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dan williams

The Beta Clutch Fix

342 posts in this topic

Fixed!

I fitted the new master cylinder this afternoon.

I am now getting just over 1mm of pressure plate movement and it stays there, left the lever cable tied back again and nothing moved, when I returned 20 minutes later, the pressure plate was in the exact same position.

Had a little ride on it just on the street out side the house and feels good.

As I did the 'fix' and changed the oil to nano trans during the fault finding it should hopefully be a huge improvement.

Thanks again for everyones help.

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That's great news, you'll have to let us know how it is after a decent run.

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Will do.

Doing a trial up at Scarborough Trials Park on Sunday so I will let you know how it goes.

Edited by whitevancam

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Woohoo good job finding it. 

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On 18/11/2017 at 5:26 PM, trapezeartist said:

Similar to my experience, whitevancam. I did the glue-removing bit and found the tabs were already good so there was nothing to do there. It made no real difference: still suffering cold stick and dragginess for the first five minutes of riding. I thought maybe engaging neutral with the engine running was marginally better but I may have just been kidding myself.

I spoke to Lampkins and they advised roughing up the steel plate and changing to 10W40 oil (mine's a four stroke so my choices are more limited). So I took the clutch out again, wiped off all the oil I could, attacked the plates with P80 wet'n'dry to get a 120 deg cross-hatch, washed with paraffin and reassembled with plenty of oil. Then filled up with 10W40. I tried the bike again today and was disappointed to find there is still no change. New clutch plates?

Attempt No 3. This time I washed the friction plates with petrol and then rubbed them over with P180, just enough to change the colour from black to speckly brown. Then washed again in petrol, reassembled with oil and filled up with 10W40 synthetic. As it happens, it's a bit overfilled because that's the way it came out.

Result: The cold stick was still there but not nearly  as bad. Very slight drag initially but also much better. Best of all, the feel and progression of the clutch was massively improved. I only had time for a few figures-of-8 but it really did seem much better. I've also switched back to the quick throttle and that was no problem with the newly tweaked clutch. Proof of the pudding: a trial tomorrow. I'm feeling optimistic. :)

In passing, I also measured the clutch throw and checked that there was no leakage past the seals (there wasn't). With the clutch lever hard against the handlebar grip, I was getting 1.1mm at the clutch. That ties in pretty well with the 1.2mm mentioned in other posts on this thread. (Perhaps I have a bit more free play or a different shape of lever.) With the lever pulled in with one finger until it contacted the back of the next finger, the travel at the clutch was 0.6mm.

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The clutch was much improved on the trial today. Now I just have to fix the nut holding the handlebars. :D

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Update following the trial yesterday, clutch and bike performed perfectly. Rider has lots of room for improvement!

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5 hours ago, whitevancam said:

Update following the trial yesterday, clutch and bike performed perfectly. Rider has lots of room for improvement!

You and me both then. I'm going to turn up the idle a little bit next time as I find a little bit of a snatch going from no-throttle to cracked open.

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Carbon reeds can help that.

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5 hours ago, dan williams said:

Carbon reeds can help that.

Not on a 4T, they can't. ;)

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 By the way the engine being overfilled can play hell with clutch engagement. The 4T only takes 700-750cc with an oil filter change and the lower filters cleaned.

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3 hours ago, trapezeartist said:

Not on a 4T, they can't. ;)

No that requires a twin scroll turbo.😀

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