Clutch Slippage and Motor Oil

[Steverinomeiste]

Hi Everyone:
I apologize if this topic has already been discussed. I couldn't find it under a search which, of course does not mean it isn't there.
When I was a kid, I read a book I found in my Grandfathers basement. It was titled The Hidden Persuaders. This book convinced me that all brands of any particular product are pretty much the same in quality. The price difference paid between off-brands and brand name items only fulfilled a perceived need in the consumers mind and created profit for the seller.
Not wanting to be one of those suckers, I've always bought the cheapest motor oil I could find and I don't change it until it's contaminated. I've never had a problem. I've run my cars up to a couple hundred thousand miles with no mechanical failure.
Last Fall I bought a pretty expensive (at least, to me) Honda motorcycle and my friends at our local Honda shop told me under no circumstances, to put regular motor oil in my motorcycles. They recommended Pro Honda GN 4 motorcycle oil. The two reasons they cited are:
1. Regular motor oil is designed for automobiles which are equipped with sensors and catalytic converters. In order to prevent contamination of these devices automotive motor oil no longer contains zinc. Motorcycle engines need the lubricating and cushioning qualities of the zinc additive found in motorcycle engine oil.
2. Regular motor oil is designed for dry clutch systems and motorcycles need oil designed to lubricate the engine while not being so slick as to cause the clutch to slip.
This second point really resonated for me. Even though I've had my CA95 clutch apart several times, cleaning, sanding the plates, and replacing the springs I still get slippage in the higher gears. This Spring I am going to flush the motor out real well and replace the oil with Honda GN4 to see if there is any difference, although, I suppose it could be argued that I've permanently contaminated the plates by using regular oil.
Anybody have any thoughts about this?
Steve

[Larzfromarz]

Steve,
Oils can be a funny thing with the older bikes and new oils are less compatible.
Spokes like an oil used for diesel engines (has the correct additives for our applications)
and there are many good oils that do work, Rotella, Motul and others. There are a few good informative threads around but beware of conflicting info.

[Spokes]

I hope member Kartgreen chimes in. He found a source of motor oil designed for classic engines.

I like

Shell Rotella straight 30wt diesel oil. No clutch slip

In a pinch:

Castrol Straight 30 wt oil and I blend in the zinc additive found at most auto parts stores.

I'm trying Castrol 30 wt with 10% straight 50 wt racing oil.

Both of the above oils give some clutch slip under heavy acceleration.

Since I live .5 miles from work, no lights or stop signs (except on the way back) I live with a little slippage until I find my Rotella again.

Never, but never, use Chevron straight 30 wt oil. I did and it glued my clutch plates tight.

[ByTheLake]

I use Shell Rotella (zinc) in my vintage bikes, and Mobile 1 full synthetic in my newer bikes. Even under full acceleration in the new bikes, I've never experienced clutch slippage with the full synthetic.

Debating engine oil in a motorcycle forum can ignite religious wars.

Here is one of the best write-ups I've seen on the subject. It's a long article but very informative.

[kartgreen]

Morris Classic motorcycle oil . I don't have any slippage problems although the plates do stick together when the bikes sit for an extented period of time .
Make sure you've adjusted the clutch freeplay properly .The barrel adjuster on the left cover should have a slight gap between the adjuster and the pushrod . Use the cable adjusters at either end of the clutch cable to reduce slack and set the lever engagement to your liking .
I use CR80 honda clutch springs but they give the clutch lever a strong pull .

[Steverinomeiste]

Good Morning:
I changed my oil to the Honda Brand a month ago and now have accumulated a little over 50 miles. It must take time, but I am beginning to notice an improvement in clutch performance.
On another forum I read of the use of synthetics causing starter clutches to malfunction.

[Spokes]

No need to worry. The CA95 starter clutch is dry.

[Steverinomeiste]

Hey Spokes, isn't the dynamo wet? I need to look at a diagram. I remember a port in the case directly below the crankshaft on the starter clutch side. I'm not doubting the Master I'm just surprised.

[Steverinomeiste]

Is the starter clutch a sealed unit?

[Spokes]

Ahh, I wish I were the master...

Alas, the dynamo on the CA95 is dry. The dynamo on the CA160 is wet. One will get some oil seepage in the CA95 dynamo if the crankshaft seal is worn.

The starter clutch is indeed dry as well. There are two crankshaft seals in the housing that accommodates the flywheel and seals the crankcase. You can prove this by removing the left side engine case to expose the flywheel and starter chain.

The starter clutch is not sealed.

[Steverinomeiste]

I spent so much time on the inside of that motor, remember my hunt for a good crank? You would think I wouldn't mix this stuff up. When you mentioned the CA160 being wet it began to dawn on me that I was confusing my CA95 motor with the CB160 I've been building. I fired up the CB160 for the first time today and it will be done in time for our local Honda Shops 50th anniversary next Saturday. I've accumulated so many cast aside CB160 parts from the CAFE racer crowd that I am starting on what will be a Factory Stock all white one now. Thanks Spokes.

[Sam Green]

Technically it is dry but not completely, As Steve says, there is an oil port after the first seal.
This allows a little oil to get through to lubricate the starter mechanism.
Over time as oil builds up in the case, you might think you have a leaking seal but you don't.
As I don't have a starter on the race bikes, I block the hole and fit two seals to stop this flow of oil, but yes, it is technically a dry system.

Sam.