Topic: CB550 Transmission - What problem does my symptom point to? UPDATED-Video Added

[psykod]

Bike:  '77 CB550F. All Stock.  Rebuilt about 7,000 miles ago.  New aftermarket clutch friction discs (I didn't change the plates) and springs (heavy duty) added during rebuild. 

I've had this problem since the rebuild but it seems to be getting worse lately.  The bike had 31000 miles on it prior to the rebuild.

As the bike begins to move when accelerating from a stop there is a distinct lurch once the clutch is fully engaged.  During up-shift into any gear I get the same lurch once the clutch is fully engaged.  It's almost like there is slack somewhere that is getting taken up right at the last instance.  Once in gear everything is fine (no clutch slippage).

I've tried every manner of clutch and cable adjustment to alleviate the problem to no avail.  I've also tried changing the rpm's as I accelerate from a stop.   I don't hear any odd noises except some slight clutch rattling at idle that goes away when the clutch is disengaged. 

I didn't put in a new primary drive chain during the rebuild and I'm beginning to suspect that is has slop in it that is getting taken up as the clutch is released. 

Update - Video Of Primary Chain Tension Added 08.11.2008 : http://forums.sohc4.net/index.php?topic=37835.msg401034#msg401034

[tonycb650]

could be the chain but its probably the heavy duty springs.

[paulages]

i've found aftermaket clutch plates- EBC and Barnett anyway- to be a little grabby in a strange way on takeoff. not sure if it's exactly what you're describing, but it always went away after the break-in period. 7000 miles seems a little long for that though. did you soak the plates in oil proir to installation? i have barnett friction disks and HD springs in mine. wow, that clutch lever is stiff...

by the way, try power shifting up. i almost never use my clutch on the 550 to upshift, as it shifts so willingly without it. i shift up just as i let off on the gas from acceleration.

[martino1972]

what is lurch..

[bryanj]

There are a set of cush drive rubbers inside the drive sprocket assembly on the primary shaft (the lump driven by the primary chain) also possibly worn primary which can wear into the oil galleries so should be changed anyway

"Lurch" was the butler in The Addams Family, ably assisted by "Thing"

[martino1972]

ah, i see...well this is a classic case of "the butler" did it...

[paulages]

There are a set of cush drive rubbers inside the drive sprocket assembly on the primary shaft (the lump driven by the primary chain) also possibly worn primary which can wear into the oil galleries so should be changed anyway

"Lurch" was the butler in The Addams Family, ably assisted by "Thing"

i would imagine worn cush rubbers would cause more of a violent shift than a "lurch" (interpreting that to mean that it actually revs for a minute before actually catching...such a thing would surely be unnoticeable at any running RPM i'd think). but hell, listen to bryan-- he's got years of experience with these motors.

hate to ask, but have you adjusted and re-adjusted your clutch to be sure? it would be strange fr it to slip down low but not at higher revs, but have to ask...

[bryanj]

Its difficult to understand what is meant by "lurch" without riding the beast and thats a bit expensive for me in air fares! Hence the flippant mention of the butler,
Those cush rubbers do have an incredibly long life with no problem normaly, i was trying to think lateraly,
Perhaps the cable has a tight spot and is hanging up?
Perhaps the "splines" in the clutch outer or on the inner have wear spots that the plates are having to jump over?

Both are possible but rarely seen on hondas

Has the mechanism been adjusted from scratch as per the book?

[paulages]

Perhaps the cable has a tight spot and is hanging up?

this sounds the most likely according to the description, IMO.

[psykod]

What I mean when I say "lurch" is that there is just a slight jerk when the clutch is fully released.  The bike begins to move almost immediately whenever I release the clutch but when the clutch completely engages (i.e. when I completely let go of the clutch handle), there is always a small jerk. 

Thinking I might have a bad clutch cable, I replaced it with a brand new one and well lubed it using the standard cable lubing device and cable lube.  I made sure my final drive chain was in good condition (it was new 7000 miles ago) and has the prerequisite 3/4" play. 

It's hard to describe the symptom but if you've ever experienced a worn automatic transmission that engages and moves the car but not fully until the torque converter is fully locked, it's kind of like that (but not nearly that serious).

The symptom does seem to occur at all rpms and in all gears.  I can be going 40 in 3rd and shift to 4th and it will do it just as much as starting off from a stop in 1st.

[bryanj]

Try adjusting the mechanism(NOT JUST THE CABLE) as per book, if that dont work all i can think of is worn splines

[paulages]

What I mean when I say "lurch" is that there is just a slight jerk when the clutch is fully released. 

i thought i understood you to be describing something that happened after you had completely let go of the clutch lever. if it happens at the moment you fully let go, i would say you are experiencing the nice feeling of heavy duty clutch springs causing your clutch to do what it is meant to do. i've had the experience that run-in clutch disks with stock springs will actually slip a second or two after engagement in a way that feels smooth (but not necessarily slippy) compared to a clutch that simply engages immediately with good disks or HD springs.

[Hush]

I always look for the easiest and cheapest solution first, could the clutch cable be snagging somewhere?
You say you fitted a new one but if "as per the book" you threaded it same way as old one maybe the problem is the route it takes and is being pinched somewhere!
On my old Suzukis they always had a small return spring at the end of the cable, similar to the ones leading shoe brakes have.
It helps to quickly pull the cable to it's end once the clutch lever is released, now there's an after market thing you could try.
At least a spring at the end of the cable would tell you if it was the cable and therefore external or the dreaded internal drive chain slop.

[psykod]

I was fixing a leak around my oil pan so I decided to check the play in my Primary Chain.  I can't find anything that says how much play there should be so I was wondering if this is too much.  I didn't see any place where the chain had been hitting the case (and no metal shavings in the oil pan).  And I don't think I can hear anything when the engine is running but it seems to be excessive to me...

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[bryanj]

Yup thats excessive, trouble is its a complete engine strip to change, 550 doesnt hit as bad as 500 BUT you cant see where till its in bits

[psykod]

Bummer...Well, hopefully it will last until the winter rebuild I had planned...