Spec 3 back firing...

[noBody]

Hi gents,

 

Juz to check with you guys...

does anyone of you here experiencing Back firing when u cold start your bike??

 

Recently i notice that, whenever I left my bike for around 24hours untouched, then when i start the bike... it will experience back fire.. it happen 3 time already ever since i brought my bike 4month ago...

 

I am using moriwaki full system....

[quaksw]

i tink its the misfire of spark plug.

[Ah Pek]

Hi gents,

 

Juz to check with you guys...

does anyone of you here experiencing Back firing when u cold start your bike??

 

Recently i notice that, whenever I left my bike for around 24hours untouched, then when i start the bike... it will experience back fire.. it happen 3 time already ever since i brought my bike 4month ago...

 

I am using moriwaki full system....

 

Your quest for an answer is not clear. Does this misfiring happened b4 or after your installation of the moriwaki? Its a "off timing" issue.

[inspire85]

I sometimes get backfiring oso.. I only have a yoshi endcan.. I asked my mechanic abt this, he say maybe my floating needle (sth lidat, forget the exact name) wear out tat's y petrol can leak into carbeurttor if the bike is left overnight for too long which leaks to backfiring.. :gun:

[YADI05]

Mine also the same im using GPR pipe i left my bike overnight and morning i start it will back fire. I change petrol from the V-POWER to 98 ron and it have minimise. Ask mechanic and they also find any fault it say it common on spec 3

[cheowseng]

I have tis prob since changed the pipe.

I did a full service on my carb still the same. I'm using moriwaki too.

?????

[Ah Pek]

Ok guys...all who are using third party exhaust system are running mostly on the lean side. Get a good mech to have the mixture tune richer...not for stock exhaust. Srvicing carbs has nothing to do with getting things right..the mech must know how to increase the fuel intake with the standard air intake level.

 

Usually, backfiring occurs in carbureted engine that are running lean where the air fuel mixture has insufficient fuel.

 

If backfire still exist..you may want to check your intake manifold for cracks (the four rubber ducts that goes into your engine from the carbs).

 

B4 doing any of the above..take a little time to check your spark plug to see if its too lean.

 

Amen!

[cheowseng]

lol!

 

Wad i did for mine was i change the 4 rubber duct, spark plug, my jet and the 4 small overflow pin(not very sure; conical liked).

Aftwhich did a relatively major carb tuning.

 

but still....

[inspire85]

but ah pek, the backfire onli occurs during start-up when the bike is left overnight for along time.. If the mixture too lean den we should experience backfiring even on the road rite?

[inspire85]

sometimes when i go dam, den my frens keep turn n turn my trottle i oso experience backfire when i start the bike..

[noBody]

lol!

 

Wad i did for mine was i change the 4 rubber duct, spark plug, my jet and the 4 small overflow pin(not very sure; conical liked).

Aftwhich did a relatively major carb tuning.

 

but still....

 

wah... after doing so much it still backfired ar... omg... i think it should be common ba like that.... nowadays when i start my bike i will always look at the exhaust and guess whether will it backfire ont... think is the petrol flow ba....

[4DToToBig Sweep]

Me using stock end can also encounter this problem...

Used 2 it le... :pity:

[Qrisx]

eh when i engine brake also got like some mini backfire. how come ah??? im using moriwaki full system...

 

or issit one of its trade??

[buttbutt8]

hi all, i am the owner of a 1-yr-old Spec III, i am using stock end can and i USED to experience back fire when i am using FP60 back then but once i stopped using it, the back fire stops too.

i also noticed that stock Spec III's factory setting iding speed is close to 1.5k rpm, which is very high and i dun know whether this contributes anything to the back fire problem anot.

[knoobie]

hi all, i am the owner of a 1-yr-old Spec III, i am using stock end can and i USED to experience back fire when i am using FP60 back then but once i stopped using it, the back fire stops too.

i also noticed that stock Spec III's factory setting iding speed is close to 1.5k rpm, which is very high and i dun know whether this contributes anything to the back fire problem anot.

 

hmm.. anyidea where to adjust idling for spec3 ? mine the mechanic once adjust my idling very low.. now lower than 1.

[4DToToBig Sweep]

hmm.. anyidea where to adjust idling for spec3 ? mine the mechanic once adjust my idling very low.. now lower than 1.

 

Unique Motorsports

MY idling below 1 also, its tune by em :thumb:

[Ah Pek]

but ah pek, the backfire onli occurs during start-up when the bike is left overnight for along time.. If the mixture too lean den we should experience backfiring even on the road rite?

 

It can happened in any situation but I'm indicating the usual. It definitely have to do with air/fuel mixture. what you can do is dial back your idling to factory setting at 1.350k and ride for a few days and see any change.

[knoobie]

Unique Motorsports

MY idling below 1 also, its tune by em :thumb:

 

mine tune by nobody.. just mechanic took a look coz of heat problem that time and turn down my idling.. mine is actually 0 once the engine start.. must trottle trottle abit then idling move. lol

[cheowseng]

eh when i engine brake also got like some mini backfire. how come ah??? im using moriwaki full system...

 

or issit one of its trade??

 

mine too...

[gene98]

eh when i engine brake also got like some mini backfire. how come ah??? im using moriwaki full system...

 

or issit one of its trade??

 

normal if u gt jettings n full system and aftermarket filter

[quaksw]

i needa find out why there are some minor backfirings when engine brakes are used ?? is it really because of the fuel mixture ??

[Ah Pek]

i needa find out why there are some minor backfirings when engine brakes are used ?? is it really because of the fuel mixture ??

 

When you said "engine braking"...its the same as shutting down throttle from a hi-rpm faster than idle speed. Below is an extract from very reliable resources by the professional. I believe most of you here can find the answers you want....

 

Backfires in Exhaust

------------------------

 

 

It is normal for many high performance exhaust systems to moderately backfire or pop when the throttle is closed from mid-to-high rpm. In fact, one should expect a well-tuned high performance engine to "pop" and "crackle" when the throttle is closed at high rpm.The popping is a result of the air/fuel mixture becoming very lean when the throttle is closed and the engine is rotating well above idle speed. It is also necessary that the exhaust system have rather open mufflers for this to occur.

Why This (normally) Happens:

1) When the throttle valve is in the idle position, fuel does not flow out of the main system (needle, needle jet, main jet). Fuel is only delivered to the engine by the pilot (idle) system.

2) The combined effect of the closed throttle and elevated engine rpm is to create a fairly strong vacuum in the intake manifold. This vacuum, in turn, causes a high air flow rate through the small gap formed by the throttle valve and carburetor throat.

3) Under these conditions the pilot (idle) system cannot deliver enough fuel to create a normal, combustible air/fuel ratio. The mixture becomes too lean to burn reliably in the combustion chamber. It gets sent into the exhaust system unburned and collects there.

4) When the odd firing of the lean mixture does occur, it is sent, still burning, into the exhaust system where it sometimes ignites the raw mixture that has collected ...the exhaust then pops or backfires.

Other possible causes:

Air Leaks:

Any source of fresh air into the exhaust system can create or worsen the conditions that bring about exhaust popping. The most common entry point is the junction of the header pipes and mufflers. Even a small air leak can dramatically increase the intensity or likelihood of exhaust system popping.A high temperature silicone sealant, as can be found in many auto parts stores, may be used to seal the pipe/muffler junction.

Lean Carburetion:

While exhaust system popping may be considered normal, it is certainly made worse by an overly lean idle circuit.Be sure that your carburetor's pilot jet is the correct size and that the idle air mixture screw is correctly adjusted before looking for other causes of popping.

 

Ignition:

If exhaust system popping is very loud, irregular and accompanied by loss of power, then you should suspect that the ignition system is not performing as it should. If for some reason, the ignition sometimes fires at the wrong time, then exhaust popping can become very energetic (loud).

Look for failing high tension leads (plug wires), failing ignition coil(s) and especially switches or connectors as possible causes.

[JbAtRaCeR]

Good one ah pek...!! My lecturer did'nt explain to me that well in class. He says we diesel guys use injectors... Guess he's abit lazy...

[hackers1]

i riding spec 1... does backfireing spoil my engine???

wheather in neutral or in gear?

 

pm mi ...ty

[BigDogs]

Hey i thought my bike is the only one doing that man. So best place to go is to unique to set the fuel mixture? Roughly how much will it cost?

 

lol!

 

Wad i did for mine was i change the 4 rubber duct, spark plug, my jet and the 4 small overflow pin(not very sure; conical liked).

Aftwhich did a relatively major carb tuning.

 

but still....

 

How much did you spend for that bro? My bike now more and more often backfiring in the morning but engine breaking standard will have like gurgling backfires i think thats normal coz bigger bikes oso have that.