cold starting

[Fireroad Express]

check the float bowls. there are small jets in the float bowl that regulate the fuel flow to the starter circuit. when its really cold out, you have to get bigger jets to make the starter circuit(choke) work correctly. the jets in the bowl are calbrated for warmer climates. the jets are located under the brass tube that sticks into the bowl that feeds the starter circuit or choke. call "sudco" and they should be able to fix you up with the right jets for the bowl. atleast this is mostly the case for mikuni carbs. not sure about keihins? don't bother messing with the idle circuit to try and fix this problem. the engine has to start first. :thumbsup:

 

sorry my explaination above wasn't very clear. beer and the internet don't mix! i'll give it another try.

here goes: For normal applications,the starter circuit or "choke",performs the task of administering the correct mixture to start a "cold" engine. what is meant by a cold engine varies greatly,between a motorcycle engine,which may only operate down to 40F and a snowmobile engine which can run at -20F. for this reason, the snowmobile carb is set up much richer than the motorcycle running the same size carburetor. this applies to the choke or starter circuit as well. this is often forgotten when someone tries to run a carburetor calibrated for a snowmobile on a motorcycle (or banshee!) and it floods out continually even when both carbs are the same size as the ones that were on the banshee or motorcycle. For this reason, the mixture can be changed,even the mixture for the choke. In the bottom of the float bowl passage,which feeds the suction tube to the mixing chamber for the choke, sits a small jet which controls the fuel flow to the choke. this jet can be removed and replaced by a larger one, effectively making the choke circuit "richer" for starting your banshee in colder weather. the reason the bike will not start in the cold is that the mixture for the choke is too lean. next time you have your carb bowls off look down the hole that the brass suction tube fits into and you will see the jet i'm talking about. again this may only apply to mikuni carbs. look at some of the parts break downs online on Sudco's site. it will show this small jet.

Edited April 22, 2008 by the grinch

[Fireroad Express]

here's a diagram. "A" being the jet i'm talking about.

[Pardee208]

very interesting, heres the thing, it can be 90 degrees outside and she still wont fire unless u pull start it. are you talking about when the motor itself is "cold" or are we talking atmospheric temp.

[Fireroad Express]

i'm talking when it is cold atmosphereically and when the engines cylinders are cold enough to draw the atomized fuel particals out of suspension.

[Pardee208]

Like I said, it could be 90 degrees and it still wont fire unless you pull start it, then after the MOTOR is warmed up, it'll start by kicking it.

[Fireroad Express]

Like I said, it could be 90 degrees and it still wont fire unless you pull start it, then after the MOTOR is warmed up, it'll start by kicking it.

 

if it's that warm out and the bike still won't start it's probably not a choke problem. have you cleaned the carbs lately. how bout a compression check?

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