Scooterotica

clutch has started slipping in 3rd just before i change to 4th now i`m still running it in but shall i change the plates or do i put a centre spring in or do i go for stiffer springs or put vespa springs in with the standerds

What is the engine set up, kit pipe? expected or known power? What is the clutch setup/parts used etc, how long has it lasted since build (was it a professional or home build?), are the cables new? Is it adjusted properly? Did the clutch drag previously and the cable been tightened to stop the drag?

thanks rich-t for that ,its a SIL stage 4 standerd out of box done 130mls so far the only diff is that i fitted a stainless exhaust,starts 2nd kick every morning,but its just started slipping now .i`ve got the correct play in the cable and no it didn`t slip before,and the cables are nearly new.

soak new plates in gear oil overnight and fit these along with some nice heavy duty springs, check the chain while your in there and reassemble with a new crankcase side gasket and make sure the cable is not too tight fill with the correct grade and amount of gear oil and it should be ok,
regards
joe

thanks joespeed,i`ll sort out the springs,i`ve got some new plates,oil and what have u will let you no if a o k

Surflex type "B" should be fine (NOT the type "C" ones)

As mentioned above- a good new set of stronger springs and you're away.

I'd only use a centre spring as a last resort (and then be prepared to lose the use of your "courting hand" )

You're not using the EP type of gear box oil are you?

Chris

thanks chris,rock oil for engine not EP and 2 stroke hope to get springs this week

Your engine is totally basic, with the best will in the world it won't be making more than 10BHP. A standard 4 plate clutch and springs will be fine up to about 13BHP. The slipping has nothing to do with the friction plate material or spring strength. I would but money that the pressure plate is binding or snagging against the spider and preventing a clean release.

Strip it all down and look carefully for notching on the edges of the pressure plate and spider where they contact near the base (if you're not sure where this is put the two parts together to see where the contact points are). Also compare the springs to check that the lengths are all equal (to within 1mm approx) and straight, also check that the pressed pressure plate is square and runs true (no wobbles, broken or faulty welds). You might also find that a circlip has partially popped or a spring become unseated. These are typically all the things I've seen over the years which have given identical symptons.

Typically this happens on cheaply built engines, usually imported or engines built out of a box of bits by an enthusiastic home builder. To rectify you can remove the notches with a file (but expect to do the job again some day if the engine is powerful). Try as best you can to tap out any run out in the presure plate or spider (some look like they have been made on a kerb stone in India...oh wait, yes they have!). If the springs are all odd sizes (it happens) then change them for standard ones, no need to upgrade just so long as they are all even. If the circlip has popped or the spring become unseated correct this in the rebuild

In your case because it used to work fine before I'd think it is just a popped circlip. Still strip it to make sure that this isn't because the spider was built out of bean tins, correct if required and rebuild.

Look on the positive side, at the end you'll know exactly how to work on clutches.

for your engine, you would go a long way to beat Surflex B clutch plates and H/D springs......

thanks all for the replys
going to roll it on the bench 2nite and get my little pinkies dirty,will let you no the outcome