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something has gone horribly wrong piston hitting valve

  • Thread starter Thread starter m.qualls89
  • Start date Start date
M

m.qualls89

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So I went to adjust my valves on my 1980 gs1100e. It has the lock nut and tappett screw so no shiming. I adjusted them all to spec which is .003"-.005" cold. Got it done fired it up and ran great. Then it started idling funny and choked itself out. Hit the starter just figuring it was cold, it spun a few times then CLANK! Locked up tight. Took it back apart and every valve would hit I'd loosen one up then the next would hit. I've loosened them all way up and they keep hitting even with a .016" clearance! But it almost looks as if it jumped time somehow which is odd as I just fixed the cam chain tensioner and all the marks lined up when I adjusted the valves but now they don't and the cam chain is tight. I'm stumped short of tearing the motor down what should I do.
 
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Re-time it, double check the repair done to the tensioner and reinstall it, re-adjust the valves then do a leakdown or a possibly a compression test looking for any bent valves.

Why did the tensioner need repair?
 
It is rather common to install the tensioner incorrectly.

Almost everybody understands compressing the plunger, locking it in place, install the tensioner, release the plunger. What they seem to NOT understand is what happens next. After releasing the plunger, turn the setscrew in until it stops, turn it back out 1/4 turn and lock it in that position with the locknut.

Too many times I have seen tensioners that were locked in place, not allowing them to move and do their job.

.
 
"they DID line up but now THEY DONT"...You answered your own question. At some point after restart, the tensioner caught and the timing jumped. Then, the tensinoer let loose and thats why the marks are off ...even though the chain is tight now.
 
That's what I figured had happened. And to think this all started with me trying to prevent it jumping time lol. Now my only problem is the rookie uh oh I made when it locked up. I tried to spin the motor with the 19 mm nut on the end of the crank and stripped not the nut but the threads.
 
rustybronco said:
Re-time it, double check the repair done to the tensioner and reinstall it, re-adjust the valves then do a leakdown or a possibly a compression test looking for any bent valves.

Why did the tensioner need repair?
Click to expand...
The tensioner had frozen up and the cam chain had slack in it.
 
There is a 19MM aluminum nut and it has a 12MM steel nut in the center...what excatly stripped? The 12MM bolt that goes in to the crank? Or the crank theads themselves?
 
Sounds like a bunch of bent valves. Tough lesson.
 
chuck hahn said:
There is a 19MM aluminum nut and it has a 12MM steel nut in the center...what excatly stripped? The 12MM bolt that goes in to the crank? Or the crank theads themselves?
Click to expand...

The crank threads I'm pretty sure.
 
Well..I hate to bear bad news, but IF the crank itself is truely stripped..Youre basically bent over a pine stump and theres no Vaseline in sight!!!
 
What exactly does that nut hold on? I haven't taken it completely off yet.
 
The 12MM ( the steel one ) holds on the governor behind the timing plate and the whole timing plate assembly to the crank. Take some picstures of itm as is before touchuing anything else and post them up. Itb takes a lot to strip the crank and I am thinking the aluminum nut ripped itself loose first.

Theres a slot that meshes with two tabs on the back of that aluminum nut..which will sometimes snap off ( like a shear pin does ) before the crank bolt strips. I sure hope thats the case for you!!!
 
Ok ill post some tomorrow. I'm in the house for the night I got frustrated lol.
 
First thing you need to do is remove the cam chain tensioner, then remove the cam chain from the cam sprockets. Next, take a shoe lace or buggee cord and go thru the chain and tie it off up to the frame so you dont drop in down inside the engine.

Then remove the cam caps...notice each one is lettered. They go back in the exact same spots.AtoA..B to B etc etc. Loosen the bolts evenly to avoid them jammimg up.

Remove the cams so all the valves will be up as far as they can. Do all this so when your working on that crank bolt you are not smashing against the valves any more than what has already been done.

NOW..you can go down to the 12MM steel bolt and try to take it out of the crank..its lefty loosey righty tighty. use a 6PT wrench or socket..12PT seems to not grip as well as 6PTers do. A few good smacks with an impact driever will aid in getting it loose. I am willing to bet the tabs on the back of the 19MM aluminum cap is what has given way..least I hope so.
 
Steve said:
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.
Click to expand...
 
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.
 
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
 
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.
 
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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?
 
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