Tweaking a G80...

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
StephenG80
Posts: 264
Joined: Sun Apr 30, 2017 10:42 pm
Location: ARGYLL UK

Re: Tweaking a G80...

Post by StephenG80 »

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
StephenG80
Posts: 264
Joined: Sun Apr 30, 2017 10:42 pm
Location: ARGYLL UK

Re: Tweaking a G80...

Post by StephenG80 »

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
User avatar
cfaber
Posts: 346
Joined: Mon Nov 20, 2017 5:37 am
Location: USA, Colorado
Contact:

Re: Tweaking a G80...

Post by cfaber »

What do you mean "give out" ? As in bearing failure? Crank failure? etc?
Fix it until it's broken!

Otherwise how will
anything get done?
StephenG80
Posts: 264
Joined: Sun Apr 30, 2017 10:42 pm
Location: ARGYLL UK

Re: Tweaking a G80...

Post by StephenG80 »

means big end bearing failure/damage
User avatar
cfaber
Posts: 346
Joined: Mon Nov 20, 2017 5:37 am
Location: USA, Colorado
Contact:

Re: Tweaking a G80...

Post by cfaber »

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.
Fix it until it's broken!

Otherwise how will
anything get done?
User avatar
Pharisee
Member
Posts: 1126
Joined: Tue Mar 15, 2016 8:51 pm
Location: Lincolnshire UK
Contact:

Re: Tweaking a G80...

Post by Pharisee »

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' :)
I'm from the Fens.... Gimme six.
User avatar
cfaber
Posts: 346
Joined: Mon Nov 20, 2017 5:37 am
Location: USA, Colorado
Contact:

Re: Tweaking a G80...

Post by cfaber »

Not to derail this topic, but is there a thread documenting the differences between the C engines and the regular S engines?
Fix it until it's broken!

Otherwise how will
anything get done?
raffles
Member
Posts: 609
Joined: Mon Jan 01, 1990 12:00 am
Location: NORTHAMPTONSHIRE UK

Re: Tweaking a G80...

Post by raffles »

All the comp engines use a roller bearing on the inside on the drive shaft.
Tony
User avatar
cfaber
Posts: 346
Joined: Mon Nov 20, 2017 5:37 am
Location: USA, Colorado
Contact:

Re: Tweaking a G80...

Post by cfaber »

Is this on both sides or just the drive side?
Fix it until it's broken!

Otherwise how will
anything get done?
raffles
Member
Posts: 609
Joined: Mon Jan 01, 1990 12:00 am
Location: NORTHAMPTONSHIRE UK

Re: Tweaking a G80...

Post by raffles »

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
Locked