What were they wearing?
How does the porting line up with each saw?
390XP
Exhaust - 97
Transfers - 114/118 staggered
Intake - 84
Blowdown - 17/21
Compression - 190-200 can't remember for sure
Timing advanced 6°
Carb bored 1mm
2188
Exhaust - 100
Transfers - 119/121 staggered
Intake - 95
Blowdown - 19/21
Compression - 198
Timing advanced 6°
Carb stock
Cool. How do you stagger your transfers? Intake one higher? Like is one trans higher then the other? Or do they slope up from ex to intake? Or vise versa?
One's just higher than the other, not sloped. Actually, I have the exhaust side one's opening up first. That's not the norm, but something another builder suggested trying. It certainly doesn't hurt!
I've always thought that you'd want the intake side to open last.
I also liked the 390 better than the 2188, but I guess the 2188 had a little more grunt, and after looking at Brad's numbers I can see why. Sure the larger bore may have played a role, but the numbers did the trick IMHO.:msp_smile:
You must subscribe to the "less can be more" thinking as well.
These saws are so close it's not funny. It depends on the wood which one will come out on top.
I tried to determine a clear cut winner, and couldn't do it. They just have slightly different "personalities". I think I'm going to leave the pipe and 2-piece head setup at home, and leave both of these setup like they are, only adding the "new" carbs to both of them. I'd like to get more time behind them, as well as some more of you guys opinions. I have a lot of testing and tuning yet to do to the pipe, and don't plan on having that done by then.
I tried to determine a clear cut winner, and couldn't do it. They just have slightly different "personalities". I think I'm going to leave the pipe and 2-piece head setup at home, and leave both of these setup like they are, only adding the "new" carbs to both of them. I'd like to get more time behind them, as well as some more of you guys opinions. I have a lot of testing and tuning yet to do to the pipe, and don't plan on having that done by then.
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