Hi Guys

Been away for awhile as bills have to be paid.

Bike running lousy..dies at high revs and wont idle. Removed carb today, stripped everything, soaked in boiling water, sprayed carb cleaner and blew all out with compressed air. Refitted carb but she`s leaking fuel badly out overflow and still running lousy...seems to get better with choke out. Could this be floats or maybe needle and seat?

seems like you have two issues

1: Sort the float height setting or the condition of the float needle valve seat, this is whats causing the overfilling

2: fuel starvation at low revs...this is why it's better with choke

you say you cleaned and blew out the carb passsageways and jets...regarding the pilot circuit did you actually witness that the air passageway to the mixing chamber and the bypass and pilot hole from the mixing chamber to the inlet venturi are actually un-blocked?

did you see the carb cleaner spraying out these passageways...reason I ask is that theres no guarantees that boiling the carb in water will clear these ways if they are blocked! ultrasonic cleaning is a better method...need some pics?

Hi Airhead..yes please..a pic is worth a thousand words.

here is a sketch of a similar carb showing the pilot cct.

You can see how air and fuel are sucked through the passageways and mixed together, the air screw regulates the ratio of air/fuel.

look for these passageways on your carb and spray carb cleaner (using a straw) throu them and witness they are clear....dont forget the pilot jet itself.

This pic shows the bypass hole as it enters the venturi...the pilot hole will be under the throttle valve I think

Here is where the air enters, yours may be similar, the air flow is regulated by the air mixture screw

HTH

Thanks Airhead..will have to take carb off again, although I gave it thorough clean..did not check float height. Is there any way to check if needle and seat ok..I can`t believe what 2 little items like that cost.

you'll see if the needle is worn, there will be a visible wear ring around it

When I get it out I`ll send you a pic.

When I get it out I`ll send you a pic.

wont do you any good that one, just have a look yourself...use a magnifying glass if needs be

Will do..carb is off again..will strip it tmorow.

Really cant see wear on the valve. Tried bending the flange down to change float level slightly. Will see if it makes a difference.

Nope no difference..fuel still evident at overflow. Surely replace needle and seat then?

something else must be blocked..replaced float valve..set float height again..cleaned all orifices again..but she still only runs properly with choke on.

Surely this also points to choke CCT not working. The plunger shaft is bent so wondering switch one over from the other DT..see if it sorts it.

Nope..swopped them over..no difference.

She run when choke on " if you take off choke and it dies, the pilot jet is blocked, remove it , And clean . till you see thru it,, side holes too.

You say " properly" do you mean it runs but not good enuff without the choke ? if so its lean . Thats why richening the mixture [ choke] makes it run better,,

It pulls like a steam train with choke out (I`ve seen now if clutch is good how well they can go..the other one needs a new clutch I think). Soon as I push choke in it starts losing power and eventually dies. After seeing your comments it must be a hole by the pilot jet blocked somewhere..not the jet itself

use a straw on your carb cleaner aerosol to spray back through the two holes in the diagram and witness the cleaner coming through the pilot jet

Ok..think I should also try again to get the pilot jet out..worried about stripping it though.

I can understand your concern ...just do it with the jet still in there, why not? you should still see the fluid coming through

Will try tomorrow...hopefully the last time carb coming off..otherwise going to try swopping carbs with the other bike. There is an inline fuel filter in place which should cancel out any gunk from the tank.