Bent clutch pushrod

[crash_davis]

About a year ago, I replaced the clutch pushrod seal and bushing on my '81 XS to fix an oil leak. When I did that, I also replaced the 2 piece pushrod with the solid 1 piece pushrod. All parts came from Dime City Cycles (which I believe is Mike's XS). I've been riding the bike for a few thousand miles and last night I hear/feel a loud clunk and I have no clutch and the bike is pissing oil. Got the bike home tonight and cracked it open to find the pushrod severely bent.

I figure the fix is to get a new pushrod, and replace the bushing, seal and pushrod. But before doing so, I want to find out what would cause the pushrod to bend like that?? It would take significant force to bend it. I inspected the worm gear and it is functional with no abnormalities. I don't think it is a problem with the clutch basket, as I don't think the worm gear could bend the rod before breaking the clutch cable and I would feel significant resistance on the clutch lever. I thought perhaps if the chain jumped off the sprocket it could bend/damage the pushrod. The bike is a hardtail, and I keep the chain tensioned and also have a chain tensioner to keep it snug. The way the rod is bent really looks like it was caused by the chain but when the incident happened I was just accelerating smoothly in traffic from a red light, pretty conservatively.

Any thoughts or suggestions on the root cause of this failure? Thanks!

 

[willis]

WOW! I’ve never seen one that bad. Are you running an 18 tooth front sprocket by chance? Doesn’t look like a lot of clearance in there.

 

[Jim]

If you're confident the chain was properly tensioned, then my guess would be the chain picked up a piece of debris and flung it against the rod.
Maybe the tire picked up something, flung that into the chain... and on to the rod.

Yeah... a million to one chance... but hard pressed to see what else could have done it.

 

[crash_davis]

WOW! I’ve never seen one that bad. Are you running an 18 tooth front sprocket by chance? Doesn’t look like a lot of clearance in there.

No, just running the stock 17 up front. I would like to run an 18 front sprocket but as you said there isn't much clearance. I didn't feel safe trying the 18.

 

[Jim]

Was this eng mount bolt always missing? Suppose it fell out and hit the chain? That would be enough "debis" to do it.

 

[Mailman]

my guess would be the chain picked up a piece of debris and flung it against the rod.

That was my first thought as well. Lucky you didn’t crack the case!

 

[Kevin Werner]

I would give the clutch actuator a very close inspection. It looks like it took one helluva side load.

edited later... Jim has a good eye there on the missing fastener. Another reason to post pics.

 

[gggGary]

Sprocket nut shows a big impact dent also...

bet if you look over that chain closely you'll find a link with some damage too.
I'm guessing what ever it was went between sprocket and chain forcing the chain to hit the push rod.
Check the bottom of the case right over the sprocket...

 

[crash_davis]

Thanks everyone, great input and most helpful! The one rear engine mount bolt has been missing, so it was not the cause (but good eye Jim, a likely culprit if it wasn't known to be missing!). I got the rod removed and there are some deep gouges on it, as well as on the case as Garry recommended I look. I'm feeling a bit more confident now that something got caught up in there. Maybe just bad luck - though I'm mindful that most bad luck is our own inattention. I feel confident now moving ahead with the repair, and adjusting the chain tension maybe a bit more snug to be sure not to have a repeat of this. Geez, every time I think I get the bike reliable and start putting miles on it something new comes along!!

 

[Melnic]

This thread prompted me to check my engine mount bolts/nuts on my engine reinstall. I had it already on my check list to do before I take it on the road but guess what I found? Lower rear (long) mounting nut was not cranked down. To check it, I had to poke at it w/ a dowel rod to see if it moved. YUP. I missed it when I went around tightening them all up before I put the exhaust on. Just have to remove Pegs to get to it though.

My single piece aluminum push rod came from a forum member here.

Thx for posting your experience and hope the repair goes well.

 

[5twins]

It looks like your pushrod was installed backwards? The stepped end should face out .....

I'm not sure if this contributed to the issue but the stepped end does fit into the worm and that helps steady the rod, keeping it centered and from shifting side to side as you use the clutch. If yours was just resting against the outside of the worm, the rod may have been deflecting side to side as you operated the clutch.