G3L High compression Pistons

[DerekAJS30]

Like many others i have purchased a pile of G3Ls bits, some good some not so. It's basically a 1952. I plan to build a sort of on-road off-roader cs replica. I'm working on the engine and saw advertised "high compression pistons" (7.5 ratio) by an indian company, Red Lizard Classic Motorcycles: https://www.classic-motorcycles.co.uk/c ... b_pid=4669
Does anyone have any experience of these guys or the piston products?
Other thoughts welcome. My Model 30 project is almost complete so i'm disassembling the G3L (where there are at least two bits bolted together) to see what's usable, and researching the project for the summer and next winter.

[Duncan]

Hi Derek, No first hand experience I afraid but for information JP Pistons are an Australian brand and the club was recently stocking them as that was all that was available, Red Lizard has an Isle of Man address on their website I'm not sure what that means for VAT you would have to confirm with them.
There are differing views about JP pistons like there are for oil but they have been available for some time.

[g80csp11]

you can buy from the club as well except currently out of stock of +040
As Duncan says JP is an Australian company
best advise is to run slightly higher clearance, (perhaps 1.5 tho per inch of bore ) , and run in well

how quickly do you need them ?

[DerekAJS30]

Hi both, thanks. I don't need them urgently, i'm just building up a plan and starting to purchase bits and bobs as i find them. I hugely value the knowledge within the club forum so I feel it sensible to gather opinions as i go along so as not to make silly mistakes. I rather like the idea of a "replica" cs albeit it will be nothing like the original. The parts i have are not matching numbers so no real pressure to build to factory spec. The G3L is quite a pretty bike in off road form and since my other bikes (both matching number machines) are a road going AJS Model 30 and a Triumph Trident T160, grrrr booo, hiss !!!, a different style and feel is appealing.

[Joker_Bones]

I've used a JP piston from Red Lizard in a G3...

There is a discussion in this thread...

viewtopic.php?t=30175&hilit=Jp&start=10

[Andy51]

I have used a JP 8.5 to 1 piston in my '54 AJS 18S, along with competition cams, for nearly 20 years without any problems. The piston came with boring instructions which I gave to the cylinder borer - I seem to remember something about 1 1/2 thou extra clearance. Andy

[Groily]

Have had a pair of JP 8.5s in my Mod 31 since 2013. Cylinders rebored by T&L to suit - they supplied the pistons.
There are comments published here and there about JP rings not being top-draw, but mine have been fine as far as I can tell. I'd happily use them again.
I have Gandinis in a Norton, also AE / Hepolites in other AMC twin engines, and I honestly can't say that any pair is 'better or worse' than any other.