"new" '84 Aspy, only runs with choke on?

[DC44]

All:

I'm helping a friend who just bought an '84 Aspencade. When we first brought it home a week ago it would startup immediately and then die after 3-5 seconds if the choke was on. It would not start with the choke off at all.

Another problem is that the engine dies immediately if you give it ANY throttle at all. So it will startup and run with the choke fully on and also with the choke reduced almost to "choke off", but if you put choke in the off position it immediately dies. At any time if you give it throttle it dies.

On a positive note the Aspy will now start with the choke full on and idle for as long as you want with the choke reduced. (10-15-20 minutes) So it has improved from only running 5 seconds to idling for a long time. Again it dies if you so much as increase the throttle 1/4".

I have read every thread in this section pertaining to only running with the choke on and haven't found the info I need to start trouble shooting. The fuel filter is open and gas flows freely. I performed the fuel pump flow test and it is at specs.

The bike had set for several months, maybe a year. I'm certain it's carb related but need suggestions on where to go next.

Thanks in advance,
DC
1986 Interstate

[85GL1200I]

Many on here are not real big on fuel additives, myself included, but in this case it wouldn't hurt to try some seafoam or another quality carburetor cleaner added to the gas. It might not help, but won't hurt anything to try. Those carbs were likely getting gummed up before the bike sat, and the period of sitting just put the cap on it.

I'm curious how you make out with this, this bike may be headed for a carb overhaul. A nice winter project. Please let us know how you make out.....

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Just happened to think, are you sure the choke is operating properly and not sticking?

[Frank]

the seafoam may help but at just an idle not much fuel is going to be running through the system so it's gonna take awhile to see any results. In the month that it's gonna take to get results you would be better off just taking a weekend and giving the carbs a cleaning and be back on the road

[KnoxSwift]

Might want to check carb sync. That would also expose any vacuum leaks that also may be causing the issue you are having?

[DC44]

Just happened to think, are you sure the choke is operating properly and not sticking?

The choke is definitely not sticking. With the choke "off" the engine will not start. With the choke full "on" the engine will start and idle at a high rpm. Once running, as the choke is reduced the RPM's decrease, once they decrease to 5-6-700 rpm's you can then push the choke "on" and the RPM's will once again increase.

I'm going to try some type of carb cleaner directly into the carbs as a start.

BTW: We're in Arizona, Winter is riding time for us!


Frank-KnoxSwift: I'm hoping I don't have to pull my friend's carbs but will if that's what it takes.

re: Carb synching?

I don't see what good it would do to try to sync the carbs when the engine will only run with the choke on. Any explanation of why I should try it?

thanks to all three of you for your time and suggestions,

best,
DC

[85GL1200I]

Well, if you're in Az. you better turn that winter project into a weekend deal! Winter is already here in Pa. - jealous

[sparky65]

Try bleeding a bit of gas out of each carb float bowl. There's a small screw at the bottom of each carb for this,it will ensure there's no stale gas left in the float bowls. Use a big rag underneath the float bowls to soak up the gas then get rid of the rag before you hit the key.The jets are quite small so they gum up easily. My 83 I was bad for that after sitting over winter, it would'nt run right until I did this purging of all 4 carb float bowls,even if I let it Idle for an hour or took a run. Its worth a try first before carb work. Usually if the engine runs after warm up with the choke on but won't run right with choke off its starved for gas and the jets are gummed up.

[DC44]

Try bleeding a bit of gas out of each carb float bowl. There's a small screw at the bottom of each carb for this,it will ensure there's no stale gas left in the float bowls. Usually if the engine runs after warm up with the choke on but won't run right with choke off its starved for gas and the jets are gummed up.

Thanks Sparky, I'll give that a try today and let you know.

[old gold]

The best solution on my 85 was to bite the bullet and pull the carbs. There may be tiny filters under the needle valves to catch dirt from the gas tank before it gets into the carbs and plugs the idle & main jets. While you have the carbs off, clean the bowls and make sure all the small passages and jets are not plugged. Of course, don't use carb cleaner on plastic parts.

[DC44]

The best solution on my 85 was to bite the bullet and pull the carbs. There may be tiny filters under the needle valves to catch dirt from the gas tank before it gets into the carbs and plugs the idle & main jets.

Thanks, I'm going to work on the Aspy tomorrow. I'll post here on what I find and what happens.

DC

[bs175dths]

The reason the bike will only idle with the choke on is because your idle jets (primary jets) are partially or fully blocked.
They need to be clean.
As was mentioned, it is going to take some miles, or hours of idling, to get enough Seafoam to pass through the partially clogged jets before they are cleaned out.
-Sorry, but the carbs need to come out to do the job right. Intake manifold o rings may also need to be replaced.
While the carbs are out, replace all those rubber hoses underneath. I used safety wire instead of those little factory clamps. Not too tight or the wire will cut through the rubber!
Clean the reed-valves too!
CLEAN EVERYTHING, BUT DON’T CHANGE THE AIR/FUEL SETTING!! Wait until you see how the bike runs after a good (thorough) cleaning.

Giving it some throttle, and the engine dies....
Easy fix…..

The throttle cable is not ‘directly' connected to the throttle needles. The cable is connected to the butterflies.
The throttle needle is tapered (large at the top and smaller at the bottom) and sits in a fixed, sized hole.
At idle, the fat part of the needle sits in this hole and as such, the area for gas to pass through is very small.
As the needle rises, and becomes smaller in diameter (tapers) the fixed hole effectively gets larger and thus, more gas is allowed to pass to the engine.

The way the needle rises up is with a difference of pressure.
In the top of the carb., (under those four small screws) is a rubber diaphragm which helps to trap some air.
As the amount of air passing THROUGH the body of the carb. increases, (by opening the butterfly), it causes a difference of pressure and the needle floats up!
The more air passing through the carb. body, the higher the needle floats up, which in turn, allows more gas to flow into the engine, which causes more air to flow through the carb. body, the higher the needle floats up, which in turn, allows more gas to flow into the engine, which causes more air to flow through the cab. body…..

Now, imagine if the needle can’t float up? If there is some resistance and the needle can’t float up, then although the engine (and your right wrist) WANT more gas to flow, the gas can’t flow into the engine because the needle is meeting too much resistance.

That resistance can be in the form of dried, gas vapor sticking to either the throttle needle piston, or the cylinder wall the piston floats up and down in.
This residue needs to be cleaned off. The best ‘carburetor cleaner’ for the job is gasoline, in a well ventilated area and well away from open flames.

To check this, with the carbs. removed from the engine, stick your finger in the carb. throat and push that black plastic piston up. Don’t release it yet! Did it go up effortlessly, or did you have to push?
Now, quickly remove you finger. The black piston should close with a ‘snap’. Now do this test to each carb.

If any one of the four failed, take the four screws out of the top of that carb., keeping the top on the carb., because there is a spring under there which wants to fly and hide under your car tire.
Slowly remove the top and see how the spring is seated on the underside of the top, and inside the needle piston. Remove the spring.
Inspect the rubber diaphragm and notice how it is seated in the carb., body. It should be sealed all the way around the top of the cabr. body. If this is not seated properly, air will escape and the process will not work as designed.
Carefully remove that seat from the indentation of the carb. body (don’t tear it!!) and slowly pull up…… the piston should come out of the carb., body. Keep in mind, you may meet some resistance because of the residue on either the throttle needle piston and/or the cylinder wall it rides in.
Inspect the side walls of the throttle needle piston. It should be clean of all residues. Do not damage the throttle needle, the metal is soft!!!!! No nick’s in the needle and be very careful of the very tip of the needle.
It is sharp (will draw blood) and is easily damaged.
I clean the throttle piston walls and the walls of the cylinder it came out of, with gas while in a well ventilated area and well away from open flames.

Do this to all four carb., one at a time – don’t mix and match parts!!

Reassemble after a thorough cleaning.
Do the finger exercise again and see if there is a difference from before the cleaning. (there will be a difference)

Do the rest of your carb. cleaning and inspection (be systematically thorough) and reassemble onto the engine.
You will want to synchronize the carbs. at some point, but this cleaning of the primaries and the residue removed from the throttle needle pistons and piston cylinders will allow the engine to start easier and idle nicely.
Some additional adjustments may be required, but at least you have a great starting point.

Good Luck.

-Ride On

[DC44]

Carefully remove that seat from the indentation of the carb. body (don’t tear it!!) and slowly pull up…… the piston should come out of the carb., body. Keep in mind, you may meet some resistance because of the residue on either the throttle needle piston and/or the cylinder wall it rides in.
Inspect the side walls of the throttle needle piston. It should be clean of all residues. Do not damage the throttle needle, the metal is soft!!!!! No nick’s in the needle and be very careful of the very tip of the needle.
It is sharp (will draw blood) and is easily damaged.
I clean the throttle piston walls and the walls of the cylinder it came out of, with gas while in a well ventilated area and well away from open flames.

Do this to all four carb., one at a time – don’t mix and match parts!!

Reassemble after a thorough cleaning.
Do the finger exercise again and see if there is a difference from before the cleaning. (there will be a difference)

Do the rest of your carb. cleaning and inspection (be systematically thorough) and reassemble onto the engine.
You will want to synchronize the carbs. at some point, but this cleaning of the primaries and the residue removed from the throttle needle pistons and piston cylinders will allow the engine to start easier and idle nicely.
Some additional adjustments may be required, but at least you have a great starting point.

Good Luck.

-Ride On

Thanks a lot for the detailed directions. I pulled the carbs yesterday and will begin the careful cleaning process today. I'll be back in touch with an update after following your advice. I really appreciate you taking the time to help us out.

best,]
DC

[DC44]

Do this to all four carb., one at a time – don’t mix and match parts!!

Reassemble after a thorough cleaning.
Do the finger exercise again and see if there is a difference from before the cleaning. (there will be a difference)

Do the rest of your carb. cleaning and inspection (be systematically thorough) and reassemble onto the engine.

Good Luck.

-Ride On

Guess what? All 4 carb pistons were stuck in place. I don't mean hard to move up, I mean like glued in place. I've got all out now and soaking in gasoline. Going to clean the openings in the carb body with a guitar string. I'm now soaking in Pine Sol to get rid of residue.

Thanks for your advice, I think we'll have this Aspy on the road very soon.

best,
DC

[85GL1200I]

glad you are on your way to getting those cards straightened out!!

Well done!

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oops CARBS

[bs175dths]

hey, just among us 'experts', you can go back and correct your spelling in a previous post. look for the edit button and you will see two choices.
Just don't let the 'others' know...... experts little secret!