Cams for stock kz900

jp-15 wrote: Can the 903 cylinders be bored to 1015? Or do I have to buy a while new cylinder?

"A stock 903cc cylinder (Z1 or KZ900) has 66mm pistons.
These blocks have thick cylinder walls and can be bored up to
71mm using all of the stock components.
This yields a displacement of 1045cc.
If you would like to leave the cylinder so that it can be bored again,
to extend it’s life, then you have the option to go to 70mm or 1015cc."

Borrowed this from Pit Stop Performance. Google them and see what they offer.

jp-15 wrote: Can the 903 cylinders be bored to 1015? Or do I have to buy a while new cylinder?

wiseco and J&E offer 10.25 to 1 compression 70 m.m. (1015cc) then jump to 72 M.M.(1075cc).... 1045cc (71mm) is NLA...... :S



:huh: I would not bore a 900 (66 mm) cylinder to 1045 (71 mm) as the bottom of the liners get very thin at 71mm bore size........ :blink: even if that kit were still available... :S


you can safely bore a 903 cylinder to 70 mm (1015cc) :blink: IMO

1015 kit in KZ900 has proven itself to be extremely durable throughout many miles over many years (35+ years).
Would say equally as durable and reliable as stock KZ900.

Good Fortune!

at MTC's site they no longer offer a 1015cc kit or 1045cc (71mm) they start at 1075cc (72mm) :dry:

www.mtceng.com/mtcproducts/products/pistons/kawasaki/kz900-1000

so it looks like your choice for forged pistons is wiseco or J&E kits :dry:

Pit Stop site shows they have they 1015 MTC piston kit. They are 10.5 "cranking compression with stock cams" is what his ad says.

I have these MTC pistons in my KZ1000 with a stock bore.

They do offer a turbo piston at 9:1 compression which is closer to the stock compression for these bikes also.

Is it cost effective to just send the whole engine out to pit stop and have it built? I'm pretty handy with a wrench as I have been building drag cars for the past 12 years. I can honestly say this will be my first bike engine though. Right now I'm looking at-

1015 (70mm) piston kit
Psp 3x cams
adjustable cam gears
head refurbishing
Timing chain and idler gears
Mikuni RS 34 flat slides.

Did I miss anything?
I plan to send PSP the cylinders, and head for sure for boring and refinishing, just curious if it would be better to send the whole thing?
Any one ever use these carbs? Are they worth the 650$? Would they work well with my combination?

these old engines are pretty simple.
if you have rebuilt any kinda engine before you can rebuild one of these,sure you need to send out the machine work or whatever.
but if you got a full set of metric tools you can rebuild your own engine.
you need a manual,timing the cams is probably the most difficult part.
but it has been done by a million do it yourselfers over the years.

if you want to do it you can.
more compression and decent cams yes those carbs tuned properly will work nicely for you.

leon

1015cc makes a nice kit in the 903. K410 cams, springs and adjustable sprockets. That will give you one of the most popular combos out there.

Mine is going on 25 years with a Superbike Mike, 1105 kit, 10.25 pistons 395 lift 260/260 cams & 29mm smoothbores. I think theres more in a good set of carbs then cams but that's just my opinion. Id degree the stock cams in myself. I think theres more in a good set of carbs then the cams, Id degree the stock ones in myself. I went 12.1 @ 210 lbs on a bone stock 73 z1 in 73. Not a world beater now but pretty stout then