G15CSR Con Rod Question

Information relating to the Matchless G15 or AJS Model 33 750cc twin. This also includes the G15 Mk II and the G15/45
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G15CSR Con Rod Question

Postby Gerard Harrison » Thu Feb 17, 2011 4:49 pm

The outside flats/Flanks of my connecting rods do not have the "spitter holes" that would spray the outer walls of the cylinders with oil.

I am given to understand that this feature was employed on later Atlas motors and all Commando motors

Is this a "non-issue" or would I be better served by having my machinist drill the appropriate sized apertures into the con-rods and down to the bearing journals? I have access to a loaner later version one that he could use as the model for the work

At 244.00 USD apiece for the newer versions I would rather put my money elsewhere


I want to give this rebuild any authentic advantages possible before we button it back up and call it a motor but do not want to gild the lily unnecessarily

Thanks
Gerard

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G15CSR Con Rod Question

Postby Don Madden » Thu Feb 17, 2011 5:40 pm

Yes, you can save money on the new design rods to spend on crankshaft regrind & possible crankcase welding instead. Cheers, Don.

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G15CSR Con Rod Question

Postby rex.webb » Thu Feb 17, 2011 8:08 pm

? ?
Is ther Two con rods in a G15csr ??
As there is two forum topics going at once?.
STRANGE THING a COMPUTER ??
Ride with Care and Live Long
Wearing your Knee out!.
r w webb

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G15CSR Con Rod Question

Postby Gerard Harrison » Thu Feb 17, 2011 8:13 pm

Thanks Don...now, are you being facetious or am I ok without the holes? :-)

No not two topics just me and my computer behaving poorly together...

I reported myself to the admin and asked that one topic be removed
Regards
Gerard

Edited by - Gerard Harrison on 17 Feb 2011 8:16:01 PM

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G15CSR Con Rod Question

Postby Don Madden » Fri Feb 18, 2011 12:00 am

I thought we were talking about AMC twin conrods. Norton rods are robust but I know little else about them. Conversely, the AMC type were fine in 500 or 600cc engines but the caps fail in 650cc engines if pushed. I must admit to being one of the "Tearaway Boys" but have eaten a lot of the twin con rods, all failing due to stretching of the big end eye.

My riding buddy stripped his Norton Commando primary belt keeping up with my ugly BitSA 441. Probably just coincidence but perhaps I will slow down on my 77th birthday next month--Or not.

Cheers, Don.

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G15CSR Con Rod Question

Postby rex.webb » Fri Feb 18, 2011 8:18 am

I am begining to be thankfull for my Diesel engine being "GOVENED".When yo only have 3600 RPM as your maximum.I hate to see Holes in Crankcases.
ride with Care and Live Long.
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G15CSR Con Rod Question

Postby Marty » Sun Feb 20, 2011 10:50 am

Gerard
When I put my race engine together I used preloved 850 rods (those with the knowledge said these were much stronger than the Atlas/G15/M33 standard fittings), then I had them crack tested and shot peened. I bought them for $200 NZ per pair.
Marty

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G15CSR Con Rod Question

Postby Gerard Harrison » Thu Feb 24, 2011 12:24 pm

Thanks all for the input. I was away for a few days and am just circling back around.

As it turns out my friend Sonny of the former Ghost Motorcycles found an unused G15 bottom end that we are scavenging for the Crank, Conrods and Bearings. Everything gauges as Spec-New.

It was tucked away and buried in the corner of their old parts basement. Covered in dust but as new as the day it left Plumstead,

Sonny explained that back in the days,, when parts supplies were problematic,, they were not beyond tearing down a whole new bike and shelving the parts to service customers' machines or their own race bikes.

Anyway....I have yet to find one damnable bit on this machine that does not have the personal "signature" of a Prior Idiot on it.....right down to every mis-matched or incorrect skinned and rounded nut or chewed-up screw head.

I am in a continual state of slack-jawed amazement at the level of thoroughness and detail involved in making every last single bloody piece of this bike that I examine somehow "wrong" or otherwise compromised for re-use....

I am actually at the point where, when I am in the garage alone....I am laughing out loud like a madman...awash in ghoulish anticipation each time I pick up or pick out a part to assess....fully knowing... as sure as the sun rises and sets....that it will have its own unique
scar, blemish or fatal malfunction

I am so far underwater on this restoration...it has exceeded my worst-case estimations by at least 2 or 3 laps

But it is so bad it is theatrical.....like some horrific "Performance Art"....I would so dearly love it if somehow there was a way to capture the historical footage of the crimes visited upon this machine over the years.....I would want to study the faces and actions of those who were previously charged with maintaining this bike

Clearly this will be a gem when completed...but I will never realize any return on this investment...other than the satisfaction of having resurrected a fine example of the later days of the British Motorcycle industry.....

and yes I will accept nominations and sponsorships for recognition as a "Knight of the Empire" for this selfless sacrifice

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G15CSR Con Rod Question

Postby Don Madden » Thu Feb 24, 2011 4:57 pm

Your experiences with the motor sound typical to me for the AMC bikes. They are different from other makers & not common in the US so not many skilled in them on this side of the pond. Methods that work on the popular Triumphs & BSAs can wreak havoc on our machines. Cheers, Don.

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G15CSR Con Rod Question

Postby Gerard Harrison » Fri Feb 25, 2011 5:08 am

quote:

Your experiences with the motor sound typical to me for the AMC bikes. They are different from other makers & not common in the US so not many skilled in them on this side of the pond. Methods that work on the popular Triumphs & BSAs can wreak havoc on our machines. Cheers, Don.



Don, this bike is transcendent when it comes to "wrong"...it exceeds in ways that seem almost deliberate...

as if 2 or more prior mechanics were trying to kill the bike and whatever owner kept bringing it back to them to work on....

no doubt it took a 6 pack or 2 of malt liquor for them to even start to work on it

and I say this is a bad one in the face of prior experience of once having rebuilt a P11 that actually had a small vise-grip wrench permanently securing one end of a transmission mount stud

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