'85 Honda Gyro S Fuel Mixing Tube.

[Garadactyl]

So I have a Honda Gyro S, and it has always ran really well. This spring I took it out of the shed and cleaned it out like normal, started it up fine, and ran it about 1/5th of a mile down the road and back. When I stopped it did not want to idle unless I played with the screw. Once I got it idling, I took it back down the road and when I stopped again it didnt want to idle like the first time. So I took it apart and made sure everything was working properly and hooked up right. It all was. Then When I went to take off again, It was like it was stuck in first and wouldnt accelerate past 17 mph. (A little adjustment with the high speed screw fixed that.)

So I assumed that the not wanting to idle had something to do with the Carb. So I went on ebay, bought one off the same model from "b4uc8r9" in which I do not recommend you purchase anything from this guy. Got the carb, cleaned it out, put it on, and it wouldn't idle at all, not even with adjustments to the screw. So I took it apart, and found that the Fuel Mixing Tube was busted off(happened before we got it, you could tell it had been like that for a while) Now when riding the Gyro with the new carb on, it ran the best it had in many years. But would not idle and took almost full throttle to start. If anyone could take these symptoms and make give me a diagnosis and a prescription for what my bike has, I want to get this thing on the road.

[Wheelman-111]

Greetings:

Hard starting and no idle suggest possible broken reed. Check that .

[wentwest]

The tube you are working with has to do with the bystarter, which enriches the mixture when you start out but closes after runnning a little while. It's an electrically activated gizmo with a pin that moves down slowly. The replacement carb could be faulty in a different way because the bystarter pin is jammed or busted. You can remove the whole assembly easily and test it. The procedures are in the repair manual.

[Garadactyl]

Greetings:

Hard starting and no idle suggest possible broken reed. Check that .

Where is this Reed you speak of?

[Wheelman-111]

Greetings:

Under the intake manifold pipe. It's a bit of a PITA to remove and clean those gasket surfaces, and of course you'll need new gaskets at the ready.

[wentwest]

Take the bystarter off the carb you bought, put it in your old carb, put the old carb on the Gyro. I'll bet it runs fine and will continue to run when it is warm.

[Garadactyl]

Take the bystarter off the carb you bought, put it in your old carb, put the old carb on the Gyro. I'll bet it runs fine and will continue to run when it is warm.

We tried this. Starting to think that it is not the Carb that is making it not idle. With the old carb and the new bystarter, it will start better (just a little throttle instead of half or full) but still refuses to idle correctly. I will try and see if maybe the Reed is the problem. Will I need to replace the gaskets once I get to the reed? Or should I just be ready to replace them in case they are bad?

[mousewheels]

Starting to think that it is not the Carb that is making it not idle. With the old carb and the new bystarter, it will start better (just a little throttle instead of half or full) but still refuses to idle correctly. I will try and see if maybe the Reed is the problem.

Needing throttle to start and not idling may be a carb float needle seal issue rather than a reed issue.

For your second carb with a broken pickup tube for bystarter fuel supply, throttle to start should not be required, if anything, it would be lean when cold. No start, or might start and run weakly. That carb in particular is worth checking out the float needle and seat.

[Garadactyl]

Would anyone happen to have a good carb for this Gyro for sale?

[Garadactyl]

Starting to think that it is not the Carb that is making it not idle. With the old carb and the new bystarter, it will start better (just a little throttle instead of half or full) but still refuses to idle correctly. I will try and see if maybe the Reed is the problem.

Needing throttle to start and not idling may be a carb float needle seal issue rather than a reed issue.

For your second carb with a broken pickup tube for bystarter fuel supply, throttle to start should not be required, if anything, it would be lean when cold. No start, or might start and run weakly. That carb in particular is worth checking out the float needle and seat.

We checked the float needle and the gaskets. cleaned the whole thing out and still got nothing. I will start fine now but will idle fine until it is drove even just a short distance then wont idle. Checked the reed and that seemed fine.

[Garadactyl]

Take the bystarter off the carb you bought, put it in your old carb, put the old carb on the Gyro. I'll bet it runs fine and will continue to run when it is warm.

We tried this. Starting to think that it is not the Carb that is making it not idle. With the old carb and the new bystarter, it will start better (just a little throttle instead of half or full) but still refuses to idle correctly. I will try and see if maybe the Reed is the problem. Will I need to replace the gaskets once I get to the reed? Or should I just be ready to replace them in case they are bad?

Ok, so just messed around with it some more. Took off the bystarter and changed it out. Ran the same way. Found there is a little hole next to the fuel mixing tube that I had never seen before and put a little wire in there to make sure it was clean. But when I put it all back together, i decided to see how it would run with the bystarter in the carb but kept the wires unplugged and it seemed to idle great. took it down the road and back and continued to idle for a while until it finally shut off after about 5 minutes. I think that it may have something to do with when the bystarter plugs up the fuel mixing tube after running it up the road.

Any ideas on this?

[wentwest]

When the engine is running and the bystarter is connected, at startup the mixture is rich. As it runs the power from the stator heats up the wax in the bystarter and the pin extends, shutting off that circuit completely. After that you idle off the pilot jet. So, if it won't idle right, your pilot jet is probably plugged up. Download the manual and clean that carb. If you unscrew the pilot jet screw there should be a spring, a tiny steel washer and a tiny o-ring. Mostly the o-ring stays in the carb and you have to pick it out with a dental pick. Get it clean inside. I use a piece of guitar string, the thinnest there is, to poke things out. The tiny jet hole in the carb throat needs poking out, too.