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Discussion Starter · #1 ·
I'm stripping down an F650 engine to put new GBox bearings in it.
I thought I'd read somewhere that the TDC bolt can be used to lock the crankshaft whilst undoing the rotor and primary drive nuts. This sounds a little dodgy to me, has anyone tried it?
If the TDC bolt is not the way to do it, then I guess it's the old jamming a soft washer in the primary gears trick?
BTW I can't remember who told me the trick of removing the head and barrel together, thereby saving the head gasket, but it worked a treat - thanks!
 

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Hi Biker Bob
I read the same in the resources about using the bolt and it would worry me a bit as it is only an 8 mm bolt isn't it. I haven't checked the Clymer manual yet about it. Can you not just stick it in gear and undo it holding the brake on or does that sound a bit to easy ( am I forgetting something here?)

Ton
 

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The rotor nut can be removed with a little heat (this breaks the loctite bond),as I have not yet removed the sprocket nut (bolt??) on lynns bike I cannot comment on but I would assume that it is also held in position by a retaining compound.
As to removing the rotor ,either follow the chain gang proceedures or have a word with your local BMW dealer for their short cuts
incidently Ocean and Cw's gave the same advice ,ie,use heat,fit extractor,use small stilsons on the extractor tucked up under the footpeg this stops everything from rotating and tighten the extractor and off it comes(sometimes with a hell of a bang and sometimes it just falls off)
You need the heat to break even more loctite which BMW/rotax put around the rotor taper :wall: :wall: .
Sorry for the war and peace write up but its easier to talk someone through than write it

Hope this helps
Mike
Lynns other half
 

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Discussion Starter · #4 ·
Thanks chaps.
It's a little late to use the back brake as I have the crankcases sitting on the bench. I was thinking of using a broom handle through the small end eye to lock the crank whilst air spanner is applied to the nuts.
The flywheel nut is loctited, but the primary gear has a tab washer, so it should come off quite readily I'd have thought.
 

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I used a chain gang tip. Put a 2pence piece between the gears such that it sits between the teeth. This will not damage the gears but will giv you enough stopping force to undo the nuts
 

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Bob,I used the TDC bolt when I ripped mine apart without any problems.Also I used the petrol tank bolt ground to a point as the TDC bolt,another chain gang tip.H.T.H.
 

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Hi Biker Bob
So you have an airgun and a compressor? I used to undo crankshaftnuts on cars with my snapon airgun and to undo them with a socket and a t bar iit would require a 5 foot metal pipe as extension.
So just zap it loose.

Ton
 

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Discussion Starter · #8 ·
I was planning on taking it down to my local bike shop and using their airgun and compressor. They also have the 30mm socket and puller for the rotor, as they have stripped down a couple of F650 engines in the past. I used to be the mechanic there so I can sort of pop in and potter around in the workshop...

I think I'll probably pop the clutch basket back on and use the 2p peice option.
 
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