Motorcycle Repair: Wont start / back fire, local bike shop, back fire

Question
Hi! I have a 1998 YAMAHA YZF 400.I recently took it to my local bike shop and they fixed the back fire in it.A coulpe of days ago I went on a trail ride and I had to cross creeks and after a couple it started back firing again? and revving very high(it would drive in 5th gear quite strongly..by itself!) so I turned it off then tried to restart it(had to push start in the end). I got home and found the idle screw had come right out so i put it back in but this did not do anything. It would 3/4 kick over but wouldnt make a sound.Oil was changed just before the ride so I dont think its seizing.

Thanks very much

Bern

Answer
Hi Bern,

The carburetor will need to be inspected.

If I were you, I would return the YZF to the shop that made the recent repairs and complain.

The shop 'should' handle the inspection and repair as a "come-back" and not charge you.

Respectfully,
Mark Shively