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Do I Need New Clutch Plates?


brenin
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Guys,

i have recently got an 08 Rev 3 250. There is lots I like about it, but i do have all the symptoms of 'Beta clutch drag'.

I am going to perform the clutch mod as detailed in the sticky post, but I have a couple of points id like help with:-

The bike is one owner and i believe on its original clutch. I wasny told it had been replaced at point of sale.

If i ride slowly down hill on a closed throttle, i can hear the wheel turning the engine, and effecting engine braking. When I fully pull the clutch in, the engine braking noise continues for some 5+ metres, before the clutch frees and the engine returns to its natural idle. There isnt any clutch slip etc at the moment, so is it worht me just buying a new set of friction plates and modding them straight from the box? That way they are clean and easy to work on in spare moments. Plus if its nice outside, I can go and play in the quarry! If so, what brand of plates should i order? Are they all equal? Should i go direct to Beta UK, or are pattern/after market parts better in price or performance?

As I will have to open the clutch cover, is it just one gasket I need to order? And will it dry seal ok, or will i need sealant?

I know they may seem trivial questions, but with limited play time, id like to get everything I need and just not fall at a simple hurdle when i havnt got the correct parts. Prior Preparation and Planning Prevents P&*^ Poor Performance....i hope

thanks

Ian

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Couple things

The diagnosis you mentioned really has no meaning to wether or not your clutch plates are good or bad

It may or may not mean your clutch is dragging badly but due to the nature of the drive train, every bike may act in a similar way

When a clutch is at the end of its life it will slip, NOT drag

It would appear when climbing a steep hill in a high gear, not when coming down in low gear

I doubt your plates are worn out but the only way to tell is visual inspection and thickness measurement

You won't need a gasket, it has an o ring on the outer cover

As for the mod, there is no need to polish the finger sides as the plates don't really slide back and forth, fully disengaged the pressure plate will only move about .030 to .040 of an inch, they are not a sliding surface, but a load bearing surface, just remove the glue and gorp buildup from between the fiber plate pads

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Don't bother with the new plates just yet. Do the mod as described. The fingers are a sliding bearing and must be polished to relieve the "light switch" actuation caused by glue and surface roughness. They may only move 1.5mm in total but if they don't move they don't release.

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Don't forget, the clutch pack combined may move this amount, but its divided by 5 plates

.040 = 1mm divide by 5 is .007 or .2mm per plate

It's even more complicated than that, the clearance is divided over 10 surfaces (each plate has 2 sides) but that makes my brain hurt LOL

They don't slide so much as just run zero clearance when disengaged, kinda like the reverse of a brake

Anyway, polishing this spot can't hurt, I just can't see it changing anything if the moment is immeasurable

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Try using putonline nano trans oil. My clutch on my 07 felt grim, I changed to nano trans and its now awesome.

Nano trans is not cheap but it lasts a long time as it resists breakdown much longer than gear oil or ATF. I've been using it a while now and do about 40hrs before I change it.

It is expensive but excellent and certainly a cheaper and a quicker mod.

Edited by pindie
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Yes. A lot. My gearbox on ATF feels very dry and not slick. It will always find the gear etc but you notice extra effort to do so.

With nano in after a couple of rides it was way smoother as the new nano oil did what ever it does. It stayed like this for week after week. In the end the notchyness started to appear again so I used to second 500ml from the bottle and hey presto the box was silky smooth again. One bottle of nano lasted me nearly a year of practice and six trials! I tend to ride very week for a minimum of an hour or two.

As a contrast I forgot I used up the nano so when I dropped the oil for fresh the other week i only had ATF to put back in. Doh!.

The gear box feels dry and notchy now. I will be grabbing a bootle of Nano trans as soon as I can get to my local supplier. The clutch also feels grabby again and not just right now using ATF.

I feel Nano is worth the money as it is the genuine article for a gear box where ATF is for car auto boxes and power steering. Has your bike got either? Try the nano and I'm sure you'll like it. .

Edited by pindie
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Good to know, going to try and find some Nano

I can't get my head around ATF, it may relate well to the clutch as car trans are similar but my problem is gear selection, Japan makes a drastically superior transmission and I dream of that kind of shifting

I should be able to confidently shift in a section and find neutral easily

Why do Italian bikes suck at this........, its not 1969 any more LOL

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It will behave a lot better once you are on the nano for a while. I could never get neutral etc and got a bruised toe changing gear.

Since being on nano it's now easy to find neutral and change gear. I have also avoided having to file down each plate as per the "mod".

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Long aluminum gear lever and two shaft transmission to save weight.

Sorry Im a noob. But what do you mean by this?

The first thing I noticed when I got my 270 was that I had to take my foot off the peg to switch gears. Is this the norm for trials bikes or do you guys just have big feet?

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Yup big gap and flimsy material for light weight. The two shaft thing is my opinion and may be daft but in other types of bikes I've noticed three transmission shafts. I think the mechanics of getting five speeds out of a two shaft transmission might make for more torque required in the actuator mechanism to get a positive gear change.

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