Yambits piston performance and quality

[RD350NL]

Hi all

I have used the Mitaka (skirted) pistons yambits sells with good experience in the past. I am now seeing these pistons have bigger inlet ports compared to the version that doesnt have the tang.

Is there a difference in performance and quality?

I am boring my cylinders to 65.00 and it looks like only the pistons with smaller inlet windows are available in this size.

Without tang and smaller inlet window: (is this even Mitaka?) https://yambits.co.uk/rd350-piston-kit-100mm-p-53222.html

With tang and larger inlet windows:
https://yambits.co.uk/rd350-piston-kit-075mm-p-8150.html

[1976RD400C]

They are all Mitaka pistons. This is the one to use if you want 65mm with the bigger holes. RZ piston. https://yambits.co.uk/rz350l-piston-kit-100mm-p-15912.html

[RD350NL]

Thanks for sharing, as far as I know I have the original porting. Will the bigger holes make a difference?

[1976RD400C]

Thanks for sharing, as far as I know I have the original porting. Will the bigger holes make a difference?

I think so, less of a restriction as it is inhaling.

[1976RD400C]

[RD350NL]

I see the difference. I am wondering about the performance part, shouldnt have yamaha put the bigger holes in the OEM pistons if they performed better?

[The Red Scourge]

I see the difference. I am wondering about the performance part, shouldnt have yamaha put the bigger holes in the OEM pistons if they performed better?

Maybe to help with emissions and/or gas mileage.

[m in sc]

the holes are mostly there to act as tranfser port (boost port) pass through windows while the reed is shut and the piston is coming down. for example, look at wiseco ones. they are just holes.  0.02

[2T5]

Would smaller cut-outs mean a stronger piston? Less chance of failure?

[m in sc]

im not sure TBH.

[RD350NL]

I have them in and they perform the same as the LC pistons.