Ok, well if you remove the bowl and turn the carb body upside down, the float arms should basically be near parallel with the bowl surface or pointing upward very slightly. The distance from the bowl surface to the point where the pin on the float contacts the arm is 18.5mm or probably 19mm if measured to the tip of the arms.

The brass thing that the needle with the rubber tip on it goes into is the seat, and should have a number stamped innto it. Mine says 250. May want to upgrade it if not at least that spec. 15quid from eurocarbs.Course if your needle is stick in the seat in the closed position, you may want to replace it anyway, as they come together as a set.

This is the thing that allows fuel to flow into the bowl at a given rate., and also the thing I cannot recall what number they were using for high load road based trials such as the Scottish. Never an issue for me with the 250, but I do not do roadwork with it. Those lads do run with choke on at high speeds though as I understand. Keeps things running cooler at speed with the added enrichment.

I'd say a new float valve is on the cards if it's sticking, just looked at the standard carb for my 290 & it was also a #250-never had a problem with fuel flow while trailriding

Are you on the throttle when it dies or backed off?

I had a stator playing up early last year & it was okay while riding slowly(up to 3rd gear low revs) & travelling quickly on road sections but would quit when you backed off to head back into the bush. It would take about 15mins to get the spark back so my guess is that isn't the problem

While you're trying your mates carb it would pay to also borrow his fuel cap & put it in your jacket pocket while you go for the test ride, if it stops again then swap caps to be 100% sure that the breather isn't slightly blocked

Have you been twisting your mixture scew whilst your throttle isnt open? As if you twist it in it can score the needle or bite and leave a lip into the slot the needle goes in. I still think its a stator problem and you need to check the spark by removing the plug and kicking the bike off whist still having the leads on and the plug, and having the end touching the engine for an earth.

Sound like the needle valve to me . Had a similar problem on my 250 sherco , changed the needle valve and it was cured . Happy days !!!

Phil

Thank lads,

Some very good pointers here,

Johnnybmac, I

Thank lads,

Some very good pointers here,

Johnnybmac, I

Edited March 23, 201016 yr by copemech

Yea, found it here from Shirty:

Remove carburettor & the float bowl, blow all jets out with airline & refit. Usually, the standard

jetting is fine for Scotland. A good idea is to change the

Thats great info Copemech,

I'll check it out this weekend.

I did have the bike actually die for a split second in a section also, only the once but it came to life with violent snatch and this was not after a long road run either, maybe the two are unrelated.

Will keep you posted,

I'm sure the 30 pilot is wrong for starters so thats coming out.

A quick check also I should try a long run in top gear with choke on to see if it fails.

Gday, for a quick check of all elements in the fuel supply side (Tank breather, lines, tap etc) - disconnect your fuel feed line from the carb and direct the end into a suitable container. Open the tap and let it run - you may need to run the entire tank out to check - you should see a solid flow all the time. If it dries up or slows, then the issue is in the supply area, all of the things mentioned earlier. It will help eliminate these things at least and is pretty easy to do. One area that might change doing this however is if you release a kink in the pipe that restricts flows at higher rates when the fuel line is disconnected. Just be aware of this in your test.

Cheers,

Stork

Sorted!

Tried my mates carb and it runs great

I didn't realise the 290 had so much power :-)

It totally transformed the bike and I will be ordering a new pilot asap.

Problem solved, thanks to everyone for the valuable advice.

Hope I can return the favour sometime

Rgds

Ian

Pilot jet won't cause it to die at road speeds, have you ordered the float jet as well?

?????

Can someone provide detail on:

"The 2002 had a problem with the vent tube inside the gas tank - take the petcock out and cut about a quarter inch"

Does this mean it runs out of gas when there is still 1/4" of fuel in the tank?

Pilot jet won't cause it to die at road speeds, have you ordered the float jet as well?

Tony yes, I took the precaution of ordering the float jet also,

The jets should be here tomorrow, The bike runs so smooth with the other carb on :-)

Can someone provide detail on:

"The 2002 had a problem with the vent tube inside the gas tank - take the petcock out and cut about a quarter inch"

Does this mean it runs out of gas when there is still 1/4" of fuel in the tank?

Have a look here http://www.sherco.com/wayne/Sherco_03_Fuel...odification.pdf