kz750 twin performance upgrades

gumby prichard wrote: that is correct i can't get a .002 feeler gauge in but i can turn the buckets with my finder easily. SO i will go down two sizes, and i believe they are measured in incriments of .05. Thanks motor head

The increments are .05 mm which is .002". If you have a loose one that won't pass .002, it's probably between .001 and .002". I would go one size thinner and recheck since it will probably be about .003.

BTW: You can get feeler gauges down to .001" (I got a cheap set online a while back) and my other set has a .0015 and .002 and .0025" which lets you accurately resolve clearance down to 1/2 thousandth. For example, using the .001 and .0025 lets you measure .0035".

yeah, i was hoping to skip a size because 1 save some money, and 2 save time, this way i can go longer before changing shims. so would i be ok with doing this, because it looks like we can't agree!

Wow. This thread started out being about performance upgrades, now it has descended into a quibbling about whether or not valve clearances should be set properly. Sloppy valve clearances will have the same effect as installing cams with less lift and less duration; that is to say, power will be down slightly. Kawasaki did not pick those clearance numbers out of a hat................

OK so just go up 1 size, .05 each shim, DO WE HAVE ANY OBJECTIONS? OR IS THIS THE FINAL ANSWER? :huh: :lol:

gumby prichard wrote: OK so just go up 1 size, .05 each shim, DO WE HAVE ANY OBJECTIONS? OR IS THIS THE FINAL ANSWER? :huh: :lol:

That's not the answer to the correct question: the answer is you change shims until you have the correct clearance. If you have a known clearance, you calculate the necessary shim,install it THEN RECHECK. Adjust if necessary.

If you don't have a measurable clearance, you estimate the needed shim and install the shim and THEN RECHECK. Adjust if necessary.

When the clearances are in spec, you're done.

yes, i know, i know. :dry: i was just wanting to see if i could skip a step to to save time and money, but i understand, not recommended.

i will let you guys know the verdict, hopefully this solves my bad running problems. ordering shims from z1 tomorrow. I'm just praying its not a carb issue. :sick:

thanks for the input and participation.

UPDATE: gto my shipment in from z1, put my shims in all were within clearence except #2 exhaust valve. it is still too thick! and the size it requires 255 they are out of! ANYONE KNOE WHERE I CAN GET A 32MM SHIM SIZE 255? BESIDES Z1?

anyway i tryied it out just to see and it ran awesome for a minute! then went back to doing the same weird idle where it idles normal then gives a really fast quadruplet then idles normal. I really am convinced its an ignition problem or coils. I noticed the coils currently on it do not match the stock wiring.

another problem i resolved is the plugs fouling. ok i had BR8es in them, turns out i should have had non resistor plugs in it (b8es) so its not fouling or burning plugs anymore.

just to verify i went from shim sizes ex1:250, ex2:265, in1:260, in2:260 to ex1:245, ex2:260, in1: 250, in2:250.

gumby prichard wrote: UPDATE: gto my shipment in from z1, put my shims in all were within clearence except #2 exhaust valve. it is still too thick! and the size it requires 255 they are out of! ANYONE KNOE WHERE I CAN GET A 32MM SHIM SIZE 255? BESIDES Z1?

anyway i tryied it out just to see and it ran awesome for a minute! then went back to doing the same weird idle where it idles normal then gives a really fast quadruplet then idles normal. I really am convinced its an ignition problem or coils. I noticed the coils currently on it do not match the stock wiring.

another problem i resolved is the plugs fouling. ok i had BR8es in them, turns out i should have had non resistor plugs in it (b8es) so its not fouling or burning plugs anymore.

YOU ARE RUNNING THE WRONG PLUGS

The 750 twins MUST run the hotter B6ES plugs or they will foul. The four cylinder engines run the B8ES, the twins run the B6ES.

ANYONE KNOW WHERE I CAN GET A 32MM SHIM SIZE 255? BESIDES Z1?

Check ebay.

Check the Kawi dealers near you, be prepared to grab your ankles.

Check ebay.

Check the Kawi dealers near you, be prepared to grab your ankles.

hahaha is it that bad? what like 10 per a shim or what?

also how come on the model info on one website that said replacement plugs are b8es. ALSO i just found this post in the kz rider archive.....

"Lemme see if I have this straight (please others correct me if I'm wrong):

Some later twins were shipped from the factory and spec'ed ORIGINALLY with the b6es. I assume this was for test rides outta the dealership and stuff. The REPLACEMENT is spec'ed for b8es.

I used a b6es for a whole season (because I thought the manual said so) and I gotta tell you - don't do it. Ran hot, lean, and bad (not-good bad).

When I got my second twin, it had b9es in it. I thought, "This cannot be!?"

Anyway, in my daily runner, I gradually moved to b7es, and now b8es - and now it runs better than ever. And, I'm tempted to try b9es like was in the one bike."

kzrider.com/archive/viewthread.php?tid=28720

All I know for sure is the factory service manual calls out B6ES for the 1979 750 Twin. I don't have the manual for the later 750 twins but have no idea how or why that would change. I have been running B6ES for 32 years.

As for dealers and 32 mm shims: the ones around here just refused to sell them at all at any price.