Backfire And Unstable Idle...

[Tammy Oldrie Agasin]

Hi brothers and other members out there... Please help me with my long time and rucurrent problem with my snipee... My idle is not good enough even if my snipee had a long ride already, coz i always observe that problem when i stopped at intersection with a stoplight(color red) my snipee went off, then the tendency i need to start it again(the engine)! The other problem here with my snipee is when im in a short and long stretch road(1st to 4th gear with 3/4 throttle) my engine is in a good running condition but when i lower or turn the throttle from 3/4 to 1/2 turn throttle the idle is something like FART(utot, pumupugak, unstable idle) then the tendency is im always forced to maintain the throttle into 3/4 throttle up to full,thats why the fuel consumption is high and it suck to my pocket... Huhu what do you guys suggest to me, i even changed my oem carb into another 2nd hand oem carb. And the problem is always came back.

 

[turbulence]

what modes did you change on your mc bro? the farting seems your mainjet is so big or either ere on the engine stop or very low idle. we need to know more details regarding your modes bro.

 

[john_carlo]

whats the engine specs

 

[astridnoelle]

Fir

Hi brothers and other members out there... Please help me with my long time and rucurrent problem with my snipee... My idle is not good enough even if my snipee had a long ride already, coz i always observe that problem when i stopped at intersection with a stoplight(color red) my snipee went off, then the tendency i need to start it again(the engine)! The other problem here with my snipee is when im in a short and long stretch road(1st to 4th gear with 3/4 throttle) my engine is in a good running condition but when i lower or turn the throttle from 3/4 to 1/2 turn throttle the idle is something like FART(utot, pumupugak, unstable idle) then the tendency is im always forced to maintain the throttle into 3/4 throttle up to full,thats why the fuel consumption is high and it suck to my pocket... Huhu what do you guys suggest to me, i even changed my oem carb into another 2nd hand oem carb. And the problem is always came back.

Sir, first off, check your idle speed & air screw position. Usually it backfires when you drop engine speed because incorrect a/f mixture will unbalance the decreasing air pressure, causing uneven combustion & backfire. Try to have your idle set between 1,300 - 1,500 rpm & see if it improves anything. These work for stock engines. If you have other mods, like air filters, cdi's or such, you have other things to deal with.

 

[Tammy Oldrie Agasin]

My snipee is all stock except the YRS pipe. Thats it.

 

[john_carlo]

My snipee is all stock except the YRS pipe. Thats it.

clean carburator and air filter. tune the carburator sinve you are using an aftermarket pipe, plug the ais since you are not using stock pipe and yrs has no catalyzer so no need for ais...

 

[Tammy Oldrie Agasin]

Fir


Sir, first off, check your idle speed & air screw position. Usually it backfires when you drop engine speed because incorrect a/f mixture will unbalance the decreasing air pressure, causing uneven combustion & backfire. Try to have your idle set between 1,300 - 1,500 rpm & see if it improves anything. These work for stock engines. If you have other mods, like air filters, cdi's or such, you have other things to deal with.

bro how can i know if the rpm is 1,300- 1,500 already?And some of the mechanic said my valve adjustment is already too lean thats why the limiter is too fast every rev and the engine is asking to change the gear.

 

[Tammy Oldrie Agasin]

No airfilter,15-42 sprocket combination additional info, it does contribute to the problem?

 

[Tammy Oldrie Agasin]

clean carburator and air filter. tune the carburator sinve you are using an aftermarket pipe, plug the ais since you are not using stock pipe and yrs has no catalyzer so no need for ais...

Sir where can i find the AIS? And what will i do to that thing? Sorry im so novice!

 

[john_carlo]

Sir where can i find the AIS? And what will i do to that thing? Sorry im so novice!

try a spark plug reading the reading must be rusty brown.. about the valve clearance have it check and if needed adjustment the adjust it..

ais plugging
http://www.yamahat135.com/threads/h...or-better-performance.4638/page-5#post-490130

 

[turbulence]

Basic first bro, do the AIS bro. Shut it down

 

[astridnoelle]

bro how can i know if the rpm is 1,300- 1,500 already?And some of the mechanic said my valve adjustment is already too lean thats why the limiter is too fast every rev and the engine is asking to change the gear.

I don't think there is such a thing as "lean" valve adjustment. Valves are set with very minimal tolerances (that's why we use a feeler gauge). Maybe the mechanic was talking about the air/fuel mixture screw. If you got no air filter, that's the key. The higher airflow velocity will feed more air to your carburetor but your stock jets in the carb cannot compensate, so the very uneven air pressure will cause backfiring. Even if you changed your exhaust only, you will have to calibrate/adjust your a/f mixture because the bigger exhaust will reduce back pressure. But changing or removing your air filter means you have to re-jet (likely, increase) your carb because of the increased air intake. No worries with the sprocket combination. On my X1R, the ideal rpm usually indicates a steady headlight adjusted from low rpm. If you can, get another snipee with the same condition as yours but with correct idle speed, run it at idle then tune your snipee to that. You'll probably have to make just minor adjustment. But if you need to adjust your a/f screw, better let an expert do it for you. Cheers!

 

[turbulence]

I don't think there is such a thing as "lean" valve adjustment. Valves are set with very minimal tolerances (that's why we use a feeler gauge). Maybe the mechanic was talking about the air/fuel mixture screw. If you got no air filter, that's the key. The higher airflow velocity will feed more air to your carburetor but your stock jets in the carb cannot compensate, so the very uneven air pressure will cause backfiring. Even if you changed your exhaust only, you will have to calibrate/adjust your a/f mixture because the bigger exhaust will reduce back pressure. But changing or removing your air filter means you have to re-jet (likely, increase) your carb because of the increased air intake. No worries with the sprocket combination. On my X1R, the ideal rpm usually indicates a steady headlight adjusted from low rpm. If you can, get another snipee with the same condition as yours but with correct idle speed, run it at idle then tune your snipee to that. You'll probably have to make just minor adjustment. But if you need to adjust your a/f screw, better let an expert do it for you. Cheers!

+1

 

[jangbest]

bro how can i know if the rpm is 1,300- 1,500 already?And some of the mechanic said my valve adjustment is already too lean thats why the limiter is too fast every rev and the engine is asking to change the gear.

try to change your stock CDI to RCDI to avoid limiter, 42 rear sprocket easy to reach limiter specially on 2nd gear.if you have that RCDI now your self is your limiter, you need also change your stock valve spring to Racing valve spring to avoid valve float, AFAIK

TS turbulence is ryt shutdown your AIS to have your back fire problem solve

 

[Tammy Oldrie Agasin]

To all, Can you suggest any person whose knowledgeable regarding shutting Down the AIS?

jangbest bro what brand of RCDI and valve spring that you may suggest which is proven when it comes to QUALITY ? thanks...

 

[jangbest]

To all, Can you suggest any person whose knowledgeable regarding shutting Down the AIS?

jangbest bro what brand of RCDI and valve spring that you may suggest which is proven when it comes to QUALITY ? thanks...

There are several type of CDI, BRT Dual band, BRT Hyperband, Rextor CDI and more its up to you whice one to use,
regarding about the AIS Plugging, you can PM sir traxxas-modifier for the procedure.

 

[HKholic]

No airfilter,15-42 sprocket combination additional info, it does contribute to the problem?

Did you rejet after tossing the air filter and adding an exhaust? I'd say if the bike runs fine except has problems idling; check your jetting and/or check for air leaks. As for AIS plugging: Look at your cylinder head cover. There is a contraption sticking up with two hoses coming out of it. Plug both of those hoses. Or have a plate made to replace the AIS valve. (thanks xclickclickx )

 

[astridnoelle]

Did you rejet after tossing the air filter and adding an exhaust? I'd say if the bike runs fine except has problems idling; check your jetting and/or check for air leaks. As for AIS plugging: Look at your cylinder head cover. There is a contraption sticking up with two hoses coming out of it. Plug both of those hoses. Or have a plate made to replace the AIS valve. (thanks xclickclickx )

I see a true "plate' here hehehe..

 

[astridnoelle]

try to change your stock CDI to RCDI to avoid limiter, 42 rear sprocket easy to reach limiter specially on 2nd gear.if you have that RCDI now your self is your limiter, you need also change your stock valve spring to Racing valve spring to avoid valve float, AFAIK

TS turbulence is ryt shutdown your AIS to have your back fire problem solve

Sir/s,

Is this recommended for all-stock engine? I may have problems if I shut out the reed /AIS valve hehe.. Don't even wanna think about valve float... I'd rather have a blown-out clutch basket than valve float hehehe..

 

[turbulence]

Sir/s,

Is this recommended for all-stock engine? I may have problems if I shut out the reed /AIS valve hehe.. Don't even wanna think about valve float... I'd rather have a blown-out clutch basket than valve float hehehe..

recommended for open pipe