Engine Idling issues (RVF)

[blacstarz]

After washing my carb, my idling has been a bit weird like sometimes when i throttle the rpm will go down as usual but at the last part around rpm 2 down to 1.5(my idling point) will slow a bit not always happen but once a while will....

 

not only that sometimes my idling is not fix meaning to say sometimes its 1.5 sometimes its 1.3 or even lower this only happens when i throttle stationery ie. now rpm idle is 1.5 stable but when i throttle, it sometimes will go to like 1.3...

 

when riding, the rpm goes up as per normal and power is there... its just the idling problem

 

anybody knows whats wrong???

 

bike is rvf...

 

hope someone can give some advice on whats the matter thanks and appreciated..

[naim]

first check that ur throttle snaps back quickly n smoothly.. cud be ur throttle cable.. if not, sounds like a carb issue.. best to go to bikeshop to sort it out..

[blacstarz]

first check that ur throttle snaps back quickly n smoothly.. cud be ur throttle cable.. if not, sounds like a carb issue.. best to go to bikeshop to sort it out..

 

hmmm.. starting thats what i feel but i changed the throttle cable already guess i had to head back to the bikeshop for a check

[PepperCrab]

I'd check that the choke/enricher cable and mechanism on the carb side is working properly and smoothly. If that checks out ok, I'd take the carbs apart and make sure it's been put back properly, and slide diaphragms haven't been torn/pinched.

[blacstarz]

I'd check that the choke/enricher cable and mechanism on the carb side is working properly and smoothly. If that checks out ok, I'd take the carbs apart and make sure it's been put back properly, and slide diaphragms haven't been torn/pinched.

 

went back to shop to check mech say its the idling not set properly... he set my idling to 1000 rpm which i think is pretty low... but den if i set to 1.5 rpm coming down problem will exist... hmmm... can anybody advise?? go to another shop??

[stsoh]

google search rvf400 idle speed......1300 +-100 rpm.

http://www.vsource.org/VFR-RVF_files/Brvf400r-mi.htm

 

norm idle speed for il4 engines is 1200rpm, should not be any diff 4 v4 engine.

[ooitn]

check your cable travel...might be over travel issue, or depending on how intensive your service your cab last time, might me timing problem between each cyclinder..sort of travel problem too.

[PepperCrab]

went back to shop to check mech say its the idling not set properly... he set my idling to 1000 rpm which i think is pretty low... but den if i set to 1.5 rpm coming down problem will exist... hmmm... can anybody advise?? go to another shop??

 

what is the "coming down problem"? if the idle isn't stable then it has to be something more than just the idle setting.

[blacstarz]

what is the "coming down problem"? if the idle isn't stable then it has to be something more than just the idle setting.

 

Eh like when at neutral u throttle the rpm goes up and come down but when ard rpm 2k to 1.5k it kinda slows a little that's when my idling is set at 1.5k if idling is set at 1.3 this will not occur

[blacstarz]

eh just wanna ask what will happen if my rvf is equiped with factory pro jet kits but one of the main jet is of different size meaning to say wrong size... its from previous owner.... does it cause the idling problem??

[stsoh]

main-jet doesn't affect idling rpm......it's relate to top rpm power.

pilot (air) screw n slow-jet r the one concern with idle n low rpm.

 

u can play around with pilot-screw.

default setting for rvf is 1 5/8 turns n u can only play with 1/4 turns left (counter-clockwise) or right (clockwise).

otherwise replace slow-jet (#35) with one size up slow-jet (#38).

 

how to set pilot-screw??

turn clockwise to bottom down (note: do not over tighten it, otherwise u will break the pilot screw needle tip).

once bottom, turn counter-clockwise to 1 5/8 turns n this is the default setting.

as per manual, u have only a quarter turn (max) clockwise or counter.

tat mean u do a 1/8 turns either way to find your best setting.

 

most important is balancing your carbs after any adjustments.

[blacstarz]

main-jet doesn't affect idling rpm......it's relate to top rpm power.

pilot (air) screw n slow-jet r the one concern with idle n low rpm.

 

u can play around with pilot-screw.

default setting for rvf is 1 5/8 turns n u can only play with 1/4 turns left (counter-clockwise) or right (clockwise).

otherwise replace slow-jet (#35) with one size up slow-jet (#38).

 

how to set pilot-screw??

turn clockwise to bottom down (note: do not over tighten it, otherwise u will break the pilot screw needle tip).

once bottom, turn counter-clockwise to 1 5/8 turns n this is the default setting.

as per manual, u have only a quarter turn (max) clockwise or counter.

tat mean u do a 1/8 turns either way to find your best setting.

 

most important is balancing your carbs after any adjustments.

 

hmmm... but what could be the problem for the idling..???

[blacstarz]

eh could the problem be due to running to rich??? cos there r some popping sound whenever i close throttle engine brake....

[stsoh]

tat's top end rich.....u can change back to orign (mj#108) or one step up (mj#110).

i think ur carbs r not balance, if it's well balance, idle will be good n smooth.

even if all carb with the same setting, each cyl draws different vacuum (hg) due to wear n tolerances.

do ur mech use carbtune (vacuum gauges) to balance after tuning?? if not u should find other shop expertise.

[blacstarz]

tat's top end rich.....u can change back to orign (mj#108) or one step up (mj#110).

i think ur carbs r not balance, if it's well balance idle, will run smoothly.

even if all carb with the same setting, each cyl draws different vacuum (hg) due to wear n tolerances.

do ur mech use carbtune (vacuum gauges) to balance after tuning?? if not u should find other shop expertise.

 

icic... so ur take is that i should go to another shop for tuning or washing of carb again???

[Tachnicolour]

In fact, might be too lean.

 

http://www.randakks.com/TechTip72.htm

 

Check out "hanging idle" under lean conditions.

 

Just quoting, cuz had the same hesitation on my old pulsar, cept mine was opposite. It would dip below normal idle before climbing. Mine was rich.

 

Another page. http://www.angelfire.com/mt2/mikesgs500/rejetting/

Look at the very last picture. Gives description for lean or rich.

 

Hope it helps.

 

BUT, you also mention that it drops when you blip, which is a rich symptom. So, can't really say. Just these pages for you to look at and consider.

[blacstarz]

In fact, might be too lean.

 

http://www.randakks.com/TechTip72.htm

 

Check out "hanging idle" under lean conditions.

 

Just quoting, cuz had the same hesitation on my old pulsar, cept mine was opposite. It would dip below normal idle before climbing. Mine was rich.

 

Another page. http://www.angelfire.com/mt2/mikesgs500/rejetting/

Look at the very last picture. Gives description for lean or rich.

 

Hope it helps.

 

BUT, you also mention that it drops when you blip, which is a rich symptom. So, can't really say. Just these pages for you to look at and consider.

 

 

hmmm.... power output wise is good.. what the website states is that power output will be weaken with either lean or rich setting... hmmm... could it be a spark plug problem causing the idling issue?? about the hanging idling before settling down at idle point it does happens but when my idle is at 1.5k its obvious... but the idling is quite shaky when its below 1.5k.. i dunno if thats normal... most of the time when i throttle my bike at neutral gear or stationery at gear 1 the rpm needle does not settle back at the usual idle point...

[stsoh]

icic... so ur take is that i should go to another shop for tuning or washing of carb again???

 

if a mech say he can tune a il4, v4 or multiple cyl engine without using carbtune, u should avoid them even they r old hand.

carbs r always in clean state due to fuel n air filter, no dirt or very few dirt can pass thru.

 

for all stock bike their setup r in lean state, it's best to go up one step.

for example, if:

stock mj#108, use mj#110.

stock sj#35, use sj#38.

pilot screw default nominal is always set at 1.5 turn, then adjust 1/8 left or right to find it's best mix.

[blacstarz]

if a mech say he can tune a il4, v4 or multiple cyl engine without using carbtune, u should avoid them even they r old hand.

carbs r always in clean state due to fuel n air filter, no dirt or very few dirt can pass thru.

 

for all stock bike their setup r in lean state, it's best to go up one step.

for example, if:

stock mj#108, use mj#110.

stock sj#35, use sj#38.

pilot screw default nominal is always set at 1.5 turn, then adjust 1/8 left or right to find it's best mix.

 

icic... understood already... think its best i head to another shop for a tuning... which shop do u recommend for rvf carb tuning??

[blacstarz]

anyway the jet kit, is the golden colour screws called the main jet or the long flower looking like needle called the main jet???

[PepperCrab]

The main jet looks like a screw (typically flat head) with a hole in the centre. The needle is the carb needle, flower is probably the needle holder.

[blacstarz]

The main jet looks like a screw (typically flat head) with a hole in the centre. The needle is the carb needle, flower is probably the needle holder.

 

icic... alright thanks a lot for the help guess the answer is there already i nidda head down to a reliable shop for retune of carb... anybody got recommendations???

[vtec88]

bro,

 

if u need a original RVF carbutor i have it.

 

PM me or visit my sale thread.

[blacstarz]

bro,

 

if u need a original RVF carbutor i have it.

 

PM me or visit my sale thread.

 

thanks bro but im getting a VFR carb from shop already...

[fx110]

wah....

idling problem need to change whole carb~