Tweaking a G80...

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Re: Tweaking a G80...

Postby Stephen G80 » Wed Nov 08, 2017 4:37 pm

Thanks for all the insight guys - Know what I will be doing in the spring!


"Dear Father Christmas,

For Christmas please may I have a set of SH cams, a light weight rocker..........." :D

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Re: Tweaking a G80...

Postby Stephen G80 » Mon Nov 20, 2017 10:42 pm

I have been doing some reading on other forums etc on these mods and some quarters believe that they cause the big end to give out. I would be grateful if someone can shed some knowledgeable light on this specific aspect.

Thanks

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Re: Tweaking a G80...

Postby cfaber » Mon Nov 20, 2017 10:48 pm

What do you mean "give out" ? As in bearing failure? Crank failure? etc?

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Re: Tweaking a G80...

Postby Stephen G80 » Mon Nov 20, 2017 11:12 pm

means big end bearing failure/damage

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Re: Tweaking a G80...

Postby cfaber » Tue Nov 21, 2017 1:30 am

Hm.. I could see that, especially on the drive side. ball bearings I don't think are the best choice for such an application, rollers would have been a lot better. I just pulled the set of RLS8's out of the drive side of mine and with only 4400 miles on the bike, the bearings were already showing a lot more wear then they should have.

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Re: Tweaking a G80...

Postby Pharisee » Tue Nov 21, 2017 5:23 pm

Shouldn't think that there is much to worry about. The C variant competition engine uses pretty much the same bottom end and that seems to cope with the extra 'umph' :)

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Re: Tweaking a G80...

Postby cfaber » Tue Nov 21, 2017 5:25 pm

Not to derail this topic, but is there a thread documenting the differences between the C engines and the regular S engines?

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Re: Tweaking a G80...

Postby raffles » Tue Nov 21, 2017 7:04 pm

All the comp engines use a roller bearing on the inside on the drive shaft.
Tony

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Re: Tweaking a G80...

Postby cfaber » Tue Nov 21, 2017 7:05 pm

Is this on both sides or just the drive side?

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Re: Tweaking a G80...

Postby raffles » Tue Nov 21, 2017 7:13 pm

If you have abog standard G80 then the timming side will be a bush. There are two bearings on the drive shaft the roller replaces the inner one up against the
fly wheel.
Tony

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