Stuck gearbox mainshaft key - Triumph Forum: Triumph Rat Motorcycle Forums
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post #1 of 15 (permalink) Old 06-07-2018, 05:50 AM Thread Starter
Grand Prix 125
Main Motorcycle: 1972 T100R Daytona
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Stuck gearbox mainshaft key

I'm pulling the gearbox on my '72 Daytona. The mainshaft key is stuck.

I tried:
1. pulling with pliers
2. gently tapping with hammer & screwdriver
3. pulling with really tightened vicegrips (slipped off several times)
4. swearing
5. hitting down on one end with hammer (since its a half moon key)
6. swearing
7. hard whacking with hammer & screwdriver
8. swearing

The key's getting damaged but it's not budging. Ideas?
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post #2 of 15 (permalink) Old 06-07-2018, 11:01 AM
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Might try drilling or using a Dremel to remove some material and weaken what remains.

Michael
72 T120R
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builder of plunger drill jig
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post #3 of 15 (permalink) Old 06-07-2018, 12:05 PM
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Is it possible to apply some heat to the shaft, without doing any damage to anything in there? Just a bit with a propane torch might be enough to do the trick...Ö.just clean out as much lube as possible.
Just a thought: Jim

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post #4 of 15 (permalink) Old 06-07-2018, 12:33 PM
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Hi Eric, Get a set of end cutter pliers. Grab it very tightly right at the shaft, squeeze as hard as you can. Then rock handles to outside (left) of bike. This gives best grip & great force to rock it out. Don't rock front/back as you don't want to widen groove in shaft.

On a stuck key side cutters may nip key off at this point. That's why I recommend end cutters. Don't round the key any further.

Regarding new key, I've recently found them .005-.0015" too wide compared to originals. I sanded them down to original thickness, but don't go too loose.
Don
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post #5 of 15 (permalink) Old 06-07-2018, 04:14 PM Thread Starter
Grand Prix 125
Main Motorcycle: 1972 T100R Daytona
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Quote:
Originally Posted by TR7RVMan View Post
Hi Eric, Get a set of end cutter pliers. Grab it very tightly right at the shaft, squeeze as hard as you can. Then rock handles to outside (left) of bike. This gives best grip & great force to rock it out. Don't rock front/back as you don't want to widen groove in shaft.
That did the trick! I've never owned end cutter pliers before, but now I know one thing they're good for. Thanks!

I appreciate all the ideas, guys.
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post #6 of 15 (permalink) Old 06-07-2018, 10:23 PM
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Hi Eric, Good going! That's great news. Very welcome. Hope the remainder of job goes smoothly.
Don
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post #7 of 15 (permalink) Old 06-08-2018, 08:00 AM
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Hi Don - this is a great tip! I experienced the same frustration as Eric a couple of years ago - don't remember exactly how the key came out eventually, but I think I might have repeated steps 4, 6, and 8 many times.

Just would like a clarification on rocking the key with the end cutters - you're saying rock it parallel to the shaft and not perpendicular, right?

Bruce Miller (hermit47)
'69 T120R
www.hermit.cc/tmc
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post #8 of 15 (permalink) Old 06-08-2018, 09:23 AM Thread Starter
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Quote:
Originally Posted by Hermit47 View Post
Just would like a clarification on rocking the key with the end cutters - you're saying rock it parallel to the shaft and not perpendicular, right?
That's what worked for me. I was rocking it in the long direction of the groove.

Quote:
Originally Posted by Hermit47 View Post
...I think I might have repeated steps 4, 6, and 8 many times.
I just hate how such a simple little thing can stop all progress! I was already envisioning popping that gearbox out in 10 seconds and NOPE! says a little piece of metal. The next thing that has stopped me is the mainshaft nut. After going to the store twice to get the right socket (I was sure it was 1") I found out I need a breaker bar, too. That'll be today's challenge: foot on the brake, leaning over the seat putting a bunch of torque on that nut and praying the socket doesn't slip off.
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post #9 of 15 (permalink) Old 06-08-2018, 10:07 AM
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Eric - these bikes have more 'gotchas' than you can shake a BSF wrench at!

What works for me on the clutch nut and the sprocket nut is an air wrench. Not sure about your Daytona, but the sprocket nut on my '69 T120R is 1-11/16" and I adapted a 3/4" socket for a 1/2" drive.

It's amazing how confused I can get over words, so in the photo of a mainshaft with a simulated key slot, do you move the pliers back and forth in the A direction, or in B direction?
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Bruce Miller (hermit47)
'69 T120R
www.hermit.cc/tmc
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post #10 of 15 (permalink) Old 06-08-2018, 10:54 AM Thread Starter
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Direction B, Bruce.

I wish I had an air wrench! My tool set is pretty humble.

My mainshaft nut turned out to be 15/16".
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