cr500 question

[clyde111112]

i read on this forum that a guy had eric bore his cr500. he bored it 1mm over and said he bored it that far because it eliminates the decompression passages. can someone explain what the purpose of eliminating the decompression passages on the cr500 would be? what r the pros and cons of doing this ? the reason im asking this question is because im sending my cr500 jug and head to be bored and ported this weekend and want to know if i should have mine bored to 1mm over.

 

[Masterphil]

Pro's - it increases compression which would give some more bottom.
Con's - it may be harder to start.

If you want to get more top out of that motor, install a 39mm PWK, the bikes are undercarburated from the factory.

 

[magneto]

Eric bored my CR5 and eliminated the decompression grooves. It is much harder to kick over. He also did a Mo'Better port job on mine. If there is noise coming out of the pipe it is in the powerband. I'm happy with my engine except for the vibration at higher rpms. The stock carb works well for woods use (low rpm running.)

 

[clyde111112]

thnx for the answer. im sending mine to trinity in next few days. i might have them bore it to 1mm over as well. my owners manual says the farthest the jug can be bored is to 1.25 mm , which if i have them bore it 1mm over, that only leaves me .25 mm. is this true? anyhow, either way i have them bore it, i hope it has the power to rip off my arms when i get it back and put together :laugh: