Massive clutch slip 120 Jota

OneThinBloke

OneThinBloke

Hero member
Location
Oxfordshire, UK
Finally got 120 Jota fettled and running sweetly :)

So did a short test ride before booking an MoT. A small amount of clutch slip but otherwise all hunkdory. MoT booked at my nearest available test station, and off I toddled.

The clutch slip became worse and worse, but stringent MoT passed all the same. By the time I arrived home the clutch slip was quite extreme and bike almost unrideable :( :(

I've stripped it down:- Steel plates had become very hot! see pics.
Friction plates measure between 2.9 - 3.3mm
Springs all in the range 46.5 - 47.3mm
There are also 3mm washers which would lighten the spring loading but by enough to cause my issues?

I had installed new push rods and ball bearing, supplied by Slaters.

Thoughts and solutions welcome :)
 

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Hi James,
The extra washers will apply a higher tension on springs.This also indicates a previous problem by a previous owner.3mm thats a lot!
The plates look very dry?
Right number of plates fitted?
Is the clutch drum and all items on the shaft correct and assembled as per book?
Warped plates?
Why did you change push rods etc.Did you compare new with old?
Could the clutch master cylinder be applying constant pressure>
More questions than answers!

Andy
 
If the pushrods & ball bearing are a different overall length to what was fitted originally, the clutch slave piston will be working in a different part of its bore which may result in it sticking
 
how many plates do you have James ?
on a 120 Jota should be 8 x friction and 6 x steel
friction plates should measure around 2.95mm - 3.10mm

when installing the pressure plate on a triple the pressure plate will only line up on the internal spline in 2 positions out of the available 6 positions
make certain that the pressure plate engages over the spline on the clutch hub

 
Someone had used the washers trying to find a solution for the problem, lucky that the extra tension didn't put too much strain on the clutch cover housing and make it toast as more harder to come by that a new set of plates.
Did you have/was the basket lined up as they will only go on properly in 2 places.. if it was in the wrong place then it will not go all the way home on the splines and cause you slip.

IMHO Do your self a favor source a new set of steels and then buy a set of frictions from Red then clutch slip (once assembled correctly that is ) will be a distant memory.  I know others will come on and say about new standard frictions working fine but I am just saying his plates are the ducks guts best thing since sliced bread.
 
redax5 said:
how many plates do you have James ?
on a 120 Jota should be 8 x friction and 6 x steel
friction plates should measure around 2.95mm - 3.10mm

when installing the pressure plate on a triple the pressure plate will only line up on the internal spline in 2 positions out of the available 6 positions
make certain that the pressure plate engages over the spline on the clutch hub
Click to expand...

I think that this is almost certainly what has caused the problem!!! I wasn't aware or this and therefore didn't check when I reassembled previously!! Doh.
 
Brett said:
Someone had used the washers trying to find a solution for the problem, lucky that the extra tension didn't put too much strain on the clutch cover housing and make it toast as more harder to come by that a new set of plates.
Did you have/was the basket lined up as they will only go on properly in 2 places.. if it was in the wrong place then it will not go all the way home on the splines and cause you slip.

IMHO Do your self a favor source a new set of steels and then buy a set of frictions from Red then clutch slip (once assembled correctly that is ) will be a distant memory.  I know others will come on and say about new standard frictions working fine but I am just saying his plates are the ducks guts best thing since sliced bread.
Click to expand...

I will order up a new set of steels from Keith or Richard in the UK. I already have a NOS set of friction plates :)
 
Lest I forget...

Thank you all so much :)

I am sure that the problem is sussed and will be easily sorted with a new set of steel plates.

I won't be refiiting small 3mm deep spacer washers and will ensure that I re-install the pressure plate in the correct position ;)

James
 
OneThinBloke said:
I think that this is almost certainly what has caused the problem!!! I wasn't aware or this and therefore didn't check when I reassembled previously!! Doh.
Click to expand...

If the pressure plate isn't seated correctly, you wouldn't have made it to the MOT station in the first place, James!  It would ride on the end of the hub splines instead of engaging with them and you would have experienced difficulties fitting the springs, especially with the extra pre-load of the washers.

piet
 
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