Tear-down in progress..

Hey guys. So I'm tearing down the engine to replace a chain guide. I'm sure I'll run into plenty of questions along the line, so I'll update this thread accordingly.

I've determined that the chain guide that's disintegrated guides the starter chain. Just so happens this is nearly dead center in the engine guts. Do I need to split the case to remove this one?

Also, I can't remove the block. I've been using a rubber mallet to knock around the perimeter, trying to jar it loose. Should I just keep at it? Manual says absolutely no prying, and the fragility of the fins makes me a bit wary. Do I even need to remove the block to split the case? I'm assuming yes..

 

There is a way to fix the starter clutch without splitting the cases, it's posted on here somewhere, someone will flag it. Yes you have to remove the block to split the cases.

 

Couldn't find a way to change the guard without splitting the cases, so that's what I'm doing. Just about everything's stripped out now. The pistons are nice and dirty, so I'll probably give them a carb cleaner bath.

I've read that you never reuse old piston rings. I wasn't planning on removing them, so should I still change them? Keeping in mind that $150 is a good amount of $$ on top of the new chain guide, gasket set, and other non-engine items I'd like to replace/refresh. Would it be a bad idea not to replace them?

 

I know it's money, but with the motor stripped right down, I think I would be fitting new rings. Take the rings off the piston, put them in the bore & measure the gap between the ends, that tells you how worn they are.

 

Piston rings it is. Couple questions on the issue:

-Do all 1982 xj650 models (maxim, seca, turbo) use the same rings?
-I had no idea my bike had a dynojet kit on it, I don't want to be surprised by bored cylinders. Any way to confirm it's stock size?
-Would an AutoZone cylinder hone tool be a good/bad idea here?

Thanks.

 

as long as your bore is straight the hone from auto zone will work fine

 

Ok, finally split the case tonight. Found I need to remove the bearing from the alternator housing.



Then I do this.



Is this thing too stripped to remove? Will a screw extractor work? I've had mixed luck with screw extractors.. Last item I need to remove before I get to the chain guide... :sad faces:

 

your using a hand impact driver, right?

 

A bit of valve lapping compound on the screwdriver tip will help grip the screw. Just a tip.

 

No, wasn't using an impact wrench.. Hindsight's a bitch..

 

Try using a left handed bit and a very slow speed on a battery powered drill. works for me when I resort to it.

HTH

Greg

 

Just tried the drill. Didn't work, but the bit's got a good bit of bite to it; not slipping around. If I get my hands on an impact wrench, I think I'll be able to coax it out.

 

Might be the perfect time for a good shot of Kroil. If the drill bit has a good bite and you still can't turn it out it sounds like you are likely to snap the shaft. Then you'll be in a real schnizzle. Can you wait long enough to get Kroil? What about the propane torch repeated heat and cool cycle method. Best of luck to you!

 

No, I can stop off for some Kroil. How long does that stuff need to soak in?

 

Doesn't need very long, Crew. Give it about ten minutes and try it. If nothing yet, another ten minutes aught to do it.

 

Waiting on the impact wrench, here's another issue.

With the case split, there are at least a couple bearings with HALF a metal ring keeping it in position.



I'm fairly certain I haven't misplaced/lost any halves of these rings, so either this is how it's supposed to be (to allow oil to pass?), or they were lost before I got the bike (unlikely).

Ideas?

 

Could they be broken what's the technical term "Jesus Clips", you know Split ring "C" clips?

 

hahahaha, I just had a 25 minute discussion about these half-rings with my friend who's helping me on my seca. Theres 2 or 3 of them in my engine too (81 750), each place only has one half of the channel for it filled with a ring. We looked and looked and looked. You most likely didn't lose any, it's just how they were built for some reason.

 

Yeah, they don't look broken at all. Not sure why they'd only be half a ring, but I'll assume that's how it's supposed to be.

 

half ring is normal. Ive rebuilt a few yamaha atvs engine and there like that too.