Fuel coming out from only 2 out of 4 carbs

1983 Maxim XJ750

Hey guys!

So after I cleaned up the carbs, I installed the carbs back on the engine to see if I would get any good results.

My setup: All carbs back in their boots (to engine), no air filter and running gas through a funnel + clear tube to the carbs (so no gas tank).

After cranking the engine a couple of times, I wasn't getting any combustion / sign of life from the engine. Choke on/off, etc...

I noticed fuel coming out from the venturi of the 2 carbs from the left of the bike and the 2 other carbs where dry. After removing the carbs, All of them did have fuel in the bowls.

So right now I have 4 carbs that fill up with gas, do not leak, but only two of them are actually doing there job.

Should I check the height of the floats? is it a pilote/idle circuit problem?

Thanks!

 

bike on center stand?

did you bench sync carbs ?
set mixture screws to 2-1/2 turns from soft bottom

can you let us know which venturi fuel is coming out of

this is how to do wet set fuel levels

Setting the fuel levels
your float needle valves could be sticking or not sealing


have you confirmed you have spark?

ohm out ignition system?

 

- Not on center stand
- I bench synced the carbs
- Mixture screws to 2-1/2
- Its coming out from the ''mouth'' of the carb 1 and 2 (so the most tilted one on the side stand)
- I just checked my float height and they are ball park between 1 and 3 mm from the edge od the float bowl (wet)
- I have spark and compression, spark plugs where dry

Update: It fired up for like 2-3 seconds and died instantly, im just wondering now if I should just slap the tank on and fill it up with gas. Maybe I didn't have enough of it? Or do I really need to reconnect the airbox? as if it was missing some pressure ore something?

 

Am I correct in thinking that you are seeing fuel run out of the carbs? If so the float needles are not sealing, or your float levels are not set correctly.

 

^^^#1 try this , drain float bowls, using a measuring container see how much fuel is in each bowl. Should be same on each bowl. Pull carbs flip over pull float bowls ,measuring from the carb body flange 17mm is to tip of the float if it is greater bend tab slightly on float ..this should get you close.

 

So I just mesured the amount of fuel in each bowl and its the same for all four of them ( ~60 ml). all my floats are set to 17 mm +- 0.5 mm.

 

And the fuel isn't pouring out or anything @k-moe , I think its just gas that's unburned that didn't go in the cylinder of the engine.

 

17 mm float height is a base line now you have to do a wet set
-Fuel level measured via the clear-tube gauge: 3mm +/- 1mm (.12 +/- .04 inches) -Float height: 17.5 +/- 0.5mm
3mm below flange of carb where it meets the bowl


read this link
Setting the fuel levels

 

Dry plugs indicate no fuel.
I assume you tried to start it with the "choke" fully engaged.
No fuel would indicate to me one of the following:
1. clogged pilot circuit--but hard to imagine all four being clogged
2. bad bench sync--
3. inoperative enrichment circuits
4. no fuel in bowls or very low level of fuel-- wet set reading would verify
5. very lean mixture because of no air filter

I would pull the carbs and double check 1-4 and then re-install them with the air filter.

 

So I shot some starter fluid in the carbs while cranking and it fired up, so its not the engines fault. I went and did a wet set and saw that the level was low. The level wasn't close to 3 mm from the end of the float bowl (it's more then 10 mm...). So I have a feeling that's the problem! I'll re-set the floats and do another wet-set.

 

I set mine at 17.5 mm ...have never wet set them ....runs great , color tune is good all 4 plugs nice color ...Morgan synch meter ...good...for giggles checked 3mm in tube .

 

some after market needles are a little longer than oem needles. wet setting compensates for that. that's one reason i got oem needles from chacal.