grey or Black) to the right-hand case sealing surfaces and then carefully lower the right-hand case down over the crankshaft and trans input shaft. Use the clutch nut to jack the inner race of the transmission bearing onto the input shaft. You do that by stacking up spacers and/or washers on the shaft such that when you tighten the nut the spacers and washers push on the inner race. As you run out of threads, you remove the nut and add more spacers/washers. Go slow. You must work back & forth between the crankshaft and input shaft to draw the case down evenly, keeping the case halves parallel with each other. Here’s what my input shaft jacking setup looked like. The tubular piece with the small oil hole is the stock clutch spacer. The rest are just washers and spacers I dug out of my junk pile. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:43:40 Here’s what my crankshaft jacking setup looked like. I think you get the idea. Just sandwich stuff between the nut and the bearing race. As long as the faces of the spacer are smooth & parallel it should work fine. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:44:22 You work back & forth between the two shafts, evenly drawing the bearings onto the shafts. Like a half-turn on the clutch nut, then a half-turn on the primary drive nut. Back & forth, slowly closing up the gap, keeping the case halves parallel. I really like the Permatex Optimum Grey sealant because it doesn’t set up right away. It allows plenty of time to get the joint closed up. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:45:10 Once the joint is closed all the way, install a few case-bolts and verify that the shafts turn free. If the shafts turn free, install all the case-bolts and tighten them up properly. Your sealant squeeze-out should look like this. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 01:46:39 The crank turns free. No unusual grinding noise. Trans shifts through all five gears. No problem finding neutral. I let the sealant set up several days and did another leak test. It was all good, no leaks. So now its oil tight and I have some degree of confidence in the balancer drive, plus I have a tool to periodically check the drive pin. I guess that’s better than nothing. All set to start engine assembly. I hope you find this report informative. As always, I welcome your questions & comments. Knowledge is power. Best regards, Mike |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by justin_o_guy2 on 08/20/20 at 01:52:46 Its cool having a tutorial,, I just never wanna need it,, Whats a BRG DRiver? |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by DragBikeMike on 08/20/20 at 02:13:17 I suspect "BRG DRiver" would be "bearing driver". I also hope you never "need" the tutorial. But in the event you ever "want" to tear open that lower end, I hope this makes it a bit easier. I simply can't help myself. I just love nuts-n-bolts. ;) |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by ohiomoto on 08/20/20 at 04:35:20 Mike, It would be great if you could make a "table of contents" type post with a listing of all of your topics. It should be locked and sticky'd up top for reference. |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by justin_o_guy2 on 08/20/20 at 06:06:18 "BRG DRiver" would be "bearing driver". well DUHH,, dont I feel smart now,, I almost wish you just acted like ya didnt even see it now,, Wadda Maroon! Is this when Im suppposed to say thanks? OOOOOKay,, thanks,, |
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Title: Re: Big Bore Engine - Part 4 - Crankcase Post by Fast 650 on 08/20/20 at 11:11:57 52555452505249523D0 wrote:
You are not the only person to suggest that. There is a lot of valuable information that is getting buried and hard to find among all of the other topics. Maybe a new section called "modifications" for those kinds of posts would be a good idea. It would make the posts easier to find. |
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