81mm piston details

[jmw76]

Hi Guys,

I am trying to sort out parts requirements for my engine rebuild.
Can anyone provide the following information for the Wiseco pistons in the CK101 (11:1) kit. Maybe someone has one lying around that they can measure up for me.
- depth of valve relief cuts (measured from piston deck to deepest part of cut)
- dome height (measured from piston deck to top of crown)
- width of top ring land (measured from piston deck to top of 1st groove)

Here are my measurements for the R1216 (12:1) pistons for those interested:
- In valve cut = 0.100"
- Ex valve cut = 0.050"
- dome height = 0.150"
- top land = 0.225"

I am looking for pistons that will work properly with my GSXR 750J head. I need CR = 13.4:1 so will probably have to cut bigger valve reliefs in the pistons to suit. JE pistons have bigger reliefs as standard but have a smaller top land and may not stand as much extra cutting. Hence why I am looking at Wiseco.

JMW76

[nick76]

If you're struggling to find exactly what you're looking for,JE can make custom pistons,to the exact spec you're after.
I know they were about $1100AU a set,afew years ago,08,but the Aussie dollar is strong,so i dare say,it should be a fair bit cheaper now.

[jmw76]

Yep.
Custom JE pistons are one option at present.
I have already started exploring this. But still a bit about 2 x the price of "off the shelf" slugs.
Wiseco will not talk custom unless you order 8 pistons. Not all that practical for a 1 off motorcycle application.

Arias will do custom forged piston sets in lots of four.

Rocket Industries are the Australian connection.

If you know exactly what you want, they can make them to your instructions.

[jmw76]

I managed to finally get the info I needed out of Wiseco in the states.
What a shocking telephone system they have.
For those intereseted:
For CK101 pistons
In valve relief = 0.117"
Ex valve relief = 0.040"
dome height = 0.060" (1.5mm)
Top ring land = 0.223"
crown thickness = 0.270" (6.8mm)
Interestingly, the valve pocket centres are also pitched slightly closer to the centre of the piston on the CK101 vs the R1216 kit (0.020").

Cheers