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Discussion Starter · #1 ·
Hi to all, I'm new to this site but have been on 2 wheels for almost 50 years now and enjoy building bikes almost as much as riding them, hence my question ; Can anybody tell me the dimensions of the headstock for a 1992 Kawasaki ZZR250, the specific dimensions i need are the outside diameter of the headstock tube and the length between the top and bottom faces?
Thanks
 

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Isn't it the dimension of the bearings and the distance between them that really matters? :unsure:
It's going to need to take somebody from Europe or Japan to answer your question, they didn't export that model into North America until Y2K and even then only in small quantities.
 

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Discussion Starter · #3 ·
Isn't it the dimension of the bearings and the distance between them that really matters? :unsure:
It's going to need to take somebody from Europe or Japan to answer your question, they didn't export that model into North America until Y2K and even then only in small quantities.
In my case not as I intend to graft the ZZR forks and yolks into a home made frame which will be restricted to a steel tube construction, race regs for the intended class, the internal dimensions i can get from the bearings themselves which are readily available.
 

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The forks are designed to accommodate a range of adjustment appropriate to your bearing pre-load, so it's an approximate measure, the thickness of the steering head stock needs to be appropriate to the material which in this case is mild steel and that will be at minimum 3mm in thickness, your bottom end bearing measures 52mm so I bet the magic number at the bottom is close to being a 58mm steel tube that needs to step down to 54mm at the top and the rest of the steel tubing will be almost as thick ? maybe 2.5mm and gussets will be half as thick at around 1.5mm

Hope that helps, next you need to know the length of the steering stem on the lower triple spoke you are buying, and I imagine that would be somewhere between 15 and 19cm
 

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Discussion Starter · #5 ·
The forks are designed to accommodate a range of adjustment appropriate to your bearing pre-load, so it's an approximate measure, the thickness of the steering head stock needs to be appropriate to the material which in this case is mild steel and that will be at minimum 3mm in thickness, your bottom end bearing measures 52mm so I bet the magic number at the bottom is close to being a 58mm steel tube that needs to step down to 54mm at the top and the rest of the steel tubing will be almost as thick ? maybe 2.5mm and gussets will be half as thick at around 1.5mm

Hope that helps, next you need to know the length of the steering stem on the lower triple spoke you are buying, and I imagine that would be somewhere between 15 and 19cm
thanks for the info, that will be a great help(y)
 

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I sure hope so (y) post pictures some time.

Make destructive test weld pieces of everything before you make a finished product, that's the only way to know if it's going to fly or fracture. Bicycle frame building techniques are worth studying, those guys know how to make tubes connect and what makes them break and where. Best luck with your build.
 

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Discussion Starter · #8 ·
I sure hope so (y) post pictures some time.

Make destructive test weld pieces of everything before you make a finished product, that's the only way to know if it's going to fly or fracture. Bicycle frame building techniques are worth studying, those guys know how to make tubes connect and what makes them break and where. Best luck with your build.
Thanks for the interest, the bike is an old project that I first put together nearly 40 years ago, i've just dragged it out of the shed with the intention of rebuilding/updating it and getting it back on the track, this is what i'm starting with but
Tire Wheel Fuel tank Vehicle Automotive fuel system

there is much work to do..
Tire Wheel Fuel tank Vehicle Automotive fuel system
 

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Thanks for the interest, the bike is an old project that I first put together nearly 40 years ago, i've just dragged it out of the shed with the intention of rebuilding/updating it and getting it back on the track, this is what i'm starting with but View attachment 71888
there is much work to do..
View attachment 71888
um, :unsure: that sure looks a lot more like a Suzuki Titan 500 engine
 

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Discussion Starter · #12 ·
Indeed it is a T500 engine, I refer to it a hybrid as the frame came from a Benelli and the running gear is Yamaha. The rebuild currently has parts from the above plus Aprilia, Guzzi & Kawasaki plus loads of homemade bits. The concept is...
Tire Wheel Fuel tank Vehicle Automotive lighting
Tire Wheel Fuel tank Vehicle Automotive lighting
hub
 

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That seat hump looks like it is going to push you forward a lot, I usually find I need to get my butt back at least to a line straight up from the rear axle.
Why would you need to move your body weight back to At Least the center line of the rear axle for roadracing?
A trick bike set up for doing wheelies yes but a roadracer?

S F
 

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Why would you need to move your body weight back to At Least the center line of the rear axle for roadracing?
A trick bike set up for doing wheelies yes but a roadracer?

S F
Have you ever seen a long tank on a race bike?
Bump stop seat tail section is suited to a long tanker, that tail section is going to be a pain in his ass unless he is one very short in the arms and legs rider.
Suzuki T 500 Daytona 1971.jpg

It's not a matter of somehow using your saddle to do a wheelie, which is impossible by the way, it's about having enough room for your elbows and knees when you are moving around on the bike. Motorcycle racers don't ride the saddle they ride the pegs and if you want to wheelie or race you better be riding the pegs or things are going to go badly.
 

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still waiting to hear what the wheelbase is
or see somebody sitting on it with that suzuki engine with expansion chambers in it (y) that doesn't look like a very big frame, it looks more like a Benelli 125cc motorcycle frame
 

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and if it is and that engine is running real good and the brakes are working real good and the tires are really gripping coming out of a bumpy corner :LOL: Titan power is going to twist that frame like a wet noodle. Even the original Titan frame and suspension wasn't up to that engines potential.
 

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Once upon a time when some manufacturers made road race bikes you could buy. Suzuki was one of them.
About 1973 Yamaha made a 350 and Suzuki made a 500. The Yamaha was more popular, and won Daytona, but the Suzuki was the better bike, IMO. I forget what the models of these bikes are, but they should be easy to find.
Jim Dunn from WA state, and Jim Allen, and others rode these bikes, with much success.
JD had the track record at our local track, and JA was the Canadian number one plate after Duhamel.
Anyway, for seat position, and other stuff, a pic of the original bike would be helpful.
The Titon 500 bike was probably the basis for the road race bike. I used the swing arm and rear wheel on my 68 Norton. We braced the swing arm to reduce flexing. UK
 
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