1st oversize

[franco]

Hi.
1) about 1st oversize, Yambits says that their ring kit https://yambits.co.uk/rd500-piston-ring ... 75987.html , which is really a Rilken 1KT-B 0.25 unit, "should" match stock Yamaha +0,25 piston.
Before I order 4 kits, what is your opinion?

2) in my basement I found a 2YK-11635-04 piston, lying there from stone age; 11635 stays for 1st oversize, I believe. But 2YK is as good as 47x, when it comes to fitting in?

Thanks.

[Jeff B]

What pistons do you have in the front cylinders? Original RD500 or the superseded part number from the TZR125. They use different rings.

[tacky1]

I would order one first and make sure they fit the piston and fit the bore, No returns at Yambits, How many miles on your .25 pistons, I usually replace the piston when rings are shot, Pistons are known for breaking with miles, age, fatigue

[silverstrom]

You can order the TZR250 1KT piston kit with rings from Yamaha. You need to order the piston pins and clips separately from Yamaha. You can use the TZR250 1KT pistons and rings for all 4 RZ500 cylinders.

This is from CMS and their RZ500 parts list. It's a very attractive price. I order mine from my local Yamaha shop. https://www.cmsnl.com/products/pistonri ... 999902109/ The TZR250 1KT/2MA pistons have 4 drilled holes for improved oiling. That came about after TZR250s started having problems early on.

2YK is TDR250.

[Speed Freak]

Be aware that CMS prices are without tax (21%, Netherlands).
The price at my local dealer is usually about the same price including 20% tax (Austria)