Kickstart shaft bush.

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willy mac

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Does the kickstart bush in the outer casing need reaming when replaced or is it a straight swap?
 
The better question is: Do you feel lucky?

My gut says a straight swap is a high probability. You can measure the ID by trying it on the shaft, you'll have to remove the existing bushing to measure the OD.

If the bushing is worth replacing the shaft that runs through it should be carefully examined to see if it, too, is a candidate for the bin.

Best
 
Reaming? Isn't the clearance, to the KS shaft, actually rather generous?
If a cosmetic replica was OK then I could make them on a lathe with soft mild steel.
It seemed to me they are hard as tool steel?
I just ran a file over one and it does not touch it...
 
willy mac said:
Does the kickstart bush in the outer casing need reaming when replaced or is it a straight swap?
Click to expand...
RoadScholar said:
The better question is: Do you feel lucky?

My gut says a straight swap is a high probability. You can measure the ID by trying it on the shaft, you'll have to remove the existing bushing to measure the OD.

If the bushing is worth replacing the shaft that runs through it should be carefully examined to see if it, too, is a candidate for the bin.

Best
Click to expand...
I've not pulled it apart yet, I have a small weep from the shaft and I've replaced the seal but still the weep. The shaft has a tiny bit of movement up and down and I was thinking this might be allowing the seal to let oil pass, so the next move would be to get rid of the play and see if it fixed it. I will however have a look at the kickstart shaft when it's all apart.
 
If your machine is a pre-Mk3 you may want to consider sending the outer cover out for the Mk3 seal upgrade.

Best
 
willy mac said:
I've not pulled it apart yet, I have a small weep from the shaft and I've replaced the seal but still the weep. The shaft has a tiny bit of movement up and down and I was thinking this might be allowing the seal to let oil pass, so the next move would be to get rid of the play and see if it fixed it. I will however have a look at the kickstart shaft when it's all apart.
Click to expand...

I take it the cover needs to be machined then for the MK 3 seal to fit?
 
Your shaft must have a good finish.
My first cheap buna-n o-ring/seal only lasted 16 years before weeping.
Then I tried a 1" quad-X oring and been OK since 2003... 50 cents
They all harden over time being bathed in petroleum, even the big bux fixes...
How much $ is a cover gasket and an o-ring?
In reality
1. a super dry shaft will rust a little-externally
2. the shaft CAN move in and out a bit.
3. the rust gets dragged into the seal and it is like mild sand paper and will grind away at the expensive seal too!
 
willy mac said:
I take it the cover needs to be machined then for the MK 3 seal to fit?
Click to expand...
I see where your coming from Dave, the play seems to be in the vertical plane hence why I thought there might be a bit of wear in the bush. It's not a show stopper but you know what it's like when you see a small weep you want it not to do it. Thanks for your input.
 
When I did the first rebuild of my bike, the only oil leak I ended up with was a slight weep from the kick start.
I found an easy fix: use a metric ( 25x4mm ) o-ring instead of the slightly thinner imperial one.
 
The 850 Mk2A and Mk3 had a small brass breather at the top of the inner gearbox cover and a very tiny pin hole in the inspection cover what do others have to say about it's effectiveness.
 
A hydraulic backing ring with the standard o ring and RTV gasket cement placed in the groove first (then fitting o ring and backing ring) and left to cure before fitting to gearbox works well with leaks. ( The backing ring is made of a similar material as the o ring and essentially is a washer with a circular groove on one side to locate the o ring). Available from hdraulics suppliers.
 
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