There's no fun like clutch fun! 1980 CB750F

Hello all humans far brighter than I!

Recently took my 1980 CB750F on a two hour highway trek to NYC.

Pulled into a reststop a little over half an hour into the trip. As I
pulled onto the ramp and began to downshift, the clutch handle felt
funny. I initially chalked it up to my hands stiffening in the cold,
pre dawn air. However, I noticed as I approached a toll barrier that
I pulled the clutch lever in and the rpm drop was noted, but minimal.
I released the leaver and tried again, this time the rpm dropped down
to idle range.

By the time I hit the stop and go traffic in the city, I noticed that
I would stall if I stood in gear with the clutch engaged and I could
not get into neutral unless I was moving. Makes for a fun trip in
such a desolate town.

Oil was recently changed, air temp started at 40 and was up to 70 by
the time I reached my destination. Tweaking the cable length adjuster
on the lever cuff seemed to have no impact. Around town here, I seem
to have some struggles with it, but it's not as clear from where the
trouble is sourcing as there are some other excitements that the bike
is suddenly sharing with me.

Did the mech (and I will NOT be offended if it is the case) use the
wrong oil, cheap oil, etc.? Does the clutch need to be professionally
adjusted? Is it shot?

 

Um, clutches aren't connected to throttles.

If you don't know how to adjust it, ask SWK. It could be shot, yes, but
correct adjustment is the first stage.

 

This is only true if someone's using very pricey synthetic car oils,
some of which have friction modifiers that do make a clutch slip.

Hopwever, this is very rare, and the fact is that his symptoms don't
indicate that. His clutch is not slipping.

 

No, you're right. Clutches aren't connected to throttles. The do,
however, influence RPM. Normally when I pull in the clutch lever (and
naturally throttle down) the RPM's tend to drop. In this case, the
engine maintained RPM's with the clutch lever pulled in. In some
cases there was a very slight drop, others none. As the day warmed,
the difficulty became less pronounced. Interestingly, this was the
first trip on an interstate, so I was now doing 75 mph for a sustained
period.

Your thoughts...?

 

I'm wondering whether it's got the wrong grade of oil in it, but I'd
still start with adjusting it right.

 

Off the top of my head, I don't recall the oil grade. The local
dealer set me up with a number of things I requested over the phone
and I just picked up a box of stuff to deliver to the mechanic. I
will call him tomorrow and ask (closed on Mondays).

Since this seems like the least expensive and simplest of the possible
remedies, I'll give an oil change a shot. When it came time to do the
oil, the guy who worked on the bike suggested leaving the old filter
in, replace the existing oil with a cheap brand, running the bike
around town briefly (30 miles or so) to clean out any residue or
deposits, then replace the filter and use the oil I had purchased from
the dealer (Suzuki brand four stroke).

I took the bike out yesterday for a stretch to get a feel for the
behavior. I noticed twice that when I was trying to downshift from
5th to 4th and once from 4th to 3d (separate events) there was that
first-gear-rejection grinding as though it was in neutral. As the day
wore on I would have to find nuetral at speed as the gear shift would
go past it as I went from first to second and back several times when
still.

 

This guy is an incompetent arse-wipe.

 

Or a smart-ass who knows how to sell extra oil.
If he's really smart he resells it to his next victim. It has only 30
miles on the clock. Or maybe 60, or 90...

Rob.

 

Heh. You have a nasty mind.