Hello All

Felt a small, but new, vibration coming from the engine the other day. I had recently done a valve shim adjustment, so I thought I could have left something loose in there, so, that night I opened up the top and looked. All was good and tight, no problems there.
The next day, I was commuting to work when suddenly I felt the vibration again, and in a matter of about two minutes, I lost about 80% of power and had to coast to a halt.
Later that day I brought the bike home and thought that I was looking at a balancer bearing, based on posts I have read here in the past.

I embarked in the adventure of opening up the engine.
Just last night I split the crankcase.

This is the bad stuff:

1. I chipped a corner of a magnet of the stator coil. If I ignore what I've read here about that part, I can simply clean and reinstall it and go on riding my bike. However, I think I'll at least try to get a replacement for this part.
By the way, I chipped this while I was removing it. I got me a 5" long screw with the right thread (M14 x 1.5mm) and a heavy piece of brass with a hole big enough for the screw to go through. This was enough to remove the stator coil with minimal effort... Only that I didn't plan on catching the part once removed... It fell and chipped the magnet with the screw.

2. I chipped a piston while loosening the primary gear. I was doing this with a 1/2" drive ratchet, using a long tube from a jack as a torque amplifier. To prevent the motor from turning, I had a smaller ratchet against a car stand, holding the screw next to the primary gear. Big mistake. That screw got loose, the motor turned, and I chipped a piston... Should have placed the clutch housing (which has a large gear that mates with the primary gear). I did that after damaging the piston, and used a washer between the two gears to prevent them from turning. This worked very nicely.

3. Got very discouraged when I removed the oil pan. Big chunks of mauled steel in there. I thought this was the end of my bike. I carried on, though, and was pleasantly surprised when I finally opened the crankcase. Upon initial inspection, what died were the bearings (lower) for the left rod.

So, so far I have: (and questions I'm asking, please)

-Piston(s?) (will have to replace both, (with rings - not reuse?)
-Stator Coil (the slightly chipped magnet will not do...?)
-Connecting Rod (Crankcase to Piston) bearings (Need I do both rods?)

Tonight I will measure the crankcase and complete the inspection of all other components.
If the crankcase is out of spec then I guess I'll be looking at getting a replacement motor, since the crankcase is very expensive at the dealership.
If the connecting rod ends up being out of spec, should this also be replaced as a set, with the other rod, or can it be only one?

Last question: When re-sealing the crankcase, any advise? Anything special to do to make sure there'll be no leaks?

Have no pics, but will take some tonight.

Thanks all for any help, opinions, or advise you can spare.


Mauricio

My advice would be to source another running engine. Save yourself the hassle of the rebuild. If there is metal in the pan then it is probably throughout the rest of the engine.

Reading all the damage, it is pretty much get a replacement engine. Probably around $500 or so. Any year will work. Get one that is newer with lower miles to get the most use out of it. Check the previous owner if possible or find out why it is parted out.

i just (two weekends ago) opened a 2004 and a 2006 engine, 3 good pistons, one seized, both engines
had a bad con-rod bearing (one each). Make sure that crank is within specs, before you spend alot, get that
bearing for the conrod and see if there is play, if your crank is out of spec, there will be play and thats the
end of the engine. I just picked one up on saturday, 400 bucks, 2009 with 4k miles...takes an hours to swap
an engine, less hassle to swap than opening one up

if you're looking to buy a connecting rod or piston, I have both, pm if interested.

and no, you dont need to replace the good piston, but why not replace the rings while you're at it on both. No, you dont have to replace both con-rods, only the one that got heated up good chance there is damage to it even if it 'looks' good, discoloration = in the trash, not worth the risk they dont cost much

I'm leaning towards buying a replacement engine. Problem is, I see nothing ~400 around. I have a pending deal for a lower engine.

In the mean time, for what it's worth, the crankshaft is within spec, but at the end of the tolerances. Also, there's discoloration on the cylinder one side.



The connecting rod is kaput (didn't realize how bad the pic was, but it'll have to do):



Feel weird replacing the lower end, seeing as the transmission is intact, as is the housing, but I can see the long-term value in going that route.

thats rod is preeeeeetty dead. I'm surprised this crank is within spec. I have 5 rods, good ones, in case you want to give it a shot. For the engine, patience, scout and jump on it, I waited 2 months before one popped up local.

Also bought a 96 one before from someone in this forum from D.C. but I can't remember who it was, 4000 miles later
that used engine I bought on here is still going strong in my 2001 GS