i'm working on my friend's old f2 and he's having a problem with his bike. it'll start up fine and idle normal but if i give it ANY gas on the throttle or choke it will die. the weird thing is if i turn the fuel switch to off it still starts. shouldn't that cut off any fuel? any suggestions on what i should check out? i checked the plugs and they are black so i need to replace them but i don't want to replace them and have them fouled if there is a problem with the fuel system. well i'm sure something is wrong since it's not supposed to get fuel in the off position right?

 

Don't know what to tell you about the bike shutting off with the choke and throttle on.....I am too new to this. But, I do know that the carbs still hold fuel in each bowl after you have killed the fuel from the tank. That would allow the bike to run briefly after shutting the main fuel line off.

 

i see... thanks for the info. haven't worked with carbs at all but i'm trying to help him get it running again. i pulled off the thank and am taking a break right now before going back to it.

 

i tried draining the float bowls yesterday but unfortunately it did not work. and the three screws that hold on the cover seem to be stripped on one of the carbs. ugh...so i'm gonna have to get those removed and i might as well replace all those screws. looks like someone tried to remove them before with a bad screwdriver and messed up almost every screw there. i got 3 of the covers off but the 4th one was just too messed up.

i took off two covers to look at the jets and one seemed to have some crap in it and i cleaned that out. i'm pretty sure the other two were dirty too but i didn't get to take them off and see. but i put it all back together hoping that that clogged jet that i cleaned would solve the problem, but nope it still has the same problem

 

check and make sure the vacuum pipe from the maifold to the petrol **** isnt split, perished, or pinched,
I would start at the top 1st check the filters in the tank, then work down checking for fuel flow,

sounds like you got some sort of fuel block somewhere

 

ah it's fixed...it was the vacuum piston or carb slide. the one that lets all the air in. that was stuck. gummed up from sitting there. got some help from a friend and took apart everything and cleaned it up. it's back up and running now and all the stripped screws were replaced with allen heads now. oh and the pilot jets had some crap in them too.