Slipping clutch on my 89 royale

[dz]

Well, I think it's time I address the slipping clutch. If I ride the bike normally the clutch does not slip at all. If I dump clutch it or rev it up to 6500 and speed shift you can feel it slipping. I don't want to race the bike but I don't want to have the clutch slip if I am in a situation where it would prove bad. Is there anything I should be looking for outside of the clutch (i.e. worn slave cylinder or faulty master cylinder)?

[StarFan]

Just send a PM to Skydoc_17. He sells clutch upgrades and will suerly know what you need. He is the clutch expert on this site He will most likely chime in though. He can never stay away if he hears of a member in trouble. Pretty amazing guy to say the least.

He also has a lovely wife that speaks a little Icelandic - She is even nicer than him

[CalhounWV]

Are you using oil specific to motorcycles, I have heard certain car oils have addittives that will cause the clutch to slip. worth.

[twigg]

Well, I think it's time I address the slipping clutch. If I ride the bike normally the clutch does not slip at all. If I dump clutch it or rev it up to 6500 and speed shift you can feel it slipping. I don't want to race the bike but I don't want to have the clutch slip if I am in a situation where it would prove bad. Is there anything I should be looking for outside of the clutch (i.e. worn slave cylinder or faulty master cylinder)?

 

That sounds pretty normal!

 

The way to tell if it's slipping is to get up to about 20mph, then shift into 3rd or 4th gear. Once it's in gear, open the throttle .... If the engine speed increases without a corresponding speed increase, it's slipping.

 

If you put it into too high a gear and try this, it will bog down and may stall, unless the clutch slips.

 

Wet clutches are designed to slip a bit, it doesn't hurt them unless it's excessive. If the clutch isn't slipping in normal riding, then you probably don't have much to worry about.

[bongobobny]

Yah!! Per above could be the discs are glazed and need replacing. See Earl for all you need. Also, do not use any additives to your oil like friction retardants. We have "wet" clutches and any anti friction additives will cause the clutch to slip. No STP, no Wynns Friction Proof, no Duralube, etc. You are best off with plain old 15W40 diesel truck oil such as Delo or Chevron...

[Snaggletooth]

My '84 was acting up when I'd be on the highway in 4th or 5th and crank on the throttle. It would slip like crazy until I'd back off and ease back into it.

 

I went with skydoc_17's upgrade kit with the additional full disk and better springs. Resolved all my slipping problems with very little time invested and for a fair price for everything I needed.

 

Now I drop a gear, hit the WOT and we are leaving!!!

 

But before that the recommendation to check your oil type and even bleed the clutch to make sure that is all in order may save you some time and money.

 

Mike

[twigg]

Yah!! Per above could be the discs are glazed and need replacing. See Earl for all you need. Also, do not use any additives to your oil like friction retardants. We have "wet" clutches and any anti friction additives will cause the clutch to slip. No STP, no Wynns Friction Proof, no Duralube, etc. You are best off with plain old 15W40 diesel truck oil such as Delo or Chevron...

 

At risk of opening up some terrible "oil debate" I will add that I agree.

 

All I have ever used in motorcycle engines is Heavy Duty Diesel Engine Oil.

 

The specs support it and in many cases the only reason that it is not specified for motorcycles is that it hasn't been tested on them

 

The reason for that is marketing .... If those oils were tested and certified for M/C use, then they wouldn't be able to rebadge the same stuff and sell it at three times the price.

 

But diesel motor oil meets all the required standards, and it's relatively cheap .... and it contains no friction modifiers.

 

It also contains few if any viscosity enhancers, which are the main issue when we try to use car oils in bikes. They are fine for cars, but bike gearboxes wreck the long chain molecules added to make the base oil a multigrade, and can be completely broken down in as few as 1500 miles.

 

There is some helpful knowledge in this .... If you are away from home, stuck and the only oil you can get is motor car multigrade, then you will do no damage at all provided you don't thrash the nuts off it, and get it changed in under 1000 miles. Get one without friction modifiers or the clutch will slip.

 

Just adding ......

 

The reason they are designed this way is all about shear strength of the oil. In a car engine, the oil is not subject to anything like the shear forces that it is in motorcycles. The main reason for this is the gearbox. So motor car multigrades use a base weight oil, and add viscosity enhancers to make it multigrade .. so far so good. They also add detergents and friction modifiers to some, which is very bad for us

 

Diesel engines are different. The compression ratios are at least double those in a bike or gas car ... typically over 20:1.

 

This subjects the oil in the main bearings to enormous shear forces, so the viscosity enhancers don't work ... They get quickly chopped up. So they make diesel moter oil by blending real oils ... which is just what we need them to do.

Edited April 22, 2011 by twigg

[dz]

I know about the great oil debate. I drained the oil this past weekend and got specific 20w-50 valvoline motorcycle wet clutch oil (advanced auto was having a sale). In my other bikes i have been using Rotella 15w-40. In my nicer suv I use mobile fully synthetic 10w-30. This isn't my first bike, just seeing if this is a common problem or not. Hopefully it will stay nice for some part of the weekend and I will bleed the clutch and see how that goes. Bike has 66,000 miles on it so it may be do for a clutch rebuild. Thanks.

[Canadian Venture]

Bought 87 VR last year and had a tow bar. Clutch slipped a lot. Did an oil change not much better. Then remembered what dad(mechainc) had taught me, use Rislone with your oil. After a couple of quick changes, no more that 2k, a lot of it went away! You substitute it for 20% of your oil change. But it still slips a bit.

 

For the diesel engine oil, he told me that there is a lot more of "cleaning" action than car oil and now that someone in this post has mentioned that I will be trying that next summer for sure.