Electrical (or maybe not) problems

[element303]

hey guys. i could need some ideas. i started working on the fj1100 i bought last week and was wondering if anyone here have any ideas whats the issue.

starts great, once its on for the first few minutes very cold it backfires a little. when hot runs very smooth in idle. however, once i get into higher rpms, lets say above 5k, it starts firing weak. almsot like it doesnt get gas in all carbs. i already took apart the carbs and i am pretty sure thats not the issue. i also checked the fuel line to make sure the gas can flow freely with gravity. the reason why i am sure its not the carb, even though it feels like its running out of gas, is that it gets much worst when driving more than 5-10 min and it really gets hot. no power all all in full throttle especially up the hill. i thought - well probably the coils are bad when its hot. i had one spare coil from the parts that came with the bike and just tested it on each side and its exactly the same. it just doesnt fire clean and doesnt have power. i also just changed the spark plugs just to be sure. i dont think its the pickup coil. from my experience they usually work or are completely dead. any other ideas?

thanks in advance.  

[element303]

i just saw this answer in another topic here below:

It looks like blocked vacuum system in fuel cap.
When Your FJ will start running rough, just stop and open fuel tank cap. If You will hear hissing of air sucked in to tank You will be sure.

http://www.fjowners.com/index.php?topic=14044.0

could that be my problem? because i CAN hear hissing from he tank when i stop.

[FJmonkey]

The hissing is normal, however, if you have a spare key, ride with the key in the cap and open the tank while you are having running problems. If your tank is going into vacuum lock you will have a fuel delivery issue. Opening the tank will determine if the tank is not venting properly. Trouble shooting is always about eliminating the simple/easy stuff first. Let us know the results, then we can work on the next few simple things to check.

[element303]

yeah i jsut read thrpugh that whole other threat. let me take her for another ride. because when i got back home the last time up the hill no power at all, then on the bottom of the hill, after letting her more or less roll down with not more than half throttle, she had power again for a few seconds, almost like the carbs fill up again. im leaning more towards gas problem again now. let me test this quick 

[element303]

same problem with the cap open. it runs good for the first and second gear when turning out from the house, but probably still nothing close to full power, and then it starts running like crap again like there is no gas or not enough voltage to spark it clean. also it was backfiring again at times. so whats the next step? empty the tank and open the petlock?

[element303]

nevermind this last post

[FJmonkey]

Still having the same problem?

[Steve_in_Florida]

Float level, perhaps? Could be too low?

...just a guess.

Steve

[element303]

yes, still same problem. i just emptied the tank, did the suck test (i hope it also counts with empty tank) but i couldnt suck any air so i guess thats good. its also holding the gas inside on ON. took the petcock out, not even the slightest dirt in the filter. cleaned it, put it back in. now i shortened the fuel line that goes from the tank to the T part because that had a way too long loop before. now it goes straight down. im about to fill gas back in. i have new sparks now. i guess i will be able to read them again. if i remember right, 2 were perfect, one was black and one almost a little too white.

[element303]

i just took a video for you guys of the carbs without filter and running when i saw that #3 is flooded as it seems and #2 is backfiring. i guess once again the carbs come off.. sighhhhhhh

[FJmonkey]

did the suck test (i hope it also counts with empty tank) but i couldnt suck any air so i guess thats good.

The suck test does not require fuel, sounds like it passed. That is good to know. Your spark plugs differences are worth checking on. They should all be the same condition. One black and one white is a problem. Keep after it, you will find it, fix it and get your Kookaloo back....

[element303]

i couldnt be more cranky right now. took the carbs out again and #2 & #3  had black sparks plugs (the new ones) already. im a little confused. when i took out the carb bank from my kawasaki and turned it on top, the fuel would flow out of the bowl, here it doesnt. when i open the bowls they are all still full of fuel.

anyways, i tried to adjust the float level of 2 & 3. when i compare them to 1 and 4 they all seem to open and close at the same position so i dont know why they flood. i tried to adjust them to a leaner level but nothing at all got better. right from the start, backfires and running like crap. the needle seems to be in good condition and im sure it closes. man, i seriously hate dealing with carburators. i cant believe i sold the kawasaki and now i have the exact same issue with that bike too.

are there any guides here on how to do it right?

[Pat Conlon]

There sure is....go to the Files section look in the Carb Files and on page 2 there is a PDF on carb cleaning.

Do a through cleaning, half measures will avail you nothing.

Also: Replace the float needle seat o rings, in fact, just get the carb ss screw kit and o ring kit from RPM.

[FJmonkey]

One more option to help trouble shoot the carbs is using a clear piece of tubing on the bowl drain. With the tube pushed onto the drain nipple, curve the tube up so the other end of the tube is above the carb top. Then crack the drain screw open. This will create a sight glass and allow you see if the bowls are filling the same. You will need to run the engine so keep a fan or two on the engine to avoid over heating.

[Firehawk068]

Are all 4 choke plungers returning to the fully closed (in) position when you turn the choke lever off?
It's possible that #2 and #3 are stuck in the open position?