Oversize Pistons 0.50mm

[Bodd]

I reckon they may only offer the big bore kit, as lots of variants to consider as the 400 in japan was just under 400cc and Europe & USA was 408cc.

Ash

So what size would these standard rings be ?

[Bryanj]

Who knows you would need to ask what bore they are for

[Bodd]

I'm thinking they are exactly the same.

"To comply with licence restrictions in France and Japan Honda also produced a 398 cc (24.3 cu in) version by fitting a shorter 48.8 mm (1.92 in) stroke crankshaft."

[stevush]

So what size would these standard rings be ?

Good question... I'd assume that they're to fit a standard 51mm piston.
I need 51.5 mm pistons and rings, however I do have another option..

I could ask SEP to make and fit new liners, then rebore to std size, then re-use my std Honda pistons with new rings.
Swings and roundabouts really, save on new pistons but pay for new liners ?

Steve

[Bodd]

As it states the stroke is altered the bore will be the same. This guy is worth keeping an eye on as he sometimes has piston kits, he has the 0.5 rings at the moment but not the pistons, I got a set off him for an FZR Yamaha a while back and they were fine.

[Trigger]

So what size would these standard rings be ?

Good question... I'd assume that they're to fit a standard 51mm piston.
I need 51.5 mm pistons and rings, however I do have another option..

I could ask SEP to make and fit new liners, then rebore to std size, then re-use my std Honda pistons with new rings.
Swings and roundabouts really, save on new pistons but pay for new liners ?

Steve

To have a new set of liners made is not cheap.

[stevush]

I'm ressurecting this thread because I've acquired a set of oversize pistons, or at least I'm led to believe that they're oversize. I have no vernier gauges or the like to measure them but the guy recons they are 51.5mm when he measured them. They are genuine Honda but looking on the crown, I can see no oversize markings anywhere to show the size, are they ALWAYS marked with an oversize ?
My bores are STD at the moment but need a .50mm rebore and these pistons slip into the bores now. Surely they should be too large to fit ?
Maybe a stupid question but I'd appreciate some help

Thanks
Steve

[Gixxer-18]

If there are no marks on the piston crown; The oversizes are sometimes cast into the piston in the pocket either side of the gudgeon pin holes.. (wrist pins)
HTH
Nigel.

[stevush]

I see nothing at all on the crown, either side of the pin theres just casting numbers 'S377' and '3'. On the opposite side just 'HONDA'
Thanks
Steve

[Johnwebley]

I'm ressurecting this thread because I've acquired a set of oversize pistons, or at least I'm led to believe that they're oversize. I have no vernier gauges or the like to measure them but the guy recons they are 51.5mm when he measured them. They are genuine Honda but looking on the crown, I can see no oversize markings anywhere to show the size, are they ALWAYS marked with an oversize ?
My bores are STD at the moment but need a .50mm rebore and these pistons slip into the bores now. Surely they should be too large to fit ?
Maybe a stupid question but I'd appreciate some help

Thanks
Steve

  the tolerance on pistons is very close,
those pistons are standard,no other piston would get anywere near ,

[stevush]

Yes, I think you've confirmed what I thought. I'm going to see him tomorrow and get a closer look at that vernier gauge he uses 

Thanks
Steve

[Bodd]

Second picture down shows where mine were marked, or not marked in the case of one of them which turned out to be standard 

[stevush]

Thanks Bodd, big help, the markings are pretty obvious now that I've seen them!!

Steve