150 miles on a new motor and this

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If there’s been detonation going on, that can give the circlips a hard time, because slight misalignments that didn’t matter before, start to matter and the pin whacks the clip.

Wear on the big end can have a similar effect.
 
GRM 450 said:
I have a 77 mk3
That had the cases so the cylinder tilted to the right and the head tilted forward .
The machinist found this when he checked the rough surfacing work . He said it looked like the surfacing was done with a blunt rock.
But being a 77 it was most likely built with reject parts under the receivers instructions

Worth checking the cases are machined correctly

Graeme
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Wow. End of that era.
 
Pulled the pistons and checked the trueness of the crank re Jim Comstock 2.643" at the top and 2.648 at the bottom. Some side to side con rod play on the piston with the broken circlips but no up and down or twisting play on either rod. Even with the wet sump mod my crankcase is full of oil. Got Hepolite pistons and rings and Jim Sent me good circlips. Hepolites came with the same tru Arc circlips as the Emgos. Off to the machine shop soon.
 
Peter R said:
I have seen Teflon buttons as piston pin retainers (although not a Norton engine) the situation we see here in Pete Komarek's engine could have been prevented this way imo.
Did anyone ever used this method on a Commando engine ?

150 miles on a new motor and this
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I always use teflon buttons...after i had two circlips come out on my racer over the years
 
Sorry if I missed it, but what would be the likely verdict on this one? Crank, inferior circlip, circlip install, piston clip groove?

Good to see the rebuild is moving along.

Scott
 
comnoz said:
If the junk black circlips that come with the Emgo/JCC pistons were used, this is the result I would expect.

The pistons are fine -the circlips are not usable.
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Yes the damage comes only from this, it is well known with the EMGOS,it is the same trouble with News Hépolite but also bads pistons rings for news Hépolites.:(

"Do not spend more than is necessary but do not risk making false savings either. Often, what starts out as inexpensive ends up being very expensive."
 
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Is it possible the new Hepolites are rebranded Emgo’s.
Or maybe sourced from the same supplier?
 
I have a set of Emgo pistons for my 750. Does anyone know a reliable source of decent circlips to suit in Melbourne, Oz?
 
You can give your money to Norton owners who test their products, who take pride in their work and provide top quality, dependable parts for the bikes we ride. Or you can give your money to manufacturers who have never owned or ridden a Norton and don't give a hairy rat about anything but making a few bucks even as they send out defective parts (bad clips and rings) that will ruin your motor.
 
Here! Here! A most profound statement on a Sunday morning. Seldom do I find an aftermarket item, say what you may of the declining years, which is going to give me 46+ years good service..... Long term rider - 1 Aftermarket mfg. - 0 for the win.
 
texasSlick said:
Agree! All made by JCC, and are very good, despite the inexpensive price. Discard the rings and circlips that are provided.

Slick
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Yes but buying rings and circlips will cost the same as GPM (Italia) or JP piston (Australia)
 
Changaroo, Road n Race are close to Melbourne. I have purchased parts from him and he is very knowledgeable, polite and the parts arrived within 48 hours of ordering.
 
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