140 keeps stalling

[fz6 tas]

Hey Guys,
I bought a Braap Pro 140 about a month ago. It runs a Yx 140. The bugger keeps stalling on me. If I am running down a hill and roll off the throttle it will just die, fart and pop first and then just die. It won't idle right too. It's done about 5 hours work and I have done 2 oil and air filter changes/clean and it's starting to really shit me. I keep on getting told from other people it'll be right once it's run in but surely it's ran in now. You can tell on idle that it's too low, it'll idle real slow for a while fart, pop and then die.

Do I need to just turn the idle up? If so where is the screw, like what side of the engine?

Or

Is it the throttle cable that needs adjusting? How do I do that?

Cheers in advance

 

[Shing]

The idle adjustment screw should be on the caby. We can't tell you where abouts on the carby the screw is as we don't know what carby you have...?

 

[rider_7]

Hey fz6 tas i would say check the fuel line to the carbuerator,check your jets to the running jet,idling jet,check your float adjustment (for flooding),your spark plug for proper sparking,defective killswitch and check the fuel and air filters.

 

[fz6 tas]

ok thanks guys, will give it a go and see how i go

 

[Metalmulisha 110cc pro]

Might be running to lean or rich unscrew the cap at the end of the throttle cable that goes into the carby and move the surclip up and down the needle try each setting till you get close to good idle then adjust the idle screw and fuel screw till perfect but only try this if you adjust the idle screw first and it still runs like crap.

 

[Cactus Jack]

If it's got an IRK on it ... piss it off and fit an outer rotor kit ... IRK's are the cause of stalling lousy idle etc ... Either that or turn the idle speed up , get used to riding it that way , and re-adjust your riding / clutching style to suit a PITA of an engine ...

 

[Gawain]

Also adjust your fuel/ air screw. Dont bother with needle/main that has nothing to do with the idle circuit.

 

[headsmess]

stalling when running downhill...makes me wonder which way your carbie points, and how high the fuel level/float height is....like, would it stall if it was sitting still and you lifted the rear wheel up? and is it ok going up a hill or on the flat?

could just be the fuel levels so low that the low speed jet clears it when you tilt everything.... the main jet sits lower in the bowl...

quick check, hose on the carbie drain, undo the screw, and hold the end of the hose against the carbie. when fuel just sits at the end of the hose, thats the fuel level in the bowl....you want it at least 3/4 of the way up the side.... but not above the top of the bowl, either.

 

[Cactus Jack]

If he's talking about it stalling down dirt hills and it has an IRK ... then it's a result of the IRK lacking the flywheel effect to keep the engine turning over smoothly at low revs ... so if he's in too tall a gear or touches the brakes or backs the throttle right off ... the engine stalls and the rear wheel locks ... He has to learn to pull the clutch in when he comes across those and other situations ... and keep the revs up and gently feed the clutch out as he accelerates from low speeds ...

T&G is a smart tech guy and he talks about annoying stalling and carrying on when he had an IRK on his YX150 in a bike used mainly on the road ... so you don't have to be on dirt to cop the same crap ...

outer rotor - Planet Minis

High end model trains run heavy flywheels to drastically improve their performance and running characteristics with NO other mod ... The flywheels allow them to operate super smoothly at crawl speeds and pull heavier loads due to greatly increased traction , they don't stop dead when the power is cut ... they coast to a stop ... That in turn prevents them from jerking and stalling on dirty sections of track where they cop intermittent electrical pickup on the wheels ... the flywheels keep them going until they hit clean track and get steady power again ...

The same goes for an IRK equipped bike ... it'll be a pig down low if the engine isn't perfectly tuned and set up plus the rider compensates for the lack of flywheel momentum ...

Trials bikes which can ride over just about anything including terrain that people have to CLIMB over ... have heavy flywheels ... without them they'd be hopeless ...

In a nutshell ... don't try to trail ride or ride an IRK equipped bike at low revs ... they are only designed for riding where the revs are kept high at all times and the bike is always kept in an easy to pull gear ...

Incidentally another fact is that Super Stock drag racers fit heavier than stock steel harmonic balancers and flywheels to greatly boost their launch off the line capabilities , traction and acceleration thru the gears for better elapsed times ... When you run big ports and cams in a given sized motor with a wide ratio tranny ... the flywheel momentum helps to stop the engine from dropping "off the cam" on upshifts ... that in turn allows for a higher revving engine without bogging on the shift or on take off ...

2 stroke MX bikes which had IRK's were relatively gutless down low and required 6 speed close ratio trannies plus a high ratio final drive to function adequately ... and they needed a multi plate clutch to cope with the tendency for them to be vibrated and lose grip ... When you cam a 4 stroke and lighten the crank and flywheel you really need to do the same things ... Early XR75's were only 4 speed ... Racers fitted special 5 speed close ratio trannies to compensate for the altered torque characterists of modded engines ... The trannies made one hell of a difference even to a stock bike ...

 

[fz6 tas]

Thanks guys for the excellent in depth answers. I changed the fuel line from the fuel tap to the carbi as the old one had a kink in it and was too short to do the job. It runs alot better now, not so much coughing and farting anymore but it still will stall on idle. I haven't had the chance to go for a proper ride yet so it might improve once it's warmed up but the new fuel line had definately made a difference to the smoothness of the revving and you can even hear that it is running better.