Making a Kawasaki Z1 race ready. Again

Thanks for posting the article!

Welcome! Now we're getting into to the zone! Giant ports? What's the engine displacement, carb size?

Racecrafters wrote: Welcome! Now we're getting into to the zone! Giant ports? What's the engine displacement, carb size?

From the article:
Valves are 39mm intake/32mm exhaust
Pistons are 70mm (1015cc minus compression space consumed at 14.5:1).
Carbs are Mikuni VM33's with 29mm restrictor plates.

DoubleDub wrote:

mark1122 wrote: Nice job on the main support plate. very simple and effective. B

Another novice question, what is the failure/flaw the main support plate upgrade is there to help with?

Engine cases crack after about 6 races. High stress from 125+RWHP and abusive riding cause the cases to flex, then crack. The gusset system ties together the center main bearing support, the upper engine case and lower case. In the middle of the engine, the 2 engine cases are independent on the stocker. After this mod...zero engine case failures after 3 seasons

how do u get in there to drill the case supports?
i have seen some pretty elaborate suports in there.





heres another

Underneath the plate you see, there's a block of billet aluminum that extends down to crank cap which bolts on to the four inner studs. This piece ties the cap and upper case with the lower case. The plate on top ties the billet piece to the lower case. There is also a shim kit in between the plate and billet piece that can be used to adjust to the variance between sets of cases (i.e. the unit can be transferred from one set of cases to another if need be).

"how do u get in there to drill the case supports? "....
Well it sure as hell wasn't accomplished with Harbor Freight tools.... :pinch: :laugh:

Damn I just LUV these images of you guys that can do this type of work, coolness at it best.
RSling, Leon, Irishwill, Testarossa etc....

Keep them images coming no doubt...

u mean i cant use my grinder and Drumel ? :laugh:

hi arthur

never worked on a 1000 so had no idea about this mod

do you know if the smaller 650-750 block should be similary protected to avoid trouble?

they might be more safe as the plain bering crank has dowels in all the cases bearing housing holes

had on my 750/810 just 4 races this season, so far so good, but would be interested to know if you ever saw similar trouble with 650-750's

tnxs

turboguzzi wrote: hi arthur

never worked on a 1000 so had no idea about this mod

do you know if the smaller 650-750 block should be similary protected to avoid trouble?

they might be more safe as the plain bering crank has dowels in all the cases bearing housing holes

had on my 750/810 just 4 races this season, so far so good, but would be interested to know if you ever saw similar trouble with 650-750's

tnxs

u may want to run that question by our member, Injected. he dragraces a high compresion, alcohol kz650.

I've never seen the cases braced like that before, it makes sense to me! I'm slowly accumulating the stuff I need for a "go-fast" Z1, those are a great few pics to save for future reference.

Mark, the "block of billet aluminum" with the shims, where'd you find that? I'm definitely interested in hearing more about it if you can provide any more details.

turboguzzi wrote: hi arthur

never worked on a 1000 so had no idea about this mod

do you know if the smaller 650-750 block should be similary protected to avoid trouble?

they might be more safe as the plain bering crank has dowels in all the cases bearing housing holes

had on my 750/810 just 4 races this season, so far so good, but would be interested to know if you ever saw similar trouble with 650-750's

tnxs

Also interested, although I won't be making nearly that amount of power

its not needed on the street. the 1 thing u need to watch out for though, is the output shaft. when u put a 5/8" or longer offset sprocket on and head to the drag strip.u should use a suport bearing and plate in that case.
unless u are using a big tire. or hammering it on every corner of a rd race track u will be fine with out case bracing. most drag bikes with small tires live a long life without bracing.the tire spins up and takes the load off.
i and many others run kz1200's on the street without.

i think Arthur has the right idea.quick and simple. if u can do it without alot of machining and expence it makes more sence.in his case , he has found it to be very nessasary.

the problem is the braces(case webbing) are not flat, they are thicker at 1 end than the other, so most fixes ive seen, involve machining them flat first, so they are 90* to the main cap.

the guy the made the second one , made a few, and there was no demand so he stopped. i can put u in touch with the guys though if u want to order 1 up. but since they are 1 off, u may fair better localy? they build top fuel bikes, and hange at dragbikes.com