kawasaki bn125

[knowot]

Hi all,

My sons friend recently seiezed his bike through lack of oil, I stripped it and found the piston had smeared the barrel but was still turning.
I cleaned up the barrel, no scores and fitted new piston. put it back together and got it running seemed ok.

Its now now using lots of fuel and if the throttle is opened quickly it starts struggling, if the throttle is opened gently it's not to bad.I've stripped and cleaned carb but made no difference it's a cv carb.

anyone got any ideas as I'm at a bit of a loss at moment.

cheers Adam

 

[Alfaman]

Hi,

Are you running it on premix, or does it have a separate oil tank?

If it's using excess fuel and won't rev cleanly, that points to a jetting/carb issue, i.e. running way too rich. How does the exhaust look, any blue smoke?

 

[knowot]

hi there,
It's a 4 stroke

 

[Alfaman]

D'oh!

Oh well, pretty much same applies though! If it's using lots of fuel (and not dumping it somewhere) it's mega rich. Poor throttle response confirms it.

Checked the choke?

 

[Chipper]

Worn float needle, float height out, leaky float maybe. Is there fuel leaking into the venturi with air filter off and fuel on prime? If you can see into it / remove filter easily enough that is. If you can't get the filter off you can often smell it. Bike not running, fuel tap on prime; if it smells/leaks on prime there's a float needle valve problem.

Choke free, cable adjustted right?

 

[mike os]

without being cheeky...

compression ok? (rings OK?)

 

[knowot]

put new piston and rings in and it starts very easily, plenty compression with finger over plug hole.

 

[mike os]

sp probably carb settings ( asy to check, just set to factory default to start with) or ignition timing off a touch.

 

[fran9r]

The best way to check if it's leaking fuel is to rig a fuel supply up with the carb off the bike, and float bowl removed. By adjusting the float height, you can check if the float valve assembely is doing it's job -usually it's dirt in it, or under the seat.

Has it been stood for a while? My bike (ZX9R) had been, and had the same problem with poor response to throttle until I used compressed air to clear all the internal passageways -I presume something was blocked.

 

[the snooper]

check the gaskets on the inlet if the bike seems to die when you open the throttle wide quick it may suggest an air leak and an engine with an air leak will struggle to produce power so the rider would open the throttle wider to compensate hence the increased fuel consumption