Need opinions and different perspectives on engine rebuild

[Guest]

I'm working on rebuilding the engine to a gs1100gk. Ran when I got it 2 years ago, limped it home (piston 4 was not firing). Finally getting around to working on it. Now I've got the entire thing disassembled, with the exception of taking apart the trans assemblies and the crankshaft assembly. Valves are still in place in the head as well, so far just doing some basic clean up before I start putting it back together.

Here's what I've found:

I checked valve clearances before I took everything apart, loose on pretty much all of them, but not too bad.
I have a friend who works as an hd mechanic, he's saying I should take valves out to make sure everything is in spec. If I take them out, do I have to replace the valve stem seals and the guides? Do I have to recut the valve seats and heads? Or is it sufficient to lap them?

Cylinders are glazed, there is a small vertical gouge on cylinder 1. No head distortion, haven't measured bore sizes yet or the pistons. If bores and pistons are in spec, is it sufficient just to hone and get new oversized rings?

Bearings seem to be all in good shape, no grinding or crunching. Oil seals seem to be good as well. There is some heavy rust on the big clutch gear, the crankshaft assembly, and some rust in the transmission gears, I intend on removing it via electrolysis. Should I take apart these separate assemblies for this step? I'm concerned of not being able to remove all the residual rust from the gears if I keep it assembled, or that it might affect bearing function during electrolysis.

Pics to come, have to head out to work atm.

I will probably have more questions as I get deeper into the project.

Thanks for reading and your input!

[Buffalo Bill]

Welcome to GSR.
Not knowing you, I just hope you maintain the energy to put it back together.

[tom203]

"There is some heavy rust on the big clutch gear, the crankshaft assembly, and some rust in the transmission gears"

This would scare me off...contemplating the stuff that likely needs replacing. Maybe you should look for another project and part this victim out.

[uk gs nut]

Sounds like a money pit to me. What you thinking of oversized rings in a honed cylinder, you want correct sized rings for bore diameter standard I would think.

[dem3500]

in my opinion it depends on what you want the outcome to be and how much work your willing to put into it. if it were me i would go through all of it all the way down to the trans, but what i would want out if it is a new reliable engine. pull the valves and take them and the head to an engine based machine shop. let them check spec and grind the seats if needed which they probably do if you have glazed cylinders. replacing the valve guides and seals to me is a no-brainer. you have the valves out anyway so replace them. glazed cylinders need to be honed, if you can get away with just having it honed. meaning if you can cut through the glazing with the hone. if not it will need bored. rings fit the pistons and pistons fit the bore. if that makes sense to you. you dont put over sized rings on the pistons. if you need to go bigger on the bore then you would need to get new pistons to match that new bore then new rings for those pistons. if you cant catch youre fingernail in the scratch then its fine to leave it. providing you dont need a bore but at that point it would cut the scratch out anyway. i would pull the cylinders and have the machine shop check for roundness and then bore it if needed. i would replace the main bearings at a minimum. if it was me i would replace all the load bearing bearings. that way you know your good to go. im in the middle of a build myself and once i get to the engine thats exactly what i plan to do. also new rings regardless if you need them or not. post some pics of the rust your talking about.

[ukjules]

Interesting thread ! I take it you want to dismantle the engine...... to make it as new or check it all over.

(I would have got bike home and purely done a top end job, leave cylinders on
and replaced valve seals and ground in the valves (lap them) oneself. (After checking compression)
Then all back on and see how she goes.)

Can you not hone your own cylinders ? Being broke i did that on mine and worked a treat.
Very interested in how you get on with the rust is on transmission gears etc? that's odd surely.

You seem to be doing things truly correctly though and the advice on here is spot on - way out of my league on engines.
Did you find out why it didn't fire on cylinder 4 ?
Why not try minimal intrusion first before you re bore, skim, new valve guides, dismantle further ?
It might run like a dream.

[urbnbrzln]

Thanks for the input!

The ultimate goal is to get it running smoothly and reliably. I wanted to learn as much as I could with this rebuild, hence why I broke it down completely. Also wanted to get a good clean through it, bike was looking pretty shabby when I got it.

As for why the 4th cylinder wasn't firing, I'm pretty sure it just required a thorough carb clean.
I think the rust on the gears is pretty minimal, no actual pitting. I tried the electrolysis without much success, may just give them a good clean and reassemble.

I honed the cylinders, the scoring is definitely still there. I'm thinking of sourcing some used cylinders, have found some pretty decent looking options for under $100. What if I reassemble with current jugs and pistons as they are now? I realize this is less than ideal, however if there is a chance that I'll get new jugs anyway, might just wait to get new rings on the pistons then. In the meantime, I would like to start reassembling the bottom end.

Manual says to put gear assemblies back together using moly paste, however since I never fully took apart the tranny assemblies I think I may just lube with some fresh oil and put them back in.

Got valves lapped today, they cleaned up pretty well. Putting in new seals, otherwise everything in the head was up to spec. Hoping to get the engine put back together before new years!

[urbnbrzln]

Here are some pictures of what I'm working with:

https://drive.google.com/open?id=0BzXcG5rPSN4KXzA5bnQxbTJLOGc