F2 Fork Conversion Question-Length Issue

Hello,

I'm in the midst of doing a fork conversion on my '87 VFR700. I'm combining F2 lowers with F3 uppers (tubes). So far everything fits together nicely, except I observed that the F2/3 forks are about 50mm SHORTER than my old VFR forks. Isn't that going to cause some issues? This is a popular conversion so I'm surprised more haven't said anything about this aspect of it. I know this would cause the bike to handle differently, but would it become twitchy or unstable in any way? Will it tend to sit or look funny with these shorter forks?

BTW, what weight oil should I run in these? I have Race Tech springs for it, spec'd for the VFR weight. They are considerably beefier than the stock F3 springs, and are constant rate. I hope they aren't too stiff!

Thank you,

Rick

 

I'm not sure about the first part of your post but I think most Race Tech set ups go with 10 weight as a starting point. Every time I have upgraded my springs on both dirt and street bikes the after market springs are both thicker in wire diameter and many more wraps for a given length. But I am a fly weight (130) so my dirt springs are always softer than stock. I think you'll be happy with the upgrade...

 

More info can be found here:

http://vfrworld.com/forums/1st-2nd-generation-1983-1989/35930-cbr600f2-forks-91-93-versus-94-a.html#post326288

 

If you are changing to the F2 wheels as well, I think it all balances out in the end. You'll be getting a 17" front wheel from the stock 16 and a 17" rear from the stock 18. It opens you up to put much better shoes on that baby. I did the conversion years ago and would never consider going back. Throw those stock wheels and forks in the dumpster.

 

Thank you for the replies...Even with the wheel change I'm still losing significant fork length. To make sure I'm understanding everything correctly, I still mount the clip-ons on TOP of the upper triple, yes? I have early 90's VFR items for that. I guess I'll just proceed and see what I get....It'll be a few weeks though, as I'm waiting on new slider bushings and haven't decided what to do about the rear brake yet.

Rick

 

Encountered the same issue on my work in-progress 41mm fork upgrade (for a VF500F). I decided on YZF600R forks as their length is very close to stock. The actual fork tube diameter is identical to the CBR so you can use the CBR F2/F3 triple (which is much lighter than the YZF's). Not sure if this is of help on your project but thought I would mention.

 

Yes you still mount on top of your Triple. I'll try to post a pic of my brake set-up. I just took my wheel and swing arm to a machinist and told him to fabricate my caliper brace.