Carb issues

[R3DS!X]

So my DR350 I picked up initially wasn't running, it would start and run but only with choke. Pilot jet turned out to be occluded, so rebuilt the carb.

now she starts with choke and after a few seconds idles fine, starts and accelerates fine, BUT intermittently when I try to maintain speed she sputters and stalls like she is running out of gas. pretty odd. I speak carburetor conversationally but I'm not fluent. I looked around to make sure there weren't any hoses disconnected or something not seated but AFAIK everything is proper.

Could it just be the AF screw? I set it to 2 turns out as was recommended by the innerwebs. I hope I don't have to fiddle with that cause it's in a bitch of a spot and I have to pull the carb to get to it basically.

Could it be bad gas or too high of an octane? i used 91 in it but maybe a lower octane would run better?


FANKS

 

[DucatiHoney]

Moved to garage.

I've tried exactly once to deal with carbs. I don't do that anymore. G'luck!

 

[bobl]

Try it with the gas cap open. I could be a blocked vent.

 

[R3DS!X]

Try it with the gas cap open. I could be a blocked vent.

Nope, vent works fine. I checked that.

 

[ST Guy]

Did you clean the carb thoroughly? All jets and passages?

 

[R3DS!X]

Did you clean the carb thoroughly? All jets and passages?

yup. sprayed carb cleaner and compressed air through all kinds of passages.

 

[wilit]

Not a fuel octane issue, most likely a carb issue.

The AF screw is only for idle. Once you crack the throttle, it's all about the needle and main jet.

How's the float level and float needle and seat? Also, how's the slide diaphragm? No tears and it's seated properly in the groove at the top of the carb?

 

[auntiebling]

yup. sprayed carb cleaner and compressed air through all kinds of passages.

that isn't necessarily enough.

find little wires to stick through everything you can

also, single cylinder bike if it ain't running right you're chasing your tail untill you confirm the valves are adjusted properly and ignition timing is correct

 

[R3DS!X]

I guess it wouldn't hurt to do the valves. I don't think I have the tools to check timing though.

Bike has only 2k miles on it

 

[R3DS!X]

How's the float level and float needle and seat? Also, how's the slide diaphragm? No tears and it's seated properly in the groove at the top of the carb?

Float level looke3d fine, diaphragm was in tact and seated proper. Float needle was replaced in the rebuild and in the same position.

 

[planegray]

Is there a screen between the tank and the carb ?

 

[R3DS!X]

Is there a screen between the tank and the carb ?

Nope, was thinking of installing an inline filter at some point.

 

[Rob]

that isn't necessarily enough.

find little wires to stick through everything you can

also, single cylinder bike if it ain't running right you're chasing your tail untill you confirm the valves are adjusted properly and ignition timing is correct

Guitar strings... get to work.

Chemicals and air won't knock off the glazed old gas that's coating your passages.... I thought what you thought and did what you did... then did what we're telling you and it ran just fine.

Edit: I think what we thought is good for maintenance... but not for raising the dead.

 

[Lucytriple]

Really sounds carby to me, but after you check the valves maybe think about the float level again. Too high can really bog that thing down, and changing the float needle requires a level check. Interesting that it's intermittent and only at steady throttle, though. I'm rambling and thinking while typing but weird things happen. Sometimes vent hoses catch the air in just the wrong way, assuming this steady throttle thing happening while riding. My last thought is if you replaced only the float valve and not its seat, your level might be creeping higher because it's letting a bit more in. Conversely, maybe that float level is too low? Can you get a tube on the drain of the bowl and see how high the gas flows?

ps they sell nifty extended mixture screws for hard to each situations and you get that thing warmed up and try turning 1/4 in, listen for change, try turning 1/4 out and listen for change. I like leaving it at the highest idle.

 

[R3DS!X]

Interesting that it's intermittent and only at steady throttle

This is the part that's got me fucked up, If it was bogging when i whack the throttle open or at idle it would be easier but bogging intermittently when holding throttle steady sometimes is kinda odd.

 

[edzx6]

Out of the 14 bikes SVJ and I are working on at any given time only 2 have fuel injection.

I can tell you right now that either one of the small ports in the carb is clogged still or something very tiny got loose after your rebuild and lodged itself somewhere new. The only thing to do is take them off again and clean again. You may do this 2 or 3 more times.

 

[R3DS!X]

The only thing to do is take them off again and clean again. You may do this 2 or 3 more times.

Can't fucking WAIT!!!!

 

[edzx6]

I am so sorry, I wish I had better news. I know it is a pain in the ass, that is why I make my son do it now

 

[R3DS!X]

Can I borrow him?

 

[Maddevill]

I'm not sure yours has it but some carbs have a screen under the float needle valve. Can be clogged.

Mad