FF: Forks Modified Steering Stem

[davidd]

I should have mentioned this in my post in 1025, above. You do not have to cut the springs to shorten them. I have mentioned this before, but it is worth mentioning again.

When you are attempting to tune your suspension it is often difficult to find the compromise between spring length and spring rate. Cutting the spring will take care of one, but not the other. You can install a spring limiter of some type to shorten the spring and not change the rate. This will change the preload, but not the rate.
Here is what I have used to test springs:

It gets more difficult as the tension rises and you will have to find a way to compress the spring to adjust the nut in the tube tighter, but once you get the ride height you want you can make a determination if the spring rate is correct for the ride you want.

David

 

[Chris Launders]

Greg, what was your last post in relation to ?
Chris.

 

[greg brillus]

Your friends Comet..........I used a pair of 45 lb springs with 25 mm cut off each spring and an original Armstrong damper which was very soft in its action. I also tried a Thornton shocker which worked very well, but as it is mine and they are now becoming unavailable, I am not prepared to part with it. The simplest test I can tell all of you to try on your bikes with this mod............Ride it down a slight down hill section with the engine off, (not running) get up to some speed, say 30 plus KPH and hit the brakes and see how the front behaves. With a soft shock absorber, if the springs are too weak, the front will bottom quite easily. If you have weak springs and a strong acting shock absorber the front end will feel quite rigid, most likely not bottom .............This is not the springs but the shocker absorbing the forward load, this is not correct, and the front end will feel too stiff. The reason it is good to do this test with the engine not running is you can more easily hear and feel what is going on without any clatter from the engine.

 

[Bill Thomas]

While we are talking about shortening springs, shorten carefully and take off small amounts until you get the required length. You can't put it back on. Shortening a spring increases the spring rate i.e. it will take more force to move the same distance. In this instance, we are removing relatively small amounts so the rate will not increase much. If you shorten a spring too much you may be able to correct the height with spacers but bear in mind that removing coils limits the amount a spring can compress before it becomes coil bound. As a rough check, measure the gap between two coils and multiply by the number of gaps to get a ballpark figure for how much the spring can compress. May not be a problem here but maybe worth checking.

Why can't you put the bit you cut off, Back in ?, Bodger Bill.

 

[BigEd]

Why can't you put the bit you cut off, Back in ?, Bodger Bill.

Can't think of a good reason except the bit you put back in would probably screw down into the rest of the spring. Maybe a washer between the two parts would stop this. (Bodger Ed.)

 

[Bill Thomas]

Can't think of a good reason except the bit you put back in would probably screw down into the rest of the spring. Maybe a washer between the two parts would stop this. (Bodger Ed.)

No, I would put the finished end to the cut end, Have been bodging for a long time !. Bill.

 

[Nulli Secundus]

The reason it is good to do this test with the engine not running is you can more easily hear and feel what is going on without any clatter from the engine.

I think it will also eliminate torque reaction from the engine having an influence on the forks.

 

[Chris Launders]

Hi Greg, I think my friend has the 36lb springs but I'm not sure, and the bearing type AVO, having tried it it's much the same as my twin but possibly fractionally stiffer as the damper has less weight to control. I liked the Armstrong damper when doing the damper testing but as you say they don't make them any more, the original AVO (for the standard set up) gives virtually no control when used with your bearing conversion that's why there's a special AVO to go with it. I had just wondered if there would be enough damping in a standard type AVO for a single with the bearing conversion but he says there isn't.
Chris.

 

[BigEd]

No, I would put the finished end to the cut end, Have been bodging for a long time !. Bill.

Good. The best bodges are the simplest ones.

 

[greg brillus]

I guess the main issue i'm trying to arrive at is that you should be mindful that whatever shock absorber you use, that it does not mask the ability of the springs. That is, that it is the job of the springs to absorb the weight of the machine not the shock absorber. My findings on this Comet were that a stiff shock absorber tended to mask the springs and the front end felt very stiff even though in the end the springs I had in there were actually too weak. The best way is to experiment with what you have between springs and shockers. In the end I have found that a Comet is softer in the front end due to its lighter weight. I feel I could still soften the front in my Rapide, but I would need to shorten the spring cases as Norman has suggested .........I must admit that I have tried to avoid this, and have only done it to this Comet thus far.