Author Topic: Motor strip  (Read 5517 times)

Offline chaterlea25

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Re: Motor strip
« Reply #15 on: 10.02. 2018 15:35 »
Hi Mark,
Is the shrapnel steel or alloy? and from where?
It looks like you caught it just in time  *ex*

John
1961 Super Rocket
1963 RGS (ongoing)

Offline tlmark

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Re: Motor strip
« Reply #16 on: 10.02. 2018 15:44 »
Yeah it steel there’s no shim’s on the crank so I’m suspicious it could be the remains of that possibly?  Big end shells are scored  :! And the plain timing bearing doesn’t look too good either  *problem*

Offline tlmark

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Re: Motor strip
« Reply #17 on: 12.02. 2018 10:48 »
Close up of the cleaned main bearing you can see traces of material around the boss on the inner race.
So do you guys think this the remains of an end float shim? 

Online berger

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Re: Motor strip
« Reply #18 on: 12.02. 2018 13:09 »
it could well be, mine did similar a few years ago , I think the crank end nut shifted a tad and this made the crank hammer the shim and destroyed it. I still ran the bike and thrashed it for miles after a triumph expert? told me the crank would find its own run. anyway I also was told it could end in a snapped crank so it was stripped and put right

Online berger

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Re: Motor strip
« Reply #19 on: 12.02. 2018 14:06 »
mark just looked at your crank web pic, it seems to me something has gone very wrong if ime right in assuming it has a recess , it should be slightly proud where the shims and bearing but up to it

Offline tlmark

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Re: Motor strip
« Reply #20 on: 12.02. 2018 19:06 »
Er... really?

Offline chaterlea25

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Re: Motor strip
« Reply #21 on: 12.02. 2018 19:27 »
Hi Mark,
Oh Burger *ex*  *work*

That recess will need to be faced off so the new shimming has a flat face to work from
Was the cush drive nut tight?
The mangled shims are almost always due to the nut not being done up properly *warn* 65ft/lbs

John
1961 Super Rocket
1963 RGS (ongoing)

Offline tlmark

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Re: Motor strip
« Reply #22 on: 12.02. 2018 19:56 »
Hmm as I didn’t have anything to fit the Cush drive “nut” I tapped it loose with a drift and then used a C spanner to take it off. I don’t think it was that tight so that sounds likely  *sad2*  glad I decided to pull it apart my wallet isn’t though.

Online muskrat

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Re: Motor strip
« Reply #23 on: 12.02. 2018 20:36 »
G'day Mark
That face should be approx 25thou" proud of the web.
Looks like the radius is undercut. It should be a nice 90thou" radius with no perceivable step from shaft to bearing surface.
With the nut done up to 65ft/lb it should take a good whack to get it moving. (your tap might be as big as my whack) *bash*
Cheers
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Online duTch

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Re: Motor strip
« Reply #24 on: 12.02. 2018 22:02 »

 I discovered my crank was same when I stripped it 7 years ago, and in addition the shaft was worn, which only became apparent when I was shimming it after a re-grind...the main journal has a well-made sleeve over it, so not obvious until it dislodged when pulling the bearing off a second time.... *eek*

 With very little options and already in deep, I shimmed it out and loctited the sleeve gone with it, ~ 12K miles later is hanging in there, but I don't flog it (I think)..

 Not ideal, but you may have better resources available to deal with it. good luck
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Offline tlmark

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Re: Motor strip
« Reply #25 on: 13.02. 2018 11:59 »
Ok, guys, I've been discussing this with a colleague at work (he's a Toolmaker) he says we could turn a spacer to fit the crank instead of shims?
and loctite the bearing to the shaft once end float has been dealt with. Maybe even make it from bronze?

Offline chaterlea25

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Re: Motor strip
« Reply #26 on: 13.02. 2018 22:17 »
Hi Mark,
Yes a solid spacer is better than a stack of shims, all depending how thick it will need to be
I have done this on various projects but it takes time and probably repeated dismantling to get it right
a slip fit bearing on the crank makes this easier, maybe hone out the old bearing so it will slide onto the crank end
I would go for decent steel as a material

John
1961 Super Rocket
1963 RGS (ongoing)

Online Billybream

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Re: Motor strip
« Reply #27 on: 14.02. 2018 05:17 »
The use of a dummy bearing to gauge end float is good advice, because for sure you will have to split cases a lot to determine shim size.
As for the cush nut, treat yourself to the SRM version with hex nut arrangement, makes tightening procedure easier and secure with addition of Loctite.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline a101960

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Re: Motor strip
« Reply #28 on: 14.02. 2018 10:54 »
Quote
As for the cush nut, treat yourself to the SRM version with hex nut arrangement, makes tightening procedure easier and secure with addition of Loctite.
Yep, I second that. tighten to 65 ft lbs.

Offline tlmark

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Re: Motor strip
« Reply #29 on: 14.02. 2018 14:40 »
Cheers Guys
I put a mic on the plain bearing big end pins and they are still round!!! quite pleasantly surprised and -.020" undersize. the timing side is round too and I need to double check but only -.010" undersize.  so I'm hoping if I can sort the drive side I'm good to rebuild.