85 250sx Question

[Headsup]

Ok so my Trike runs great now.
Just when i fire it up, and let it idle.
when its at idle if i Hit the gas to hard it Dies,
Like if i let it idle and tromp on throttle It just dies..

Now if i have it idle and slowly push the throttle it revs fine. Also its only when its at idle.
If i have the trike at about half throttle and tromp on it, its fine.
Only when its in idle it dies when i give it to much gas..
Any ideas on what this could be, I tried the manual troubleshooting, But nothing there helps me in my problem.

ok also while im riding it it is fine, Runs great cept for the throttle dieing at idle. When im riding it and it gets Hot. Like maybe after an hour.
My trike will just bog out and die., Like its flooding or not getting enough gas.
wont start back up unless i drain overflow from carb, or let it sit a while and cool down, ANy thoughts on what this might be.
Cleaned the carb, Got a new rebuild kit for it.
Cleaned gas line etc..
Could it be water in my tank? But i think if it was it would bog out half throttle or non.
No idea, any help is appreciated.. Thanks guys, Hope to have this running great soon.

[Headsup]

Pretty overwhelming when the Trike kings have nothing... lol

[Nubbinz]

Ive played with carbs a little, i want to say your idle mix is too rich so when you press the gas its just overwhelmed with fuel. too lean can do that BUT the idle will usually be like 2x maybe 3x what it should, you said your idle is fine, just mashing the gas it bogs and dies. so ya, try tightening that idle mix a quarter turn at a time and testing it. be sure to let it run for like 10 min so its warm when you tune the carb

[dougspcs]

My 1st thought would be to have a second go on the carb 'cold-start' plunger. Sounds like it's letting fuel by and causing you to flood out..

If it was lean it would have more tendancy to backfire due to high cylinder temp..

You carb kit may be to blame. I have had a couple cheap carb kits that didn't fit just right..especially on the 'cold-start' plunger.

Tear it down and do it again..

Also, how old is the gas in the tank??..if you don't know drain it completely and replace with fresh.

[Headsup]

Ok thanks i will try to Turn the Mixture screw a 1/4 of a turn at a time and test after it is warm.
Thanks again, the gas is maybe 2 weeks old.

Also
not sure what carb 'cold-start' plunger is..
All the jets are the same on my Rebuild kit, It the mixture screw doesnt seem to fix it. i will tear it back apart and try again. thanks guys

[dougspcs]

you're call..just telling you what I have seen with this style of carb.

idle mixture isn't your issue..it's choking!!

[Headsup]

choking,, What can i try to do about it? Idle mixture i tried nothing, Still the same,

[Thorpe]

not sure what carb 'cold-start' plunger is...

Choke plunger I think is what he meant... Sounds like your pilot screw is in need of tuning... I too, have have bad carb kits for these machines, especially the Moose brand ones....

[tri again]

yeah
Take a look at the choke plunger
see if it's actually moving.
either with or without the choke lever and cable.

Some of the plungers have a square cut 'o' ring that can get terminally stuck so do Not pull to hard
on the cable trying to get it out.
There is a needle on the bottom of the plunger that reminds me of the
main jet needle.
ComPletely different animal than a regular filp flapper choke.
These are more of an 'enrichment' circuit that opens internal passages in the carb by pulling the piston and needle up.

bikebandit.com has exploded diagrams
and maybe even in the
'world class help' section here on 3ww.

[Headsup]

Intersesting stuff there. Thanks i am goign to remove the carb again, Try to use that 1/4 screw and screw it into the Starter jet and pry it out. Never thought that came out, Seeing the i didnt get one with the rebuild kit.
Any places you guys know of that i could get a starter jet by it self??

thanks guys, I will take a look into the choke plunger also. Thanks again i will let u all know how it goes

Just looked at the choke plunger, It does move with the cable, Its not getting stuck, But i see no O ring in there.

The previous owner said it needed a choke cable. But there is a wire i pull on to choke it. Witch lifts the Plunger jet needle up.
No idea what is still going on . i would have thought i would have got this fixed by now...
idk guess i will remove the carb again and try the starter jet Removal option in that pic u showed me..

[Headsup]

Ok so i read up a bit in the world class help section in jetting..

Seen this..

"If the engine does not quickly return to idle after a good rev, it's too lean and needs a bigger pilot jet. If there's bogging when taking off or reving from idle, it's too rich."

Bogging when taking off or reving from idle.. = rich..

Maybe i can try to raise the needle clip? 1 notch and then try? Think that would work? Anyway im going to try it, Have nothing else to try.

[Thorpe]

Pilot Jet is not the needle you are talking about adjusting... The needle you are talking about, is the mid range circuit... Pilot screw for fine tuning the ES carb....

[tri again]

Ok so i read up a bit in the world class help section in jetting..

Seen this..

"If the engine does not quickly return to idle after a good rev, it's too lean and needs a bigger pilot jet. If there's bogging when taking off or reving from idle, it's too rich."

Bogging when taking off or reving from idle.. = rich..

Maybe i can try to raise the needle clip? 1 notch and then try? Think that would work? Anyway im going to try it, Have nothing else to try.

I personally wouldn't fool with that cold start jet especially if you don't have a replacement.
If draining the carb a little helps, the float level could be too high.
It can be cehcked with a small piece of clear tubing, connected to
the float drain and then held up against the carb to see how high it goes.
Way easier than taking it apart.
Raising the main needle seems like it would make it richer.
by increasing clearance for more gas to flow.

When mine bog like that and I give a little choke, they take right off
but that is completely backwards from what I just read about lean and rich
carb states.

[tri again]

Ok so i read up a bit in the world class help section in jetting..

Seen this..

"If the engine does not quickly return to idle after a good rev, it's too lean and needs a bigger pilot jet. If there's bogging when taking off or reving from idle, it's too rich."

Bogging when taking off or reving from idle.. = rich..

Maybe i can try to raise the needle clip? 1 notch and then try? Think that would work? Anyway im going to try it, Have nothing else to try.

I JUST remembered something that I missed 2x on my first 250 carbs.

There's an emulsion tube under one of the screw out jets.

It's about an inch long, the diameter of a pencil lead
with a bunch of holes in it and it hides under a jet.
It can be pulled out with a dental pick type tool and is usually full of rusty muck

[Headsup]

Yes ^^ above i got that out and replaced it with a new one, Not understanding the Measure the float with a tube?? Not following with that one..

Also as i said i Messed with the air fuel mixture screw it is not that..

Was thinking Float to high,
Like stated or.
Where my throttle needle goes into the bottow of the card into the bowl.
There is a Little metel thing i think the needle has to enter and it stops the fuel. when it closes the gap..
Maybe that is not happning, Like its worn out. I got a new piece in the rebuild kit that ooks like that piece, Just not sure it they come out, I tryied prying on it to see if it would pop out but didnt, I dont want to break it..

[Big Sal]

Hey heads up...it sounds like your talking about the inlet needle on the float, there should be a rubber tip on it and at the other end is a spring loaded "pin" sticking out of it and it should move freely, it puts extra pressure on the valve to help stop the flow. If your float needle doesn't stop the flow, the gas will pour out of the overflow....if the float is "out of adjustment" you have to buy new floats...they are plastic and not adjustable. If you missing the O ring on the choke plunger it could be letting fuel past it, as far as the main needle goes, you lower the main needle to make it leaner, you raise the needle to richen it...

(bottom) ---------lllll- (top)
richer< >leaner

Factory setting is second notch from the top. Pilot screw is 2 turns out from lightly seated (starting point), and zero gap on the linkage that "syncs" the butterfly and slide..