Current wisdom on 84/85 VF500 forks required

Hi folks. I searched the forums and didn't come to a conclusion, so maybe someone (Jamie D?) can advise what to do with my VF500 forks.

The problem I have is that they bottom out too easily under brakes. I measured the spring rate of the springs currently fitted and they seem to be a lot softer than the RaceTech listed standard rate. Mine measure about .4kg/mm where the RT spring rate is listed at 0.61. I'd even consider going harder than this if it's likely to help things.

Would cartridge emulators help with bottoming out without stiffer springs? Would they be necessary, or just nicer with stiffer springs? I presume (could be wrong) that I'd need heavier fork oil with stiffer springs too.

Very important to me; how much does this lot cost to do and what's a good source for the parts required?

 

First and foremost you need to get the spring rate correct. This is based on combined bike/rider weight, and to some extent riding style. After that, you select the proper damping to meet your needs. Usually this would be a revalve, but since these are damping rod forks then the emulators are your best bet. Oil choice affects damping as well, but since the emulators are designed with a specific viscosity of oil in mind then the best route to go is with the RT recommended oil. You can fine tune viscosity if adjustments to the emulators don't get you your desired result.

 

Ah, second part....

Figure about $125 for the springs, $170 for emulators, and $30 for oil, + shipping and maybe tax, all from Racetech. Figure several hours labor if you don't do it yourself. I would PM Jamie and see how busy he is right now. He has a different source for springs and could probably pass some savings onto you.

 

As Greg mentions, I wouldn't suggest doing anything with the valving until the springs are correct. I think you'd still find that you have some problems with the front because damping rods are just crummy (to be nice). Emulators are a decent choice if you want something relatively cheap and easy to install. I can also swap over complete cartridges from a newer bike as well. This is major surgery and requires several custom parts so price reflects that. Shoot me a PM, I can get you some good pricing on the parts and service.

 

Oh man, this is springtime! This is by far the busiest time of the year, I'm working 7 days a week just to keep up. It's a challenge, but the kind that I like the most.

 

Anti dive question

Does the anti dive system have any beneficial effect on the VF500? I fiddled with the 4 settings on mine and couldn't tell with a seat of the pants ride test ride. Maybe all I need to do to prevent bottoming under brakes is crank this up to the max?

RaceTech recommends much stiffer springs than I have and recommends straight rate.

 

The TRAC system is pretty bogus - the problem is it actually works. The bogus part is that you don't want it to work! You want a decent amount of fork dive under the brakes to get the weight transferred. Do a stopping distance test and you'll find a surprising difference betwee, #1 and #4 - with #1 being much shorter. Put it on #1 and forget about it.

Yes, straight rate springs are the way to go for performance. This applies to all bikes, in fact. The stock springs are way light, so going up to a considerably higher rate makes a big improvement.

 

So springs it is. Where would I get them and how much should I expect to pay? I'm in Ireland. Shipping stuff here isn't usually a problem, but can be expensive.