Broken bolt in the worst possible place

[Jethro]

I have had a small oil leak since I got the bike last Sept. coming from right at the junction of the cases, directly beneath the #1 cyl. exhaust pipe. It seemed to be located right at the lower case bolt that is right between the frame downtube and the motor. It wasn't leaking enough to ever drip on the floor, but it was slightly bleeding onto the lower case. In a last ditch attempt to stop the leak, I decided to try and torque the bolt a little bit more. Well, you know the most likely result of that- SNAP. Luckly the bolt has broken beyond he threads, meaning there will be a small amount of the stud to grab at when I split the cases.

What I am asking here is how much of a project is it to split the cases? I know what it will take to pull the motor, but I've never actually split the cases. Can I simply unscrew all the case bolts and lift the bottom case off? Do I have to worry about transmission stuff and crank bearings and all that? Is there anything else I should do while I have the cases apart?

I probably won't do this till next winter, it doesn't appear that the leak is anyworse becasue of this. I just want to get my head into it. I plugged the bolt hole with RTV for the time being and went for a ride, no more than the leak that I already had- hopefully the summer heat won't change that. Should I worry about the cases being able to twist a little more under torque and fudging up the crank bearings- or worse?

[Anonymous]

My guess is that no harm will be done to the motor if you don't race it. These things were overbuilt.

As for splitting the cases, they come apart with a little tapping. Use something soft, like a rubber mallet or wodden block and if they don't pop look for a bolt you missed.

The bottom lifts off without any problems if the top is suspended properly. At that point everything is exposed and it's all pretty simple. Once you are in there I would replace all of the seals, crank ends, shift shaft, etc. I would also clean everything up nice and inspect every part for wear. Replace the cam chain now and the rear cam guide.

I don't know if anyone makes a complete rebuild kit. I couldn't find one when I did mine. Kind of a paint to get some to the stuff one at a time.

[Jethro]

Yeah, the Vesrah and Comet gasket kits are kinda incomplete. Rear cam chain guide, I wouldn't have thought of that one, thanks Swanny.

Anyway, I was gonna do it with the motor upside down, that should be ok, right?

[Anonymous]

I just split the cases on a 450 getting them apart was no problem, but however getting them back together was not fun. You need about 4 hands to do it.

[marcovandevelde]

Boys,
What Jethro was asking is if he can split the cases by just removing the bolts that hold the cases together. NO you can't, there are some plates behind the clutch that hold the cases together, these need to be taken off too. You need to remove the complete clutch before you can reach them.
Undo the clutch hub nut first when the block is still in the frame so you can put it in gear and use the back brake to be able to unbolt the nut easily.

Greetz, Marco.

[moto_dan]

Didn't see what kind of bike you're talking about, but with 16v engines there are also some bolts hidden by the oil pan.

[Jethro]

Yeah, it's a 16v 83 1100 motor. I had forgotten about the plates behind the clutch.

[Don Lobacz]

You might be able to extract that bolt just as it is. The bolt wasn't siezed, you just overtightened it. If you can get a small endmill and glue a properly sized sleeve near the end, you should be able to flatten the broken stud end without gouging the case. A careful drilling job and an easyout should work then, again mainly because the bolt was not seized. Goop the shaft of the new bolt with gasket sealer (not the threads) and you may stop the leak.

[snowbeard]

that was going to be my suggestion, tho I was sorely lacking on the details!! may as well try to extract it?