bike free reving on hills: HELP!!!!!!!

[larrybuck]

1983 Honda Silverwing Interstate full dresser/shaft 650 (673!)

Owned the bike about 3 yrs., not even taken on 1 long overnight trip yet.

Has about 18K or so.

A few months ago, on a long uphill grade where I was hoping to maintain a steady 50mph., part way up the bike slipped revved up about 1000, to 1,200 rpms higher temporarily until I backed off the throttle to compensate, thusly losing speed to about 42mph. when regrip of top gear w normal rpm's appeared under lighter right hand.

It started at first only on very steep hills w moderate to low (lugging?) rpms.

Now, even on a fast entry 55mph on flat to a quite moderate hill, it's slipping along with my piece of mind.


This is my 2nd Silverwing w shaft. Unfortunately with my 1st, I experienced total failure on a trip. Before the trip, I had a bike shop put a new rear tire on. They did not refill the shaft differential level, so it wore on a skeleton plate, where the gears are supposed to match up to.
Bike too old for that fresh part, they found a used one good enough to get me 400 freeway miles home.

2nd Silverwing was owned before me by one who used regular car oil in it instead of motorcycle oil. Very early on, I had my shop drain and refill w fresh diff. fluid NEVER wanting that problem again.

Everybody tells me that they have NEVER seen problems w shaft bikes, supposedly bullet proof.

I'm just a bit paranoid now! I'm trying to keep three cars, and 3 bikes going on 16 months being out of work. I just put a new rear tire on my CB400; had $250. work done on my 250 Enduro. The seasonal rains have returned, so for most, motorcycle season is over.

I'm not much of a wrench. Could just the clutch be slipping, and it's not shaft related at all? Can a simple adjustment of some kind be the cure?
A new clutch? I can relate to car clutches more. What (how deep) is involved w that $$$ wise, especially w a shop's $70. + an hr. rates?


Thanks for any feedback; I wish I could find a kit to make it a belt drive!

[Clev]

I don't know about bikes, but the symptom seems to be classic clutch slip to me.

[Ryland]

You can not have synthetic oil in a motorcycle with a wet clutch unless it's wet clutch compatible synthetic oil, so the first thing to do after you check that things are adjusted correctly is to do an oil flush.

[euromodder]

Originally Posted by larrybuck

Now, even on a fast entry 55mph on flat to a quite moderate hill, it's slipping along with my piece of mind.

Sounds like clutch slippage to me.

There's a few causes for that.
- Unsuitable oil, if it's a wet clutch.
- worn clutch plates
- worn clutch springs

Don't ride it if you don't have to before it's sorted.
Keep it out of the conditions where slippage occurs if you have to ride it.

At 18K (really, after 28 years ???) it shouldn't have its clutch slipping.

Everybody tells me that they have NEVER seen problems w shaft bikes, supposedly bullet proof.

They can have the very same problems as chain driven bikes.
A belt drive won't sort clutch issues either.

Shafties tend to be driven more by older, more relaxed drivers over longer distances though - that's probably where the difference is

Could just the clutch be slipping, and it's not shaft related at all?

I'd look into clutch issues rather than / before looking at the shaft.
And do it soon, it might still be recoverable.

Can a simple adjustment of some kind be the cure?

Unlikely, but make sure the clutch is fully disengaged when it's pulled in.

If it uses an external pushrod to operate the clutch (as Suzuki does), make sure it's straight and moves freely either way when the clutch is operated.
At least on chain-bikes, there can be a lot of grime & grease sticking to it and the clutch linkage mechanism.

2nd Silverwing was owned before me by one who used regular car oil in it instead of motorcycle oil.

Does it have a wet clutch ?
If so, have you had the oil changed since ?

Wet clutches and car oil usually don't go well together.
A wet clutch needs an oil that won't let the clutch slip.
Most of these are dedicated bike oils.
In a wet clutch set up, don't skimp on oil, it has a very hard life in there.

If it has a wet clutch and the previous owner's oil, get a cheap but wet-clutch rated oil, drain and refill.
If that cures the slippage, drain and refill with a better quality wet-clutch rated oil.

If that's not curing it, the most likely issue is worn clutch plates.
It's something you can do for yourself with the guidance of a manual.
Make sure you put everything back in the way it came out though - especially clutch plates.

[Varn]

Change the oil to a diesel grade of engine oil. Problem solved. Your clutch is slipping because you are using oil with friction reducers and your clutch hates it. Diesel oil doesn't have friction modifiers. You don't need synthetic oil for your motorcycle. It is basically a waste of money.

By now you may have fried your clutch plates. If the oil change doesn't help then get new friction disks. Something like a hundred in parts.

As far as ruining your first bike because they didn't fill the rear axle. It has nothing to do with changing your tire. The tire and final drive are separated by an oil seal. A trip to a salvage yard could have supplied you with a new final drive for a couple hundred.

Belt drive? Don't go there. What happens when your belt shags. Probably you will need 3-400 in parts.

[Ryland]

MrCycles Honda Kawasaki Polaris Suzuki Yamaha Motorcycles ATVS Scooters Utility Vehicles

Looks like it'd cost you about $120 in parts, good thing is you don't have to pull the engine to get at the clutch.
I've seen this happen twice before with motorcycles where a "high grade" of engine oil was used and it had friction modifiers in it, they make the clutch to slippery so it doesn't grab.
If you want to try to fix this on the cheap, pull the clutch and rough up both the shinny steel rings and the cork covered rings with some sand paper, 100 grit sand paper should work well, this will allow you to remove some of the slick surface on the cork exposing new sticky cork, roughing up the steel rings will put new cross hatching in, these will hold oil while the clutch is disengaged so it doesn't heat up as much, the cross hatching will also give a little more bite when it starts to grab and the oil gets squeezed out.

[larrybuck]

First, I want to thank everyone for their advice. You guys are quite deep.
I apologize for differential terminology!

I had upgraded from half/half to full syn. in this last yr. The previous car oil was only for eng./trans.; wasn't in shaft area.

My update is that I rode it yesterday instead of two other bikes, because there was a threat of rain, and this bike is better suited to handle the wet.

What I noticed like starting from a stoplight, that the clutch lever was lazy to return to normal position, I manually pushed it outward from me with the back of my hand.

When I came to the same moderate hill I've mentioned earlier at 55mph., this time I preventively pushed out w the back of my hand to make sure the lever would stay in it's proper place, I had no slip problem at all.
I get the gut feeling that as Frank mentioned, that I simply may need to make an adjustment there at the cable end.


The reason this old of a bike has so few miles, is that there are a lot of fair weather only riders here in the wet Pac. NW.

[Everett]

Sounds like the clutch cable to me. And if it's a shared sump you needs an oil with the JASO spec. I use the rotella t-6 for my jap bikes and I was using amsoil in my Harley but it's getting the rotella next too. Great oil.

[TXwaterdog]

Originally Posted by Everett

Sounds like the clutch cable to me. And if it's a shared sump you needs an oil with the JASO spec. I use the rotella t-6 for my jap bikes and I was using amsoil in my Harley but it's getting the rotella next too. Great oil.

Same thing happened to my Buell, it was a dry clutch/ chain driven.. swapped out and adjusted the clutch cable.. and that didn't solve the problem. it turned out to be the internal adjustment + clutch discs. How does this translate to your bike.. well it could be a number of things and until you start toying with it you'll never know. The quicker you tackle problems like this, the less they wind up costing you. good luck on the fix/ give us an update please.

[GMPG]

Originally Posted by Everett

Sounds like the clutch cable to me. And if it's a shared sump you needs an oil with the JASO spec. I use the rotella t-6 for my jap bikes and I was using amsoil in my Harley but it's getting the rotella next too. Great oil.

This, exactly. It's a common misconception that you can't run a full synthetic in wet-clutch motorcycles when in fact it can be the best thing for them, especially old bikes. What you need to avoid are oils that say "Energy Conserving" in the lower part of the rating circle on the label. I've been using Rotella T6 since it came out and I'll be running G-Oil 5w40 next season.

If you feel more comfortable running a non-synthetic I'd stick with Mobil Delvac, Rotella 15w40 diesel oil or another quality diesel oil. These oils are made with higher quality base stock and better additive packages for motorcycle applications, especially where the engine and transmission share the same oil.

I'd start trying to solve your clutch issue (which it almost certainly is) by adjusting the clutch, not just the cable. I don't know your bike specifically but it's likely that you also have an adjustment at the actuator rod. Your owners manual should have instructions but if not teh googles will.

It's unlikely you needed new clutch plates at 18,000mi although you may now that it's been slipping. If adjusting the clutch doesn't help then I'd go ahead and order the clutch plates, discs and springs. Do that and you should be good for many years of riding!

Good luck!
-GMPG