Blake1221

Hi im new to the forum and new to my superhawk (just got her last week). I'm having a problem with smelling gas, shitty MPG, and stumbling/ backfiring and low throttle positions. The bike has D&D slip-ons the Airfilter made in Italy (BMC) i think. The bike runs great from half to WOT, but i always smell gas. i noticed gas leaking from a tube by the chin spoiler, havent got a chance to follow it to see where it is hooked to. i did notice that there are no tubes comming from the carb overflows, so where could this gas be comming from. I think its a rich condition but havent pulled the carbs. Can anyone tell me the stock main sizes, and stock Air mixture screw setting?

Any help would be greatly appreiciated!!!

Blake1221

traced the tube with the leaking gas to the bottom of the petcock.....all diagrams i look at online don't even show a tube going to the bottom of the petcock. why would the petcock have a drain? why would gas be coming out of it?

Little_Horse

It isn't supposed to have a tube on the bottom. It needs a vacuum tube to the back of the petcock and a similar looking drain tube from the tank to the chin fairing. But that still means you probably need to rebuild the petcock the diaphragm inside is leaking and this is the probable cause of your rich condition.

Blake1221

I have the vacuum tube hooked up to the back left side of the petcock, to the back cylinder intake(the tube was cracked at the petcock conection I cut the tube back to get rid of the cracks). The tank drain tube is bigger and runs straight down under the motor. Should i pull the carbs and clean the floats? It has a jet kit installed (i looked at the needle on the back carb while still on the bike) should i lower the needle? It is 1 up from the bottom.(have no idea what mains are in it) I guess what im asking is would the petcock leak make it run rich? Would'nt a properly working float valve, stop too much fuel from entering the carb?

Blake1221

Thanks so much!!!! i pulled apart the petcock and sure enough a 3/4inch rip in the diaphragm. I have the part on order, should be here tomorrow. Ill let you know if it does the trick. Thanks again!!!

Blake1221

The petcock rebuild kit did the trick! She is up and running like a new bike. i still have a little popping from the exhaust on deceleration but i can live with it for now (going to tear into the carbs this winter to see what the PO has done.

drew_c14

That popping could be from the PAIR if it hasn't been removed yet. Or if it has then all the ports might not have been blocked off right. Look for open vacuum ports around the valve cover areas.

Little_Horse

slight popping is characteristic to the hawk as well, don't loose much sleep or time wasted trying to sort the pops out. That is unless by popping you mean 50 cal backfires .

Blake1221

It popped like hell when i first took her out after the fix, but i think it was just unloading the excess fuel in the carbs. By the time i got out to the main road 1/4 mile or so she was purring like a kitten. I don't mind the pops so much but i do plan on looking into the PAIR dealio, right now i just want to ride!!! I'm loving the Hawk!!!

Thanks again