Trials Australia Forums

hello all, i have recently bought 2 betea trials bikes a rev 3 and an EVO 290, the clutch especially on start up and at other times it just sticks dose not disengage immediately. is this a quirk or an issue ? and advice welcome.

Gday, have a look at this link to the UK forums.

http://www.trialscentral.com/forums/top ... lutch-fix/

Cheers,

Stork.

Use Shell Advance Lightweight gearbox oil. If it still sticks take the clutch plates out and use a stanley knife to remove any excess glue in between the friction pads. This will fix your problem.

David Ryan - Beta Racing

thank you very much for your help guys ,i changed oil this afternoon there was an improvement.can i get workshop manual ? to help with cleaning the plates and putting it back together!!thanks macka.

Can you email me on [email protected] and I will email you a workshop manual.

David Ryan - Beta Racing

Hi, my experience with clutches tend to return to the same conclusion, if the steel plates are too smooth and highly polished, then the cork plates "stick" to them better. In my experience the steel plates need dimples in them, these dimples hold very tiny amounts of oil and help the plates let-go when you pull the lever in. See old 315R Montesa plates by SUREFLEX I think is the name, these were same as CR250 plates and were dimpled. Now thats no help with a Beta but you can dimple then your self, I used a vice with nice new serrated jaw faces / diamond pattern. Crush each plate several times to dimple both sides and them file them flat with a very smooth very fine file to remove any high spots, its a faff but it does the trick but you need to end up with only dimples .... dimples inwards !! No high spots or proud edges otherwise it will rip the cork off.
Another technique I used was to have then shot blasted or sand blasted .... anything to give it some surface finish that will hold a tiny bit of oil.
HTH

Before anyone rushes out to the shed to put dimples in their steel plates using a bench vise, please consider that not all bench vises have perfectly flat jaws. If a set of jaws is not flat, they have a high risk of removing the flatness of the steel clutch plates, which will cause clutch engagement to become too gradual and imprecise and maybe not completely disengage.
Safe methods for roughening the steel plates are wet-and-dry abrasive paper or light abrasive blast