Clutch slip

[florence]

has anyone successfully cured the dreaded clutch slip and if so how? mine is bugging me, I can't seem to get up to a good speed without it being a problem, especially if I go over a bump in the road; gear changes I can usually manage but road bumps are frequent around here.

I have thought about stronger springs.  If so, does anyone know a good supplier. 

Surely the racing ones don't have this problem and they have even more BHP to contend with.

[Johnwebley]

I replaced my clutch plates about 10 years ago,used the original springs,and so far seems to cope,

no slip,but lots of drag !!!

 I finally decided that as the plats got hot,they stuck in the basket,so I trimmed/filed the outer "tangs" so there was more movement
and so far the drag has gone,

I suggest the springs are ok,but you need new fibre plates,

[LesterPiglet]

I haven't had a problem since I rebuilt mine 5k miles ago. I filed the rough off the edges off the basket. Previously it was like yours, slipping when hitting bumps, especially in the upper gears.

[matthewmosse]

I cannot recall how I fixed mine when it last played up, but it was a non invasive  fix, either the adjuster or the push rod through the gearbox, service, adjusting etc. That didn't slip even tugging a chair with a whole 500/4 and toolkit spare fuel and oil in the chair. It did at one stage get really bad but whatever the fix was didn't even need the cluch cover off. The new boxed heavy duty plates and springs the bike came with ready to fit were never fitted in 100 000 miles and are still floating around the attic awaiting being needed.

[Lobo]

Understand that using a full synthetic oil can give rise to clutch slip...  if indeed using this a swap back to recommended oil might be a start.

And assuming clutch set up as per the manual..

In my CB500/550 manual these various specs if of any help... eg length of springs & so on. 
Good luck..

[matthewmosse]

I did once try a really cheap semi synthetic oil as it was cheap, and had horrid cluch slip, mostly went after an oil change but took a couple of oil changes to cure completely.  I'm sure I am  running semi synthetic now but it is ok in all my bikes I suspect the specific formulation of that particular oil had some fancy anti slip compund as it was car intended stuff so to bd fair to the oil makers wasn't intended to see a wet clutch. Worth a thought though if you changed oil brands or the makers of the oil possibly messed about with additives.

[Rumpelkrankshaft]

Changed the plates for genuine Honda ones some 23000 miles ago-never had any problems with slip despite it being the lightest clutch lever I had ever encountered up to that time!

[s7paul]

I did 34000 miles in 2 years on my first CB500, and never experienced clutch slip. I sold the bike with 46000 on the clock.  I've only experienced slippage on my current CB500 when I stupidly put fully synthetic oil in it.  Since I got rid of that, I've had no further slippage, but the clutch has been very grabby - more like an on/off switch.  I read that a cure for this is to fit the friction plates from a CB450, which I did, though only recently, so I haven't yet had chance to fully test it under all conditions.

[florence]

The clutch on mine has always slipped a bit and I thought this was just a 'feature'.  It has the same clutch as my CB350 and that was prone to slipping under hard work.  The mad thing is I think it also has more or less the same clutch as the CX500 and that never slipped.

The mileage of this engine is pretty low but it is using the plates which came with it from the factory.

The oil I am using currently is 'Rock Oil Gamma Mineral Motorcycle Oil 10w40' which is, I think, very 'mineral'.

I might start by checking the adjuster and re-adjusting.  If that fails then I will take off the clutch cover and try some heavier springs and new plates. 

It's driving me mad.

[Ian DB]

The clutch on my 500 K2 would engage all at once when setting off and also slipped badly when opening up the throttle. I too thought that this was normal especially after reading the article in the brooklands book (Honda CB500 & 550 fours performance portfolio page 74).
However when I replaced the clutch cable which was too long as the bike was a USA import but the previous owner when putting UK handle bars on didnt change the cables, I also striped down the adjuster, cleaned out all the old grease etc and replaced the return spring that had stretched, re greased the adjuster and all now ok. Lets hope it stays that way

Ian

[Bryanj]

I will say that cable run (and cable type) makes a vast difference to the 500, my first 500 would always slip if a gave it some severe wellie from standstill and would keep on slipping through the gears BUT the takeoff was spectacularly quick and in 3 years of trying i never burnt it out---Ahhhh those were the younger days!!

[matthewmosse]

I've always found with all my Hondas that any seemingly bad fault developing is very often cured by some element of servicing, cable runs, and lubing and chain tension etc. They tend to remind you they are due a service - I know where the oil level is on my bikes by the engine noise, as it reaches the 'low' level on the dipstick they all develope a definate rattle and I know to top up, particuarly handy on my rebel 125 as it will do 1000's of miles using no oil then burn 1/2 a pint in a few 100. The thing now rattles most of the time though regardless of oil.

[K2-K6]

I'd go with the others here and check the outside stuff first.

Take both ends of the cable off and pull the inner back and forth to see if it's dragging at all and sort that if it is, try silicon grease in the worm mech as this will not usually change and get gummy over time and use.

Ride it with excess slack in the cable to make sure that is definitely not holding the clutch open at all.

The different oils mentioned earlier (don't think it's this as you seem to have an appropriate spec in there) as I understand it are to be avoided if they contain "mollybdenum" (maybe not the correct spelling) as it's this friction modifyer that is considered accumilative in clutch materials, making them slip and hard to get rid of with a change back to other oils. I don't believe that "synthetic" as a general term is to blame.

[florence]

thanks everyone, this is all very good advice.  I will try to find time at the weekend to check all the ourside stuff.