carb issues, I think

Sorry to make my first post a question, but I'm stumped and need some help. I recently traded for a 1983 f750f cali emission bike (I live in Georgia, how that happen) it has full cobra f1r exhaust, and a uni filter. I have cleaned the carbs twice and checked everything I can think of. The problem is this thing is very sluggish and revs slow. Very slow. When riding it it is extremely week like it is starving for fuel. The manual says that cars 1 and 3 use shorter springs and thinner needles than 2 and 4. I found this out after putting it back together the second time. Thinking maybe they were switched. Think that would cause that severe of a problem? Oh forgot to mention that the second time I was in there I switched the mains from 122(which should be way lean with exhaust and filter) to set of 135's that a buddy had thinking it would go rich. Didn't really make a difference. Also tried running it with one airbox intake hole covered up thinking maybe a vacuum issue, no real difference. Any ideas?

this may sound silly.. but check your oil level.. in fact.. drain it.. and refill it. with 2.5 quarts..( yes thats LOW) and see if it revs faster.. than top it off to the right level

i have seen bikes with T E N ,,,TEN quarts of oil in them.. they run.. but rev horribly slow.

[image: View Post]gll429, on 18 November 2010 - 09:22 PM, said:

this may sound silly.. but check your oil level.. in fact.. drain it.. and refill it. with 2.5 quarts..( yes thats LOW) and see if it revs faster.. than top it off to the right level

i have seen bikes with T E N ,,,TEN quarts of oil in them.. they run.. but rev horribly slow.

I checked the oil, to make sure there wasn't any gas in it. In it's normal level.

ok.. take a spray bottle.of water or cleaner.. run the bike for a few min.. spray the header pipe about 2 inches from the head.. . water your just about vaporize on contact.. if it doesnt.. A)your not getting a spark, or B ) your not getting gas

Haven't tried the spraybottle, but I removed the plug wires one at a time, it if firing on all 4

the plugs should be the color of a dark mocha coffee...
you have the manual right?? if this was my bike.. remove the gas tank.. hook up a hose straight to the carbs.. add a funnel.. pour gas till its 1/2 way up the funnel.. run the bike.
if it revs right..you know your petcock or tank or fuel pump is the problem.

[image: View Post]gll429, on 18 November 2010 - 09:45 PM, said:

the plugs should be the color of a dark mocha coffee...
you have the manual right?? if this was my bike.. remove the gas tank.. hook up a hose straight to the carbs.. add a funnel.. pour gas till its 1/2 way up the funnel.. run the bike.
if it revs right..you know your petcock or tank or fuel pump is the problem.

runs a full stream with the line off the tank, fuel pump was pumping, i wound it over with the fuel line off of the carbs. Now whether it is still working, or running enough fuel I'm not sure. Thinking of trying gravity feed to see of anything changes.

ok.. now i am guessing that your petcock is gummed up or if its vacuum operated.. the line is kinked or has a hole in it.. or the diaphram in it is ripped.

Despite getting spark, you should still check the headers for heat. Start it up from cold and touch them with the back of your hand. It will become obvious as it warms up if one or more isn't firing.

Not vacuum operated. I have pulled the line off the tank and it ran a full stream of fuel.

well if the bike goes full power with the funnel.. and the gas pour out of the tank.. then either A your gas line gets kinked.. or b) the fuel filter is clogged up..or C) the pump is on the way out and only pumping with very little pressure.

[image: View Post]gll429, on 18 November 2010 - 10:43 PM, said:

well if the bike goes full power with the funnel.. and the gas pour out of the tank.. then either A your gas line gets kinked.. or b) the fuel filter is clogged up..or C) the pump is on the way out and only pumping with very little pressure.

After all the time and work, it'll probably be that simple. gonna play with it some saturday and will post what happens.

Tore into them again today. The springs were in the right spots, but the needles were switched. I put the 122 jets back in after the guy at factory pro reminded me of something I already new, but for some reason I didn't think of. "if the mains are too small, you will have a flat spot but it won't cause a severe bog". Haven't got to try it out yet, because I found something extremely ignorant. Some dumba$$ put a piece of cable tv coax on there for a plug wire. I thought I'd seen it all. Anywho, gonna borrow a plug wire off a buddy's parts bike tomorrow. Crossing fingers.

[image: View Post]dcil, on 20 November 2010 - 06:16 PM, said:

Tore into them again today. ...
Some dumba$$ put a piece of cable tv coax on there for a plug wire. I thought I'd seen it all.

That might be one of my old bikes--i used to do that on all my bikes too--that way i could get free HBO and pay-per-view...

Put it back together today. Cranked easier than it ever has. Took off down the road. Runs a lot better. It is pulling through 7000 now. Gonna order some 130 mains and see if that will clear it the rest of the way up. Also goin to the parts store tomorrow and see about some plug wires. It has a pretty bad miss above 7000 so I figure the cable coax is arcing to ground. Either that or it is trying to pick up re-runs of american chopper.