Low End Carb Sputter

[GMP]

Have you guys tried the NECJ needle yet? I ask because it addresses specifically the area your having an issue with, as the straight dia is longer than the N2ZJ and cleans up off idle. JDs are hit or miss, no half clip options.

Also, for the hell of it, disconnect the kill switch and try it.

[DaddyTJ]

I used the NECJ #3, 38 pilot, 162 main and added the float drain loop and WOW! this is an awesome set up on my bike. I have a lot of the same issues as discussed here.

[GMP]

Thats my jetting exactly. You other guys should do this before tearing your bikes apart.

[ktm526]

I'll give that a shot. Hopefully I can get my hands on that needle before the weekend. As for the drain loop I'm definitely gonna try that after three attempts adjusting the float I still can't get any better than 32 miles to a tank. Thanks!

[BETAGAR]

Responding to ktm526, I have not resolved my issue yet. I've reached out to Beta USA for help, since my dealer has thrown his hands up.
I've contacted another dealer to get there opinion, before I either trade this bike in or return it as a lemon lol. I'll keep you guys posted.

[GMP]

Was stator actually swapped by the dealer? It's the most PIA of ignition parts to swap so I'm sure they were reluctant to do so. Resistance values can change when hot so functional test is best. Flywheel key intact? And for sure disconnect the kill switch, that was my fried katoom400's issue here a few weeks ago. Just wire in a normal waterproof kill switch if it helps. I had a GG once that was more of a bitch than normal to jet. One thing I found was a piece of center case gasket that was not trimmed completely and sticking up about 8mm in the path of the intake flow after the reed block. Stuff like that is very rare but so is your problem. Also assuming the bike is not using coolant?

[Mark Donovan]

I have a new 300rr race edition and I'm dealing with a 1/8 to 1/4 throttle sputter (blubber is another word).

BETAGAR, My bike does the same thing. Here is what I'm starting to think about it. I have always rode 4 stroke bikes and until the past two years I have never had any significant seat time on two strokes. I bought my sons 2014 250RR Race edition, It ran great nothing seemed abnormal to me at all as far as throttle reaction or sounds. (Pinging or Burble.) Late last year I decided to do a top end on my daughters 2013 300RR after it won the women's class at the Perry Mountain 24 hour race. This 300 engine has two race seasons and the 24 hour race on it. At that time I decided to replace the piston on my 2014 that my son had raced for one year. Since she is 110 pounds wet and I am 200 pounds I thought I would swap the engines also. (By the way the 250 piston looked like it had the same wear as the 300 piston, neither one showed much use at all.) So now I have the 2013 300 engine on my 2014 race bike. Immediately mentioned that it sounded different, it had a burble at 1/8 to 1/4 throttle. My son said they all do that it's normal. Seeing as the motor wore so well and the bike never once ever fouled a plug I thought oh well maybe he is right. Fast forward to now. DaddyTJ a member here is a friend and one of my Beta customers. He said his bike was doing the same thing and that he fixed it with the needle and jetting changes mentioned earlier on this thread. So I made those same changes in Jetting and I installed the same needle. I rode the bike this past weekend and it still has the same "burble" You can hear it on the Video I posted this week on another thread. I am beginning to think it's not a problem with the bike at all but a characteristic of the larger displacement 300 and pipe/mufler combination. After all if it was misfiring or jetted incorrectly I would think this high hour bike would have shown some damage somewhere at this point. I agree its irritating, to hear but It doesn't seem to cause any issues. I may later try a FMF Gnarly and see if that effects it. My son seems to think it's the exhaust pulses in the factory expansion chamber that creates the perfect environment for what we are experiencing. I'm tending to agree with him. Maybe I will knock a dent in my pipe with a hammer and see if it changes. LOL

[GMP]

I'm not sure about that one, but I never heard his bike. Both my '13 and my brother's '14 don't burble off idle either, and run excellent with the NECJ needle. Mine didn't do it with the stock jetting. Hammer's bike did though. Some variables like all bikes. Plus, on 300s you tend to be in this range more than on 250s and some people are more sensitive than others. I had a KTM 300 that was a PIA and either too rich or too lean, never right. Much of this can be fixed with a head mod that tightens the squish up a bit. Maybe thats the issue, easy enough to measure. Funny when I got my 300 I was thinking I'd have to do this, like on all my GGs before it, and jerk with jetting being its a 300, etc. Turns out in two years I have never had the head off the bike and changed the needle just to smooth it out even more off idle.

[Mark Donovan]

I am no two stroke jetting guy at all, Heck I don't even have an ear for how a two stroke is supposed to sound, but this 300 is an awesome bike to ride. I plan on riding with TJ this weekend and we are gonna switch bikes a bit and see if they are much different. I can live with what mine is doing. But would love for it to sound smooth off throttle like the 250 was. I may try changing the base gasket the next top end.

[ks9mm]

mine is jetted per chart and someone rode my bike and told me it's too lean right of idle and small throttle opening. and it's definitely not as crisp as my friends husky TE250

I was thinking to put 38 pilot back in to see if it helps..