Enrichment Circuit (Choke) Ineffective

1985 XJ700N - When cold starting, the "Choke" does little to nothing - especially compared to my XJ650 where the choke makes a huge difference. It looks like the plungers are actually moving.

I am just assuming that there is probably a family of raccoons or something living in the carbs, and that the enrichment circuits are probably full of goop.

Is that a good guess or should I be checking something else?

 

check the wells in the bowls to make sure they will allow fuel to flow. then check the jet(brass tube) to make sure fuel will flow through it

make sure the plungers are not stuck

with them being mikuni carbs the plungers are most likely tips set in rubber do not soak them in carb cleaner

 

XJ700N is an airhead, uses Hitachi HSC33 carbs...........

 

Raise the tank , disconnect the fuel line , with a meat syringe squirt MEK into line several times let it sit for about 30 minutes, hook back up fuel line and try to start . This has worked for me at least

 

Do all the mini carbs on the X use rubber coated tips? Just curious because when I recently did my carb job on my 86 X the tips were copper. Not that anyone before blasted them in a carb clean meltdown....

 

Mikuni....

 

the tips are seated in rubber , metal tip rubber seat. the 550 carbs are like this I do assune mikuni would do it for all the carbs of that era.bike in question is not an X so he has nothing to worrie about

 

MEK i am suprised it did not melt the rubber bits in your carbs

 

Nasty stuff.

 

Nope if you have fuel in the bowls , fuel distillates etc will not harm the rubber as long as you don't leave it in the bowls for long , carb cleaner is as caustic as well.

 

I did a little exploratory surgery tonight. Popped the carb rack off and removed the float bowls.

I could get some carb cleaner to shoot through where the enrichment circuit pickup tube thing goes for two of the bowls - #1 and #3.

Couldn't get any carb cleaner to go through on #2 or #4 - so they are blocked with something. So at most I had two functioning enrichment circuits - I suspect maybe one was actually working.

Put all 4 into the chem-dip for 30 minutes. #2 and #4 are still blocked, they went back in the chem-dip for now.

Anybody got a good way to unblock those little passages in the bowl?

Just to be clear, this is the airhead with Hitachis.

 

For future reference for myself or anybody else, I found this: https://xjbikes.com/forums/threads/how-to-clean-the-enrichment-circuit-well.8918/

Common problem.

"The Church of Clean" document was helpful too, and references the above link.

 

Finally success!! I went back out to give it another try. Someone mentioned using a bristle from a wire brush to get into those holes and dig the crud out. That worked for me.

This project is a pretty good warm-up for doing a full rebuild.

 

Crap. After getting those passages in the bowls cleaned out there is no difference in how the enrichment circuit works.

Crap crap crap

 

OK, false alarm - maybe.

Appears that sometime when removing/reinstalling the rack and doing the cleaning that the idle adjustment got turned way down, so that may have been why it didn't like to run when cold without the throttle applied.

Need to wait and try another cold start now that the idle is set properly.

 

Was able to cold start tonight. Much better. I don't know if it's 100% yet, but it is progress.

Not hard to see how somebody could try working on these carbs, get frustrated, give up, and sell the bike.