Which oil to use?

[bhf]

I resently rebuilt my cbx 79' and put 15w-40 semisyntex oil with these specs. API SL - JASO MA, MA2.
When cold it is ok to drive with, a bit hard shifting but thats it. But when warm after 30-50 km driving in hot weather 20-25degrees Celcius it is very hard to shift and pull clutch and sounds very hot, like its not probaly cooled. It is always hard to get it in neatral gear. Would a fully mineral oil and thicker oil help me or? Please give your inputs!

Note. The clutch is ajusted like the book says!

Hope the best ! Benjamin f:)

[daves79x]

I would suspect a worn set of shifting forks/slider gears. I'm about to tear into a '79 with the exact same symptoms and no amount of external clutch adjustments/clutch changes fixes it. Center shift fork is prone to wear as well as it's mating gear.

Dave

[CopperCollar]

I pretty much agree with Dave on these bikes but one thing I would look at is the clutch.

The Travesty acted the same, almost exactly except once warm I could never get it in neutral unless I killed the engine then popped it into neutral. Don't force the gear selector into neutral, the fork will bend.

Dave may be right but it couldn't hurt to check the clutch out before pulling that monster engine and splitting cases.

So far as the oil I would stay with the recommended weight and stay away from synthetic or blended oils.

Mike

[Goss]

Try 10w-40 semi or mineral especially in the colder months, higher temps 25C plus a 20w-50 is better.

[daves79x]

On the bike I'm about to tear into, I think what you describe Mike, is exactly what happened. Someone put a Xtra-plate clutch in it years ago that was all the rage. The clutch has one extra fiber and you buy an extra Honda steel. Only way it fits is that the fibers are thinner than Honda's and the Xtra-plate stack barely fits. If not adjusted exactly, very stiff shifting and hard-to-find neutral results. This bike was run that way for lots of miles and the very stiff shifting must have finally wore or bent something. I've tried 3 different combinations of Honda clutches in this bike and none allow normal shifting. So time to split the cases and see what's wrong.

Certainly adjust everything by the book and if all's right inside, the bike should shift normally. I use 10W40 Honda GN4 oil in most of the bikes I service. Your oil is not the problem.

Dave

[bhf]

The clutch case is a rebuilt one and the plates should have the right meassurements. I had the intire engine appart last year when rebuilt, and checked the shift arms wear by book and it looked ok. But dont know if something went wrong when we took the engine back together. I had everything out to meassure by book specs, and assambled like the book says. .?

[CopperCollar]

I don't have the experience Dave has with these engines but I have noticed the clutches seem to like proprietary Honda parts.

Louis sold me a used but matched set of fiber and steel plates at a great price to I might add. I installed them in the Travesty and she shifts well now, no problems finding neutral.

Like Dave says there could be a tweaked shift fork. I only know that the fork shaft can go two ways, one you get all five gears, the other way you be missing a couple.....hmmmm. wonder how I find that one out.....lol
Mike

[daves79x]

Yes, Mike, installing the shift fork shaft backwards gives you an instant 4-speed transmission! Several of us have found that out the hard way.

Dave

[bhf]

Can you tell me how to check if the clutch plates and steel plates are original parts or from some other firm?

[CopperCollar]

Wished I knew how to tell myself.

I know others have great results with the fiber plates that Cruizinimage sells on eBay. Rumor is they are made by the same company in Japan that made the plates for Honda.

The price is right too!

Steel plates, I cannot comment. I have heard good and bad.

Mike

[EMS]

The same friction plates as in 1978/79 are probably no longer available as these most certainly contained asbestos

[CopperCollar]

Yeah, that pesky asbestos.

12 years working with it in the Navy....before they took it's health effects seriously. Three shipmates dead from
mesothelioma and I am sure more to come. Stuff is nasty.

You say 79/80 Mike, are 81/82 made of a different material?

Mike

[daves79x]

Part number for the clutch plates is the same for all years. I've bought 2 or 3 new sets from Honda over the last few years and they seem like the original in every way, but in any case, work like the originals. I have installed TIMS aftermarket clutch packs also and they have performed quite well also. For many years the aftermarket couldn't get the CBX clutch right as you could never find neutral and they would drag horribly. From my recent experience I would not hesitate to use either Honda or TIMS plates today.

Dave

[EMS]

You say 79/80 Mike, are 81/82 made of a different material?

Mike

I did not mean to indicate that! If there is a material difference, I would not know. I just referred to the 79/80 because of the age and the time asbestos was still in use.

[bhf]

Okay thanks for det reply, is there any difference to see on the plates, to tell if its original?