Clutch slip

Can anybody please help. I have a 1991 FLHTC which I bought last year. When I bought it it had severe clutch slip and would not go above 60 mph, so I changed the clutch.
However, the clutch still slips, not as bad, but at higher speeds it slips. I have adjusted it according to the workshop manual but did not use Harley oil in the chaincase. Could that be the problem?
I have noticed an additional plate on the side of the gearbox which wasn't on my previous glide and a receipt for a Muller clutch kit being fitted in 2005. Could they contribute to the problem?
Many thanks for your help.

[Spen]

Try a different oil, I use Castrol ATF in the primary as recommended on some other thread on this forum.
Works for me

[kiwidave]

you ''changed the clutch''.......what exactly did you do?

sounds like a spendy fix for something that could be as simple as worn friction plates.

Are there the right amount of plates in there? Steels and frictions? Any wear? Any meat left on the friction plates? If you still have an OEM clutch there will be a stack height in the manual. If you don't hit that height with the plates, you won't get a good clutch action.

Clutch hub nut correctly torqued?

Never heard of a Mueller clutch kit so did a websearch and it would appear to be an improved ball and ramp plate for easier lever action. But that won't correct a deeper problem.

Is the pushrod/clutch adjuster nut at the hub set up correctly? Adjustment is just not a handlever/cable issue

Type F or G ATF is the good stuff for the primary as Spen says.....not used anything else for years cos it is cheap, sold everywhere and it works....but you need to make sure everything else is right.

(sorry for the guesswork, I am running the earliest Evo clutch so no actual experience with yours)

Thank you for the replys.
To clarify I changed the clutch friction plates with new, the steels were left as they were fine.
I will try changing the oil and see if that helps.

[kiwidave]

OK cool, but open your manual, check you have the right stack height, torque the nut correctly, make sure pushrod end is adjusted as per the book. It should not be a big deal - though with the post-1989 clutch you will need a diaphragm spring tool, i do believe....the club loans one out to club members.

Pretty rare for the ''wrong kind of oil'' to only have an effect at high speed. All your symptoms point to pressure/adjustment issue....

[Phil]

1/ Pull out all the plates, clean them with alcohol or similar.

2/ Put the steels on a straight edge to make sure they are flat.

3/ Sandpaper the friction discs to a fresh surface.

4/ Take the steels to a local garage & have them glass beaded, then clean.

5/ Re-install per the manual.

6/ Make sure the diaphragm spring is adjusted flat per the manual.

7/ Use a correct type oil.

[Hawkeye]

Originally Posted by kiwidave

Type F or G ATF is the good stuff for the primary as Spen says.....not used anything else for years cos it is cheap, sold everywhere and it works....but you need to make sure everything else is right.

(sorry for the guesswork, I am running the earliest Evo clutch so no actual experience with yours)

Read this thread with great interest, my clutch is on it's way out. The pickup is not till the last bit of the lever being fully out plus when i changed the primary oil recently it stunk to high heavan of a burning clutch.
I would like to point out here thati am not one for riding the clutch, i was like this when i bought the bike last year so i suspect it has a few miles onit's corks. I am about to phone my indy for prices, will include new springs as well.

On the clutch pushrod adjusment......when i first got the bike i adjusted the clutch as i had for many other bikes but being a Harley this is no good. First slacken off the cable adjustment all the way, you then have to screw in the push rod adjusting screw in the center of the clutch till you feel a very slight resistance where it touches the pushrod, then back it off 3/4 to 1 full turn, do the lock nut up then make the final cable adjustment to leave about 1/16 of free lever play.

Dave i have never heard of ATF being used in the primary but on your and spen's say so i will now. I have used it in the forks to great success. Give nice smooth damping.

[dodgyloner]

When you don't know who's had their hands on the bike previously then check absolutely everything back to the manual - its amazing how many idiots can have had their hands on a bike in 17 years.

I agree with the clutch adjustment - once lost an evo clutch because the pushrod was done up too tight. Symptoms were that it was ok up to a certain revs then started spinning. Best go for more end play rather than less - 3/4 to a full turn at the adjusting screw as has been said. Make sure you don't take up too much tension when you adjust the cable.

You can get the diaphragm spring out without the special tool.

Began to adjust the clutch again yesterday, starting at the locknut. I then could not get any adjusment on the cable and realised the cable was not moving in the casing.
On checking it found that it had not been put in the guide that Harley Davidson thoughtfully provide to stop it melting on the exhaust. Oh hum need a new cable now.
Thanks for the help, I also did not know you could use ATF in the chaincase.

[Spen]

ATF fluid is used as a lubricant in Automatic Transmissions, these usualy contain several clutches, band brakes as well as cogs & gears that are generaly worked hard. So it follows that it would work well in a wet clutch/primary situation that you find on Harleys.
It's also used in some power steering systems and as fork oil in some Triumphs & BSAs.