i run a 900 twin with 44 rounds 56 th squish on vp red 105 octane. i started to see my pto a little dry so i went up to 400 from 340 and went to c 12 108 octane fuel and still not happy i went to 490 pto 460 mag with the 108 octane and did a run and at the 400-500 foot she started to miss fire or something it just stopped pulling ,i lost 10 mph and a 1/4 sec in 660 ft , it did the exact same thing 2 consecutive runs , it almost sounded like the dess cord came loose but as soon as i went through the traps and hit it again down the return lane it was ok up to as far as i could hold it on the return lane, i wonder if coils, mpem rev limiter or is it the fuel i'm banging my head , any feed back is welcome

What rpm do you spin at? I know there is a rev limiter at 8700 rpm. We had it taken out to spin 9200 on our 600.

well i spun it on the stand today and saw that my fuel lines were emptying so out with the stock pump and in with the new, it makes sense cause as soon as i put in larger jets my problem just got worse, i teed off the stock pump with a 5/16 line to the carbs but i think the new pump with twin outlets is the way to go

oh ya rad chad i only spin at 8000 with the big bore

welli went back up last night and it did the same shuting down at 400-500 ft mark so i went back to a set up a had earlier and no change so i went up the track and held it this time and she back fired enough to blow the v force into little pieces so i tore it down and put it back together and went up tonite and the same stuff so i put on a mpem from my 02 x and it did nothing , coils next i guess or voltage regulator