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Discussion Starter · #1 ·
I made a thread a while ago, but then got tied up in other projects, and now that thread is dead lol. So starting a new one. I have a 2000 640 LC4-E that had a knock when I inhereted it from my father in law who had passed away. It's been sitting a couple years now, it did run when I got it but was not rideable. Only has like 10 or 15 thousand miles on it. I tore the engine down, didn't find much wrong initially other than scoring in the piston skirt. Well after not working on it for months I came back to it and immediately found the problem (can't believe I overlooked it before). The left side crankshaft bearing inner ring/race is very rough and chewed up. Oddly the actual bearing was not. So, today I cleaned up the case halves, removed both crankshaft roller bearings (and the left side viton seal), and removed the main shaft ball bearing. I just ordered a piston kit, and all the bearings, gasket set, etc. The only thing that hung me up today was I could not get the inner rings/races off the crankshaft (tried heating them). I bought the ktm special tools today also, however, I suspect they are actually on backorder (like every other website) and I'll get a refund once the site figures that out. Any tips or thoughts? This is pretty much my first time doing a full rebuild, but so far it's going ok.

I'm about $700 deep into a non running bike, for just a few bearings, gaskets, and piston, and have a long way to go...lol.

I ended up getting a proX piston kit. Couldn't find much else. My cylinder measured out right at 101.00 mm everywhere I checked (within like 0.01 mm). My old piston measured ~100.92 mm (not sure if it's cast or forged). The proX piston says it's cast, and says it's a 100.96 mm which works with the repair manual's clearance specification of less than 0.05 mm (will be 0.04 mm). Admittently, I am not a highly experienced engine builder, and don't have many tools for this type of work, but was able to find one of those inside diameter spring loaded checker thingys (technical term...) and am pretty confident with my measurements. I also have a dial indicator and will check runout on the crank.
 

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Discussion Starter · #2 ·
Well we got started this weekend but it was a slow start. Only had a few hours. We got a few seals changed on the cases and also got one of the races changed on the crankshaft. The tool worked awesome. We couldn't get the other race, though, I think due to it being damaged. We put the whole crank in the freezer and are gonna try again another day. I was able to get it to move just a hair one time but it took a lot of force, and we tried several times. I actually bent the handle of the tool. I think due to the race being damaged it is slightly smaller OD, so it's not getting enough grip/heat transfer from the tool. I'm hoping freezing/cooling the crank will help shrink the crank shaft so when we use the tool to transfer heat onto the race it'll slip off. Hopefully by week end we will have that done and the bearings pressed into the cases halves.
 

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Discussion Starter · #3 ·
Been working at it a little at a time, we have been able to get that other crank bearing race to move like 1/16" each attempt. By that time the temps are equalized and it just won't go. Hopefully after a few more attempts like this (tool heated and crank straight out of the freezer) it'll be moved far enough that it'll let loose. This surely has been frustrating...
 

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Discussion Starter · #4 ·
Finally making some progress. That left side crank bearing race/ring was really messed up and it just would not come off with the removal/install tool. I tried about 10 times over a few weeks. Even froze the crank and I only got the race to move maybe 1/8". I gave up and broke out the grinder and dremel. After about an hour of carefully cutting I got it off. I did pretty good, didn't damage the compensating washer or crank web or anything. I did cut too deep in one spot and nicked the crank journal a hair, but it's all good. Got it all cleaned up and the new race installed. The new one went on easy like it's supposed to with the tool. I also got the crank bearings pressed into the cases and the new roller main shaft bearing installed. Checked crank journal runout, crank axial play, connecting rod axial and radial play, etc. Everything seems good. Ready for assembly now!!!
 

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Discussion Starter · #6 ·
So I put a couple more parts together today since I had a spare hour. I went to put the kickstart lever on and noticed almost all the teeth are missing. Seems very bizarre. Is this supposed to be this way, maybe???
 

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Discussion Starter · #7 ·
I didn't think to take a pic, so just happened to find one online that basically looks exactly like mine. Is this damaged or is this made this way???
 

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Discussion Starter · #8 ·
Well, the frustration has really set in!!!! I put the crank in and assembled the case halves, then the crank wouldn't rotate. It was too tight. If I loosened the case bolts the crank rotates fine. Obviously I messed up on my crank axial dimension or I didn't fully seat the bearings in the cases, I guess. I removed one compensating washer (had 1 on each side, like it was prior). I tried to get the other race off (the side that was faulty before) and again could not get it off. I was starting to scratch the race so I quit. It scratched slightly, but I think it will be ok. If I want to get it off I think I'll have to destroy it again (another $100 bearing!!!!!). I'm hoping I find I didn't fully seat the bearings in the cases. I will try pounding on them a bit more tomorrow. As of now, if they don't sink in any more, then even with no compensating washers, the crank assembly is wider than the dimension it's supposed to fit in in the cases by ~0.05mm. So not sure what to make of that... Really hope I find the bearings not fully seated...!!!!!
 

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Discussion Starter · #9 ·
Well got some good news. And some other news I'm not sure what to do with yet lol. The left case bearing was not quite seated apparently. I got about another 3mm out of it which is just what I needed. I'm using the "diy-home" method during this rebuild and not the recommended repair manual methods lol. I heated the area around the bearing in the case with a propane torch and hammered the bearing in with an install tool. I didn't use a hotplate and heat the whole case as specified. The bearings were actually very difficult to get in. I was somewhat worried about breaking the aluminum cases (even though I supported them under the bearing), so guess I just didn't quite hammer enough on that one side. So that's the good news...

So, I pulled the one race off the right side of the crank, as I can get it on and off pretty easy with the tool. I reinstalled the compensating washer, then the race. Put the crank in and torqued the case bolts. Then measured axial clearance of the crank, and I have about 0.23mm I believe it was. The book calls for 0.03-0.12mm up to 2003 then I think 0.1-0.2mm 2004 and later. Mine is a 2000. So, I probably need to add one more compensating washer (0.1mm) and call it close enough. Or, I can let it fly as is (not sure what's different for the 2004 and later...???). Thoughts!?!?!?

Also, I mentioned that I slightly scored the left side race trying to remove it. I attached a pic here. That tool is sort of damaged from trying to remove the old messed up race. I don't think I can get that race off without cutting it again. So, question is, is it bad enough to warrant replacing? Thoughts? Can't really feel any significant catch with a fingernail. If I do need to remove and replace it, I'll just cut it off and add the compensating washer on that side. That's another $100 bearing lol.

Any help is appreciated!!! I'm new to this...
 

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Discussion Starter · #10 ·
Turns out they do have varying thickness compensating washers, so I ordered a few. They sell 0.10mm, 0.15mm, and 0.30mm. I ordered a 0.15mm as that should put me right in the middle of the specified range, but I ordered a few extras in 0.10mm also since they're only $1.00 each and most of the cost is shipping. And now we wait another week....
 

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Discussion Starter · #11 ·
Great news (after a lot of frustration....self induced....lol). The bearing race polished right up with almost no effort using a scotch pad, (yay!). I then installed the 0.015mm compensating washer I bought (on top of the existing compensating washer, which I thought was a 0.10mm but turned out to be a 0.15mm), assembled everything, and although the crank turned freely, I had 0 axial clearance. Hmm... Odd I thought... as this should have been perfect based on my prior measurements. So I removed the race from the crank again, replaced one of the 0.15mm with a 0.10mm compensating washer (luckily I bought some extras!). I reassembled, and had some axial clearance, but not in spec (or so I thought!!!!). I removed it all again, went through this process a few times and then FINALLY realized I'm an idiot lol. My dial indicator reads in inches and the axial clearance spec is in mm, doh! Well, at least I figured it out... So I had to remove the race AGAIN (I am getting good at this...) and finally got it right (where I already had it set...lol). I'm sitting at about 0.06-0.07mm axial clearance on the crank, which is close to midway between the 0.03-0.12mm spec. So happy I finally have this step behind me. This was a learning experience for sure... I'm beginning to wonder if this thing will even make it out of the driveway once it's togehter :(
 

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Discussion Starter · #12 ·
Still making slow progress. Got through another page in the service manual. Put the timing chain and tensioner pieces on and the oil pumps. That flat head bolt for the tensioner is a PITA. Might get an hour or two in during the week af ter work. Gonna be out of town all the following week, though. Can't wait to fire this thing up...
 

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Discussion Starter · #13 ·
Got another bit of progress done. Been out of town on vacation for a week but worked about an hour or so on it today. Got the balance shaft in, and the clutch components started. Will have the clutch done sometime later this week. Starting to be able to see the "light at the end of the tunnel". Hoping if I hit it a little harder I can have the bike up and running in the next month or so...

Question, I don't have the special clutch holder tool (used an impact to remove). Is there a way around the tool? I haven't really looked at it that closely yet, I'm hoping I can rig up a way to not have to buy another specialty tool.
 

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Discussion Starter · #15 ·
I appreciate that input. I actually was able to tighten the clutch hub nut without the tool this evening though. I was able to rig up another holder I had and it worked fine. Luckily it was only 90Nm, not to crazy. Got the clutch discs soaking in oil, will complete the clutch assembly tomorrow. Parts are starting to dwindle away on the workbench...(yay!)
 

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Discussion Starter · #16 ·
Well.....clutch is assembled, and I forgot pictures again! lol. I get so concentrated on the task at hand then get rushed to get cleaned up I forget... Should make some more progress tomorrow. I think piston is next. I'll be SURE to get some pics...
 

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Discussion Starter · #17 ·
So I need some help now. I remembered to take pics today lol. I got the new piston on (Those circlips are a PITA lol). Got the rings on also. The instructions that came with the piston say to put the side of the rings that have the marking facing up, as the rings have a top and bottom. I believe they have shaped/contoured edges, and the pictures show it in the instructions. The problem is the rings didn't have any markings, other than the top ring had a number stamped in it. I also looked and felt very close (even zoomed in with a camera) and the rings don't appear to have any contour or anything, they are perfectly square/rectangular. I eventually figured out the skinnier ring was the top ring and the thicker was the bottom (that's the only way they would fit). And I figured out the two really thin rings and the corrogated piece all went together as the oil scraper ring (these two thin rings also had no markings and appeared to not have a top/bottom). I did put the stamped number facing up on the top compression ring. Anyone got any input on this? This is a ProX piston kit, it is a forged piston.

Next, the service manual states "Only for 640 LC4 engines a black (0.7mm) cylinder base gasket is used, the other LC4 engines need the green (0.5mm) gasket". I looked at the old gasket that came off the engine when I tore it down and it is a green one, so now I'm confused. I measured them and the old green one is indeed also 0.5mm. I thought my bike was a 1999 640 LC4-E (keep in mind I inhereted it). I'll have to double check this to ensure I'm correct. But based on the service manual I think I need the black (thicker) gasket. But I don't know what to do. If green was on there before, maybe I should go with that again and get that slight bump in compression. If it was there before it should be fine, right? Also, which side is up? I can't remember when I took it off...

The service manual also states to use "sealing compound" or something of the sort around the timing chain "tunnel". The green gasket has a sealing compound applied to one side of the gasket at that area, the black gasket does not. Should I put a perimeter of black RTV both below and above the gasket at this location?

The service manual also states to install the bracket with the "preassembled microfilter" to the rear studs. I don't think my bike has this filter. It's about where the electric starter goes. I luckily took a bunch of pics at teardown and don't see this thing anywhere in my pictures....so I guess my model doesn't have this...?

Lastly, can I use a torque wrench with a crows foot to access the nuts for tightening down the 4 cylinder studs? If so, is there anything I need to do differently to account for the crows foot throwing the torque measurement off?

Lots of questions now.....Thanks for any help!!!!
 

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Discussion Starter · #19 ·
Here was ProX's response:

"Rings that require a specific orientation will have a mark on the top side that shows which is up. It appears that this is not the case with this kit."

So I think I'm good on that front. Just need to decide if I'm gonna use green or black base gasket. Leaning towards green since that was what was on it. Then I guess a real thin layer of black RTV above and below the base gasket at the timing chain tunnel area...??? And I gotta figure out which side of the base basket faces up...
 

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Discussion Starter · #20 ·
I'm wondering if this bike isn't actually a 640 lc4-e after all. Using the vin decoder, it uses the letters "GSL" which could be any of the below:
GSL640 LC4 99
GSL640 SUPERMOTO 99
GSL640 ADV R 99

So maybe it's a supermoto or adv r? How can I determine? If that's the case, that may explain the green base gasket that was in there, since it says in the manual only "640 LC4" engines use the black gasket. And if so, I need to go back and see if any of the other specs during my rebuild were different for this model, maybe I screwed something up. I can't recall if there were any other clearances or anything that were different based on the model...
 
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