FJ600racing idle

Hello,
I have a 1984 FJ600, the carb had the main jets cleaned.
I balanced the carbs too, roughly, but it sounds smoother.
However, I once my bike warms up, the idle goes up to 2500-3000 rpm,
why is this?
The chokc is off.....at least it seems off? Could it still be on, inside the carb, while looking off,
from outside the carb?
What else could it be?
Al

 

do a propane test to see if you have any air leaks at the manifold boots, then the throttle shaft seals and the airbox boots.
use an unlit propane torch
to check choke pus down on the plungers on the carbs.
it could be your idle is set to high to start with have you tried to turn it down with the knob between the center two carbs under neath?
does your throttle cable have any slack in it ? it should.
also cleaning just the main jets is not all you have to do to clean the carbs

did you set the idle mixture screws yet?

 

read this link
IN THE CHURCH OF CLEAN
this one too
THE SECRET LIFE OF CARBURETORS

another
Something New, Something Naked

this too
The Information Overload Hour
all will help you understand better whats going on

this is how to build a carb sync tool
http://www.xjbikes.com/forums/threads/how-to-make-a-2-bottle-synch-tool.15650/

 

Could be your running Lean, Check the idle adjustment screw, bench sync the carbs, make sure those carbs are clean enough you could do surgery with them

 

too late for a bench sync his carbs are on the bike

 

did you try to just turn the idle down? if you set the idle before it was fully warm, it will go up that much when it's hot

 

1) What is a propane test?
2) I did try setting the idle screw mixture as low as I could without killing the engine. Once it warms up, the engine revs start picking up fast, with choke off...
3) How do I adjust the fuel mixture ratio?? (I know where the idle screw is and where the synch screws are)

4) How difficult is it to remove the pilot jet to clean it? On an FJ600 can I go up a jet size (heard these bikes are jetted lean) 7 what size? Can I do this without dismantling the carbs?
5) Would it be helpful to remove the enrichment tube to clean? Is this difficult?
I will look at it again.
Al

 

Mixture screws are on the engine/output/arse end of the carbs at the top sunk into the casting. They might be blanked off with caps you need to drill out carefully.

Theres b*gger all you can do with the carbs in situ. You will have to remove and clean as much as you're confident to do. The more the better is the perceived wisdom, but you may encounter hurdles in form of seized screws etc..

 

you take a propane torch and turn on the gas to the torch. then you go around the carb to motor boots and listed for an rpm increase. then do the carbs at the throttle shaft seals, then the air box boots. if you want to see the effecttry some into the airfilter box first. any rpm increase indicated a leak

with the mixture screw its on the jug side of the carbs and under a little alumnim cap. to remove cap drill a small hole in it be carful not to go deeper than the cap .put a sheet rock screw into the hole and pull it out

it unscrews should be easy to do with the correct screw driver
you have to dismantel the carbs.
do not change the size of the jet you can fix the lean with the mixtere screw adjustment. you should buy a color tune to do the best results

you can not remove the enrichment tube , you can remove the plungers. also you will want to clean the bowls and er well and passage

 

when the engine revs up and the choke in off did you try to set the idle then? you need to set idle when motor is fully warm

fj does that have 2 carbs you will need to sync them.