Slipping clutch

[phonetrouble]

I have looked through the posts, and haven't seen one like this, so here we go...

As the original owner of our '84 Venture (Not Royale), I have started to notice a problem with the clutch.

2 things,

1st when bike is warm and we are stopped at a light, the clutch starts to engage, causing the bike to try to move, so I put it in neutral at lights now.

2nd thing is that if I am doing 65 and roll hard on the throttle, the clutch will slip and I have to let off some to let her catch up.

I don't see any slippage under normal driving, even up to 85mph.

 

We always ride 2 up, and with 74k on the bike, it isn't very high mileage. 90% of the time, we are 2 up, and about 40% of the time we have pulled a trailer.

I don't remember changing the fluid in the clutch, but have kept the reservoir full and check it regularly when I check the brake fluid.

Are we due for a new clutch, or is there some maintenance we can do that will stop these problems?

[MiCarl]

You probably have two issues:

 

1) You're losing pressure in the clutch hydraulics. If the fluid level is going down it's likely the clutch slave cylinder. If you're not losing fluid it's probably time for a master cylinder rebuild.

 

2) The clutch itself needs service. New friction discs and springs. Steels are likely still good, but you won't know for sure until you inspect it.

 

Oh, and after you fix it replace the brake and clutch fluid at least every two years. DOT 3 and DOT 4 brake fluid absorb moisture over time. That moisture and resulting gunk are not good for the master and slave cylinders.

[Marcarl]

So much for my input,,, can't see why I keep all that info in my head,, maybe I should clear it out to make room for more.....

Thanks Carl, that would have been input exactly.

[RedRider]

IIRC, it is actually less expensive to just replace the slave cylinder rather than rebuild it.

 

RR

[Flyinfool]

I would start by flushing the fluid in the clutch system first to see if that helps the creeping at a light. Brake fluid is cheap. If that does not fix it then you will have to do the rebuilds / replace master and slave.

 

It is usually better to replace the slave with a new slave rather than rebuild. The issue in the slave is usually corrosion and the rebuild kit will not fix that, and the rebuild kit is not much le$$ than a new slave.

 

 

There is a good chance that your clutch is fine, the stock spring is known to die of old age and the first symptom is slipping when you get on the throttle. You will not know if you need new clutch plates until you take it apart and measure them. New plates are 3mm (0.1181 inch) thick and worn out is 2.8mm (0.1102 inch) thick.

Skydoc_17 sells a spring kit with a slightly stronger spring that will not slip. If you need them he also has the plates.

[MiCarl]

It is usually better to replace the slave with a new slave rather than rebuild. The issue in the slave is usually corrosion and the rebuild kit will not fix that, and the rebuild kit is not much le$$ than a new slave.

 

I rebuilt mine. Only took half a day to polish it up and I think I saved a whole $10!

[phonetrouble]

Thanks Everyone!

Plenty of good info, and I will take a look at it over the next two days as it is supposed to be cold and rainy again in Oklahoma.!

[SilvrT]

Bleed the system and get a clutch spring upgrade from .... is it Skydoc?

[jfman]

Well crap I have the same problem as phonetrouble(the slipping)

 

It only does it if I downshift to pass a car and I gun it at high rpm. In normal driving there is no slippage at all.

 

So the 30 year old springs are likely suspects?

[Marcarl]

Well crap I have the same problem as phonetrouble(the slipping)

 

It only does it if I downshift to pass a car and I gun it at high rpm. In normal driving there is no slippage at all.

 

So the 30 year old springs are likely suspects?

 

Easy answer: YEP!!

[Condor]

All good advice.... One last thing. Check to see if the expansion hole located at the bottom of the reserve is plugged.... just because... Due to the location of the slave a plugged expansion will cause the clutch to slip as the engine heats up. More so in high gears when passing. In @phonetrouble's case, with the creeping at a stop, it probably isn't the issue.

[skydoc_17]

Hey JF,

Here's the kit I offer for the MKI VR's in the Classifieds:

 

http://www.venturerider.org/forum/photopost/showproduct.php?product=61&title=first-gen-mki-heavy-duty-clutch-springs-upgrade-kit&cat=17

 

Good luck with this project!

Earl

[cowpuc]

Lots of really really good advice here Phonetrouble!! Wanna add a couple things.. Any chance you been using regular car oil in your scoot? IMHO - that stuff is disasterous on the clutch plates. Also, another thing that can cause your scoot to develop what you have mentioned, again - IMHO, it what I refer to as "saw toothing". That is an ailment where the clutch plates have worn a small notch in the clutch basket and the plates are not able to move properly across the surface of the basket edge.. Might be worth taking a real close look at the edges when you got it apart to make sure they are not notched a little.

 

Never have had a good clutch in any of my 1st Gen's,, thinking they came stock with weak Clutch springs and that the engineering theory of the 1/2 plate buffer in the clutch basket was not a good idea.. If I were ever gonna actually take an attempt at creating a REAL good clutch that didnt slip even in 4th and 5th gear when the scoot was fully loaded and taching 4 grand when I nailed it, I would ditch the 1/2 plate and get stiffer springs.. Then I would also make sure that I NEVER used energy efficient "car oil" with all its non friendly slippery additives - got a theory of my own that tells me once glazed always glazed and that energy efficient oil can sure glaze a clutch plate..

[GaryZ]

All good VR clutch advice! I suspect old fluid causing clutch creep and old springs causing slippage.

 

The clutch started slipping at upper rpm under hard throttle on my '85 after the cam upgrade. The '87 engine was only a little over 40,000 miles old and the clutch still looked good. I ended up replacing the clutch and using two stock clutch springs, stacked. I can't remember who suggested it, but, it worked. And the clutch handle pull is reasonable.

 

Edit:

I guess I didn't realize the '84 uses the six coil springs, not the flexing piece of metal on my '87 engine . . . Sorry

Edited March 29, 2016 by GaryZ

[GeorgeS]

First , make sure you are using Motorcycle Spec: Oil, ----- NOT Car Oil. ----- If so change it, and check for high speed slippage.

 

Second: Replace the clutch actuator Fluid. Use DOT 4. ( do this every couple of years anyway ! ) Reminds me, I am due for fluid change myself.

 

If still having trouble, then get SkyDoc's clutch upgrade, Or, get a " Barnett Aftermarket Clutch kit " ( Don't forget new gasket for clutch cover )

[Venturous Randy]

His 84 should have the 6 clutch springs and they are easy to replace with stiffer ones. The clutch starting to engage while stopped sounds to me like the master cylinder is leaking internally and not holding pressure. All the other suggestions are good too. I have been running the Rotella T 15/40 and it works good in mine.

Randy

[bongobobny]

Ya know, I might have some Barnett clutch springs laying around, I will have to check. My price is VERY reasonable if I do, just ask any of the members...

[Venturous Randy]

Ya know, I might have some Barnett clutch springs laying around, I will have to check. My price is VERY reasonable if I do, just ask any of the members...

Yep, I can sure vouch for that. I am still using the fuel pump you sent me and I still appreciate it.

Randy