FZRSupport: the FZROnline Archive

Hybrid Question,
We all like the FZR because of it's handling, so I assume its a well balanced bike. So sticking the 600 engine into the 400 frame will change this balance by adding more weight to the front, correct me if I am wrong. A) So that would be the best way of first measuring the bike balance point? B) Once the 600 engine is bolted in, the best way to restore the bikes balance?

Thanks

Don't think I've ever heard that question before. I also don't think swapping the motor will disturb the balance that much. The 400 frameis lighter and a bit stronger than the steel 600 counterpart. That being said, I don't have a 4/600 hybrid to do any comparisons with.

buzzawak wrote: A) So that would be the best way of first measuring the bike balance point? B) Once the 600 engine is bolted in, the best way to restore the bikes balance?

A: The weight distribution is relatively at the same point within the 400 frame, it is simply heavier with the 600 motor. IIRC, the FZR400/600 (US) engines take up very similar space. Even the YZF600 (US) engine wasn't much larger.

B: I'm not certain why you are even concerned about the balance unless you intend on racing the bike. In that case, I would have a suspension expert work on your balance between the forks and rear shock. You could always put an upgraded set of forks, such as YZF600, on the front.

I'm not even positive that the 600 motor is heavier than the 400. Same cases, cylinder blocks, gearbox...

600 = More aluminum (pistons larger), less steel(cylinder liners thinner)....this may be offset by the longer crank throws.

I'd like to know what exactly the weight difference is.

As far as the balance point question:

Bathroom scale under each tire

If you intend to do this swap then I suggest you refer to Tony Foale's excellent book "chassis design" which covers the subject of C of G and forward / rear weight distribution rake & trail etc in some detail and is a must if you wish the bike to handle well for racing etc.

I do believe that had you looked this is covered in the WIKI recommended book section.