Im looking for a keihin but havent found one but as soon as i do itll be on it but i agree this should run a lot better than it does.
240 bbk problems need expert help
- Thread starter Budget_Blaster
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If you advanced your timing 4 degrees as your sig suggests and you have 170-180lbs compression, you should probably be running 93 or a 110-93 mix in fuel. Timing advance and upped compression are both reasons to run higher octane.
Do a leakdown test.
Its all process of elimination
Do a leakdown test.
Its all process of elimination
u mess with the main jet? is there a little brass washer under the main jet. something simple, check the fuel petcock. worth checking. make sure all the wires under the hood are connected correctly.eliminate the easy stuff
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also mabey try cleaning your gas tank mine gave me headaches forever tryed just about everyhting and had pine needles plastic from who knows what dirt out the ass mabey it got bumped around when you took the tank off to swap out the cylinders
Ok...i just spent the entire night in the garage heres what i did/found.
First i put the 340 main back in along with stock pilot jet as its bigger than the vitos and was told to do so by paul at vitos.i also thoroughly cleaned and disassembled the carb lettding it soak in container of gumout carb cleaner and used the air compressor to blow out all the passages its clean as a whistle.i also set the vitos jet needle at the 2nd from top setting.
I pulled the flywheel and the vitos advanced woodruff was fine but to eliminate any further headaches i replaced it with the stocker.
I went over the base gasket with a high intensity led look for leaks and found none along with the head all is well there.i also checked the vf3s and theyre fine.carb boot it new but i looked for hairline cracks and seen none.
Batteries are dead in the fluke meter but i fired it up and wiggled the plug wire and it made no difference but when i go to town ill get batteries and check it properly.
I also flushed the tank and nothing of any importance came out a little sediment but not much.
It fires up on the first kick and idles like its EFI i dont get it i really dont i appreciate the effort guys i know its something stupid and has to be in the carb.i hope one of you can figure this out ill call ken tomorrow and get his opinion.but if you can think of a solution ill try it.only thing i havent done is a leak down as i dont have the needed tools.but ive checked everything else i can think of.
First i put the 340 main back in along with stock pilot jet as its bigger than the vitos and was told to do so by paul at vitos.i also thoroughly cleaned and disassembled the carb lettding it soak in container of gumout carb cleaner and used the air compressor to blow out all the passages its clean as a whistle.i also set the vitos jet needle at the 2nd from top setting.
I pulled the flywheel and the vitos advanced woodruff was fine but to eliminate any further headaches i replaced it with the stocker.
I went over the base gasket with a high intensity led look for leaks and found none along with the head all is well there.i also checked the vf3s and theyre fine.carb boot it new but i looked for hairline cracks and seen none.
Batteries are dead in the fluke meter but i fired it up and wiggled the plug wire and it made no difference but when i go to town ill get batteries and check it properly.
I also flushed the tank and nothing of any importance came out a little sediment but not much.
It fires up on the first kick and idles like its EFI i dont get it i really dont i appreciate the effort guys i know its something stupid and has to be in the carb.i hope one of you can figure this out ill call ken tomorrow and get his opinion.but if you can think of a solution ill try it.only thing i havent done is a leak down as i dont have the needed tools.but ive checked everything else i can think of.
when i first put my vitos bb kit together it seemed to do the same thing... i rode it around and it didnt want to go into the power band. i think it was just because i was afraid to really get on it. the fatty is such a low pipe the bottom end seems to carry and i wasnt letting it get to the powerband. your going to run into problems if your compression is that high and you advance the timming. maybe not detonation right away but after you ride for a while the heat build up will. keep messing with the jetting until its right and i bet you it will clear up.
i would say your plug looks pig rich because its sitting at idle most of the time its running. Ken should know what to do
Really dumb question, but when was the last time you changed your spark plug? Install a new NGK BR9ES, be sure it's gapped properly (.028"-.030"), and try again. Also check your plug boot on the ignition coil to be sure it fits tightly onto the coil wire.
I've chased my tail for hours only to find out I was dealing with a bad spark plug. And yes, an engine will run (just not well) with a bad plug.
I've chased my tail for hours only to find out I was dealing with a bad spark plug. And yes, an engine will run (just not well) with a bad plug.
leak down test.
I had an issue like this with my YZ400 it had a bad crank seal. unless you do the leak down test you will never know.
FWIW I have seen guys run many 240cc blasters with stock carbs, fmf pipes that were still rich at 280. I would try a 260 after you have made sure there are no air leaks. Remember better reeds will make an engine run richer.
I had an issue like this with my YZ400 it had a bad crank seal. unless you do the leak down test you will never know.
FWIW I have seen guys run many 240cc blasters with stock carbs, fmf pipes that were still rich at 280. I would try a 260 after you have made sure there are no air leaks. Remember better reeds will make an engine run richer.
Somebody needs to explain how it runs rich with an air leak :-/ . X-2 on new plug. Even if plug is new try a different one. Ohm plug cap, cut 1/4in off wire, reinstall. Check coil, coil ground, all conections.
I assume the WET plug could be a crank seal drawing in trans oil.
if it is rich lean it out.
but dont go leaning it out unless you do a leak down test. otherwise you could blow it up.
An easy test to see if its rich or lean is to run it and once you get it in the higher rpms slowly open the choke... if it gets better its lean if it gets worse its rich.
next turn off the fuel. as it runs out of fuel it will lean out if it gets better the longer you run its too rich, if it just runs poorly until it dies its too rich...
if it is rich lean it out.
but dont go leaning it out unless you do a leak down test. otherwise you could blow it up.
An easy test to see if its rich or lean is to run it and once you get it in the higher rpms slowly open the choke... if it gets better its lean if it gets worse its rich.
next turn off the fuel. as it runs out of fuel it will lean out if it gets better the longer you run its too rich, if it just runs poorly until it dies its too rich...
