Valve clearance too tight?? '77 KZ650

650ed wrote: I would double check those measurements. ALL of them except #6 Intake are too tight, and that is not good. The spec is 0.08 - 0.18mm. If you measured the clearances correctly you need to adjust. Ed

Does that mean I should shoot for 0.13mm as the new clearance?

I used 0.13mm to calculate the shim size I need.



I'm wondering if these shim adjustments look correct?

Also, can you reuse shims? I can check the actual size with calipers, but I only need to reuse one 2.65, and I have five to choose from.

You can certainly reuse shims, just check that there is no spalling or deterioration on either surface of the shim. When you put them in make sure the printed number is away from the valve so it won't disappear
Your "new shim" calculations look correct

Re-using a shim should not be a problem. They are case hardened and shouldn't wear much (if at all). Those new shim sizes look correct to me. If I calculated correctly you should end up with the following clearances after the changes (but please double check my math):

EXHAUST
#1 0.126
#2 0.151
#3 0.126
#4 0.151
INTAKE
#1 0.126
#2 0.102
#3 0.126
#4 0.126

I use a daily pill box for storing my shims. Each lid is labeled for size. Protect them, they are like money but these can rust.
Steve

650ed wrote: Re-using a shim should not be a problem. They are case hardened and shouldn't wear much (if at all). Those new shim sizes look correct to me. If I calculated correctly you should end up with the following clearances after the changes (but please double check my math):

EXHAUST
#1 0.126
#2 0.151
#3 0.126
#4 0.151
INTAKE
#1 0.126
#2 0.102
#3 0.126
#4 0.126

It all checks out to me! Thanks for the help Ed!



And here's how the bike's looking currently..

Since you have it apart was Wondering if you should go one more smaller a #260 on the #2 Intake and get it up to 1.52. Its in spec at 1.02 but wouldn't take a whole lot to tighten up.

Since the 180* method is being used the true clearances for those valves is all lower than measured. You can move all the .126's up to .176 with thinner shims, and when measuring per the manual procedure they will be more like .150 or so (depending on how worn the head and cams are).

Do those heads have bearings like the larger bikes?

Nessism wrote: Since the 180* method is being used the true clearances for those valves is all lower than measured. You can move all the .126's up to .176 with thinner shims, and when measuring per the manual procedure they will be more like .150 or so (depending on how worn the head and cams are).

I was thinking about it but didn't know if I should, you make a valid point! I did read that slightly loose is better than slightly tight.

Here are the new numbers:

swest wrote: Do those heads have bearings like the larger bikes?

No. The cams in the KZ650 ride in the journals that are machined as part of the head and the corresponding cam caps. That's why it's important to keep the original cam caps with the head and in the correct position (they have numbers cast into them to make that easy). During manufacturing the caps are bolted to the head and then the head and caps are line-bored for the cams. Ed

I thought so. They are all line bored and the caps numbered. That's how it's done. Looking at the cam plugs and the small sizes suggested this was the case. I've been out of the game too long.
Steve :blush:

Hey all,

Resurrecting this thread because I've finally gotten around to changing the shims. The problem is, now my clearance is tight still! Some valves are tighter than before! Exhaust #4 is extremely tight.

Read under "Actual New Clearance":



My only hypothesis.. is that I torqued the caps too tight. I only have a foot-lbs wrench, so I assume it's not very accurate at the very low range that I had to use. So I might go pick up an inch-lbs wrench and try again.

Any suggestions? My timing seems correct, 36 links counted, and it turns over easily.

Thanks,
-Stephen