Fourth Gear - Mysterious acceleration problem

[silversurfer1050]

OK, I couldn't decide which of the categories to post this in. Here goes.

I was trying to relate a problem I've been having with my '79 to my mechanic. All of my gears seem to work fine Xcept fourth. When I shift into fourth and Xcellerate, it seems like the clutch is slipping.

Larry, I believe I read something you wrote about this once. Could you refresh my memory please? My mechanic owns two CBX's and has never heard of it.

Apparently when the clutch cable tension is set incorrectly (too tight?) it presses against the fourth gear dog and keeps it from fully engaging fourth gear. Does this sum up correctly?

Thanks,
Bill

[alimey4u2]

OK, I couldn't decide which of the categories to post this in. Here goes.

I was trying to relate a problem I've ben having with my '79 to my mechanic. All of my gears seem to work fine Xcept fourth. When I shift into fourth and Xcellerate, it seems like the clutch is slipping.

Larry, I believe I read something you wrote about this once. Could you refresh my memory please? My mechanic owns two CBX's and has never heard of it.

Apparently when the clutch cable tension is set incorrectly (too tight?) it presses against the fourth gear dog and keeps it from fully engaging fourth gear. Does this sum up correctly?

Thanks,
Bill

Strange one this Bill of which I too have never heard off. The thing I wrote was about was jumping out of gear..... However, this would seem to me that the clutch is very close to slipping in the other gears, it's just a matter of torque loading.... Ensure that you have ample end play at the lever, or you need new clutch plates/springs. ??
Failing that, it may well be a serious gearbox problem relating to the 4th gears meshing...... Drop the sump plate & look for steel debris....

[silversurfer1050]

I took it in to my mechanic for a cable adjustment. They took it for a ride and said they had it adjusted. (We added two quarts of oil after this though).

One of the guys at the ride this weekend suggested a bent clutch finger not allowing fourth to engage totally. I've shifted without the clutch before and think I would know what that feels like. It would jump in and out, right?

Wouldn't 5th slip also at least if it were plate wear/tired springs? It's a taller gear.

[alimey4u2]

I took it in to my mechanic for a cable adjustment. They took it for a ride and said they had it adjusted. (We added two quarts of oil after this though).

One of the guys at the ride this weekend suggested a bent clutch finger not allowing fourth to engage totally. I've shifted without the clutch before and think I would know what that feels like. It would jump in and out, right?

Wouldn't 5th slip also at least if it were plate wear/tired springs? It's a taller gear.

Bill, The clutch is totally independant of the gearbox, it doesn't know what gear you're in or really cares. It's either in, out or slipping, it's a dumb clutch. The slippage depends on how much you want & that is dependant on your clutch lever position controlled by you.... All this is of course with a clutch that's in good mechanical repair....
It's all a matter of torque...if the clutch is on the ragged edge of direct drive, it will slip when the torque required is at it's greatest....

I find the two quarts of oil as top up, troubling Bill....

[EMS]

..
It's all a matter of torque...if the clutch is on the ragged edge of direct drive, it will slip when the torque required is at it's greatest....

I was thinking exactly that. Maybe the way Bill is driving produces the torque peak in fourth gear...

[Jeff Bennetts]

You using syn or dino oil?

[silversurfer1050]

I'm using Honda GN4.

I've only put about less than 10,000 miles on since 1988. I'm embarrassed it got two quarts low since the last change. - just didn't think it was using any. It's still fairly clear right now, but probably due for the next change. I probably won't get another 400 miles on the X this year.

I drive my Hurricane on a more regular basis.

Bill

[silversurfer1050]

..
It's all a matter of torque...if the clutch is on the ragged edge of direct drive, it will slip when the torque required is at it's greatest....

I was thinking exactly that. Maybe the way Bill is driving produces the torque peak in fourth gear...

Mike,

I think it starts slipping somewhere over 7 1/2 Grand.

[alimey4u2]

Bill, I personally think it's nothing more than either clutch/cable adjustment or your clutch plates are on the way out.....

[silversurfer1050]

...shop says $170 for the plates alone and 1 hr labor.

It runs and holds really well in all the other gears. I'm budgeting for nest year. Like I said, I put most of my miles on the Hurricane.

Thanks guys.

[Rick Pope]

I've noticed that all my older bikes will slip the clutch if they're ridden little, or infrequently. But you have to be accelerating hard, or power shifting to make it happen. After using the clutch a while, normal riding for perhaps 30-40 miles, the clutch is fine.
My thought is that the oil needs time to get really warm in the clutch pack, and the additives are coating the discs too well when it's parked. Gee, the very things we DO want in a motor oil, we DON'T want on our clutches.
I cured the CB750 hot rod by sanding the steel discs radially with 80 grit.

[chuck_b24]

Hello if your plates are worn (just worn NOT trashed) just add a steel in the middle of the clutch & readjust!!...chuck

[Terry]

Silver, still having the problem? I can't see why one gear or another would slip and not any others. I found a great clutch combo that I've used for some years now both in the 82 and the 79. After 20,000+ miles I can speed shift thru all the gears and get no slip whatsoever. I use EBC frictions and Barnett steels. I've heard that stock OE frictions are good too but apparently not the steels. I use EBC's slightly HD springs in the 79 but when I change again I think I'll go back to stock springs. They work very well on the 82 despite my right wrist. BTW, I run Valvoline m/c specific dino oil in the 79 and full synth Amsoil in the 82.

[silversurfer1050]

Hi Terry

Do you have a link to parts - nad are they possibly any less expensive? Or a phone number of a supplier?

Thanks,
Bill

[Terry]

Its been awhile Bill but as best as I can recall, the last clutch I bought was thru Tims. Can't remember now if I also got the Barnett steels thru Tims or thru my local Honda dealer but the EBC frictions I got thru Tims. Don't recall doing a price comparison but they were only 7-8-9 bucks per plate if I recall correctly. Like I said, its been awhile.