I have to take mine in on Wends. or Thurs. for the low speed miss, just thought I'd ask what jets you have in yours I have the dyna and exhaust mod, and soon a different air filter. Any thoughts then on main jets?

 

My bike is stock right now...I have the mixture screws at 3 turns on both carbs.....NFKL needles in both carbs with one shim under each and stock mains......with the CDI and exhaust mod you need at least a 155 main (front) and 160 (rear) maybe even a 158/162 combo.....I would definitly put the NFKL needles in both carbs with TWO shims for your mods, if you still get the miss you will have to go with the NAZH needles in both....these are the stock needles in the 650 Brute and Prairie's, they are about 3-4 sizes richer than the stock 750 needles...........

 

Stakk,
Do you know off hand if the BF 650 carbs are the same as the BF 750 carbs?

 

Wow are you sure on those jet sizes I know these are different carbs than my 700's but wow I have 148 145 in the 700 and it runs absolutley perfect nevers misses a beat. Does the brute require going that high. I don't won't it too rich cause of mountain riding. I live at about 700 ft here but ride to 12000+. I need a good all around jet (if one exists) so I don't run crazy rich in the mountains. The 700 runs perfect up there and here just a few less ponies. I beleive the bf650 is the same as every other 650 and 700 engine as far as carbs.

 

Alltoys, the BF650 jetting is identical to the 650 Pra. #40 pilots 2 1/4 turns on the screws NAZH needles and 138/142 mains......If you are going to be at those elevations I would leave the mains alone and the screws at 2 1/2 turns but you will have to use the NFKL needles with TWO shims to get rid of the Dyna lean miss.......The actual updated needle for the front carb is a N4MT but the NFKL is slightly richer, trial and error is the only way to get it dialed in but this will be real close.......another post from a brute owner had completly stock jetting and said it ran without a hiccup all the way to 13,000 ft, this tells me the 750 is lean in stock form.......as far as the 750 needing 152/158 mains and the 700 so much smaller, consider the difference between 697cc and 749cc...... the cylinder bore's on the 750 are 3mm larger, this may not sound like much but it is when you consider that the 750 carbs are 34mm and the 700/650's are 32mm, the 34's pull alot more air velocity thus you must have more fuel, and to think that the 750 is lean at anything below 1000-1200 ft with these large jets....LOL