Thanks Tracy. Just the kind of information needed. Let us know what the YouTube title is so that we can look for it.
FF: Forks Modified Steering Stem
- Thread starter greg brillus
- Start date
The 36 pound springs are too weak for a twin, it is the shock absorber that is taking the load, if you remove the shock absorber you will see how easy it is to push the forks up and down. Everyone's thoughts indicate all is well, but the front end is still being inhibited by the shocker. My opinion about this mod with the bearing upgrade is that you need stronger springs than you think, but with less pre-load and a softer shock absorber. Every bike I have done, I have had to chop the springs shorter, or else the front end is "Topped out" regardless of whatever shock absorber you use, and I have always used the longer eye bolts. This Comet I have done now has a pair of the 45 lb springs with 25 mm cut off both, and for now an old original Armstrong shock absorber to allow a softer ride. If a strong shocker is fitted this really stiffens up the fork action, and this has nothing to do with the load carrying capacity of the springs......That is something that needs to be sorted out first, or else the front end will bottom quite easily, even if the cases are shortened. This is almost the same set up I've got on my Rapide except I have a Thornton shocker up front...........I tried a softer spring and found it would bottom out under hard braking..............Just what I have found.............
.
.The reason that I think that this might not be the whole story is the way that the forks deflect over very small bumps in the road. If anyone cares to go back and look at Chris Launder's video you will see how just pulling away or breaking slightly or even very small road irregularities causes the forks to deflect and then recover their position quickly. If the damping was too stiff it seems to me that this would not happen. However, I am open to being convinced otherwise. I understand from Tracy that their video shows similar behaviour so let us see what we think. There is absolutely no problem supplying stronger springs but twin owners with 45 springs are asking for 36s to replace the stronger springs. When Chris was doing the test riding as soon as he changed to bearings at the rear of the lower link we had to go to a stiffer damper. We did try a rear AVO but that was much too stiff and so we ended up with one which is stiffer than the standard front AVO but softer than the rear. I'm sure that there is a consensus in there somewhere.
Can I point out here that Tracey's Chris is about half my weight and I think would certainly need softer springs, him on a twin would be about the same as me on a Comet !!
Don't forget on a B/C the passenger and luggage weight is carried almost entirely by the rear.
He could also try one 36 lb and one 45 lb spring just to see.
I had occasion to do 60 miles on mine the other week without the damper and although a bit livelier it wasn't radically different, ok I wasn't pushing it just a steady run out but to me it says I have it about right for me.
Chris Launders.
Don't forget on a B/C the passenger and luggage weight is carried almost entirely by the rear.
He could also try one 36 lb and one 45 lb spring just to see.
I had occasion to do 60 miles on mine the other week without the damper and although a bit livelier it wasn't radically different, ok I wasn't pushing it just a steady run out but to me it says I have it about right for me.
Chris Launders.
Probably but without proving it by doing an actual check with a softer damper you can't be sure. Have you got an old Armstrong damper for instance that you could stick on? I know you have shelved the Comet for the time being but it wouldn't be a huge job to try a different damper and it would at least be something else you have tried to get to the bottom of the "too stiff" problem.
Chris makes a most valid point here that it is difficult to compare like with like unless you know the loaded weight. Load weight can be so different due to many factors, e.g. rider weight, no passenger, passenger/passenger weight, luggage, etc.
I agree with BigEd here. An old Armstrong damper, I have one you can borrow if you do not have one, would immediately show whether it is the damper which is the problem or not. Even an old Vincent damper would be useful for a quick test. Neither is as sophisticated as a modern damper but would do for a test.
What intrigues me is that Chris and Tracy, two up with a lot of luggage on a twin, find 36 springs preferable to 45s and yet Greg finds the opposite and even has 45s on a Comet. Removing an inch is only altering the pre-load, which gets the lower link to the correct angle as a starter, but then I would have predicted would be much too resistant to movement over bumps.
What intrigues me is that Chris and Tracy, two up with a lot of luggage on a twin, find 36 springs preferable to 45s and yet Greg finds the opposite and even has 45s on a Comet. Removing an inch is only altering the pre-load, which gets the lower link to the correct angle as a starter, but then I would have predicted would be much too resistant to movement over bumps.
I think the standard length spring boxes are causing some problems sometimes, I know I was right on the limits with mine when doing the spring testing so shortened them early on. Greg may think it's the damper bottoming out but it might be the spring boxes.
Chris.
Chris.
All you really need to do is temporarily remove the shocker which takes only a couple of minutes, and you can push the bars up and down with no resistance from the shocker. The only reason I was suspect of things was how stiff the front end of this Comet was when riding and this felt so wrong after all the others I have done. There is a definite limit to how soft you can go or else it will certainly bottom, especially with good brakes and going down a hill.............My drive way is about 70 meters long and slightly down hill, I can test a bike just by rolling with the engine off in neutral, get up some speed and hit the brakes.