KZ750 All Inlet Valve No Clearances, Why?

Hello Everyone,

I have a KZ750 EE engine on KZ650 frame., which means I have to run a different set of carburetors. I am running VM 22 carburetors, Also I have 39mm air pod filters with a 4to1 exhaust. I can get the bike started and running and it rides great too and handles amazingly. However, I can not idle the bike no less then 1300-1500 rpm without hearing one of the pistons not firing correctly.

After messing with the carbs for days I finally decided there is nothing wrong with the carburetors. So, I started researching about valve clearances. And yep you guessed it, its the valves. So, I tired measuring the valve clearances, All the inlet valves absolutely have no clearance. The exhaust valves were in specs or slightly higher then usual, which I am okay with.

However, why are all the intakes valves have no clearances?? After removing the shims on the intake, All the shims measured to be 2.55mm +/- .03mm. Is that factory stock or did someone already messed with them?

I am guessing since the bike is running a different carburetors, it somehow messed with the valves clearances, mostly since the carbs were not properly tuned.

Here is the link to the other post for the bike when I was tuning the carbs. I am currently running size 20 pilot jet, two turns out does the trick.
www.kzrider.com/forum/3-carburetor/609034-help-tuning-the-carbs


-Yuriy

Maybe. The valves get tighter with use. Do the lifters spin freely? If so I'd get two size smaller shims anr check again. Normally the exhaust valves wear faster.
Steve

Valve adjustment is part of normal maintenance and as mentioned they get tighter with mileage. It's remarkable how few people bother to do maintenance or even review the maintenance schedule.

I'm not sure about the 750-fours, but the first series of shims that come from the factory on 650's are usually more like #260 and #265. The Kz550's start out at #255 and #260. Maybe when the 750 was designed they tightened it up a bit and started out with #255-ish as well.

If the engine truly had zero clearance on all intake valves, it would have had major idling problems way before the valves got to the condition they are in... so I wonder if someone may have swapped in some shims they didn't need and took the ones that were in there. It makes more sense since it seems they only bothered to steal the ones from one camshaft.

Okay, I believe that the engine only has 16k miles on. All the information was very help. Thanks

I also have another question, Since I forgot to position cylinders 1 and 4 at TDC, how do I align the cams correctly? When I align the exhaust cam with marks according the service manual, one of the valves seems more open. And when I start tightening the cam bolts, the mark slightly moves.


-Yuriy

START FROM SCRATCH OR BEND A VALVE.

I have some questions, the video will explain all my questions

Did you count the pins on the cam chain mark to mark starting with the next pin up? Cam chain tensioner installed?
Steve

Yes, I counted exactly according to the book. While aligning the camshafts I removed the chain tensioner completely. After bolting the all the bolts I re installed the chain tensioner. And i also removed the locking bolt in the chain tensioner while it was removed from the engine

I am able to align the Z7EX mark with the cylinder head. However I can't say the same for IN mark.



Should I first set up the exhaust camshaft, bolt down the bolts and then work on the inlet side? I have a feeling I am missing something?

-Yuriy

The cams look to be off one tooth. Try rotating the crank two turns and stop at 1-4 T and then look at the cams again. Install the cam chain tensioner spring/wedge before turning the engine over of course.

Nessim,

I see the problem now, When I'll get home I'll work on the motor and I'll let you guys know of any more questions I have. Don't worry I sure will have more questions.

A big Thanks!!