crosser 125 throttle response issues

[jammandan69]

hello there im more of a two stroke guy and have never taken a fourstroke apart or seen what it looks like inside but im asking for help as my bike had been sat for a year had fresh fuel put in changed oil and oilfilter problem is the bike starts perfectly fine and easily but if i twist the throttle hard and fast it will rev up cut out and back fire with a massive flame :P can light my fags of it lol not good idea though :P jw if any one can help should i adjust air mixture screw and it idles fast only mod done it is full arrow exhaust does it need a good ride to clear out any crap?? many thanks dan i would upload pictures but dont know how to lol

[FastDoc]

I'd wait for Weld to chime in. He's our jetting guru. I'll guess you are lean on the needle (and main too probably) due to that aftermarket exhaust and I'd recommend raising the needle one notch.

[jammandan69]

as in raising the needle go up one on the needle and ive undone one bolt on the airbox and put a little spacer in havent started it up yet but as you said it sounds like its running lean that would make it even more lean with it opend up a little sounds nice a meaty though il take the carb apart tmos and see whats what :)

[Wild_Alaskan]

Some bog on a carb not equipped with an accelerator jet is normal,you can richen (raise) the needle or lean the pilot to hide it a little. Also a more free flowing exhaust will help since it usually richens the mixture a little bit due to increased suction.

[FastDoc]

http://www.dansmc.com/carbs2.htm

Raising the needle, ie lowering the clip, richens the mixture in the mid throttle settings.

[jammandan69]

i have a free flowing exhaust its a full arrow pipe front and back and so i need to bring it down a notch so that it draws more fuel in :) thank you hope it stope the bike cutting out at full throttle it back fires massive bang like a gun shot lol

[FastDoc]

I also agree with Wild Alaskan BTW. These non-CV carbs are not tolerent of sudden throttle opening. They draw more air before they can suck up the additional needed fuel and will stall/misfire/backfire momentarily.

BTW WA is one of the most knowlegeable bike mechanics I know. :D

[Aj1]

Jamma,

What you are describing is the result of old fuel turning to varnish in the float bowl. You mentioned that your bike sat for a period of time. When that happens usually you end up with what youre describing. The remedy for it is simple, you just need a good carburetor cleaning. It is not difficult to do for someone that understands the internal mechanics of a carburetor and has a few simple tools. Most likely what you have is one of several things. 1: It may have a clogged pilot/main jet 2: it may have a clogged air bleed in the venturi. These are the two most likely solutions to your problem.

~AJ1

[Weldangrind]

I agree that the carb likely has varnish in it, but simply celaning the jets won't likely resolve the issue, which is mostly due to the Arrow exhaust. You can likely go up two sizes on the slow jet and main jet and see how it runs. Jets are cheap, like me. :D

[SpudRider]

...Jets are cheap, like me. :D
:lol:

No, jets are inexpensive, and you are prudently frugal, dear friend. ;)

Spud :D

[Weldangrind]

You're very kind Spud, but I'm very aware of my Scottish heritage. :lol:

[FastDoc]

You're very kind Spud, but I'm very aware of my Scottish heritage. :lol:

I can relate with my Jewish heritage... :lol:

[katoranger]

I'm Dutch. :wink:

[openthrottle55]

Buy a 110 jet at Honda its 4.00 bucks, also ditch the air box and put on a pod/ cone filter that plus your exhaust will give it way more power and will level it all out

[SpudRider]

I'm just cheap (frugal). ;)

Spud :lol: