Project Honda CB450 Cafe Racer: Clutch This!

I haven’t updated this build log in a few weeks because I was so pumped to nearly be complete, that I wanted to hold out more posts until a grand unveiling. I’ll do another post on the battery issue I ran into and the new headlight bucket, but focus this mainly on the clutch issues I’ve been experiencing.

Something tells me this will all boil down to an assembly mistake on my part, like one of these things is on backwards or I’m not adjusting something correctly. However, the problems I’ve been seeing seem to be a common trend among all these Honda CB DOHC’s, especially the 450, 500, and 550’s.

In a nutshell, I replaced the clutch cable with a shortened version from Dime City Cycles, and now my clutch won’t fully disengage when I pull my lever.

Over on Hondatwins.net, there is an excellent write-up on how to adjust your clutch properly. I’ve read this thread about 40 times, and have also scoured their forums for a solution to my problem. Because no matter how much I try to adjust it, I can’t get it a smooth action out of the clutch.

To complicate things, the bike was running well and the clutch was performing just shy of optimally two weeks ago, while I test drove the bike around and around the neighborhood. When I say the clutch was sub-optimal, I mean that it would not always want to shift into a neutral, and sometimes when I was in first gear, the bike would stall. This to me, meant the clutch was not fully disengaging and putting some load onto the gears, and without throttle, would stall the bike.

I re-routed my clutch cable to remove any sharp bends and tried adjusting it. Somewhere in the past two weeks of adjustments, including swapping out the clutch return spring for a shorter one, something went wrong. At this point, I can’t even get the clutch to do anything when the lever is pulled.

Luckily, motorcycles can still switch gears even without a clutch, so I’m able to limp around the driveway while I adjust stuff to see if I get it right.

Yesterday, I completely disassembled the sprocket cover again to ensure that the spring, ball bearing, and clutch lifter assembly were still functioning in proper order. Although I had to rig up my clutch lifter arm to hold the clutch cable end (using a zip tie and bending the two remaining teeth of the clutch cable retainer), it’s all still there.

Here’s what it looks like, all freshly greased and recently sworn at:

20130807_192647

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I think what’s happening is either

  1. I have assembled the lifter arm and lifter stop wrong, the clutch plates inside the case are sticking, or I still need to keep trying different adjustments.
  2. My cable (brand new) is entirely too short, or improperly routed. Currently it runs straight up, around the outside of the left carb boot, over the intake cam chain cover, under the tank, over the lower triple and bends right and back toward the clutch perch. I don’t see any other way of routing it though.
  3. The rubber accordion-like cover to protect the cable is somehow not allowing the clutch lifter arm to fully lift and allow for travel, but since its such soft rubber, I don’t think it would impede its travel that much.
  4. My clutch lifter arm is not starting at the right position when I install the cover onto the motor and not moving far enough out to push on the clutch rod.

My questions, for anyone who might have an answer, is the oil seal correctly placed on the end of the lifter arm/cam? Should it be farther pressed down?

Currently, the way this is assembled, the clutch lifter stop (the boomerang shaped piece) sits behind the oil seal and between the seal and the case cover. Does this actually need to sit above the seal? As in, between the seal and the arm of the clutch lifter?

Also, when installing the entire assembly into the case, should I back it out via the slot on the outside of the case, and then turn it inwards (possibly several rotations) until I get it to press the clutch lifter rod while I fit the case back on, and then adjust (CW+CCW) from there?

Comments

  1. says

    I’m struggling with a similar issue on a CJ360. Ugh.
    To rule out the new cable. Take the cable off the handle bar and have it come straight up from the cover and manually pull the cable out… see if it is the same result. I bet it’s not the routing of the cable.

    • Sahil says

      Thanks Kioskguy. I tried that out and now can rule out it wasn’t the routing. I also made sure to lube up the cable with some mystery oil, turns out they come bone dry from the manufacturer. I think, after a lot of trial and error, fixed the problem to the point that I can ride it at least. I had to back out the adjuster at the case nearly fully out, after adjusting the clutch lifter (on the case) about a 1/4 turn past it’s index mark. This leaves very little play in the system, but at least my lifter/cable won’t rub the front sprocket, which is a common issue with these bikes even when you’re using a non O-ring chain.

      The friction zone is about half way out when the clutch lever is fully depressed, so there’s not much room to be sloppy!

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