Don't want these Ads? Why not sign up as a Trials Central Supporter.

dan williams

The Beta Clutch Fix

342 posts in this topic

OK folks, being off work for a week (mandatory holiday shutdown) I had time to complete the fiber plate modification document. This makes the clutch progressive, eliminates drag, cold stick, slip and reduces lever pull (if you leave two springs out).

And the best part... It's free (if you already have the files and Dremel polishing wheel)

Yes it will cost you some time but hey you're working on your bike. That's still quality time compared to working on the car.

The PDF came out over 10Meg so if you don't have a high speed connection it may take a bit. Sorry but the pictures are necessary.

Enjoy

Andy Edit: File optimised and size reduced to 1.8MB :rolleyes:

Clutch_Fix.pdf

(Also going to pin this topic so it stays up top)

Edited by Dan Williams
5 people like this

Share this post


Link to post
Share on other sites

Don't want these Ads? Why not sign up as a Trials Central Supporter.

Carried this out when you first came up with it a while back, it works.

Very clear instructions and well explained.

Clutch AND carb OCD, what next?

Share this post


Link to post
Share on other sites

Excellent presentation Dan it's not entirely a new discovery I can remember doing this (the Tab bit) on old british bikes (the friction material then was cork and the friction pads of cork werk dependant upon being wet to fit..no glue!) I think the sharp edge on the friction pads is important and your work explains this very well.I think you are dead right about clutch being important as are all controls ( I make footrests) and went into the ergonomics of that as deeply as you have investigated clutch action. I will be doing your mod to one of our bikes My missus and I have "identical" bikes. I may add a bit of a twist also as I will programme my mill to effectively profile the tabs with a small milling cutter prior to polishing and deburring. I use a wheel of 200 dia consisting of nylon bristles impregnated with abrasive grit material it rounds sharp edges /corners perfectly for this job and will speed up the process no end. I may be able also to mill out the glue from between the friction pads leaving an excellent sharp edge. Only other comment is that I have a spring supplier whom I buy replacement springs for these clutched they are rated at c. 80%( there is a lot of tolerance in spring ratings unless you want to pay a fortune) of factory and cost me

Share this post


Link to post
Share on other sites

having had my beta since easter, the cold drag is annoying and a way of getting rid has got to be looked at. good post and like others say well presented :rolleyes:

Share this post


Link to post
Share on other sites

What did you use to hold the plate whilst filing the side of the tab?

Share this post


Link to post
Share on other sites

Nice Job Dan. Me like the pretty pictures..... :rolleyes:

Share this post


Link to post
Share on other sites

Yay! Andy pinned my post. That's the internet equivalent of Mom sticking your schoolwork up on the refridgerator.

Jezza> Er what's next? Working on an ignition system that even I have to admit, after swapping everything else, now looks to need a stator rebuild. I de-potted the CDI I thought was bad and am trying to build a simulation model.

chewy> No it's not a new discovery. As Frank Zappa said, "There are only so many notes. It's all been played, unless you go micro-tonal." I miss Frank. You have a milling machine? Now I'm wicked jealous. (NOTE: use of the term "wicked" to amplify the following adjective. This particular affectation is indigenous to the city of Boston and its surrounding environs. For further study see, Matt Damon). I would be very interested in the softer springs as there can be a little chatter with four springs that may be due to uneven pressure on the pressure plate.

HAM2> My fat little fingers. One problem with doing this by hand is you get bored and stop paying attention. That is until you punch a hole in your hand with the file. Stings a bit.

Edited by Dan Williams

Share this post


Link to post
Share on other sites

does this help the automatic take off?

Share this post


Link to post
Share on other sites
does this help the automatic take off?

Yup, that's what I refer to as "cold stick"

Share this post


Link to post
Share on other sites
What did you use to hold the plate whilst filing the side of the tab?

Been doing mine thi avvy..tried vice but by hand against flat surface is quicker....incidentally touched (flattened) the faces by using bench grinder..it's literaly a touch... broke edges with needle file and finished with bit of emery..getting the glue out from between the friction material is tedious. Only two more to do tonite for the wifes bike ..then start o mine arghh

Share this post


Link to post
Share on other sites

many thanks dan, best post ive seen :wacko::rolleyes:

Share this post


Link to post
Share on other sites
Yay! Andy pinned my post. That's the internet equivalent of Mom sticking your schoolwork up on the refridgerator.

Hehehe. Nice analogy B)

At 411 views already and clearly a lot of work gone into producing your extensive instructions, it's worthwhile pinning it to stop it from dropping into the ether :)

Share this post


Link to post
Share on other sites

Very nice work, Dan!

Having followed some prior posts, I had done some inspection on the Sherco plates yet did not seem to find the same roughness on the tabs. I am totally unsure who is making these things for either brand, as it did seem sureflex was doing the Sherco ones, and not sure aboiut the Betas at all.

Has always seemed to me to be overall very similar overall in the fundamentals of design between the brands, although sort of reversed left to right.

I am not totally sure how all this directly relates to potential cold stiction issues which seem common, yet I would guess that the elimination of the glue in between the pads on the plates might at lease help improve things.

To take things even to a further extent, it has been suggested that micro grooving in an X or / pattern upon each clutch pad on the plate may be a potential solution.

I have other thoughts on this, yet not sure if anyone really cares! B)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now