Author Topic: GB outer cover bushing holes oval shaped  (Read 582 times)

Offline coater87

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GB outer cover bushing holes oval shaped
« on: 18.08. 2016 13:53 »
 Is this common, or another weird thing with just this bike?

 Im making bushings for the kick start and gear change levers. Using a good set of snap gauges, the hole for the kick start is badly oval shaped. Matter of fact, im getting .014 thousandths out of round. Didnt believe it, gave it the feel test and sure enough its worn badly.

 I plan the rebore a clean hole, and just fit the bushings to that.

 Is this common, or another case of odd wear on this bike? Nothing is cracked, its just distorted badly. Almost like a heavy person used it for a foot peg and rode standing up all the time *eek*


Lee
Central Wisconsin in the U.S.

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Re: GB outer cover bushing holes oval shaped
« Reply #1 on: 18.08. 2016 14:06 »
14 thou ovality doesn't sound excessive to me, - massive amount of pressure on the kickstart bush everytime it's started eh?

Offline coater87

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Re: GB outer cover bushing holes oval shaped
« Reply #2 on: 19.08. 2016 00:48 »
14 thou ovality doesn't sound excessive to me, - massive amount of pressure on the kickstart bush everytime it's started eh?

 So its common for the aluminum cover to be worn that far oval? I t must be a bad design.

 Its a marvel they bother to sell stock bushings for this, if I had to use a stock bushing I would have to glue it in the hole or it would just fall on the ground. *sad2*

Central Wisconsin in the U.S.

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Re: GB outer cover bushing holes oval shaped
« Reply #3 on: 19.08. 2016 02:56 »
Apologies coater, I misinterpreted, I thought you were referring to the bush wearing oval.

Offline paulmbsa

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Re: GB outer cover bushing holes oval shaped
« Reply #4 on: 19.08. 2016 08:31 »
14 thou is not a lot and i would not say design issue after all bsa were not expecting 60 years of use, these are new problems coming to light with age not quality

regards

Offline duTch

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Re: GB outer cover bushing holes oval shaped
« Reply #5 on: 19.08. 2016 08:56 »

 I've considered the idea of using a needle roller in there- dunno how well it would work *dunno*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline coater87

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Re: GB outer cover bushing holes oval shaped
« Reply #6 on: 20.08. 2016 13:53 »
14 thou is not a lot and i would not say design issue after all bsa were not expecting 60 years of use, these are new problems coming to light with age not quality

regards

 I would agree with you except for this bike has not been kicked over in a serious way since 1971, thats the last time the bike ran. At that time the PO decided to build a chopper, got as far as taking it completely apart and then stopped.

 So really, its 13 years of use.

 Its an easy enough fix for me to bore out the cover and just make the right size bushings. It just seems odd to me that the hole in the cover where the bushing fits would be worn that far out of round. The only other thing is if it was made badly in the first place, thats why I asked if this was a common problem or if once again the odd-ball wear on this bike is completely unique.


 Some weird observations. The frame is completely straight, yet the rear wheel hub had been fixed twice. I can tell this because one guy knew how to braze and the other didnt.

 One cylinder bore (both on standard size) was warn 10 thousandths more than the other. I dont think the bike saw many miles, yet the sludge trap was plugged tight.

 The headstock bearings were completely worn out and even grooved the cups, yet the lower sliders are like brand new inside.

 The covers that came with the bike were in good shape, but the transmission main shaft was cracked.

 and on and on with the weird wear.

 Its almost like someone bought the bike, never changed oil or did any kind of maintenance and just ran it until it would not go anymore. But that does not explain the rear hub, worn out bearings in the headstock, or stuff like the bushing hole being worn to the point a correct bushing would just fall out AND never having been rebuilt and still on standard big ends and barrels  *conf*

 

Back when I started all this I made sure the frame and the engine left the factory together, so I have pretty much ruled out massive accident just because of the frame being so good.

 Lee

Central Wisconsin in the U.S.

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Re: GB outer cover bushing holes oval shaped
« Reply #7 on: 20.08. 2016 15:07 »
...this bike has not been kicked over in a serious way since 1971, thats the last time the bike ran...So really, its 13 years of use.

About the same story for my bike  *smile*

Online Joolstacho

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Re: GB outer cover bushing holes oval shaped
« Reply #8 on: 20.08. 2016 23:21 »
Some of those issues are consistent with the bike having had a sidecar attached.

Online edboy

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Re: GB outer cover bushing holes oval shaped
« Reply #9 on: 26.08. 2016 16:31 »
the kickstart bush is quite thin and the kickstart force is high especially when reluctant to start, so not suprised by a worn case. i have a problem with oil seeping from the shaft and bush even though the bush looks o.k. i think a thicker bush with an o ring slot would improve that niggle no end.