Hi guys, I may have brought this up before, but need some advice anyway. Mechanically, I'm a bit of a novice, so bare that in mind. Anyway.................
I am running a Dellorto PHBL 24mm carb on a SIL 200 stage 4 engine with a clubman exhaust. Remote air filter fitted onto standard hose, connected to carb mouth. My jetting at present is:
Main Jet-98
Idle-48
Needle-D22 Clip 2nd from top
Atomiser-AQ264
Idle/throttle stop screw about 2 turns out, mixture screw about 2 1/4 turns out.
Scoot will now tick over nicely when warm. However when I fire it up from cold, it feels like it struggles to fire up, and I need to give it a lot of throttle. After that it needs to be kept revved to prevent it from cutting out, for at least a couple of minutes till it warms. After that it's perfect. Does the starter jet(choke jet, same thing, right??) need changing??? Maybe choke cable needs tightening??? Any others thoughts???
Carb set up
I dont have much experience with phbl carbs but i think checking the choke is a good place to start.
Take your filter and hose off. Look at the point where the choke cable goes into the carb and then look down the bellmouth of the carb in that direction and you should see an air hole on side of the carb with a brass plunger in it (left hand side of the bellmouth if its the same as phbh).
Keep looking down this hole at the brass and turn your choke on and off. The plunger should lift up clearing the hole when the choke is on and it should close off the hole when the choke is closed.
If its not lifting up you will have to adjust the cable tighter as in this scenario the choke wont be working.
If it is lifting up try slackening off the cable a little so you can make sure that the plunger is completely closing the choke off.
Take your filter and hose off. Look at the point where the choke cable goes into the carb and then look down the bellmouth of the carb in that direction and you should see an air hole on side of the carb with a brass plunger in it (left hand side of the bellmouth if its the same as phbh).
Keep looking down this hole at the brass and turn your choke on and off. The plunger should lift up clearing the hole when the choke is on and it should close off the hole when the choke is closed.
If its not lifting up you will have to adjust the cable tighter as in this scenario the choke wont be working.
If it is lifting up try slackening off the cable a little so you can make sure that the plunger is completely closing the choke off.