Just sounds like fuel starvation. Dirt/water in fuel?
Check tank is venting OK - no shite in tank. Run a litre out the tap/fuel ine & see how long it takes & how well it flows. If slow, try with fuel filler cap off.

Hi all,
Have you checked that little filter under the needle and seat in the fuel bowl.
Search this site for the thread.

Cheers from Oz.

Ken

__________________
I'm not getting older; I'm just progressing through LIFE!! Harleys do not have a throttle- they have VOLUME control!!!

That would be my first move.

__________________
2006 XT660R daily ride, 1994 XT600E about to be reborn, Blog: http://goingfastgettingnowhere.blogspot.com/

Hi all,just an update,I stripped the main carb down, took out the main & primary jets,took out the filter under the needle/seat,couldnt find any blockages so I blasted everything with carb cleaner then blew everything through with the air line.I then reassembled everything,gave it full choke and after a couple of kicks she fired up.At first the bike was running a bit rough but after a minute or so the motor cleared and the bike's running fine.I then put on pair of boots that are'nt so bad for pushing a bike in and went for a test run,I made a point of not going anywhere that would involve a uphill push but the bike was running great. When I got back home I put a new plug in and did 20 miles on it with no problems (after the first journey the original plug looked less weak than when I was having problems).
Anyway a couple of questions;
1) The pipe between the main carb & secondary main jet had split so I replaced it with a piece of fuel line,the problem is this pipe is pre-formed and when I replaced it with ordinary fuel pipe it has to bend through 90 degrees to attach to the secondary carb.If the pipe has slightly kinked I can understand it affecting the fuel flow but wont that just be at the stage were the secondary carb opens and be irrelevant at start up and low revs?
2) I recently bought a locking filler cap,so if it's not venting properly I can understand that causing problems,but if the revs pick up when I give the motor choke does'nt that mean the carb is getting enough fuel,it's just not getting it in the pilot circuit?
Thanks for the advice
Mark

The secondary carb will have some effect on the idle, and could well effect idling, coz its open a little bit !

On the YDIS the secondary has a butterfly that is sealed airtight when closed and adjusted properly. Spray some carb cleaner in there the next time you have one off. It will not leak out. Evaporate yes, but not leak.

There is not idle circuit provisions to the secondary. There is a crossover that equalizes the vacuum between the primary and secondary.

Cheers Zecatfish..... I didn't imagine it would be 100% air tight when shut.... ?

But thanks for the tip, new one on me this type... The old CV's were never air tight even when fully shut.