Author Topic: Closing the crankcases GTR (1970)  (Read 3316 times)

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alan86a

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Closing the crankcases GTR (1970)
« on: January 31, 2015, 08:28:31 PM »
I am looking for any advice i can get before i close up the crankcases on my GTR.
Having done so far what i think is a pretty good resto job on the cycle parts and thoughly enjoyed it, i am a bit more than hesitant to bolt up the crankcase halves.
I am going to leave out the large crankshaft end seals as they weren't present on disassembly, it seems this is most peoples thinking right or wrong?.
I'm really concerned that the gearbox may be out of sync when up and running, can anyone advise what to check gearbox wise before final bolting up? I haven't disturbed any of the cogs on each shaft just renewed bearings.
On a different subject had a parts buying trip to Kempton park bike jumble(UK) last weekend. went with a couple of mates one of them came back and presented me with a Bridgestone BS lapel badge for 50p it was sitting on the top of a box full of assorted badges, that alone made the trip worthwhile, thats how sad this Bridgestone thing gets (will try posting a pic if any interest).
Also got Shell synthetic based 2 stroke £3 a litre amongst many other brilliant buys thoughly recommend the place.
happy Stoning

ziggy stardust

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Re: Closing the crankcases GTR (1970)
« Reply #1 on: February 01, 2015, 05:45:40 AM »
Alan, the large crankshaft seals have been discussed in the past and and there does seem to be divided opinion if they should be there on a rebuild. BS advised to remove them at service but I think I'm right that they later reversed that decision?

I left them in on my first restoration but making sure they wouldn't come loose by center popping the housing to hold them tight, on my second restoration they were fitted so again I did the same. This bike had done over 40k miles which is very rare from what I've seen on U.S. imports so to cover that mileage with no problems to the seals I personally wouldn't hesitate to fit them again.

Regarding the gearbox, I always take photos of such things on the strip down and this has helped myself and others many times, there really shouldn't be a problem as everything lines up, chances are there is a photo in my first gallery to cover most assembly questions.

 

Z

Offline BRT-GTR

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Re: Closing the crankcases GTR (1970)
« Reply #2 on: February 01, 2015, 08:51:26 AM »
Hi Alan,
           Just yesterday I was mooching through my BS Bookmarks and rediscovered Ray Oliver's web site,  http://bridgestonemotorcyclerestoration.com/ and learned a couple of things that I hadn't read before but relate to your questions. Look through the  'Service Letters', particularly the 5th one down, BSG-0000, Continuous Customer satisfaction, Issued in July 68. It sheds new light (to me) on the issues you refer to.
    Crank Shaft Seals
   Although BS have stated the engines will run quite happily without the crank end seals, they still thought they were worth retaining and redesigned the crank recesses after 21F05701 'to permit positive seal retention'. So there's your answer, leave them out before 5701, unless you can improve the retention as Z's reply, and refit them after 5701.
        Crankcase Sealing
  It seems BS originally used dilute sealer on one side of the cases only and leakage was known to occur, usually by the front right engine mount in my experience. After 21E05455 they used full strength sealer applied to both sides of the cases. This maybe explains why, on a later engine I've just stripped which had never been apart, there was excess sealant all round the case joints including the gear box seals.

    I don't think the gear box can be out of sync, just make sure you can shift through all the gears and that there is clearance on the change dogs when in neutral, before bolting up , maybe do a dry run first.
Hope that helps,  Brian.               P.S. There's nothing sad about a 50p BS lapel badge (Great buy), I've still got one from 45 years ago !!
« Last Edit: February 01, 2015, 10:37:20 AM by BRT-GTR »
Unspoiled by progress.
I'm so glad I grew up in the 60s & 70s. I did so much stupid stuff and there's no record of it.............Anywhere !!

alan86a

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Re: Closing the crankcases GTR (1970)
« Reply #3 on: February 01, 2015, 04:55:31 PM »
Thanks for the replies Ziggy Brian i very much appreciate you taking the time to respond.
Part of my problem with the crank seals was - for the life of me i couldn't see where they went but another investigation this morning i now see where they are located, hard up against the weights making it look like part of the crank.
Also this morning i looked at your (Ziggy) series of rebuild photos which was a mine of useful info and discovered lots of things that fell into place, just brilliant.
Even though i did take photos on strip down i think I'm paranoid about after all that effort and she runs, then gears won't select.
I do have new seals available so will now consider looking at replacing/inspecting them.
Coincidentally i had a look at my gearbox innards and i have found that i have exactly the same disscolouration on the same cogs as yours Ziggy. Though apart from discolouration everything else looks good.
By the way I'm hopeful to have the bike running in about a month, barrel plating, NOS all obtained etc etc just need tank chroming and red paint job.
Have you started your resto yet Brian, have you had any luck sourcing a crankshaft.

Regards Alan

 


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