The Beta Clutch Fix

[stanmet]

Hi the Honda crf 250 are to small as well

[dan williams]

Yeah that's what these fit. So much for believing what you read on the internet.

[wheelieman14]

Couldn't you provide the Beta Clutch Friction plate dimensions to Barnett and have them check for a size match?

[dan williams]

I'm talking to them and have offered to send them a Beta plate. Barnett has asked for the information to be removed as they have gotten a few return requests already.

Edited November 15, 2016 by dan williams

[oslow]

I received an email from Barnett Clutches that the Part number is wrong. Mike Taylor has given me the correct part number.  New/# is 301-35-10012

Be sure to specify the number of plates needed. I hope this solves any problems.  If you have any doubts or problems, be sure to contact Barnett and

ask for Mike.  I am not associated with the Barnett company, just a fellow Beta rider.  Sorry if I caused any problems. Is there any way to correct the previous post to prevent any confusion?

[dan williams]

I received an email from Barnett Clutches that the Part number is wrong. Mike Taylor has given me the correct part number. New/# is 301-35-10012

Be sure to specify the number of plates needed. I hope this solves any problems. If you have any doubts or problems, be sure to contact Barnett and

ask for Mike. I am not associated with the Barnett company, just a fellow Beta rider. Sorry if I caused any problems. Is there any way to correct the previous post to prevent any confusion?

Fair enough. I've gotten the same information from Mike but I'll not say the plates fit until I return the ones I have and get the proper set. The wrong plates are on their way back. From my measurements and Mike's comments it looks like the Barnett plates are approximately 0.3mm thicker than the standard plate I measured. That'll add 1.8mm to the clutch pack. It'll be interesting to see how that affects pull.

 

EDIT: Close but not quite. See post below.

Edited December 3, 2016 by dan williams

[heffergm]

Wow, those are million times cleaner than the stock plates. Curious to hear how they work in the Evo.

[dan williams]

Ya see here's the thing, clutches operate with a very narrow set of tolerances. These fit beautifully in the basket but they are too thick. Might they work? Yeah they might but I won't use them. When all six are used in the clutch pack the clutch pack is ~2mm thicker (eyeball measurement). My initial belief was they would merely make the spring preload higher. I'm an idiot (see Foot Note 1.) they also move the pressure plate out. The practical upshot being the slave cylinder doesn't have the travel to actuate the pressure plate. This could be corrected with a thicker thrust washer on the throw-out bearing or even a longer push rod. But you are now pushing the pressure plate, what I consider, dangerously close to the outer cover. The other thing I really didn't like was the top steel plate was right at the top of the inner hub. Would it work? Sure, but I don't have the warm fuzzys about long term reliability and failure of one plate in a clutch can lead to a cascade of problems. There is one place these plates would work great and that is replacement of the thicker two plates in the later clutches but replacing all 6 is not ready for prime time. I'll talk to Mike at Barnett and see if there are thinner plates in the same form factor.

 

In summary,

These plates are too thick to be OEM replacements

 

Foot Note 1.: This is why you don't rely on calculations and actually put things together!

Edited December 3, 2016 by dan williams

[dan williams]

Mike from Barnett confirmed that they do not make plates thinner than 3mm. Oh well, it was worth a look.

[stanmet]

Hi dan my beta 4T comes as standard has the six thicker plates instead of one at each end like the later two strokes witch are 3mm thick the surflex plates I put in are 10 thou thinner reducing the pack by 60 thou making it a lot better and some free play on the thrust washer that I didn't have before

[dan williams]

Hmmm maybe Beta went with a deeper basket or a shallower hub on the later bikes. On my 2013 2t the thicker plates just push the clearances beyond my comfort zone.

[stanmet]

Hi dan my beta 4T is 2012 unless the last owner changed it for some reason ? It's good now so no problem just trying to help with measurements

[carlos]

My 2016 4t factory 300 has 6 thick plates as well. I put in one thinner plate and it does make it easier to pull in.

[fxstbi]

This has been an interesting topic. Dan, you have done a tremendous amount of work that we all benefit from, thank you. I just got a new 300 4t Factory and my clutch appears to be decent at least better than my '15 Sherco 250. I do have to break my plates free by rocking the bike in third gear but that seems to be a common ailment on the last three trials bikes I've had. I did read on a different board that you can improve clutch feel by removing two of the stock 4t plates and putting in two 2t plates. I asked my dealer friend what the differences were between the two types of plates were and he said the 2t plates were .3mm thinner.

    In your experience, do you think this will help alleviate the sticking plates and give better clutch feel? Might there be slippage? I'm looking forward to making a great bike even better!

 

[dan williams]

It's been interesting and I appreciate all the knowledgeable people who have contributed to this thread. Especially the ones who thought it was all bollocks but tried the fix anyway. I have many teachers here.

 

I know that the previous research showed the initial clutch stick was from excess glue cold flowing onto the metal plates but with the new clutches this may not be the case anymore. On my 2013 the plates were better but I still swapped them out for a set of "processed" fibers that I still use. I still don't have to "break the clutch free" after three years of use. They will drag when cold but that's probably more down to oil viscosity that anything else.

 

The thicker plates will increase the spring preload which can help reduce the tendency to slip but also increase the pull at the lever if the same master/slave hydraulic cylinder ratio is used. I suspect they will also reduce flex under load but I have nothing other than speculation on this. I don't have a set of new plates to examine so I can't really hazard a guess as to their behavior.

 

If you do decide to pull your clutch pack please post pics. I'm curious at the current state of Beta plates as it seems there are changes recently. If you try the fix post your results.

 

Trials is such a weird sport. We actually like to see our competitors improve. Strange lot we are.