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thrust rod broken
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- Posts: 53
- Joined: Thu May 22, 2014 11:45 pm
thrust rod broken
Everything worked great until about two weeks ago, I got excess play in the clutch lever. I thought it had gotten out of adjustment, but I couldn't improve it and finally the clutch went totally slack.
Before I order a new thrust rod, I want to get help on what may have caused this so I'm not back in the same boat later. I'm including a bunch of photos in case someone can see something I can't.
Thanks so much in advance.
- schrader7032
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Re: thrust rod broken
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
- srankin
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Re: thrust rod broken
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Re: thrust rod broken
Thanks
- srankin
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Re: thrust rod broken
- vechorik1373
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Re: thrust rod broken
And, an assembly procedure, in case you don't know.
1. Take a bore brush for a gun, and thoroughly CLEAN the inside of the input shaft.
2. With a new (oiled) felt, on a new push rod, it must be installed in the front of the input shaft, and it will be tight, and require some wiggling to get the felt into the input shaft. That's why you want the hole through the input shaft CLEAN so it does not bind up when installing the clutch push rod.
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- srankin
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Re: thrust rod broken
My teflon memory is acting up so I will ask; "is the unit oiled from inside the transmission by gear oil"? St.
- schrader7032
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Re: thrust rod broken
I don't think this is the model bike, but I recall a situation where the pieces didn't fit inside the tunnel well and/or swelled a bit when heated. Vech talks about honing out the tunnel, but I was under the impression that the piston, the larger piece at the end of the rod had to be machined in some way to reduce the diameter to fit the tunnel.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
- srankin
- Posts: 1078
- Joined: Fri Jul 14, 2017 8:45 pm
- Location: Spencerport, NY USA
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Re: thrust rod broken
Vech, as always makes sense as did you in your first reply. Having put one of those felts in myself a couple of times, I could very well see how they could be installed improperly.
Hopefully this doesn't happen again, but what a surprise it must have been! St.
- vechorik1373
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Re: thrust rod broken
No, not the tunnel of the transmission. You misunderstood me. I was talking about the hole through the input shaft.
You need to get it CLEAN before installing a new felt and push rod.
You must think about what caused the push rod to snap in two, in the first place. And, what I forgot to mention previously, was that you need to examine the female tapered hole in the spring plate, that the push rod seats into. If it is galled up, it will chew up the tapered end of the new clutch push rod rapidly. If it is in that condition, replace the spring plate.
But the clutch push rod can only snap in two, if there is excessive drag inside the input shaft, and/or if the clutch was incorrectly adjusted which caused the throw out bearing to be under pressure and spinning all the time. If I recall the owners manual correctly, they said to never pull and hold the clutch lever at a stop light, while the transmission is in gear. Always put the gearbox in neutral, and release the lever. This keeps prolonged pressure off of the tip of the push rod, and the throw out bearing at the rear of the push rod. Repeatedly sitting at stop lights in first gear will accelerate the wear of these components.
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