Yoshimura R&D Superbike

No Mark my pressure cast pistons are three ring pistons.
Mark

OldSchoolZ wrote: In regards to high rpm. I rode a Z1R years ago that was lightly bored and mostly stock minus valve spring, retainers ad valves. It had huge cams in it. Even the valve cover was grinded for clearance, shim under buscket.
The power came on at 9K and would light up the tire from 9k-13k. It was insane. :woohoo:
3rd gear when power came on simply lit the rear tire up and pulled like a freight train.
How long that motor would last, might be a different story though. :laugh:
I can more specifics on that motor is anyone wants them.
I'm stiil in touch with Jay in Houston. He owns JB Cycles and does a lot of turbo work and insane modding.
His goof around bike is an 86 GSXR1100 fuel injected.

I wouldnt run my bike at 13k. That poor bike. I keep my limiter set round 9,700, Just because i want to be a little lower than what i consider max rpms for me.

mtb, that piston you posted looks already a much better proposition

and guys, just like with speedos, dont believe everything that your tacho shows :ohmy:

show me dyno curves with RPM's numbers on the bottom

I'll be happy to see the dyno chart of a fast road/track (not drag) 900-1000 motor that peaks after 10K

Larry, have you ever seen one?

BTW, my worry wouldnt be pistons coming apart, but running two rings / very high domes.

My 750/810, being a big bore is bound to peak at lower rpm than a 716. do you have a dyno chart showing peak hp @ 10.5 or is it feel of the pants?. its got andrews #35 cams BTW.

I am pretty sure that there are plenty of huge valved drag motors that can peak higher for 10 seconds, but not quite relevant for MTB's fast road track intentions.

I am sure people do run there bikes and make power above 10k. But If your that worried about revving that high and possibly doing damage a expensive built motor, wouldnt be smarter to buy diffrent cams to move the powerband down some? So the motor isnt tached so high, Talking street riding, not dragracing at the strip.

if u dont plan on racing, then a bigger bore is in order. it will help u take advantage of newer flatslides, that r only available in larger bore sizes. keep the compresion at 10.25:1 and it will be much more user freindly. pump gas is easy to find, and u will need a refill every hour and a half(100 miles).

I really appreciate all of the feedback, but I don't want to go the big-bore/low-end torque/stump-pulling cams route; that's not "true" to the bike. If I were making a street bike, I'd most certainly be going that route, but that's now what I have in mind for this build. This is NOT a regularly driven street bike.

I'm also not worried about damaging anything at high RPMs because I will have built the engine to run at high RPMs. If I'm willing to spend two grand on crank work (emphasis on WORK, I don't even get a new crank out of the deal) and rods, don't you think I will have put an appropriate amount of time into properly researching my valvetrain, modifying oil passages/pump, and setting up piston/valve clearance? Additionally, I'd be running an electronic tach, not a mechanical tach; with a Dyna2000, which has a limiter on it.

The Yosh pistons I have are 10.8:1 compression, so it's fine to run premium spiked with additives, especially considering it's not going to be frequently used.

I also completely understand the warnings regarding the 2 piston rings, but why is a high piston dome an issue? Other than valve clearance and compression of course.

If you don't mind me asking Mark, how many times a month are you out on your KZ [it's an 1197, no?]? What compression are you running? Do you have 93 octane up there, or just 91?

How many other of you have bikes with extensive engine work that you ride? How frequently do you ride? I have a stock 903 that I ride everyday, when/if I do any engine work to it, it will be minimal as I don't want to lose ANY streetability.

turboguzzi wrote: and guys, just like with speedos, dont believe everything that your tacho shows :ohmy:

That reminded me, I've been meaning to hook up my cable to an electric drill and get creative with photoshop.

I'm headed out of town this weekend, but I wanted to get this article uploaded so you can check it out. Hope you enjoy!

MMS_0920 by mmsmithgall , on Flickr

MMS_0921 by mmsmithgall , on Flickr

MMS_0922 by mmsmithgall , on Flickr

MMS_0923 by mmsmithgall , on Flickr

"but why is a high piston dome an issue? "

Pretty old school, no detonation preventing squish band.

If i was you, i'd rather take "Cycle" mag's story on Muzzy's work on the 1000 (and 750 too) as a reference..... with all due respect to Art Friedman, he was never too technical, Kevin Cameron was way better in explaining Muzzy's tunning approach in detail.

info might not be exactly period for the bike by a 2-3 years but muzzy deployed much more advanced tuning techniques to the kawi fours.

turboguzzi wrote: If i was you, i'd rather take "Cycle" mag's story on Muzzy's work on the 1000 (and 750 too) as a reference..... with all due respect to Art Friedman, he was never too technical, Kevin Cameron was way better in explaining Muzzy's tunning approach in detail.

info might not be exactly period for the bike by a 2-3 years but muzzy deployed much more advanced tuning techniques to the kawi fours.

I did a quick search but was unable to find that article, any chance you have it or could give a little bit more information so I can hopefully look it up?

Thanks!

turboguzzi wrote: "but why is a high piston dome an issue? "

Pretty old school, no detonation preventing squish band.

If i was you, i'd rather take "Cycle" mag's story on Muzzy's work on the 1000 (and 750 too) as a reference..... with all due respect to Art Friedman, he was never too technical, Kevin Cameron was way better in explaining Muzzy's tunning approach in detail.

info might not be exactly period for the bike by a 2-3 years but muzzy deployed much more advanced tuning techniques to the kawi fours.

Flatter piston dome promotes better flame travel/easier combustion