Racing my 650 hot street bike

GPzEric wrote: If there were no engine restrictions, I'd find a wrecked '83 GPz750 and build it with an 810 Kit !

Sounds like you're having a lot of fun.

well, the white bike in the pic started life exactly like that.... a 200 euro wreck the guy was happy to get rid off..... and ended up with an 810 kit (and much more) in the open class

leitz wrote: Thanks to all and sorry for my poor english.
Tg: the tire i want to fit is z1r 2.15 18"
19" stock gets more tire on asphalt so more grip than 18" due to the bigger diameter. If i fit 90/90 18 will get less grip ( and better steering) than stock 90/90 19".
So maybe z1r wheel is not the best option if i can't fit 100/80 18 tire (better grip and steering)
Am i right?

in vintage racing many times you have to accept "not the best option" because of time, money, whatever.... if you have money to throw, you can get anything:

www.marvic.it/en/prodotto/vintage-morris/

www.pvm.de/en/wheels/forged-5-spoke-neo-classic-front-wheel/

so if you have already that Z1 rim, definitely try using, it, even with a 100 tire

if you see it limits you, then you'll need to go wider. if you are like me, not that much money for stuff, you will need to adapt a wheel from some other road bike, the brake discs, etc. for example, honda vf750 is 2.50 X 18, Honda ST1100 3.00 X 18 etc.

Nice wheels but expensive!!
Now i'm trying to make a race seat without cutting the frame

I really love the look of my stock flat seat but am thinking of building a step into it to hold my skinny butt in place...... I Armor all it often and if not careful I was about kicked off it more than a few times....... once a few years back has my heart pumping thinking about it. :laugh:

Not easy to make a cool race seat without cutting the rear of the frame

the honda 2.50 x 18 and 3.00 X 18 rims i bought from ebay where around 80 euros each..... I am not using the 2.50, in case you want it, you will need discs and make caliper adapters, but it will be a much better braking system than your 260mm with the 295mm honda brakes

nice seat shape but have you ever produced pieces in fiberglass? not easy to achieve a good, solid result, not to mention the mess in the workshop.... and the time that you could spend on more important stuff...

for 60-70 euros I would pick one of these.....

www.polyalu76.fr/coque-de-selle-cafe-racer-28-c.asp

just the investment in materials to first make the molds and then the seat itself will cost you more.

That said, I raced my gpz750/810, a bike with 90 rwhp with the stock seat for five seasons, it was never a problem.

KZB2 650 wrote: I really love the look of my stock flat seat but am thinking of building a step into it to hold my skinny butt in place...... I Armor all it often and if not careful I was about kicked off it more than a few times....... once a few years back has my heart pumping thinking about it. :laugh:

Bad idea for obvious reasons. :laugh: :laugh: :laugh: Ed

It takes me few hours to do it. I'm sculptor and work with clay and resins all day.
I love that japanese style seat that sell them for 900 and kz1000. For my bike need to be shorter
Probably i'll make a mold to sell some ready to bolt on in the 650's
Which honda model is your wheel?

good to know, will order some fiberglass parts from you
and I could tell from the clay model that you know how to sculpt

I am an industrial designer, very handy with prototyping but i just hate fiberglass work inside my small workshop, specially when there are open engines around... need a another room for it.

The 2.50 X 18 rim is off a VF750.

leitz wrote: It takes me few hours to do it. I'm sculptor and work with clay and resins all day.
I love that japanese style seat that sell them for 900 and kz1000. For my bike need to be shorter
Probably i'll make a mold to sell some ready to bolt on in the 650's
Which honda model is your wheel?

seat looks great. when i first saw it i thought of the Bulldock seats. nice work.

Thanks for the compliments guys.
With racing numbers on the seat step and painted tank with racing stripes bike would be amanzing.
Today a non experienced racer friend who uses avons said me he usually buys little used avons from a good friend of him who is a racer and can get me both tyres for 100 euros!!!
Not the best option for the front like you said Tg but it gives me the chance to check them on early may at track with no more modifications. No more time/money to spend on the bike for that date. Anyway thanks for your offer, maybe later...