SLOHawk83

I recently purchased an 03 SH with less than 3500 miles. Since then i have put on about 1500 miles. i have replaced the stock cans with Two Bros high mounts, replaced stock filter with a BMC, had it rejetted by a local mechanic, while at the same time he removed the emmissions control charcoal canister, i dont really know what that entitles. I have put about 800 miles on the bike since the work was done, and it has run excellent. About a week ago i had throughly washed my bike with water, for the first time. After i had dried it off with a towel as best i could i started it an jumped on the freeway for some air drying. It ran perfectly fine. I had then parked it and let it sit for about 3 hours. I then started it again and rode it into town. Before town i stopped to refuel. About 3 miles into town i noticed some backfiring/missing and the engine seemed to lag a bit. I tried to make it to a friends house but the bike would miss, backfire, stall out, lack of power, so i parked it and picked it up a little later with my truck.
I first thought that i had put in some bad gas. I took gas samples from the bottom of my float bowls and could see no visible signs of contamination. I still wasnt satisfied so i syphened the rest of the gas out of my tank and replaced it with chevron 91. I had then checked the airbox and filter for any signs of water or other contaminants. I started it up, and it seemed a little better when it was cold and the choke was on, but once it warmed up it was acting like crap and popping and missing on acceleration.
My next thought was that i had fouled a spark plug. I pulled each plug and noticed that both were a bit blackened and brown, so i replaced them also. Still runs like crap on acceleration after it has warmed up. Most of the missing and popping happens at around 2300 rpm and seems to only run on one cylinder after that.
I can only think now that there is something wrong with the electrical or the bike has some sort of vaccum leak.
I have read the thread that someone posted about kind of the same problem "popping missing help?" but my bike has never come apart and my vaccum hose does come from the rear of the fuel valve an all the other hoses seem to be in place.
I can only imagine it is something simple like a plug came off from somewhere or an electrical connection is loose.

please help, its the 4th of July and i cant even ride

RickB

Sounds like you may have a piece of dirt stuck in one of the carb passages blocking the fuel flow - when the choke is on you get more fuel and less air so it will run ok then. probably a good idea to pull the carbs and give the a good cleaning out.

nuhawk

I think bad gas! You have to blow both the bowls and reload the tank. Chas pumped his CBR full of water and we had to dry tow it around for nearly a half hour before we could get it to fire on its own. It would sputter, fart, fire and did it endlessly. Finally it started to clean out and once the engine heated up it pretty much ran itself clean. This is a big effort and teaches you to trust your source.

ietgixxers

if i fill my tank all the way to the top it will run like that,i will open fuel cap close it and it will run fine

Hawkrider

I'm thinking water in the gas. There's a good possiblity that the overflow line on your tank is clogged between the tank and the end of the line at the bottom of the bike. Reason I say that is because this all started after you washed the bike. If there is water in the space above the filler cap seal and the tank then as soon as you unlock the cap the water will go in the tank. There is a hole right where you fill the tank that is the overflow drain. Blow that passage out with compressed air (from the top down). See if anything strange comes out.

Assuming it is water in the tank, a bottle or two of Heet (or similar fuel water remover) and a few tanks of gas will alleviate the problem.

Hawkrider

That's vacuum lock because you got fuel in your tank vent, and is entirely normal for this bike.

SLOHawk83

Well shes back up and running. The culprit was bad gas not vapor lock(I had checked that in the beginning just forgot to say), but water had somehow gotten into my tank, I think it could have been the overflow drain im not sure though. But i know now that you cannot get all the gas, or water out of your tank by simply syphening. The water stays on the bottom. This time i physically emptied the whole tank of gas, blew out the overflow drain from the tank down and nothing unusual came out an then drained and sprayed out the carbs. I also added some HEET to my new tank of chevron 91. It took a little coaxing to get the fuel to work its way in but it did and it seems to run beautifully now. Thanks for all the advise. I just added a pic of my hawk in the members gallery. Beautiful day iv got to go for a ride now

nuhawk

RickB

glad it was fairly simple...