milling head with no high compression piston

I have a 1978 kz 650 which i have milled the head 25 thous i also have a set of 1984 gpz cams and stock over sized pistons. will i run into any problems with clearence issues being that the pistons i am using are domed? thnaks

I dont think you will have any problems, but nothing like a clay check prior to final assembley to make sure, better safe than sorry

You didn't say, but you did slot the cam sprockets so you could put the cams back in time after shaving the head, right?

On the clearances issue, same answer as above, except don't even think about assembling it without checking.

Yes i hvae slotted the cam sprockets to adjuct the timing. I have done everything that the gpz faq says to do except for using a 810 kit. I have already assembled the motr but have never ran it. I have used stock kz 650 valves and springs as well as having the head ported and polished and milled 25 thous. the pistons i put in the motor are two over.

i thought by using the same valves it would eliminate a clearance issue from valve to piston. I also felt like the gpz cam springs and the kz 650 valve springs where no different. thanks for any help!

Steell, "slot the cam sprockets"... Caught my eye, can you explain more on this please...

Reason I ask is I'm updating the KZ900 with .365 CAMs and was wondering if this is something I'm required to accomplish over the stock CAMs.

OMR

You can slot the cam sprockets even if you don't mill the head. Even with the new cams or with out them it would be a better upgrade to go head and slot the sprockets. cam chains get stretched throwing off the timing a bit. If you slot the sprockets and redegree the cams you will probably have a lil better performence. the only reason i slotted the sprockets is because i am milling the head to get better mid range from the cams thus making the cam chain longer making m have to change the degree of cams.

Yep, what he said.

The reason for slotting the cam sprocket bolt holes is milling the head moves the cams closer to the block, effectively making the chain longer. The tensioner will take up the slack, but it's on one side while the slack is on both sides, so when it takes up the slack on the far side it rolls the cams toward the tensioner. So you slot the bolt holes to allow you to roll the cams back where they are supposed to be.

I read where someone else on here said the holes should be enlarged (elongated) by 1/3 the diameter of the hole. That makes absolutely no sense to me, elongating the hole by two thirds the amount removed from the head should be more than enough. Mill .030 off the head, make the hole .020 longer should work just fine. I'll know for sure when I assemble my motor, but my calculations say it will be more than sufficient.

Interesting...

Anyone have any pictures of the sprockets completed?
Learning curve for us all...

OMR

Just pick up the phone and order a set.

kzzone.com/sprockets.html

APE Jay wrote:

Just pick up the phone and order a set.

kzzone.com/sprockets.html

What he said. It's a lot easier then spendy a day in the garage with a dremmel. :laugh:

Actually I just read the first post again, and we don't make a sprocket for the 650.

Jay

I have a set of GPz cams with the stock sprockets slotted. They are buried in the Garage but I'll pull them out and snap a shot.

Just for documenting what is possible.