At 8.4 k miles the piston of my 610 looked like this: A mechanic looked at it and said that it was still good. I've covered only about 1.2 k miles since then, but all of them on tracks: mainly supermoto tracks and also motocross/minicross tracks and my bike seems to run well.
Crank, piston, rod assembley is in the mail. Ordered a crankcase splitter tool today, and got order placed for the assortment of seals and bearings and gaskets I'll need. Haven't put much more time into it lately, been cleaning up the KDX220 I picked up for the summer.
Well. It's been awhile since I updated here. Combine waiting for parts, with little free time, and riding the KdX when ever I could, meant not much got done with the Husky. I did get motivated last night, only to get stopped here. Any tips on removing that counter weight from the shaft end, I tried a little heat and prying, but had no luck. EDIT. Got it off. Found a prying device that worked. On to the other side, then split the cases!
Cases are split! Found lots of metal in the left hand side screen. Not seen anything yet that I would suspect to be the source. Crank bearings feel ok, although they will be replaced. I'll update with pics soon.
Let me start by saying the Tusk case splitter tool worked great. The cases did start to separate at the rear before the front let go, so you can see in this picture I used a big c clamp to hold the back while applying a little more force to the puller and a love tap with a rubber mallet got the front to break free. Here's another shot, fully disassembled. Now just have to wait for the wife to be out of the house long enough for me to pop these puppies into the oven, warm me up, and drive the bearings out. I've been looking for some cause of the ruined rod bearing but nothing is standing out. All the other bearings seem smooth. The transmission gears do have a little slop on their shafts haven't read enough to know how much is normal.
. While going through my parts to confirm I'm not missing any (I am) and the ones I have are correct, I found this. Have a look at these two photos. Here's the existing right side counter shaft bearing. Runs in same space as the crank. And here's the new one. Notice the old one is missing the "sealed" part. Possible it came loose and got chewed up by the shaft and crank. Would explain the amount of metal I found in the case and screens. What u all think?
bushwa, the stock bearings do not have the seals, at least on the 610. Also, that's some MASSIVE play on the rod!
In my 610 I found this axial play: https://imageshack.com/i/5ugiocobiellaalberoj 0.50 mm: complying with what the manual states. The radial play was not noticeable. As far as I remember, the gudgeon pin, the little end of the rod and the piston didn't have any noticeable radial play either. Bushwa, from your video I can't understand whether the play is in the small or in the big end of the rod. Are you sure that it's in the big one?
Positive it's big end. Small end was tight. Piston is now off, I have a dial gauge and could measure the radial play, but it's not much point, it's obviously fubar.
MG94, We're talking about number 15 in this pic. It is a different part number than the 610 part. It's even illustrated differently than the other bearings in the 630 fiche. Bearing numbers match, but the one in the bike is missing some metal compared to the new one. Odd thing is, I don't see any obvious signs on the counter shaft, bearing, or case in that area that would leave me to believe there was a random ring of metal rolling around until it eventually got chewed up. Anyone that's been into a 630, can you confirm the bearing didn't have the enclosed rollers? Thanks.
There's no doubt about this because, from the pics you posted, we can see that the writings on the two bearings are the same: SKF BB1-0724/+ BG. On the new one there are some tabs which hold the seal, but those tabs are missing in the old one and it doesn't seem to be damaged: it doesn't look like it lost them. Well, a question arises: is the new one sealed on both sides? Maybe the old one has a seal only on the other side...
Yea, new one is sealed on both sides. Pick up my press this week, and dug out a table top roaster I use for slow cooking ribs that I can use to heat up the case halves. I'll get that bearing out this weekend and see if the other side of the existing one is sealed up.
The new one may be sealed, but I don't think the old ones are. I had to replace my 630 casings this past winter and I am very certain none of these bearings were sealed. If you want I should be able to snap some pics of the insides of my old casings tonight (which still have all bearings in place)...even if only to try to provide you some peace of mind so you needn't be concerned about the possibility of a plate/seal that went throughout the engine. I can post pics around 10:30 (EST, U.S. time), but perhaps as soon as 6-6:30 this evening. Ultimately I think you and Theo have nailed it- the bearing numbers match so I'd say you're good to go on the upcoming roast/swap.
Looks the same as mine, thanks man. I appreciate it. I was kinda hoping that it was missing a part of the bearing as it would explain the metal bits and could have contributed to the rod bearing dying at 10,000 miles, but I think I'll have to keep looking, or accept the fact I ran the piss out of it for 3000 miles on the highway and it was too much :-(
No problem. I don't think 3K highway miles would've toasted it- that would be remarkably unusual. In my case it was the RH oil screen that came apart, but that's a whole diff. issue than what you're facing. There's obviously a tighter tolerance at the rod bearing so...I dunno...my guess is that something very fine would have had to have worked it's way in, or perhaps a defective rod bearing or something like that. All that said you're going through it thoroughly, so while I'd also want the peace of mind of knowing the cause you'll at least know whatever it was (object or contaminant) is gone.
