www.zxrworld.co.uk

No, not 250, been there, done that started my racing career on an Aprilia RS250, great bike, can carry sooo much corner speed

I'm no suspension expert, but am trying to learn and understand the basics. Yes, less offset gives you more trail, therefore will slow the steering down. You can compensate by dropping the front and raising the rear, but this is where I don't know how to work out what making those changes does to the geometry. Also, by doing that, it changes other things too, like weight distribution, squat, etc, but again, that would be lost on me. On my race bike I dropped the front by 15mm and raised the rear as far as it would go on the top zxr adjuster and then another approx 15mm on the bottom of the Ohlins, so in total something like 30mm at the shock, which works out a lot more at the rear axle. So using yokes with less offset will negate some of what I was trying to acheive.

PS, don't try this at home, you will have clearance problems to the rad, stability problems on bumpy roads and you would definitely need a steering damper.

a larger amount of trail is more than slower steering though, with high amounts of trail a bike will want to continue onwards in a straight line rather than steer when at speed. It will be more adversely affected by bumps and grooves. Once turned in the effect that was making it want to continue going straight becomes the opposite and will steer itself, high amounts of trail(like a ) would cause the bike at this point to steer the front wheel until it locks and you fall off.

lowering the amount of trail reduces the effects of these two forces, but to maintain stability under braking some trail is needed to cope with the weight transfer and geometry change of a compressed fork.

a bike would steer fastest while maintaining stability with a zero degree rake, but braking would obviously be a problem as the forces would be trying to bend the forks backwards, so a small amount of trail is needed to cope with the slight change of rake angle while the forks are compressed. very low amounts of trail also, while being ideal for corners are unstable at very high speeds.

wheelbase, ride height and weight distribution, as you said play a large part, but concerning forks themselves i think this is mostly it off the top of my head.

I know this is an old thread but I thought I'd share my experience of doing this conversion.
So, zxr400L and 2005 zx10r forks.
I have used the standard zxr top and bottom yokes, but had the lower yoke machined out 2mm to allow for the wider legs on the zx10r forks. Forks are 25mm through the top yoke.
I have used the zx10r front wheel and brakes.
I have replaced the zxr clocks with an aftermarket digital set that gets its signal from a magnet attached to the brake disc.
The bike is now very stiff, fine for the track but may be a little to much for the road.

I also have the zx10r rear wheel fitted into the zxr400 swinging arm.

Hello matey, thanks for the info. So front end is basic enough. Just need to get the bottom yoke done.

As for the rear wheel care to explain what's needed?

Many thanks ben