Need Help Cbr f4 Runs Rough AND idles very low
#1
Need Help Cbr f4 Runs Rough AND idles very low
it doesnt matter where my choke is set ..the bike idles very low .. i did the cbr f4i conversion ..i also grounded the 20km/h wire .. this all happened when i ran out of gas and filled my tank up that the bike started runnning liek crap ... also when the 20km wire is hooked up ..is the fuel pump supposed to keep ticking if there is no fuel in there ..Thanks all help is appreciated ..
I also wanted to mention that i already drained all of the fuel that was in the fuel tank thinkin that was the problem ...
I also wanted to mention that i already drained all of the fuel that was in the fuel tank thinkin that was the problem ...
#3
If you ran out of fuel you may have pulled a load of crap though from the tank, and its now blocking 1 or more idle jet/s. very common problem on bandits..
Other than that make sure your fuel hose isnt twisted and that all the inlets are done up, if too much air is getting in it'll run like crap, but personally id check the idle jets
Other than that make sure your fuel hose isnt twisted and that all the inlets are done up, if too much air is getting in it'll run like crap, but personally id check the idle jets
#7
ok an update ..i cleaned the carbs, jets, float bowls ..and everything else involved with the carbs .. new fuel filter, cleaned the fuel lines . changed spark plugs . added fresh gas and bike starts right up but wont idle ...it will stay runnig good if i open it up the throttle jus a lil bit .. but as soon as i let it go it dies ....any suggestions ... also the battery is cmpletely charged
#9
I had a simmilar problem with a bandit refusing to run ages ago. Took me 4 months to get it to go again, by which time it was cold 'n' horrid.
Turns out the tank was full of crap, who'd have guessed ? and when i put the tank to reserve it pulled about 20 years of surface rust into the carbs and jets.. After buying 2 sets of plugs, new caps and leads we realising it was carbs and not the spark.. Where we had taken them of to ultrasonic clean them all the idle mix screws and the flaps were totally out of place. So after dicking about with it for months we had a thourogh read through the service manual and we found we had totally screwed up the settings on the carbs.. For bandits the flaps need to be almost shut to push air through the idle system otherwise it just will not start regardless of spark and fuel..
If your sure theres a brilliant spark, take them out and leave them for a few hours to dry out and let the cylinders dry too..
Clean the plugs and put them back in..
This is how to tune your carbs if theyre all messed up from the cbr f4 manual
" Turn the throttle stop screw (idle to you n me) to align the throttle valve with the edge of the outside by pass hole in the No. 4 Carb (when theyre on the bike its the one of the rhs) this should be the same in all 4 carbs"
So they want to be pritty much shut to begin with. If you have a carb balancer, well dont, youll need it !
The pilot screws to start with want to be 3-1/8 turns out from all the way in for 48us states version and 2-3/8 for california type (from the manual).. If the bike starts at this point this is the time to balance the carbs/flaps.
do this to all 4 and start the bike, you then want to adjust carb 4 in or out till you get the highest rpm's from the engine but make sure to count how many turns and in which direction (probably inwards) and set the rest to this. The screw the No.4 piolet screw out till the engine drops by 50rpm and then back in till it picks up the 50 again, repeat with the other 3.
now rev the bike a few times and reset the idle **** to 1400 rpms. the screws should end up about 3/4 of a turn out.
Check the carbs are still balanced if not adjust them.. All that tinkering with carbs can be avoided by getting a colour tune. just set them all to 3 turns out start it and starting at No.4 use the colour tune plug to get the ideal colour and set the rest to that, and then check/adjust the other 3 indervidually..
take about an hour or so once it starts the hardest bit is turning the screws as theyre in a hard to reach area..
Hope that helps !!
Luke
Turns out the tank was full of crap, who'd have guessed ? and when i put the tank to reserve it pulled about 20 years of surface rust into the carbs and jets.. After buying 2 sets of plugs, new caps and leads we realising it was carbs and not the spark.. Where we had taken them of to ultrasonic clean them all the idle mix screws and the flaps were totally out of place. So after dicking about with it for months we had a thourogh read through the service manual and we found we had totally screwed up the settings on the carbs.. For bandits the flaps need to be almost shut to push air through the idle system otherwise it just will not start regardless of spark and fuel..
If your sure theres a brilliant spark, take them out and leave them for a few hours to dry out and let the cylinders dry too..
Clean the plugs and put them back in..
This is how to tune your carbs if theyre all messed up from the cbr f4 manual
" Turn the throttle stop screw (idle to you n me) to align the throttle valve with the edge of the outside by pass hole in the No. 4 Carb (when theyre on the bike its the one of the rhs) this should be the same in all 4 carbs"
So they want to be pritty much shut to begin with. If you have a carb balancer, well dont, youll need it !
The pilot screws to start with want to be 3-1/8 turns out from all the way in for 48us states version and 2-3/8 for california type (from the manual).. If the bike starts at this point this is the time to balance the carbs/flaps.
do this to all 4 and start the bike, you then want to adjust carb 4 in or out till you get the highest rpm's from the engine but make sure to count how many turns and in which direction (probably inwards) and set the rest to this. The screw the No.4 piolet screw out till the engine drops by 50rpm and then back in till it picks up the 50 again, repeat with the other 3.
now rev the bike a few times and reset the idle **** to 1400 rpms. the screws should end up about 3/4 of a turn out.
Check the carbs are still balanced if not adjust them.. All that tinkering with carbs can be avoided by getting a colour tune. just set them all to 3 turns out start it and starting at No.4 use the colour tune plug to get the ideal colour and set the rest to that, and then check/adjust the other 3 indervidually..
take about an hour or so once it starts the hardest bit is turning the screws as theyre in a hard to reach area..
Hope that helps !!
Luke
#10
Theres the manual i found after a quick search
Has pictures and diagrams explaining everything i said above ^
https://cbrforum.com/forum/cbr-600f4...al-here-63411/
Has pictures and diagrams explaining everything i said above ^
https://cbrforum.com/forum/cbr-600f4...al-here-63411/