picking up the pieces 81 gs850g

[Burque73]

It does look like that, but didn't hit the valve. Almost though!

[Burque73]

Ok, I haven't given up on this head yet. I called around Albuquerque and left messages at some machine shops about timeserts, no return call yet. I'll try again tomorrow. In the mean time I decided to try and remove a couple of exhaust bolts that had snapped off. If I couldn't get these out without really screwing up the threads, then I wouldn't worry about the helicoil, timesert issue and just replace the whole head. Thankfully there was still a little of the bolt outside the head to work with. I decided to weld a nut onto the bolt and thought I could unscrew it that way.









It worked, well almost. It loosened the bolt a half turn then snapped off again.



Next I decided to grind a slot into the bolt and unscrew it with an impact driver.



Success!!

Now the other one. This one wouldn't cooperate at all. Tried the same techniques alternating heat, PB blaster, welding the nut on, grinding the slot thing and no dice, it broke off flush with the head. Have to get easy outs tomorrow and try drilling.

[Burque73]

After work I was able to get the second exhaust bolt drilled out and used a tap to re thread the hole. It took a while as I used three bits, increasing in diameter as I went. The valve seals arrived last night, but not the compresser tool. Maybe next week. Napa around the corner has a grand opening sale today. I'll check on valve lapping compound, degreasers, cleaners, and anything else I may need for getting this project going. Oh, I ordered a complete gasket set, should be here in a couple of weeks. Checked with Chef on rebuilding the carbs and plan to ship them shortly. Brake lines, caliper rebuilds, then test ride. Ugh, maybe this fall I'll ride!! Waited 25 years for this bike so what's another month or three! Here's some pics of the drilled and tapped exhaust bolt.

[ShadowFocus603]

Congrats getting those bolts out. Happy for you.

[Burque73]

Can someone advise me on the valve guide seals? I am planning on changing the oil seals, but didn't plan on removing the valve guides unless it's advisable.

[Burque73]

I finally found those pear shaped o rings part number. Should receive them and piston circuits in a few days. This is going to be fun. Anyone know if I will need a piston ring compressor to get the cylinder lowered down in place? Also, when I pulled the cylinder up the crank rotated half a turn and all pistons are level straight across. This also wrapped the cam chain up and I may need to rotate it back a half turn. Is that bad?

[Brendan W]

I finally found those pear shaped o rings part number. Should receive them and piston circuits in a few days. This is going to be fun. Anyone know if I will need a piston ring compressor to get the cylinder lowered down in place? Also, when I pulled the cylinder up the crank rotated half a turn and all pistons are level straight across. This also wrapped the cam chain up and I may need to rotate it back a half turn. Is that bad?

Won't need a ring compressor. Some use fingers, I use a strip cut from a plastic paint bucket and two hose clamps and do the inner two first.
Free up the chain gently pulling and rocking the crank if you have to. No harm done unless you force something.

[Burque73]

Cool, thank you. I meant circlips in the last post. Darn auto correct. There were a few posts on this thread that are gone. Talking about gaskets and copper washers. How do the posts get deleted?

[Brendan W]

Cool, thank you. I meant circlips in the last post. Darn auto correct. There were a few posts on this thread that are gone. Talking about gaskets and copper washers. How do the posts get deleted?

At this stage of a rebuild most missing things go down the cam chain tunnel

[Burque73]

I'm really paranoid about that happening. Or just junk falling into the crank case. I covered the opening right away with plastic. Was going to clean the pistons in place but too much hassle. I'll pull them and shine em up.

[Brendan W]

I'm really paranoid about that happening. Or just junk falling into the crank case. I covered the opening right away with plastic. Was going to clean the pistons in place but too much hassle. I'll pull them and shine em up.

This time last year mine looked just like that.
Not paranoid or anything but............did you count all those bits of tape ?

[Burque73]

[QUOTE=Nessism;2296291]One of the photos seems to suggest that when the spark plug hole was enlarged for the threaded insert that they hit the valve seats. If that's the case I'd ditch the head and start searching ebay for a replacement. Be sure to get a 1980 and newer head, the 1979 version had smaller intake ports because those bikes came with VM type carbs.]

I have been away for a while and am getting back to working on this bike little by little. I had to bite the bullet and buy a head. Finally took the advice offered and scrapped the other one. Those threaded inserts were going to be problematic!
I sent my carbs to Chef and plan on getting this engine together real soon, Lord willing!