Only the dyno jet kits say to drill. The factory pro kits don't require it. And the drilling isn't required for the needle. The needles are the same size, factory or aftermarket. The difference is the ability to adjust the clip position. The holes on each side of the needle hole are what need to be drilled. It allows for more airflow, which, when using the stock springs, is supposed to create the right amount of pressure. Factory Pro kits replace the springs I believe. Dynojet used to and then went to using the stock springs but having to drill the slides.shredex wrote:![]()
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No need for this.
Just read and follow the instructions that comes with the kit. Don't forget to tune,tune, tune...... the carbs till you get it right!
depends what kit you get. most will requiring drilling.
Kits will come with two drill bits. one for drilling out the mixture screw caps, and one for drilling the slides
I've never drilled the slides and my bike runs like a champ. I don't believe Darrin ever drilled his either. Drilling the slides is a last resort I would say. If for some reason you just can't get it tuned right and you've tried everything else, then I would drill the slides.