Author Topic: Jetting, a pain in the D! (Read 12948 times)

pinned250r · « **on:** July 04, 2013, 09:53:35 AM »

Last year i rode Morse250r's stock cylinder with an RB racing drag port on it, insane. So i went ahead and had it done to my cylinder, We have the exact same set up(40.5, trx5 cm, esr elim kit, same plug, pilot, main, needle, and clip position, and mine has no bottom end. Lost alot of rideability. It boggs/cuts out hard 1/2-WOT, We decided its just too rich, agreed? Thinking of going up on my needle clip and down on the pilot. Any input/reinforcement?

pinned250r · « **Reply #1 on:** July 04, 2013, 09:54:21 AM »

I did forget, Johann has the cr ignition, im just running oem, but RB said it shouldnt make a huge difference, it didnt on the dyno.

motofool250r · « **Reply #2 on:** July 04, 2013, 10:02:54 AM »

are you gapping the spark plug tight?

not all motors are the same some times its the carbs sometimes its just different.

RIDE-RED 350r · « **Reply #3 on:** July 04, 2013, 10:44:16 AM »

When you say it bogs and cuts out hard, is it a smooth bog or blubbery and smokey?

Need to figure out if its a lean or rich bog......

pinned250r · « **Reply #4 on:** July 04, 2013, 11:07:04 AM »

Definitely a blubbery bog, I think it's just getting too much fuel in the top, and I will definitely make sure to gap the next plug right.

Polonda · « **Reply #5 on:** July 04, 2013, 11:55:38 AM »

Definitely gap the plug at .018. Then work on the jetting. You should be able to tell if its rich at wot by reading the plug. What size main are you running now? Move the main a couple sizes and see if it gets better or worse.

A lean bog will almost feel like the motors cutting out. Rich will bluber and smoke a bunch.

pinned250r · « **Reply #6 on:** July 05, 2013, 09:04:15 AM »

Right, i dont think its the main thats the issue, plug is right where it needs to be at a WOT run, its the half throttle to 3/4 that blubbers out on me, I went 4 turns out on the air screw(supposedly its equivalent to 1 size down on the pilot) and it helped a little, I am running a 52 pilot, think im gonna drop a 48 in it.

pinned250r · « **Reply #7 on:** July 05, 2013, 09:04:51 AM »

And go up a clip position.

Polonda · « **Reply #8 on:** July 05, 2013, 09:12:40 AM »

Adjust your air screw for the highest idle and then turn it in a quarter turn or so. If you are out over 2.5-3 turns put in a smaller pilot. If you are out less than 1.5 or so you need a bigger pilot. Make sure the motor is warmed up good when doing this. What does a plug chop look like? Once you get the pilot close you can work on the needle/main.

jcs003 · « **Reply #9 on:** July 05, 2013, 09:55:58 AM »

sounds like a float height issue. fearlessfred has a trick to adjusting the floats without completely removing the carb. hopefully he will help.

john

pinned250r · « **Reply #10 on:** July 05, 2013, 10:36:26 AM »

I didnt even think about float height, I have been meaning to adjust that anyways due to a little fuel leaking after shut down.

RIDE-RED 350r · « **Reply #11 on:** July 05, 2013, 04:21:18 PM »

Quote from: pinned250r;708

I didnt even think about float height, I have been meaning to adjust that anyways due to a little fuel leaking after shut down.

That could very well be your smoking gun! Too much fuel in the bowl will certainly throw your jetting off.....

BJR88250r · « **Reply #12 on:** July 11, 2013, 08:53:20 PM »

What needle are you running? Diameter such as going from D"" to C"" series will lean out 1/2 to 3/4 throttle. I'd check float level though that could be prob. What slide cut away you using also? All this I'm talking about is related to a keihin though.

Morse250r · « **Reply #13 on:** July 13, 2013, 06:49:29 AM »

seemed to me when i rode it that it was fat 0-1/2 throttle it wouldnt build any power i was constently shifting to keep the thing in the power to get me around.

Rupp250 · « **Reply #14 on:** July 13, 2013, 10:57:44 AM »

Two port jobs are never they same, so it each one will need a little tweaking here and there.

Did they just run it on the dyno to get power figures or did they do in initial tuning on it. Should be pretty easy to get it on there and see what the a/f looks like.