1985 Honda Gyro Mixture and Idle screw adjustment

[dsandwich]

Hi folks, just wondering what the ideal screw adjustment is for the 1985 Honda Gyro for both fuel mixture and idle. I see two screws and if my memory serves me correctly, I screwed them in all the way, then backed each of them out 1.5 turns. Just wondering what others are doing.

I had this thing running beautifully a few days ago, then it sat for 3 days and won't run again without starting fluid. I'm wondering if I need to clean the carbs again, take apart petcock, etc. Bummer.

[motormike]

Initial setting for the Air screw is 2 & 1/4 turns out.
Idle screw has no initial setting, but should be set so that engine idles at 1,800 rpm.
Float level is 12.2 mm (0.48 in.)

I suggest you remove the bystarter and check it.
Once removed (and cold), connect the leads to 12 volt source.
Monitor the length of the brass needle.
As the bystarter warms, the needle should extend approximately 1/4 inch.
As the bystarter cools after disconnect, the needle should retract same amount.
Another item of great importance is the orifice that feeds the bystarter reservoir.
This must be fully open to allow the bystarter a proper fuel supply.
This orifice is inside the float bowl at the bottom of the bystarter reservoir...VERY tiny hole.

[dsandwich]

Thanks, Motormike. Bystarter is functioning as you said it should. I played with the air screw and throttle screw and the bike eventually started but it will idle for 30 seconds, then stall if I'm not applying throttle. I am unable to really adjust the idle with the throttle screw. It's just not doing anything to affect the idle. Regarding the air screw, I can get it to idle and NOT stall if I screw in the screw all the way.

My gut says I'm going to have to tear down the carb again but I'm really just throwing meatballs against the wall to see what sticks.

[motormike]

An unresponsive air mixture screw that runs best when fully
closed indicates that the pilot jet is probably clogged with residue from evaporated fuel.
Make sure the bystarter reservoir is filling with gas.
Remove the carb bowl, empty it, and refill the float chamber with fuel.
Watch and see if the bystarter reservoir slowly fills.
The bystarter can function properly, but the reservoir not filling (or filling VERY slowly) will cause your problem.
It takes some real persistence with the carb cleaning to open this jet (orifice) into the reservoir.
The pilot jet is not removable, so keep trying to verify some flow through that pilot by spraying cleaner through it.
I use a jet-file kit available from K&L company,,got mine on Amazon.
Guitar string can work in a pinch.
Use caution...go slowly...probe and poke with care.
If you are using a chemical dip type carb cleaner and following with compressed air,
eventually it can be cleared.
Also pay particular attention to the air passage leading from the throat opening through the pilot jet.
This passage is what the air mixture screw regulates.

[dsandwich]

Thanks for the guidance, Motormike. Busy work week. I will take apart the carb this weekend... hopefully.

[dsandwich]

OK, bystarter tested fine. I cleaned the jet under the bystarter. There was definitely some residue in there as the jet hole is much bigger now (relatively speaking). Machine fired up, though the throttle screw did not adjust things as well as hoped regarding turning up or down the idle. There was some change in RPMs but it wasn't very pronounced. The Gyro ran well for the 10 minutes I rode it.

When I came out later to start the scoot, it was hard to crank and would not start. Fuel started * out from pretty much everywhere-- exhaust (I had loosened the nuts on the muffler) and carb overflow. I assume that means a stuck float on the bottom of the carb. Man, I don't want to pull the bowl off again, but I guess that's the next step. I suppose I'll tap, tap, tap on the carb but I wish I hadn't put the bodywork back on it already. Bummer.

[Gyroman]

Ooops. Ignore.

[dsandwich]

Thanks for the response. There is a significant amount of silicone where the carb enters the airbox, and the gasket around the bystarter is pretty beat up. Probably not the most efficient system.

I was able to get it started again by cleaning out the gas tank. As mentioned earlier, I was able to get it to run on ether/starting fluid, but then it would die. I pulled off the fuel line and, if all is well, gas should have poured out of it due to gravity. Nothing was coming out. I detached the fuel line from the petcock, shot some air through it. It was not clogged. I removed the tank (a second time). I had done this before when I purchased the Gyro just in case there was some gunk in there. Long story short, it appears that something was blocking the fuel pickup inside the tank. That's the best I can come up with. The scoot fired up after that. Now I just need to get that idle figured out. I suspect the idle screw is not as reactive as I'd like because of the gasket/silicone issues mentioned above. If I'm introducing unwanted air in to the system, I'm not doing myself any favors.

When I have time, I will research kits for dipping the tank. I've never dipped one but I know it's not rocket surgery. I considered doing it for an old motorcycle I once owned but I ended up buying a case of beer instead (I was in college). If I find a kit and buy it, I'll post it on the forum.

Scoot on!

[motormike]

Lots of products out there.
One item that is a good place to start is the rust remover called "Evapo-rust"
Available at the O'Reileys auto parts stores here.
It is safe to the enviroment and re-usable.
Once you clean out the rust, immediate filling the tank with some pre-mix fuel will stop the flash-rusting.
Then, if you really need to "SEAL" the inside of the tank. I really like the products made by "Caswells"
I just cleaned a tank that has sat for 30 years... with Evaporust.
NO sealing was done...the outcome has been trouble-free...

[dsandwich]

I will look in to the tank treatment. Many thanks for the input, folks.

[dsandwich]

Ok, so I keep playing with this Gyro. Went outside, started the engine, it ran fine for 30 seconds, and now it won't run EXCEPT with starting fluid/ether. It simply won't start after those 30 seconds of running. It will only burn ether. I pulled off the fuel line end which goes in to the carb and gas is pouring out of the line, so I know that gas is at least getting to the carb. I removed the air filter just in case it was super-dirty, which it is not. Still get the same results.

Not sure if I should tear down the carb a 3rd time or not. Maybe I should replace the bystarter? No idea. If anybody has some ideas, I would appreciate it.

Have a good night, and thanks.

[Gyroman]

I hesitate to say anything, because I've said so many stupid things already in the past. Just when I think I have solved the problem, the next time I try and start it up it's the same old thing.

It appears that I am in the same position as you. There is gasoline coming out of my fuel line when I disconnect it from the carburetor, so at least it's getting to the carburetor.

I had done everything I could short of cleaning the carburetor, due to my lack of skill and experience, but finally took the plunge and have now taken it off and cleaned it twice. (Although it didn't solve the problem, I gave myself a pat on the back for learning something new.)

I have done everything else you have, including testing the bystarter.

I'm sure you have googled the heck out of this problem in addition to seeking advice here.

I tried something just now that I saw somewhere (http://www.provoscooter.com/forum/showthread.php?t=4464), which will probably prove to be a temporary fix, but may provide some further information for diagnostic purposes, from those more knowledgeable.

I covered the air intake at the back of the airbox, and it started right up and continued to run without dying.
Try it and let me know what happens with yours.

I will be going back out in a few minutes and try starting it without doing this, but I suspect that it will be back to the no start, or start and then die scenario.

Well, I went back out after about 20 minutes, and it started right up and continued running without covering the air intake.

Once again I have no confidence that this is anything but a temporary fix, but I'm going to let it sit for a couple hours, and try to start it again without covering the air intake. If it doesn't start, I'm going to try covering it again and will report the results.

Follow-up (two hours later):

Went out to start it without covering the air intake. Wouldn't start.

Covered the air intake, started right up, continued running without stalling.

Going to wait for comments as to what this might indicate.

[dsandwich]

I'll try covering the air intake tomorrow. Gyroman, what are your screw settings? Are you using the 2-1/4 for the air screw? What's your idle screw set to?

[Gyroman]

I've had them at the service manual recommended two out for the air screw, and various settings for the idle screw.
I have tried dozens of different variations, and the only thing that worked was covering the air intake.
I don't believe that our problem is related to these settings. More detail in the PM I sent you.

[motormike]

The covering of the air intake on the filter housing indicates that the filter is allowing air to pass through very freely.
So freely, in fact, that the fuel does not react to the vacuum, or lack of vacuum, created by this free-flowing filter.
ME TOO ! !...My Gyro S currently has a filter foam that I fashioned from a piece of filter material sold by UNI brand.
I also am required to cover the air intake on the filter housing in order to start my Gyro.
My opinion is that WE ALL have some small bit of varnishing inside the carb that reduces the pilot jet size and not until we create more vacuum with our hand will the pilot be forced to pull fuel from the bowl.
Not sure how this answers the question "why does it die after 30 seconds"...but mine always fires right up after stalling the first time and never stalls again.