Squish band grooves

[(F5)]

Well 13.6 is pretty jolly high for a 300, perhaps it is finding its sweetspot.

 

[Zrt1200]

I have seen head swirl porting done on 3 different snowmobile engines. The CC volume & squish gap was the same before and after using two different sets of heads for each engine. On the dyno one engine gained 8HP and the other two gained Nothing. The swirl porting was done on a 600cc, a 700cc & a 800cc Polaris race engines. The 700 twin gained HP the two triples (600cc & 800cc) gained nothing. IMO Get you CR & MSV (Maximum Squish Velocity) set and be done with it.

 

[motopsycho87]

only problem I've seen with the polaris ones is the grooves don't look deep enough, and the "professionally" grooved ones are done a mill, which in my eyes is less accurate than filing directly at the plug gap.

 

[motopsycho87]

Been a few months now, main case seal decided to blow so it's time for a full rebuild... Yay!

Anyway, head looks perfect and the bike has been through utter hell in the last few enduros!