Topic: Yoshimura cb750 pistons, we're they all cast, none forged?

[gschuld]

These all appear to be cast.  I'm suprised, as I had assumed that Yoshimura would have used forged pistons for top level road racing use.

George

[Bill/BentON Racing]

Nope he believed in cast, he used ART same manufacturer who made Honda pistons

[gschuld]

And RC 836 10.5:1 cast pistons apparently.

George

[MRieck]

Because they were tight with ART George. Nothing wrong with GOOD cast pistons. I loved Yosh stuff.

[gschuld]

So road racing today with aftermarket NOS (ART blank) 836 or smaller cast pistons (with fresh rings of course) is a reasonable thing to do?  I'd never have guessed.

George

[PeWe]

Need rings for the nice 65mm ART pistons?  I ordered a set to my old Action Fours just for sure. Fit also RC forged and even older RC cast.
http://www.ebay.co.uk/itm/Honda-CB750-Piston-Rings-x4-sets-836cc-65mm-1969-1976-Oversize-rings-Big-Bore-/361834612842?hash=item543f06086a
That price must be bought just for sure

Almost double price but for Yoshi 64mm
http://www.ebay.co.uk/itm/YOSHIMURA-TYPE-RACING-HONDA-CR750-CB750-SOHC-812cc-PISTON-RING-SET-4-NEW-NOS-/152141197252?hash=item236c526fc4:g:NJ0AAOxyAs9SO0TW

[gschuld]

Thanks, but it makes me hesitant when I don't know, and the seller doesn't disclose, who made the rings.  I have the original NOS rings from the kit still wrapped in the waxed paper.  At the least I'd get new oil rings as the originals are one piece, and I'd prefer fresh 3 piece rings.  FWIW, I have had good dealings with Hastings rings and have yet to be dissapointed.  I'm OK paying a little more from a known source with whom I have done previous business.

George

[MRieck]

Thanks, but it makes me hesitant when I don't know, and the seller doesn't disclose, who made the rings.  I have the original NOS rings from the kit still wrapped in the waxed paper.  At the least I'd get new oil rings as the originals are one piece, and I'd prefer fresh 3 piece rings.  FWIW, I have had good dealings with Hastings rings and have yet to be dissapointed.  I'm OK paying a little more from a known source with whom I have done previous business.

George

Hastings...Total Seal....is there anybody else?

[RAFster122s]

Ask the seller who made them...if they are Japanese then it is likely to be decent quality, as long as it is not counterfeit coming out of China.  Strange thing about China is you can get good quality products made there, but if builtto a price then all bets are off. Problem is you don't know if it was built to a price of quality level.

[gschuld]

This issue for me is trust.  A guy selling low-grade Chinese or whatever ring sets on E-bay likely isn't going to admit to it when asked.

If I order from Hastings, my level of confidence goes way up since they stand behind their products.

Plus, if an oil ring gets damaged on installation (it happens), I know exactly where to get just that single oil ring if needed.  I prefer to order a full set for 5 pistons when needing new rings, just so there are spares of everything on hand.  Can't do that on Ebay.

It's just a personal preference.

George

[PeWe]

The cheap rings have different marking than my old Action Fours. TOP on one side only, AF has T on one side end, 100 on the other end. On top and 2:nd rings.
So they might be of a cheaper make... My clutch plates are made in China according to the package from Cruzinimage.

These oil rings are not that flimsy.
Not as my last experience with 71.25mm JE that gave me more experience

I need a new cyl for my old 65mm pistons since the clearance is about 0.1mm. No oil smoke last time. There is a risk that the garage wil get some cylinders.
The old 836 can be bored to 849 and new cheap pistons. Old 736 to be bored to 836... My Action Fours 836 look like to be possible to use with 1.5mm longer rods (CB900)....