[rsss396]

I have a CR500 powered TRX quad that I sent to a shop out west that is very experienced in sand drag motors.

I won't name the company because I am not here to bash just want your opinion on the final porting specs.

I put my degree wheel on and this is my results:

The exhaust has been raised to 192 degrees open(stock is 180)
The transfers are stock at 122 degrees open

Compression is 13.5 to 1 (have not verified this, just the info that was given to me)

The motor pulls hard through mid range but is flat on top.

I have always ported my own motors but being the 500 was new to me I thought I would just save the headache and time experimenting to get the right port timing combo and went with a known builder.

So now that I am not happy with the performance I figured I would just finish this port job myself.

My experience on 265 motors was to take them to 130 degrees on the transfers when running 192 degrees of exhaust.

I thought trying 128 degrees on the transfers would be a good start then maybe a little more down the line if needed.

Any thoughts would be appreciated
thanks Dave