I am new to this forum, Lots of great information that has helped in locating and fixing a problem with my "new" bike.
I have had this for 1 year and every time I went for a "long" ride the bike would run out of fuel when running at 3/4 to full throttle, riding between sections that are quite some distance apart. Stopping and waiting for a small moment the engine then slowly returned to its happy state.
I had looked at float level, Jet sizes, and float jet size. none of these fixed the issue.
I increased the float jet size from the factory 2.5mm to 3.0mm, no luck on running out of fuel.
I the pulled the fuel tap off the tank and disassembled this and the plastic tube (that is the main) had a hole of 1.8mm down through it, this looked as if was the restriction I was looking for. I have made a new tap from a very small ball valve and some manufacturing, it now has a opening in the line to the carbie no smaller than 3.8mm.
Something I have also noted the tap lies horizontal and then as such the reserve on the tap is pointless, It seems not a lot of thought has gone into the bike beyond getting them out and keeping the cost down.
To date touch wood, all is running as I would have expected from the factory. The engine is one of those Sherco excess to their needs engines using one of those Delorto PBH26 carbies (I hope I have the numbers correct here).
I must add I LOVE the bike, Steers Really great, Starts ALWAYS, Has lots and lots of Snot (more than the rider can always handle).
I really hope this helps someone else in the same way the information here (mostly in the Sherco section) has helped me.