I would agree with spanners..but with the oem overbore pistons becoming rare or out of stock for the bikes that allow them anywyas...what are they going to do? They'll have to get aftermarket pistons...and then be running outside the rules on this technicality...

Just waiting for Bemsee 400 rep to ring back,but the secretary seys as far as she is concerned its OK. rules get changed when parts become unavailable,or expensive.LCs had a maximum overbore rule of .50mm which made the barrells and piston worth fortunes,CB500s had to run standard footrests,same thing there. It could get expensive running 20 year old pistons up against a fresh reworked head and valves that cost hundreds.We spent a fortune building a fresh 55mm bore 29 last year for the Manx,only to be told by the chief scrutineer when we got there that our 1mm over engine was legal anyway.

Just had the Bemsee rep on the phone,he says 1mm over is fine whatever make of piston.They have a minimum weight of 145kg,and a way measuring the bore with the engine together,dont know how that works.He says they have had a tool made.

Excellent..

All we need now are 1mm over pistons...

I am on the case,might be a group buy thing though.

racesupplies wrote:I am on the case,might be a group buy thing though.

How much set of 1mm pistons (rings, pistons, etc) cost ?

They have allready done a batch for someone else,but wont tell me who. I have used them before for other bikes,I saw the RVF ones at the Autosport show so asked the same question.They can make oversize,higher compression,whatever we want.That is what I want to know.Higher crown,over size? I have sent an original,plus details of some other pistons and am waiting for them to get back.Its going to have to be a batch to get a good price,I am thinking RVF 1mm over,but do we need higher crown to increase compression.

I am in for a set of +1mm pistons if they would suit my NC-30. I also have a friend here in the states that will definitely buy a set for his RVF. You can count on two definite orders from me, depending on price of course... but I'm hoping it would be somewhat reasonable!

This couldn't come at a better time, as G-force seems MIA, and I called JE Pistons (US Manufactured) and you can ONLY get them in the UK for a 433cc kit, but the availability is slim to none and according to DynaPro you have to rebuild a 433cc motor once / season. I'm hoping a +1 over would be close to a stock motor in terms of maintenance.

I'd be interested in slightly higher compression, but my personal interests are for a "mild" piston, nothing too extreme, that is.

Keep me posted please, I've subscribed to this thread!

I rang them today to see what is needed for an order.They caught me on the back foot yesterday when they said they had allready done one batch.I left it a bit late and there was nobody there.I will ring in the morning and see what they want to do.I dont really want more than two sets,and if its OK with the company I will post their details so you can contact them with your requirments.They have just combined two companies,I have dealt with both in the past and found them faultless.They are 3d machined from forged blanks,and safe to anything you would want to rev to,I have been told.Perhaps we should start a new more relevant thread and see what the interest is to maybe get a bigger order/better price. Let me contact them in the morning and I will see what they want.Regards Carl.

Cheers Carl, much appreciated. I believe the pistons from an NC29 have the same valve angles and such as an NC-30 and NC-35, at least according to a post made by g-force performance about his RVF pistons being used in an NC29. So that should be all set. His Cosworth pistons were $1200 / set, or around 735 GBP. I'm hoping (praying) we could do better than that with a group buy if the company is all tooled up and ready to run another batch. Post a link to a possible new thread here please!