Evo scenario...Littlebear, feel free to jump in here

Keith Black 18cc domed pistons, .010" overbore, stock heads, .030 Cometic head gasket.

Cold compression calculates out to 10.62:1 (Gasp!), with the cam I want to run, corrected compression is 9.36:1, cold cranking compression works out to 186.

Is this asking for trouble?

[bigjailerman]

[dynageno]

[route66paul]

I am pretty sure that it would void the warranty.

[Deejay]

I would stick with flat top pistons and 10:1 compression max.

I am having a hell of a time with tuning a 10.5:1, .010" SE domed piston, SE heads, Evo
on 92 octane in the 90+ degree summer days. Octane booster helps, but is a PITA to
carry on long trips.....

You also have to worry about your starter. After the upgrade, mine quit and I had to go
with a Compufire Gen III 2kW.

Damn, it's quiet in here...

[Berserker]

No expereince at atll with that build. But comment on higher compression.

But how is the gas in your area? I've gotten premium on the interstate in ND. Places off the interstate in MT got that 86??

My thing with higher comprasion, is, its fine if you don't go far. Myself, I may got back to stock compression on next build. Less to deal with. Run any lousy gas you want. Stock ignition.

[thrasher]

Woody, whatever you do, just don't lower the idle. Berserker doesn't like that...

Originally Posted by thrasher

Woody, whatever you do, just don't lower the idle. Berserker doesn't like that...

He wouldn't like mine, then. It has that nice "potato, potato" idle., barely running.

[Type O]

i have the kb pistons and ther a great choce but dont go over 10.1. im running 9.5to 1 and when i get a slite ping and thats where the damage is done .fuel to day is crap even if you run the top grade . its up to you but for me id stay away from it .

[LittleBear]

Originally Posted by Woody218

Keith Black 18cc domed pistons, .010" overbore, stock heads, .030 Cometic head gasket.

Cold compression calculates out to 10.62:1 (Gasp!), with the cam I want to run, corrected compression is 9.36:1, cold cranking compression works out to 186.

Is this asking for trouble?

Only during starting. You must have a high lift long duration cam for that beast to get your Corrected compression down to 9.36:1.
It may be a beast to tune though without a programmable ignition module.
More info on the cam may help with comments.
Just one note for others, The 10.62:1 affects starting but has little to do with pinging. The cold cranking compression has everything to do with ping when the engine is running and domed pistons do not help with pinging either since they change how the fire wave front moves across the combustion chamber.

[Berserker]

Originally Posted by thrasher

Woody, whatever you do, just don't lower the idle. Berserker doesn't like that...

Glad we got that squared away. I was worried about your engine getting enough oil. Wouldn't want you to risk anything, over a few minutes of idle. Woody on the other hand I don't care. Hell his probably spends most of its time idling, thats why he worries about what it sounds like at idle.

Originally Posted by LittleBear

Only during starting. You must have a high lift long duration cam for that beast to get your Corrected compression down to 9.36:1.
It may be a beast to tune though without a programmable ignition module.
More info on the cam may help with comments.
Just one note for others, The 10.62:1 affects starting but has little to do with pinging. The cold cranking compression has everything to do with ping when the engine is running and domed pistons do not help with pinging either since they change how the fire wave front moves across the combustion chamber.

Littlebear, it's an SE-2 cam, loads of duration and overlap, not a low rpm cam by any means. Either I use that cam with those pistons, or else I will have to have some of the dome milled off the piston crown to get the compression down to a more manageable level, and use a cam with less duration.

I agree about the domed pistons changing the way the flame front moves in the combustion process. The only other alternative is to mill .060-.080 off the heads and use flat-top pistons. Thinking about it, this is probably a better alternative to domed pistons.

Berserker, I know that deep down, you care, you really care...

[Berserker]

Originally Posted by Woody218

.

Berserker, I know that deep down, you care, you really care...

I got to keep up my tough guy image.

Paul, I also forgot to add that the bike has a Compu-Fire Elite 1 adjustable ignition module, set up for single-fire.