The Best oil for my Clutch Semi/Fully Synthetic

[dhunt]

Hi Guys,

I did a trackday on Monday but my day was cut short when my clutch started slipping when ever I tried to rev the bike over about 10k.

Now I was talking to the bike shop about getting some new fibre plates and during the conversation oil came up. Currently I'm running Castrol R4 Fully Synthetic which was what the guy I bought the bike off was using. The guy at the bike shop said that this is probably too slippery and will make the clutch slip easier (Which is bad).

So what's the best stuff to run in a race bike? My understanding is
Fully=Slipperier=Better for Engine=Worse for Clutch?
Semi=Less Slippery=Worse for Engine=Better for Clutch?

Obviously any oil is a compromise in a bike where you share the same oil between the engine,gearbox and clutch.

Any thoughts guys? Bike is a GSXR600K1.

[Wheeliemonsta]

Hi Guys,

I did a trackday on Monday but my day was cut short when my clutch started slipping when ever I tried to rev the bike over about 10k.

Now I was talking to the bike shop about getting some new fibre plates and during the conversation oil came up. Currently I'm running Castrol R4 Fully Synthetic which was what the guy I bought the bike off was using. The guy at the bike shop said that this is probably too slippery and will make the clutch slip easier (Which is bad).

So what's the best stuff to run in a race bike? My understanding is
Fully=Slipperier=Better for Engine=Worse for Clutch?
Semi=Less Slippery=Worse for Engine=Better for Clutch?

Obviously any oil is a compromise in a bike where you share the same oil between the engine,gearbox and clutch.

Any thoughts guys? Bike is a GSXR600K1.

Gidday dhunt,
Is the R4 thats in the bike a type specific motorcycle engine oil ? If not you may find the the friction modifier's (additive package in synthetic oils) have got at the fibres in the clutch as the oil was not designed to be used in an emersed (read wet) clutch...

First things first, you need to arm yourself with a workshop manual & go through the clutch peice by piece & check that evertything is within tolerance - (it is a race bike after all) main points of concern here will be the "free" length of the clutch springs, the thickness of the fibre plates & any runout in the steel plates (this is easiest done by placing the steels on a known flat surface & trying to pass the recommended feeler gauge between the steel & the flat surface - a sheet of glass works well in most instances)

Once you've got that all sussed, bits replaced - if need be, & the clutch re-assembled, particular attention needs to be paid to the set up on the activation lever where the cable attaches, get the angle wrong & you'll have a clutch that doesn't engage (drags) or disengage (slips) properly...
Its not that daunting a task - & you generally only get it wrong once

In as far as oils go, I've always used Golden Spectro in all the Suzukis I've owned (theres been more than a few !!!) it, simply put, transforms the performance of the clutch & gearbox...

I now run it religously in my ZX 12 R which see's a fair bit of abuse at Meremere on a regular basis...

My suggestion for you K1 would be 15w 50 full synthetic (Part # GSFS1550/L) changed every third meeting

I.M.H.O it simply does not get cold enough in N.Z to warrant running a 10 weight oil

Watch the fur fly with that statement !!! !!!

It's only available in a 1 litre container & it sure as hell ain't the cheapest stuff in the world, but good oil, like good tyres are cheap insurance

Cheers

[Tony.OK]

Gidday dhunt,
Is the R4 thats in the bike a type specific motorcycle engine oil ?

Castrol R4 is fully synthetic bike oil.

Dhunt I've wondered the same thing mate,depends on which mag you read or who ya talk to,I use GPS or Spectro semi only because I read on a forum fully syn could make clutch slip."BUT" why then is R4 called Superbike oil?
How old are the clutch plates in it at the moment?

[dhunt]

Well I've just finished changing the fibre plates. Didn't have time to test the bike before it got dark so will have to wait till tomorrow evening.

I measured the springs,fibre and plain plates and all were in spec. The fibre's were about 1-3mm worn compared to the new ones so possibly that was enough to make it slip???

I've no idea how old the plates that were in it but judging by the number of old sets I got with the bike possibly only a year or two.

I'll probably stick with the Fully Sythethic oil I've got till I've used up my supply and then possibly switch to Semi and see if that makes any difference.

[Max Preload]

I run Castrol R4 with no clutch slip problems, despite my clutch being very worn (I've got new kevlar frictions, genuine steels & heavy duty springs just waiting to go in to cure the slight clutch shudder.)

It's the friction modifiers in oils designed for use in engines without wet clutches that cause the problem, not whether the oil is synthetic or mineral base. R4 is only API SG rated BTW, compared to the SM rating the Magnatec I use in the car is.