something has gone horribly wrong piston hitting valve

[sedelen]

[QUOTE=Steve;1856916]Too many times I have seen tensioners that were locked in place, not allowing them to move and do their job./QUOTE]

Or the screw not backed out far enough to allow it to work correctly.

[sedelen]

It really hurts to read this thread.
At first I thought it was gonna read a lock nut came off one of the valve tappets or something along those lines.
I hope the damage that was done was "minimal."
it's just so easy to make a mistake or overlook something when performing maintenance on these old relics, or trying to do something you don't quite completely have a grasp on.

I know I have made my fair share.

[Gs1000G83]

Okay so how is that avoided ? I read that those adjusters are not to be touched EVER but doesnt everything fail eventually? The reason i ask is because when i do my top end this winter i planned on replacing it

[chuck hahn]

Ther adjuster failure is almost always linked to how it is reinstalled.

You force the rod back and use the adjustment screw and jam nut to hold it in the retracted stance.

Next you reinsert it with the new gasket and tighten the flange bolts.

Then you undo the jam nut and back off the adjuster screw about 2 turns.

The here is where the trouble begins. Most folks turn the adjuster screw in until it touches the tensioner rod and then give it a little snug and set the jam nut against it. THIS IS THE WRONG WAY!!!

This is what you do..Once you have released the rod upon reinsertion, you turn the adjuster screw in until it touches the tensioner rod inside. Now you turn the adjuster screw OUT 1/4 turn and lock the jam nut against the body of the adjuster. You MUST WATCH the adjuster screw as you tighten the jam nut to ASSURE THAT THE ADJUSTER SCREW DOES NOT MOVE.

If the adjuster screw turns itself in and you dont realise it...then you get what has happened to this guy...it jams the tensioner rod and the cam chain skips teeth on the cams.

To test to see if the tensioner rod is working....Start the bike and EVER SO SLIGHTLY turn the big knurled knob to the left. You will hear and feel the rod clatter at that point. Release the big knob and leave it alone after that.

[m.qualls89]

Well it ended up being the tabs. Now what to do as the tabs It looks like were on the crank and the slots in the nut. Can I turn the motor with the 12mm or am I up a creek?

[chuck hahn]

Yes..but find another aluminum nut...thats what its designed to do. Break BEFORE you gunk up the crank. AND do NOT turn that engine again until the cams are out and the valves are ALL up as far as they can be.

Your gonna have to pull the head anyways to do a real inspection, so just take the cams out and get the head off. Youll need to look for bent valves and piston tops being damaged.

To turn it again is just gonna compound any problems that already exist.

[m.qualls89]

The nut looks fine its the tabs it sits in that broke. Or am I looking at this wrong?

[chuck hahn]

The back of the 19MM aluminum nut has two tabs that fit into the slots..its a male / emale meshing arrangement. Take out the 12MM center bolt and remove the aluminum nut thing. See if the tabs on the back of the aluminum nut have sheared themselves off.

Is that a clear enough description?

[chuck hahn]

How about some pictures...we cant "see" what you see without them.

[m.qualls89]

[chuck hahn]

OK..now thats better. How does the back of the aluminum nut look...like theres some sheared off tabs? take a flat tip screw driver and knock the broke off tabs out of the slots on the crank. does the STEEL bolt thread back in without any problems? Does the threads on the bolt look damaged? I suspect not...you simply twisted then tabs off the aluminum nut...which saved your bacon.

[sedelen]

Okay so how is that avoided ? I read that those adjusters are not to be touched EVER but doesnt everything fail eventually? The reason i ask is because when i do my top end this winter i planned on replacing it

Indeed, everything seems to be designed to fail eventually.
Here's your service manual if you don't have it already.

http://www.mtsac.edu/~cliff/storage/gs/80-83_GS1100T-LT-EX-1000SZ-EZ-SD-ED-ESD.pdf

You will find references on pages 7-10, 7-19, 7-20, and 7-21.
You will find out how to rebuild it on pages 7-30 through 7-32.

This might help you also.

http://www.bwringer.com/gs/camchaintens.html

[m.qualls89]

The 12 mm bolt is fine. It looks like the slots are actually in the nut and the tabs I broke were on the crank.

[chuck hahn]

Did you knock the aluminum tabs out of the crank slots? Youll need a new aluminum nut..it actually does two jobs. Its a spacer AND a safety shear keyway for preventing what you did from ruining the crank and / or causing further damage.

Its a lesson you had to learn one way or another..but now you know.

just put the bolt back in the end of the crank and leave it alone. Get the cams out and get the head off. Dont do anything else..just get thentop end opened up.

Get a service manual downloaded and read it step for step and ask questions BEFORE if your not sure.

http://members.dslextreme.com/users/bikecliff/

[m.qualls89]

Ok thanks a lot for the help guys. This was a hard lesson but I guese those are the ones we remember most. I've already got the cams out and the chain is hanging from the frame. I really want to time it and do a compression test. I mean worst that can happen is the valve be bent in which case I will tear the entire motor down anyway because if your gonna do the top end you might as well do the bottom.