Yoshimura R&D Superbike

LarryC wrote: Why do you think you need hollow cams?

If I'm getting a Falicon Ultra-lite Supercrank paired to the 1 piece Knife con-rods and [possibly, I know it's a hot topic right now] slipper pistons, a set of hollow cams will complete them and vastly reduce the weight being thrown around inside the engine.

mark1122 wrote: its sad to say, but these bikes, even built to 1200cc's, still dont have the power of a modern 600 sport bike. and unless u do the work to get massive ground clearance, u they get smoked in the corners by a 125.
my pals little ninja500 smokes my kz in the corners, because my cases hit.

i would love to follow a high end Yosh build thread, but i would also hate to see u spend all of that money and get no performance gain for the effort.

i sure would love to see this evolve into something that looked like a vinage racer, or a Sanctuary bike look.

this is just my opinion, please dont be offended by it.

No worries Mark! If I didn't want people's opinions, I certainly would not have started this thread.

Seriously though, I know full well that I can go get a used R6 for 8k and lay down 125 hp. I'd rather put 8k into a bike that is MINE and only mine. A friend is building a v-twin motor that will have 140 hp and 200 ft/lbs, he's spending 8 grand on the motor alone! Why do we do it? To make something unique, to spend years building it properly, so when someone asks what is it, you can give them the exact answer down to the size bolts you used. That R6, with it's 17,500 RPM redline and fetal position ergos, is a bitch to ride on the streets. A properly built Z1 with rearsets and superbike bars, as well as a rider who didn't just march in to the closest powersports store and plop down 10 grand, will beat the R6 stoplight to stoplight, at the drags, and potentially on the track.

I'm just trying something different, that's all. If I was completely power hungry, I'd slap a turbo on. That will be a different build, this one is to make something that no one has seen before (or at least since 1977). The right combination of frame bracing, suspension tuning, brakes, engine, and ergos that's leans a little bit more towards the track than the street.

Did you give DutchZ this much shit on his build?

LarryC wrote: You need hollow cams like you need another testicle.

I could always use a 3rd testicle.

mark1122 wrote: i have a pic of lange hindel racing down a straight. it looks like his bike is JACKED UP BIG TIME.

Post it!!!

In my grand scheme, I'll have 6 Z1s and KZs: a showroom floor restored '73 Z1, my Dad's period correct '74 Z1A, this '75 Z1B vintage superbike, my daily driver '76, a '77 KZ built up with Brembo/Ohlins/Marchesini Sanctuary/BullDock-style, and a '78 big-block turbo drag bike.

And no wife and kids because no one will want to date/marry me, but all I'd have to do is fire up the engines and they'd keep me warm at night. :side:

So I do have aspirations for a Sanctuary-type build, but I'm not ready to tackle that yet.

mark1122 wrote:

wireman wrote: If Im gonna spend that kind of time/money building a bike Im gonna take on anything/everything that comes my way,and when I lose to a little ol 600 at the track Im gonna be really pissed! :sick: :woohoo:
Thats why I race in a straight line ! :woohoo:

straight line racing does help even the field a bit. :laugh:

Exactly,all I have to do is light the fuse and try and keep it straight for 660' at our little track.
Then try and keep it out of the sand then the bean field after the shut down area! :woohoo:

It's clear that you're not going to settle for anything other than what you have in mind Why not just ship Yosh the motor and let them do you a stage 3?

If it were mine and I wanted a screamer for a nice chassis that behaved good on the street but needed a little shifter flogging from below 6K RPM...here's what I'd build.

J head with 38/32 valves - 105cfm
Cam Motion Z4 - OEM buckets, .004 lash on both cams, 106 centers
1075 J pistons 10.5:1 - Joe Hooper
900 crank, Pearson prepped
33mm CRS Keihins
Vance Pipe with Competition Baffle

But that's just me Nothing exotic or ultra trick / expensive....but it would put lead in your pencil when you twisted it open :side:

here you go

cant think of a better bible

That last page pretty much sums it up for me anyway!

That last page pretty much sums it up for me anyway!

Did you give DutchZ this much shit on his build?

first off, i'm not tring to give u shit. just my opinion of what i would do. second. Dutch didnt spend much on his build, he did it all himself, and he rides it, like it was meant to be.

Just a heads up. u cant build the bike u r talking about for 8 grand.

What do u think u will run for rim size?

Here r some pic's of race bikes with added clearance.



look at the angle of the swingarm on Rueben McMurter's bike.

Thanks Mark, I do appreciate your advice. I hope I don't sound cynical in my past or future replies, I genuinely appreciate [and NEED] advice from folks like you, Larry, wireman, turboguzzi, etc., I have a dry and/or sarcastic/smartass sense of humor at times. :lol:

I know I can't build this bike, the right way, for 8 grand; everything is a trade off though. A nice crank, set of rods, and cams are justified way of spending $3,500; that Dormei/Yosh 4-4 superbike replica exhaust system is not a justified way of spending $3,500 at this point. Who knows what'll happen when I win the lottery next week.

Regarding rim size, the Yosh race bikes ran the standard 19"/18" combination, in cast magnesium of course. Since I can't find any cast magnesium wheels and likely couldn't afford them even if I knew where a dozen sets were, I'm planning on using the standard mag wheels.

Though, I'm very strongly considering using a stock front Z1R 18" wheel, but that won't be true to form. Additionally, I just got off the horn with Kosman, I'm considering getting a rear wheel widened so I can fit a 140-150 rear in it.


All this being said, I'm heading to Norway on Sunday for three weeks. I'm disconnecting work email from my phone and won't be bringing a laptop - this will be my first TRUE vacation, I am very much looking forward to it!!!

I often find that thing that r written r taken in the wrong context.
Knowing more details of your intent, make it more clear.
I have seen way too many projects go unfinished do to lack of funds, and as time goes on, ambitions and priorities change.
I would like to encourage u to place more emphasis on building that killer frame and body, first. Get it running with a pretty looking, stockish, motor. Make it a running work in progress, so to speek. Then use it and enjoy it, as u save and build this enviable motor.

i sold my close ratio tranny to a racer in florida 2 years ago. i found that it wasnt too street friendly. it has a tall 1st gear so burnouts and drag launches were out of the question. it reved so quick with a z1 crank that i bent the valves.
1 of these would be a great addition for the build u have in mind though.


u may want to do a thorough check up, on what size your rubber is available for your needs, before committing to a rim size.

Have a great holiday, and don’t stay out of the red lt district.

mark1122 wrote: I would like to encourage u to place more emphasis on building that killer frame and body, first. Get it running with a pretty looking, stockish, motor. Make it a running work in progress, so to speek. Then use it and enjoy it, as u save and build this enviable motor.

i sold my close ratio tranny to a racer in florida 2 years ago. i found that it wasnt too street friendly. it has a tall 1st gear so burnouts and drag launches were out of the question. it reved so quick with a z1 crank that i bent the valves.
1 of these would be a great addition for the build u have in mind though.

Yes sir!

mtbspeedfreak wrote: I'm looking into a Falicon crank and rods - haven't initiated any conversations just yet though. My plans are to get the frame, suspension, and brakes sorted out before working on the engine. The engine will be the largest money vacuum of my life thus far, so that's better off waiting until I have a clearer idea.

Also, forgot to ask this earlier: does anyone make a 17" old school mag wheel? The standard Morris "mags" were 19/16 and the Enkei "mags" were 19/18 or 19/16. Enkei did make an 18/18 combination for Z1Rs and KZ Police bikes, I believe the police wheels were a tad wider.