Rod Replacement

[Kawadog]

Mike absolutely...My brother in law who used to race a 165 Hp kz1000 in the late 70's and early 80's thinks I bent a valve. He says it has always been the only weak link in the Mama Kaw's 1ltr motor.

Mike like you... he said today I should pull the head and I will know what is wrong. He said at that point that you will see you bent an exhaust valve. We will see...

You have know Idea how much I appreciate everyone on this web site...
It is like I am not alone in my depression..

Thanks soooo much Mark

[WillyP]

So this started after the valve adjustment? You say you did a valve adjustment, then started it up and it made noise, but did it make the same noise before the valve adjustment? Or did you do the valve adjustment after hearing this noise?

[Syntor]

Bad news!!!Did a ramp ck on piston height and never got past #1. after I put her in TDC on number one. Marked my dowel. started to do # 2.

By my reckoning you STILL have not done a bent rod check, just do it!

[Kawadog]

Willy, this happened before my valve adjustment. I just did it because I wanted to see the I something broke in the valve train. It was spinning ok before the adjustment. after I started it is when it quit spinning free.

I cannot do the rod check. I placed it into TDC did #1 started to rotate it right before #1 turns 180deg it hits metal. Either a bent rod on #1 or 4 or a bent or dropped valve #2 or 3.

I was able to get all the plastic off, radiator, oil cooler oil lines today...She is neked big time.

Tomorrow or Saturday I will pull the carbs, cams and head. At that point I should have a good idea what happened.

I have a guy coming to help me on my screened room tomorrow. This is my second project.

Not looking forward to the carbs...They truly are a PITA...especially putting them back in.

Here is where I am right now...see photo

You really have to take it all apart to get the head off.

I'll keep y'all posted...Thanks fore your input ...Mark

[Lee]

I would have to say in my opinion that a bent rod on a zg1000 is due 99.9% of the time from hydrolock.. .  I bet the crank is fine, I even bet the rod bearings will "look" fine also.  The piston pin will be oval (.002~.004in) and if the piston is still in one piece the cylinder will still be fine.

I have to say. This was a hell of a good piece of diagnostic information! Thanks! It explained what I was finding after a dropped valve. Had a .005 in difference between #1 & #4 measured but could not explain why. #3 & #4 measured .002.  Will pull it down further to confirm wrist pin or other damage. 

[Lee]

Sorry misused quote feature in above post. Did not see how to correct it. Second paragraph is my comment to rk970 quote and post. Thanks again for info....

[TimR]

 


Wish I had only pulled the head when replacing bent valves on the old 900. If you do pull the motor from the frame take pictures of mounting bolts and any mounting bolt spacers you might have.

[Stasch]

You have some confusing info in your posts.  I suggest you pause things and figure out what's really going on.

I cannot do the rod check. I placed it into TDC did #1 started to rotate it right before #1 turns 180deg it hits metal. Either a bent rod on #1 or 4 or a bent or dropped valve #2 or 3.

Not sure why you were spinning the engine to do the bent rod test as it can be done with the engine at rest with the head on or off (it can be done through the spark plug holes) for both pairs of cylinders.  1&4, 2&3.  If both pairs match (engine position is irrelevant) you can move away from the bent rod theory.  See the SISF vids on how to do this.

I did a valve adjustment. Then started the motor afterward. It started banging on the left side.

So something was going on, then something more once you did a valve adjustment?

I do not know if this would have anything to do with this but Number 3 intake valves had 30 ths clearance.

That is a LOT of clearance ! - over 4 times the top of the recommended range for intake valves (.005 - .007).  Are you certain of this measurement?  Is it possible it was incorrect and you overcompensated in your adjustments there?  I would want to find out how that measurement was possible.

My brother in law who used to race a 165 Hp kz1000 in the late 70's and early 80's thinks I bent a valve. He says it has always been the only weak link in the Mama Kaw's 1ltr motor.

You may have bent a valve, but its not common to hear about a ZG1000. 


Before pulling engine, I would start gradually with the easiest most likely things first, until you know what is actually wrong because it sounds like you still don't know for sure.

All of them can be done with the engine in the frame.  Number 3 does require draining the oil.

1 - Do a bent rod test and verify for sure if you have a bent rod or not.  See the vids on how to do this - there is no engine turning required!  You can tell which rod(s) are the culprit(s) if measurements don't match up between the pairs.  (1 vs. 4,  2 vs. 3)   What are the differences if any?  It doesn't have to be much to indicate a bent rod. 

If its a bent rod 2 or 3, they can be replaced without pulling the engine.  If 1 or 4, pulling the engine is required.

2 - Since some of this seems to have started after your last valve adjustment per your previous posts, pull the valve cover to see if something is missing / loose / binding up in there.  Verify clearances, check for loose / missing locknuts and or adjuster screws.  Not being cute here, but did you follow the right procedure to adjust valves?  This does require rotating the engine into 2 separate positions to do all 16 valves.  Did you double check them?  Did you properly torque the adjuster lock nuts down and double check?

3 - This is a more remote possibility, but pull clutch cover and check the ACT (Alternator Chain Tensioner) - these can let go and create a lot of slapping / banging noise or even engine binding if errant pieces get in the wrong places.

4 - Pull the head and look for bent valves / damage or foreign / broken stuff in cylinders.

All this can be done with engine in frame to determine what is actually going on.

[batboy]

Stasch posted some good info. However... this is a 7 year old thread resurrected from the dead.

[Lee]

Useful and vintage info was surely relevant to me in diagnosis of what I was observing in my comparison of 1&4 after piston hit by screw and broken valve. Was getting .005 difference with dial gauge.  Now I know the mechanics of why. I know further tear down is indicated though difference is technically in spec. Love COG's data base. Sure glad the old stuff is still available, Though search is a iffy roll of the dice sometimes.

[Stasch]

Stasch posted some good info. However... this is a 7 year old thread resurrected from the dead.

I only saw it pop up on 'recent posts'

LOL - Better late than never? 

BTW, I hope to be late to my own funeral - real late.