im gona be buying a biggun revbox for my 650ds when i do this should i go down a tooth in the front or keep it stock thanks for any help

 

I have a BIG GUN rev box on my ds. I would keep the stock gearing. You should gain a little power and some top end because of the higher rev limiter. Gearing it down would just make it rap to fast and you wouldn't be able to utilize the added power.

I race a lot on dirt and I'm considering gearing it up some. I launch in 2nd and can't get traction to save my life.

 

Depends on what you're trying to do with it. 15/42 is the best combination that I've found no matter what carbs and CDI's that I've used.
What is it that you're trying to achieve with the CDI???

 

beat my friends 450r in 600feet drag race lol

 

I would go down one tooth in front, use 2nd gear starts....then tire selection and tire pressure along with suspention setup....