Hey guys i have a 95 f3, i finally got it out to ride it this weekend after about a year of it sitting there. The bike will start fine but acts like its running on 3 cylinders, it wont idle or hardly run at low rpm, if i ride the bike it runs like crap until i am around 1/4 throttle then it smooths out and runs perfectly through the rest of the rpm's i can ride it as much as i want like that but if i am below 1/4 throttle or so it just idles down and dies. The rpm doesnt really matter as long as i am above 1/4 throttle its fine otherwise it runs like crap, any ideas on where to start or a way i can tell which cylinder isnt running right?

 

make sure your fuel pump is working properly

 

Likely an idle jet. You may end up pulling the carbs and cleaning. You could also try a carb cleaner like seafoam.
In order to find out which cylinder isn't firing, take a little water and place a few drops on each exhaust pipe after you start the bike. If the water doesn't steam off, or if it does so slowly (not like the others).... you've found the nonfiring/misfiring cylinder.
In addition to carbs, I would also check your plug wires for scuffs/cuts. I've had this issue before on another bike. It turned out that at lower rpms the spark was jumping enough to make it stutter down low, but the higher rpm's produced a more powerful spark and would consistently ignite. I found a rub mark on a wire (not even all the way through), I shocked the chit out of myself a few times and then wrapped electrical tape around it and it ran 100% afterward.
Just a couple thoughts...

 

i honestly think it's the carbs.

 

It did this same thing a few years ago when i first got the bike, but it finally just cleared itself out, it has always only ran what seemed like 3 cylinders for the first 10 minutes or so then as it would get warmer it would run right, but now it wont clear out at all untill i get into the throttle a good bit, dnt know if its related or not, but i thought i would mention it anyway.

 

still think it's the carbs. when was the last time you had them cleaned.

 

I have never cleaned them how big of a pain in the *** is it?

 

its def gonna be a pain in the ***, and i agree with it being the idle jets. look up a "how to" on cleaning carbs. take the carbs off the head, and turn them upside down (there is 4 carbs, and they will come off as 1 peice) and take the float bowls off. there is 3 screws holding each float bowl on. the idle jets are the single jet in each carb that there is no flat head on the top to remove it. most recommend using a peice of guitair string to stick down the hole to clear it, though i dont have any and use a garbage tie stripped of its paper down to the bare wire, and it works fine for me. if it gos down in the jet about 1/4 to 3/8".. its clogged up. just keep punching at it and rotating the wire till you go through it. the wire should punch through to about 1-1.5".

the hardest part of this job is getting the carbs off / putting them back on. the rubber boots that hold the carbs to the head of the bike are gonna be stiff, and make it hard for you to pull them off. but keep at it and youll get them off. a trick that i found that works is that once you get them off, put the 4 boots into a big pot of water on the stove on low temp and keep moving them around with a spoon. temp shouldnt be more than you cant stand for a second or two. i did this and took them out and worked them with my hands to get the elasticity and stretchyness back. when you put the carbs back on, use a small small dab of motor oil to rub around the insides of the boots to help the carbs to slide in them easier.

as for the slow / main jets... they have small holes on the ends of them that get clogged up by varnish and debris and trash. soak them in seafoam for about an hour. hold it up to the sky and make sure you can see through the small holes. also turn it so you look through the length of the jet and make sure you see light through that as well. i found that compressed air helps in clearing them after the soak in seafoam.

pour seafoam into each float bowl as well and let it soak, and clean them out with a toothbrush of any varnish or gummed up stuff or debris.

 

try going with the seafoam first before you rip everything down. fill the tank up and add about 1/4 bottle of seafoam and see where that gets u. if that doesnt clear it up i would then rip into the carbs. good luck

 

I took the carbs off and cleaned them when I was taking them apart i noticed that 2 of them didnt have clamps on them could that have maybe been the problem or is it maybe something else.. When I cleaned them I didnt find any dirt in any of the jets but I also found that the throttle sensor had a broken wire.. I put on new clamps and repaired the wire is it possible either of the these 2 things was causing my problems?