Group Buy - Honda 400cc +1mm pistons -

[ScottieDucati]

If your org can't go +1... you can always go standard bore and higher compression :D

Lets get this moving mates!

57mm for me... wheeeee!

[racesupplies]

Good man,Im in!

[racesupplies]

Just checked with New Era and they said 1mm oversize is fine with them.

[Simon_Ed]

to be honest even if they were illegal who could afford the £300 or whatever it is now to appeal or lodge a complaint?

[racesupplies]

Thats more or less part of what the man said.He also said a lot of rules are being looked at to try and make things easier/cheaper.

[brooky]

what sort of time scales have we on these? weeks, months?

[racesupplies]

Dunno mate,need anything for your bike? In your neck of the woods in about a fortnight for the ferry to the island.

[ScottieDucati]

Si... I might grab an extra set of the +2mm's to toss in your race bike should things work out....

[CMSMJ1]

Right on.. We have an answer from the Omega people..

1: The thermal expansion of the pistons – relating to the person who will bore these motors for us – is there a spec sheet with the pistons to confirm the material properties?
Your pistons will be manufactured from 2618a aluminium. We supply fitting instructions for your engine builder.

2: The rings – are these custom rings or off the shelf parts? (asked by a chap who may just be after some rings as he has some Cosworth 57mm pistons) Can they be bought separately if required?
We can supply both custom rings (which are manufactured in house) or we can supply “off the shelf” rings. We will fit whichever rings we think are the best for this piston unless you specify otherwise.

3: Specifics of crown etc - I know Carl is after some higher compression pistons and has asked for a tall crown with the same valve cut outs. – if some wanted these and some didn’t – does this affect the group purchase?
This would affect the group purchase. I will only be able to group together pistons of exactly the same spec and bore diameter.

4: related to 3 – if some people wanted 56mm and some 57mm or maybe 57.5mm – does this affect the group buy? (I have told them I assume it would)
As above, yes this would affect the group buy.

5: What is the expected piston weight with pin and rings for 56mm, 57mm and 57.5mm?
Our technical design team will be able to discuss this in more detail when I have all the orders in.

6: Do you have any facility, or associated companies that might complete the boring of engine blocks to match these pistons? Do you recommend anyone?
There is no specific company that we would recommend.

7: Are they 2 ring or 3 ring designs?
We can supply either, depending on everyone’s preference.

8: Do you have a picture from one of the previous sets that have been produced? I think a visual idea of what we will get will help any people who are undecided at present.
We do not photograph any of our pistons at present (something I’m looking to change in the future).


So...to get some bargains in the house we need to try and club together some of the same exact specs to take advantage of the discounted pricing.

[ScottieDucati]

Thusfar, I haven't seen mention of someone after 55mm pistons. Seems to me that the club racers who need to stay within the +1mm rules are happy with 56, I will be after 2, possibly 3 sets of 57mm... and I think Mike from G-Force might grab a set of 57's as well to check them out.

Maybe start a list?

Name / # of Sets (x4) / Piston Size / Compression Rate

ScottieDucati / 2 sets / 57mm / 13.5:1