checking overshift

Single & twin cylinder model BMW Airhead specific discussions
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ScottA
Posts: 7
Joined: Sun Sep 22, 2013 9:04 pm
Location: San Diego, CA

Re: checking overshift

Post by ScottA »

sweet streamlined R26 :!:

is that a race-seat?
"If you want to fix it with a rock, you have to stick to stone-age technology" -Anton
"...solving the latest crisis that is preventing my Airhead from taking me to the bar." -Beater-
User avatar
ScottA
Posts: 7
Joined: Sun Sep 22, 2013 9:04 pm
Location: San Diego, CA

ok, figured it out

Post by ScottA »

re: overshift

I'm sure everyone is impatient to know...

this:

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means this:

In 1st gear with the shift lever held down against the stop, look for 2mm clearance between the cam lobe and up-gear side of the pawl.
In 4th gear with the shift lever held up against the stop, look for 2mm clearance between the cam lobe and the down-gear side of the pawl.

This in each gear, while up-shifting and down-shifting.

clear as mud?
...figured it out all by myself (plus a few beers).

It didn't help that my shift mechanism has about .25mm (.010") clearance, when cold.

but hey, all we need is "enough" clearance, right?
"If you want to fix it with a rock, you have to stick to stone-age technology" -Anton
"...solving the latest crisis that is preventing my Airhead from taking me to the bar." -Beater-
User avatar
ScottA
Posts: 7
Joined: Sun Sep 22, 2013 9:04 pm
Location: San Diego, CA

from overshift to shaft shimming set-up

Post by ScottA »

alright, so... I went ahead and adjusted the overshift by adding shims, which in this case are small precision washers under the heads of the stop screws. Backing out the staked, slot-screws was the hardest part, next to scrounging for suitable washers... but that's what makes all this fun, hmm?

I bought this rotisserie oven off craigslist for just this purpose. Finally get to use it.

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The gear cluster was in for shift fork adjustment preview. After removing it again, I installed the input shaft and then the intermediate and output shafts with the shift forks.
2nd attempt succeeded. having the whole gearbox up to temp helped a great deal.

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This morning I get to begin the shaft shim calculations. I don't get to use this surplused anvil mic very often... have been looking forward to giving it a try in this application.

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-Scott
"If you want to fix it with a rock, you have to stick to stone-age technology" -Anton
"...solving the latest crisis that is preventing my Airhead from taking me to the bar." -Beater-
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