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View Full Version : Jetting advice...



Socket
12-08-2008, 05:20 PM
The bike feels like it's hitting a wall at about 5K part throttle...If I add some choke at this RPM, it doesn't get any better. Will leaning out the needle do what I need?

Steve / AF1 Racing
12-08-2008, 05:29 PM
The bike feels like it's hitting a wall at about 5K part throttle...If I add some choke at this RPM, it doesn't get any better. Will leaning out the needle do what I need?

We actually richened up our needles on the two demo/race RS125s we have.

Ours came on 4 of 5 and we lowered to 3 of 5, which seems to have improved part throttle slightly. We need more time on the track to get a better base setting.

Then again, RAD changes can change quite a bit depending on where you are.

HONDARACER
12-08-2008, 07:44 PM
WHat does the spark plug look like? Also I am confused what you mean by part throttle? Mine would hit a wall at 8000 and had no power to pass wide open.

HONDARACER
12-08-2008, 07:55 PM
I guess your talking about the 34mm Dellorto. Ya the needle should take care of part throttle issues. Definalty look at the plug too. WHat main jet is installed?

Socket
12-09-2008, 09:39 AM
part throttle is controlled by the needle and main at 5k, correct?

Adding choke effectly richens it and it doesn't act any better. Going up on the needle is leaning it out, right? I'll do this and try it out and report back

HONDARACER
12-09-2008, 11:46 AM
If your running an open element air filter, its probably getting too much air. Just my .02

Socket
12-09-2008, 02:42 PM
If your running an open element air filter, its probably getting too much air. Just my .02

too much air? That isn't possible without a turbo or S/c. My goal is to stuff as much air into the motor without forced induction. More air, means you need more fuel, and with more of each, means more power.

You can never, ever, have too much air, unless you don't have enough injector to back it up.


Back on topic...I leaned the needle, which was already one off from the top, to the top rung, and the bike runs terrific. Going to order the K58 needle, and a leaner main jet also before I get the bike to the dyno.

HONDARACER
12-09-2008, 05:19 PM
Well I meant that with a normal air box it would get less air. With the open element you would thing it would get more air than with the box. Glad its running ok now..

jokerio
03-30-2009, 08:05 PM
Back on topic...I leaned the needle, which was already one off from the top, to the top rung, and the bike runs terrific. Going to order the K58 needle, and a leaner main jet also before I get the bike to the dyno. Socket, is this astock 28mm or the 34mm carb you are jetting ?
And how did it run after you tried the leaner main and different needle ?
Where did you end up ?