1250 tuning/power questions

i have a 2002 883r, i put on the nrhs 1250 kit over the winter, and N4 cams, i also have a ness big sucker intake and ultima ignition on the 4th curve, with the rev limiter set at 6500. i've got the carb jetted to 45-180 but it's got the dynajet stage 7 (i think) kit on it, so the 180 jet isn't stock, and it has a stiffer spring and and different needle and the accelerator pump is removed.

finished my break in miles finally a few weeks ago, and the bike generally runs pretty good. i haven't gotten it tuned by anybody who knows what they are doing yet, and i need to have that done soon, but in the mean time i just have a question about what other people are running.

as is, the bike is topping out at around 90mph, and i guess i just don't know enough about engines to know why it's doing this (pretty new to this, only had the bike for a little over a year). with the throttle wide open, it sounds like it's cutting out or not gettting fuel, if i roll off gently, it sounds a lot better, but still won't accelerate past 90.

is it my carb? anybody else running this kit, or should i go back to stock?
any help is greatly appreciated.

Not sure why you would drop the accelerator pump on a street bike.
Not sure you need a stage "7" kit in that carb. What do the plugs look like?
Sounds like the main could be off or perhaps the emulsion tube w that kit is funky. Is the diaphragm ok? Did you call dynojets tech line?
Also check your initial and final timing. Do you run a voes?
What about fuel delivery to the bowl. Still got 1/4" line?

Originally Posted by Sky

Not sure why you would drop the accelerator pump on a street bike.
Not sure you need a stage "7" kit in that carb. What do the plugs look like?
Sounds like the main could be off or perhaps the emulsion tube w that kit is funky. Is the diaphragm ok? Did you call dynojets tech line?
Also check your initial and final timing. Do you run a voes?
What about fuel delivery to the bowl. Still got 1/4" line?

Dropping the pump is what the kit called for... but reading more on it, i guess the kit is specifically made for an 883. diaphragm is relatively new, and it sounds like it's good, but i haven't inspected it. i am running a voes. i haven't checked the final timing, just set it static according to the ultima instructions. i still have the stock fuel line.

i think my first step is going to be putting the carb back to stock so i know what i'm dealing with.

You should be getting way more than 90 out of that setup. Mine used to run over 130mph with my fat ass on it. If it's rolling off that early, I'd check your timing and advance and bump the rev limiter to 8K+, (maybe try a different curve). It could also be carb jetting. I recall using a 190 main jet but maybe a 200 but your exhaust system may be too restrictive too. Double check for intake leaks, valve adjustment if you put pushrods in it, your fuel flow, (good gas cap, clean tank, petcock, line, etc). and maybe your plug wires, (good wires and if it's single fire; wires going to correct plugs).

The stock jetting isn't much different so I wouldn't bother with that. Your current jets should be about right. Maybe a little change in the main. You should toss the aftermarket needle and get onto a stock needle. There are a few good ones to choose from. I wouldn't raise the limiter higher than around 7k if at all. I would reinstall the accel pump as well.

Check the plugs and all other vitals as stated above.

You're jetting might be too rich. Since it pops and sputters at WOT then gets better when you roll back it sounds like its flooded at WOT. I had this happen to me on an 883 with a CV carb when I went up in altitude a few thousand feet. I ended up going to a 170 main and on notch more lean on the jet needle and then it ran fine. If your jet needle has a cir-clip and different levels on it try moving one notch up which would be more lean as well. Don't know too much about the S&S but it should be the same principle. A lot of different things are factors here too. Timing, intake, and exhaust. Good luck!

I had this same problem when I installed a new ignition on my bike. Didn't run for shit until I got it dialed in right. did you turn the spark advanced up until you got spark knock then back it down one click?