My bike seems to run perfect except from 2000-3500 rpm's it seems to sputter and want to die. I did notice if i ran the bike super fast, that it seems to fix the problem for a few minutes... Does this sound like bad spark plugs??? If not, what could it be?

I did have the bike in the shop last summer and it had all the carbs rebuilt, sync'd, new air filter and plugs.

 

how long has it sat? Gas is terrible and any extended period of time sitting will result in poor performance due to to things. the fuel loses combustability, and it gunks up the carbs. Put a can of seafoam and fill it with fresh gas and see if it clears up after a few rides.

 

It hasnt sat for any extended period of time, I used several tanks of gas with the same resulting problem. Never used seafoam before, do i just put it in with my gas? Is it used to clean out carbs etc? would you still reccomend i use it even though it hasnt seen any old gas to my knowledge?

 

Yes, Yes, and Yes. Its a fuel additive that originally was designed for marine use but has been used everywhere now. It really is some awesome stuff. If you dont know the age of your plugs though, that it would be a good idea to go ahead and change em.

 

sounds good. Ill change the plugs and shoot some seafoam in there and see what that does. thanks!

 

ok, so lastnight, i went to take off my rear fairing(doing f4i tail swap) and i noticed that the voltage regulator/recifier is damaged. The outer black coating has cracked off and i can actually see the mircochip board... Does this seem like it could by the problem with my sputtering????

 

Replace it for sure as it will damage the rest of the system. It can could be the cause of the other issue but at this stage all that matters is fixing it.

 

Before you drop a 200 dollar RR into your charging system inspect all the wiring. There is a reason that your RR is burnt out, if you replace it with out fixing the problem you will just destroy your new RR. Check the wiring from the stator, the connector between the stator and the rr often gets hot and shorts/grounds, causing the RR damage.

The F4i RR is recomended, you'll have to plum in the extra wires (one hot recharge lin - RED, and one ground - Green) Put the red into your + terminal on the Batt, and throw the green in a frame ground; there's one on the fram right by where the subframe attaches at the top.

As for the stumbbling, Do you have a canadian model F4? Look at your water pump cover on the left had side of the bike behind the Stator cover. If there is a small coolent tube running off the top heading up twords your carbs this could be the issue. The CAN models have a water jacket in the carbs to heat them up because when we're not building igloos us canadians like to ride Japanese sport bikes. This is a problem when the bike gets hot as it starts to boil the fuel when there is a low ammount of air running through the venturi.

Remove and plug off this section of the water circulation system. I'm going to upload the photos of my work here in a few weeks when I get some time.

If it's not this then it's a carbouration issue. When you change from your slows to your mains there is probablly a miss match in the ammount of fuel being delivered.

GL

 

Ok... I had a problem kinda like this with my F4. Check your vacuum hose's. Now my sputtering was at higher RPM's. Like around 5k but none the less it could be the issue with your sputtering. Popped off the tank and whammo one of those suckers jumped off. put it back on and was back to running good