Evo 250 Clutch

[trapezeartist]

18 hours ago, dan williams said:

I used to use the shorter levers but now I use the stock levers with the perch in as far as it will go. Gives more leverage to reduce pull and also makes it less likely to break a lever in a fall.

Where did you get the short levers? I’ve looked on all the usual e-shops but couldn’t find any.

[dan williams]

Was many years ago so I don’t even remember.

[lineaway]

21 hours ago, thall1 said:

what do the shims do for the clutch?

Being my Japanese is non existant, I am hoping for better clutch action. As eliminating clutch drag and a better hitting clutch. I have known about the shim trick for years , but could never find them thin enough till recently.

[Sir Real Ed]

On 3/22/2019 at 11:33 PM, dan williams said:

I used to use the shorter levers but now I use the stock levers with the perch in as far as it will go. Gives more leverage to reduce pull and also makes it less likely to break a lever in a fall.

I like that idea.  I prefer short levers, but this is too simple and obvious not to do.  Especially as the lighter clutch pull is a bonus.  thanks.

[Sir Real Ed]

On 3/24/2019 at 12:18 PM, lineaway said:

Being my Japanese is non existant, I am hoping for better clutch action. As eliminating clutch drag and a better hitting clutch. I have known about the shim trick for years , but could never find them thin enough till recently.

Please let us know how that works out.  With such thin shims, it would seem to me that only the superhumanly sensitive and precise World Riders would be able to discern a difference.  It will be interesting to learn what you experience. 

[trapezeartist]

I finally got out on a trial this weekend. I had spent a lot of time fine-adjusting the clutch actuation. The best I could manage had just a hint of drag when the lever was pulled in to a finger thickness from the grip but it seemed a long way out before it would bite as I tried to slip the clutch. Not ideal but better than before.

[lineaway]

On 3/25/2019 at 7:50 PM, Sir Real Ed said:

Please let us know how that works out.  With such thin shims, it would seem to me that only the superhumanly sensitive and precise World Riders would be able to discern a difference.  It will be interesting to learn what you experience. 

https://advrider.com/f/threads/how-to-correct-beta-clutch-drag.1375397/

[Sir Real Ed]

16 hours ago, lineaway said:

https://advrider.com/f/threads/how-to-correct-beta-clutch-drag.1375397/

Lineaway,

Thanks for the information and effort. The theory makes perfect sense.  Hydraulic clutches have so little movement at the plates, that taking out the slack at the plates is a good idea.  I've haven't noticed a problem on my 2019 EVO 250, but it is my first Beta after riding a 2001, 2005, and 2011 Sherco since 2003.  Some have suggested I'm inherently insensitive before.......?

When looking for stuff like this, I suggest always trying McMaster.com.  Excellent selection and the best vendor search engine I have ever found.  We have ordered as late as 8pm and had the parts by 10am the next day.

McMaster-Carr pn 98055A218 is a 16 x 22 x 0.1mm shim washer.  $5.52 for a quantity of 25.  Also available in 0.2mm, 0.3mm, and 0.5mm.  Or in 18 x 25 x 0.1mm size.

I am going to give it a shot.  Thanks again.

Edited April 6, 2019 by Sir Real Ed

[trapezeartist]

Any idea what the Japanese mechanic was doing when operating the clutch lever against the Allen key? Feeling for free play?

I’ll look forward to your report after full testing of the 0.5mm shim, lineaway.

[lineaway]

After almost 4 hours of riding today, it did the job perfectly. I was worried about it slipping when the engine heated up after hours. It is the best I have ever had a Beta clutch. It actually has a positive realease when you pull in the clutch with one finger. No more slughtly lingering drag  Granted my clutch was better than most in the first place. But I am tired of the little stalls while hopping or when landing a nose wheelie. Now it us quicker as the realease zone is smaller. But eveything is positive about it. I went with the .5 mm amount of shim due to the plates are 3 years old and I wanted to see results. It only takes 15 - 20 minutes to change it again.

 We have a full day event tomorrow and I do ride our Exoert class. But we also have a Master and Champ (Pro) above that, so our Expert is not our top class like it was years ago. Should be a great test day!

[trapezeartist]

I completed another trial today but was frustrated by the continuing clutch issue. As before, it drags a bit when pulled right in, yet needs to be released right out to bite properly. It’s not conducive to fine clutch-slipping control on tight turns.

I have a few ideas but no clear hypothesis on why any of them should work. It will be just stabbing in the dark.

1. Add a shim to the thrust bearing. I don’t understand what this does but lineaway seems happy with it.
2. Change to a different oil. I currently use Castrol 10W40 motorcycle gearbox oil. I might try ATF next as it’s a cheaper experiment than putting in Nanotrans.
3. Swap one or both thick plates to thin ones. Hopefully this would reduce the clamping force and get rid of the drag. Then I could adjust the lever the get a nice engagement point.

Edited April 28, 2019 by trapezeartist

[totty79]

Consider replacing the plates both friction (all thin) and steel and using a proven oil like 300v or nanotrans (or atf but you may find it like an on off switch). It's not cheap but might save you a lot of time, I wasted ages on mine before throwing parts at it which was the only thing that made a significant difference.

 

 

 

[trapezeartist]

I took the cover off tonight and tried to measure the release movement. I couldn’t really get a good place to get my depth gauge in, but full movement appeared to be about 1mm. The more I think about it, the more it seems like oil drag on the plates is the root cause, followed by over-adjustment to try to compensate. So I need to try a different oil. Probably something nice and thin. Is ATF really going to give an on-off feel?

[pindie]

I’m not an ATF fan. It was terrible in my Rev3, caused drag and was snatchy. I changed to Nanotrans GP and after the first change after a couple days use (I used just 500ml so two changes out a bottle) it was fixed. No drag. Smooth action. I’ve been using it in any 2t bike since. Always the same result. No clutch issues. It ain’t cheap per litre but it cheaper and easier than changing clutches if you ask me. 

[ChrisCH]

9 minutes ago, pindie said:

I’m not an ATF fan. It was terrible in my Rev3, caused drag and was snatchy. I changed to Nanotrans GP and after the first change after a couple days use (I used just 500ml so two changes out a bottle) it was fixed. No drag. Smooth action. I’ve been using it in any 2t bike since. Always the same result. No clutch issues. It ain’t cheap per litre but it cheaper and easier than changing clutches if you ask me. 

I run Nano Trans in the Rev 3 with the same results.  Hard to credit an oil with so much effect but after half a dozen changes it is a different bike.  The cold stick "breaks" after a gentle push in 3rd.  A couple of clutch actions remove the last of the stick and the bike rides perfectly.  I had intended to do the "fix" but I will not bother now.  Bleeding the clutch also made a big difference.  I read about the oil on here and have not used any other oil so nothing to compare with other than how the bike arrived with whatever it had in it and whatever it had run before.  The cold stick was very bad when I first got the bike and I thought there was a fault with it, so I looked on the Internet and found this forum (thank you everyone for your contributions to this topic).