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Norton 650ss +030 pistons - availability?

Submitted by mark_walsh on Sat, 02/10/2021
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Heavy Twins

Hi 

 Im after a pair of +30 pistons for my 650 ss  . The barrel I have was bored to +30 bore by the previous owner but I realise there arn't many makers of +030 pistons.  

 Cant see a pair on ebay or RGM, Thorntons or Andover Norton.  Anyone got any suggestions?   - be a shame to go out to +40

 

regards

Mark 

Submitted by robert_tuck on Sat, 02/10/2021

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I have used 650 pistons in my 99  , it may be possible to use 99  or Nomad pistons  if the skirts are shortened  , need to check  pin diameters  and  avoid  slotted skirts.

Submitted by david_cooper on Sun, 03/10/2021

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Not much help but if it's like the 88, one year they are missing and then they appear a couple of years later.  As a last resort they might be available from JP direct from Australia. Time and money...might it be better to bite the bullet and sleeve to standard?

Submitted by mark_walsh on Sun, 03/10/2021

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Robert 

 thanks  - had thought of  600 pistons but thought the skirts were shorter on the 650 ones to allow for the extra stroke .

David - hadn't thought of JP , will look them up. I am considering re-sleeving but wasn't sure on non spiggoted liners availability. I probably would go +040 first if the machinist can get away with it

Thanks both for the suggestions

 Mark

Submitted by robert_tuck on Sun, 03/10/2021

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600 pistons are too long  and skirts would have to be  shortened .  I much modified  my 650 and Atlas pistons  to reduce weight and pumping losses.   No issues up to date  with the mild use a classic gets.

Submitted by mark_walsh on Sun, 03/10/2021

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All

  in addition to the above ,  has anyone any experience in the advertised 4 cut pistons on ebay. I see they are done in +030 but have never seen this option before, Why the 4 cut anyway. to avoid handed pistons??. 

  Anyone out there used these on a twin???

Mark,

I have a pair of 650ss pistons, new old stock Hepolite +0.030". I've had them tucked away fors years but have never needed them. Let me know if you are interested.What ever you decide be wary of the Aussie JP pistons. I bought a pair of JPs for my 650 AJS & they weighed 90g more than the original BHB type.

Submitted by anthony_curzon on Sun, 03/10/2021

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I have a pair of the four cut away pistons, and they were for a 500cc Norton and they came from America, and i still have them. I got them many years ago, when i was looking for pistons for my 500 Nomad. 

Submitted by robert_tuck on Sun, 03/10/2021

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Perhaps the extra valve reccesses  were cut to provide a balance to the pistons  or even just to reduce weight .

Submitted by mark_walsh on Sun, 03/10/2021

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Hi Martyn

 I would be interested in your pistons if they are surplus to requirement, I assume they have rings and pins?

  Let me know how much you want for them through this forum or email me at walshbredgar@yahoo.co.uk, or  contact me on 07980 683323  

 

Many thanks 

 mark

 

 



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