Clutch cable (thread) rubbing on front sprocket? (HELP)

[the_nutt]

I've been working on my 73 CB450 for a bit, and one of the most difficult replacement parts to find was the clutch thread. The old one was half gone, and I found a perfectly new one on eBay.

Last night was the first time to try and start it after putting everything together.

When I initially rolled it out, it was in neutral and was rolling fine. I pulled in the clutch to shift into 2nd (engine still off, was planning on a push-start), and felt that the clutch lever was jerking as the bike rolled (now I know this was the cable being pulled/hit by the front sprocket).

I took apart the left cover and found what is pictured below. To my knowledge all parts are stock (or stock replacement (front sprocket)), but apparently this is the same issue that roasted the old clutch thread.

Do any of you have any ideas? I thought of measuring the neutral pin to make sure its not too short, but I would need another measurement to compare it to. I also could bend out the clutch thread, but then it would pull the cable at an angle. Plus, I don't feel like this should be happening at all...

Thanks in advance,
Cody


Where the thread sits installed.

Top view.

OLD thread with similar damage.

Damage seen on the bolts where contact is made with the clutch thread.

New thread, original side cover, as installed.

Same as above, closer.

 

[lingo]

Do you have an o-ring chain on the bike? I have heard that those are known to cause a rubbing problem on the cb450s.

 

[the_nutt]

Do you have an o-ring chain on the bike? I have heard that those are known to cause a rubbing problem on the cb450s.

Nope, replaced with a regular chain. I had researched/read the horror stories of O-ring chains prior to changing parts out.

 

[Bozz]

Does your clutch pushrod have a ball bearing that is supposed to go between it and the clutch?

I know several Kawasaki's used one to isolate the clutch spin from the pushrod.

If you are supposed to have one and dont then the pushrod will be about 8mm shorter, which will change the position in the worm gear and could result in the rub.

Just a thought...

 

[the_nutt]

Does your clutch pushrod have a ball bearing that is supposed to go between it and the clutch?

I know several Kawasaki's used one to isolate the clutch spin from the pushrod.

If you are supposed to have one and dont then the pushrod will be about 8mm shorter, which will change the position in the worm gear and could result in the rub.

Just a thought...

If you mean externally between the worm gear and the pushrod, yes, and it is installed. That is the first thing I thought to check, haha.

If you mean inside the case, between the internal workings of the clutch itself and the pushrod, I don't know, and don't think so. I don't know how it would have fallen out, if indeed it is supposed to be in there.

 

[Bozz]

The parts fiche might tell you if there is supposed to be one or two.

Also, are you %100 sure the pushrod is the correct length?

I'm just trying to figure out what all hasn't changed between the first failure and now that could cause it.

Best of luck!

 

[the_nutt]

The parts fiche might tell you if there is supposed to be one or two.

Also, are you %100 sure the pushrod is the correct length?

I'm just trying to figure out what all hasn't changed between the first failure and now that could cause it.

Best of luck!

Yeah, I just looked up the disassembly diagram, and there is only the one bearing that is listed.

I need to check on the length of the push-rod, but don't have a control to measure against.

 

[lingo]

Yeah, I just looked up the disassembly diagram, and there is only the one bearing that is listed.

I need to check on the length of the push-rod, but don't have a control to measure against.

I can check when I get home tonight.

 

[the_nutt]

I can check when I get home tonight.

That would be awesome. Thanks in advance.

 

[lingo]

I couldn't find my calipers, but it measured 10 1/16" on a tape. I will throw it in the truck and give you a better measurement in the morning


edit: My calipers at work aren't big enough.

 

[the_nutt]

I couldn't find my calipers, but it measured 10 1/16" on a tape. I will throw it in the truck and give you a better measurement in the morning


edit: My calipers at work aren't big enough.

Thanks so much for doing this. I'll measure mine after work today and compare.

It was also brought to my attention that since the bike has been sitting for a bit the wet clutch plates can get stuck together, possibly letting the push-rod slide further inward. I'm going to pull the clutch and soak it, but has anyone experienced this before?

Again, thank you all.

 

[650hardtail]

could you do an offset bend on the release arm ( to space it away from sprocket )

 

[the_nutt]

could you do an offset bend on the release arm ( to space it away from sprocket )

Yeah. That's what I plan on doing if I can't figure anything else out, but I want to try and make sure I address the cause of the issue.. so something doesn't go wrong further down the road.