Thread: DR350 Thread
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Old 01-05-2013, 08:17 PM   #14096
Beastly Adventurer
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Joined: Feb 2006
Oddometer: 2,777
Originally Posted by 2bold2getold View Post
You may be right about the slide spring preload, but not sure how much .020" more compression makes on these 20+ year old springs.
How old the spring is makes no difference to the fact that shimming the needle will increase the preload on the spring, and, except when the slide is at either stop, will richen the mixture by lowering the slide rather than by raising the needle.
I see what you're saying about throttle rotation and slide height. Maybe thats why all these jet kits say to cut off some of the spring after shimming the needles.
Doubtful for two reasons. One, most jet kits include an adjustable needle (otherwise, why buy one at all?). Two, while clipping the spring does reduce the preload, it also increases the rate.
It would take a lot of equipment to determine if those kind of changes made significant improvements.
I use a 5-gas EGA equipped eddy current brake dynamometer for this purpose.
I think it's hard to beat the factory guys with their budget and testing.
It depends on how you define "beat".
I wouldn't do any of it on my DR350.
Definitely understandable.
Mine is bone stock and runs great.
Not to say that it doesn't, and I might well agree with you, but in my experience, there seem to be varying definitions of the word "great".
And just wanted to illustrate idle concerns can be connected to the idle air jet as well as the fuel jet.


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