Comet rear springing too stiff, remedies?

Monkeypants

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Springs can be made less stiff by removing some of the material on the outside of the spring. This can be done quickly and easily on a large stationary belt sander. Slide a piece of tubing inside of the spring and allow the spring to rotate slowly on the tubing as the belt removes material from the outside of the spring.

One of our club members is also a motorcycle shop owner and all round cheap guy. He uses this method to reduce spring stiffness on moden mono shock bikes. He has done this for lighter riders who do not want to purchase an expensive new spring, only to find out they require an even lighter spring.
At some point the spring will become too weak for the job, so some testing is involved. You might try a 5% removal then a refit and tryout.
The easiest way to keep track of the amount removed is to weigh the spring before sanding then again after a small amount of removal.


Note that a small portable belt sander can be used to create the wear marks on sidewall and chamfered gearchange referred to by Vibrac.

Glen
 
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vibrac

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Note that a small portable belt sander can be used to create the wear marks on sidewall and chamfered gearchange referred to by Vibrac.

Glen

Not to the satisfaction of anyone with 100 comparison samples next to his elbow in the scrutineering shed to say nothing of the boots.....
 

Monkeypants

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the belt sander will work on the boots as well. Make sure to smear some Castrol R into the sanding marks;-)

Im sure Vibrac has authentic chamfers and wear marks, Ive seen the videos posted.


Glen
 
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Black Flash

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I remember being at school many years ago when a schoolmate arrived on his Yamaha RD 350 YPVS showing off his worn off footrests.
Problem was the scratchmarks where pointing up and down not fore and aft when you were sitting next to the bike looking at the footrests.
Telling him about that he turned a red face and rode off immediately, to stupid to cheat.
Bernd
 

Albervin

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My first RD350 needed no help from the tool shop to grind the footrests and tyres:) What a sweet machine... Nearly 40 years later I have another RD350 and it is everything I remember..
 
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