FF: Forks Modified Steering Stem

[Little Honda]

Well I took the bike for a good blast today, and the front end felt no better if not worse. So I removed the Icon shocker, pushed up and down on the bars again with no shock absorber and the forks feel great. So I have reinstalled the AVO and just leave it at that, as I think taking more off the springs is definitely not necessary. With the lighter weight of the bike verses a twin, it seems as though it is more sensitive to the restriction of heavy damping............I have an original Armstrong which is much lighter in its action on the rebound, so I might even try that as an experiment. This bike has enough power that the Conway's Honda clutch can barely hold the torque even after I shimmed up the springs...........Does anyone know if stronger ones are available.........?

It might also b caused by mismatching friction and steel materials of the clutch plates, if not oil in a dry clutch.
Possibly a talk to textar or ferrodo people will bring you forward. On Ernst´s Comet racer, I can change gear
full throttle without closing the gas, if in eager. It really jumps forward, even from third to fourth. And it´s
not a Laverda clutch, very light operation!

 

[greg brillus]

I covered about 45 to 50 miles today on the Comet on some pretty rough roads and the bike rides and handles extremely well. I will be leaving all the suspension parts as they are now, no need for further changes. The extra capacity of the 600 top end certainly makes them much more tractable and less gear changing than a stock one. A very nice bike to ride overall..........

 

[macvette]

It's too hot to get leathered (lathered) up so decided to ckeck my front end.
SeriesD, Gregs bearings, 45 lbs springs ( I think), standard damper, long eye bolts, original rear monoshock.
I weigh 191 lbs (no gear). The deflection at the damper, measured from a position of both wheels off the ground to me sitting on the bike is 1ins. Will see how this changes when riding
Mac
Hope this helps

Here's an update, took the bike out around the moor roads in N. Yorks, no bad potholes, plenty of bumps dips and hollows. Max. Compression on the damper 1&1/2 ins which means the damper was moving 1/2 ins with the bike in motion. When I drop the bike off the centrestand, there is barely any compression of the damper and as you can see with me on the bike, not moving, the damper compresses 1 ins which is about 1/3 rd of its travel.
Comments welcome.

 

[BigEd]

Here's an update, took the bike out around the moor roads in N. Yorks, no bad potholes, plenty of bumps dips and hollows. Max. Compression on the damper 1&1/2 ins which means the damper was moving 1/2 ins with the bike in motion. When I drop the bike off the centrestand, there is barely any compression of the damper and as you can see with me on the bike, not moving, the damper compresses 1 ins which is about 1/3 rd of its travel.
Comments welcome.

As a rule of thumb the static sag with the rider sitting on the bike should be approximately 1/3 of the total travel. There is lots of information on the internet for setting up suspension sag. You can adjust the sag by changing the pre-load on the springs by using spacers. Timetraveller gives an example in the fitting instructions of an adjustable spring tube bottom fork that you can make to adjust your pre-load.

 

[macvette]

I have set up suspensions in the past on my modern sports bikes so am familiar with the range into which static sag should fall. The Vincent damper is said to have 3 ins of travel so I think I'm already at the top end of static sag but the lack of movement from no load to having the bike ( no rider) on it's wheels has me concerned.

 

[BigEd]

I have set up suspensions in the past on my modern sports bikes so am familiar with the range into which static sag should fall. The Vincent damper is said to have 3 ins of travel so I think I'm already at the top end of static sag but the lack of movement from no load to having the bike ( no rider) on it's wheels has me concerned.

I lift up the front of the bike so that there is no load on the front wheel and then put a tie wrap on the fork tube. On the Girdraulics you can lift the front and put the tie wrap around the lower fork tube butted up to the top fork tube. When you've carefully sat on it you can lift the front again and measure from the bottom of the top tube to the tie wrap. Not sure what your total travel will be. It is easier to measure when you have the springs out. (You probably don't want to do that again just yet.) Can't tell you how my setup works as it is not fitted yet. I got too involved with other projects.

 

[timetraveller]

I will be back in the UK and available after the Hever rally which I hope to be at. The only internet available does not work if I am more than ten yards from it sp please bear with me. It sounds as though you are also finding the 45 springs too hard. The thing to check is that the bottom link is horizontal, or very
slightly down at the front., when the bike is on its wheels and you are seated. For the moment do not worry about what fraction of the total possible movement you are getting when you sit in it. The cable tie dodge should be showing one and a half inches of movement over normal bumps and up to three inches over potholes.
I cannot check from here what springs you have but it sounds like 45s How Greg can find these suitable in a Comet is beyond me but that is what he is finding. Check either of the two videos available to show you how the front end should behave. Have you shortened both inner and outer spring boxes?

 

[vibrac]

Wow! shortened the inner as well as the outer?

 

[greg brillus]

First question is what damper are you using, and did you use the springs without chopping anything off their length. Cutting an amount off only the upper or lower spring cases will not work on its own, you have to remove same amounts. I have only done this to the Comet I recently carried out this work on. I have found that a stiff damper masks the effect/strength of the springs, so using light springs with a stiff damper gives a very hard ride, and more noticeable on a lighter bike. The opposite is the answer, heavier springs and a soft damper. I have the benefit of having many different types of damper and springs to choose from to set up a bike to what I feel is best, so with the Comet I did last week, I did just that. I have not done a bike yet that I have not had to chop some of the spring off, If you compress the springs as they are on both sides, you will find the suspension "Topped out" and you cannot push down on the bars.........Too much pre-load, you should be able to push down on the bars with the front brake on and compress the forks by some amount. If you can't do this then something is wrong. Either too much pre-load, too stiff a damper or too much friction somewhere, usually in the spring cases that are grabbing from dirt or dents in the tubes. To check if it is the damper, simply remove it (takes no time at all) with the bike on its wheels, then push down on the bars to "Feel" how it is just on the springs alone.............this is your suspension how it should be........Not masked by a stiff damper...........The damper is there to absorb the bumps and keep the wheel/tire in constant contact with the road, it is not there to support the weight of the bike.

 

[macvette]

I have checked these measurements from a starting point of the front wheel off the ground. When the bike is dropped off the centre stand, the front compresses and settles at 0 damper deflection. With the front brake on, I can easily bounce the front which was not the case before mods. When I sit on the bike and bounce it, the damper defection settles at 1 ins( 1/3 of travel), carrying my weight. Riding increases the damper deflection to a total of 1&1/2 ins ( 1/2 of travel). Vincent damper, Greg bearings, long eye bolts, standard length 45 lb springs and spring boxes. The fact that there is no damper deflection under only the weight of the bike suggests to me either too much preload or springs that are too stiff.