86 Aero 50

jack1018 · Post by **jack1018** » Wed May 06, 2009 2:45 pm

Hi, I just bought an 86 Aero 50 and I am looking for some input to guide me on track. Here is the deal. It would only start if I remove the air cleaner housing and cover the carb. Once it started, it would not stay idle. I have tried to adjust the mixture screw and idle speed screw with no success. Also there is a vaccum hose on the side of the carb is currently plugged with a screw. thanks in advance.

teeoce · Post by **teeoce** » Wed May 06, 2009 2:59 pm

Clean the carb. The carb in this guide is different than yours but the concept is the same:

http://www.hondaspree.net/phpBB2/viewtopic.php?t=5389

Pictures of your hosing problems would be helpful. Take a look at the Service Manual:

http://www.hondaspree.net/phpBB2/viewforum.php?f=11

evilone · Post by **evilone** » Wed May 06, 2009 8:22 pm

Jack, are you in Portage Michigan? Just curious because i was out cruising tonight with the wife and i saw a guy on a sweet aero sitting there on the sidewalk. I couldn't tell if he was having problems or waiting for someone so we kept going. It's my 1st sighting of an aero in person, nice

. Maybe it was you, you cleaned the carb, and it acted up on you again??

turtle13 · Post by **turtle13** » Wed May 06, 2009 9:58 pm

i had the same trouble when i got my aero, except that once i got it running right i realized that it was with out the filter at all, so had to go back to square one.
take it back to factory settings and go from there, once i went back to factory settings, i was less than a half turn away from running perfect. well that was after i cleaned the carb and took a torch to the exhaust pipe for a good hour.

1. Screw in airscrew until it lightly seats then turn it
'84-'85 1 7/8th turns out
'86 1 1/2 turns out
'87 1 3/8ths turns out

2. Reset the idle speed with the throttle stop screw

3. Turn the airscrew in or out to find the highest idle speed

4. Reset the idle speed wih the throttle stop screw

5. Make sure that the engine does not miss or run erratically, if necisarry repeat steps 2 through 4

Kenny_McCormic · Post by **Kenny_McCormic** » Wed May 06, 2009 10:18 pm

Need pics of this hack job vacuum line, there is only 1 hose that is vacuum on an aero, it runs up to the gas tank, the rest are just vents/overflows for the carb, oiler related, and the fuel line.

jack1018 · Post by **jack1018** » Thu May 07, 2009 10:02 am

I am from Alberta, Canada. Thanks for all the input. I will take the carb apart this weekend. For the vaccum line, the previous owner has replaced the auto fuel valve with a pet * (ball valve). What is the function of the auto fuel valve and what is the impact of the current set up using a pet *? Thanks in advance.

Wheelman-111 · Post by **Wheelman-111** » Thu May 07, 2009 12:28 pm

Greetings:

The automatic vacuum-operated petcock prevents fuel from flowing to the carb when the engine's not producing vacuum - i.e. running. If you don't make a habit of closing the fuel valve, this can lead to a saturated filter, a puddle of fuel under the bike, unhappy neighbors and/or family, and in the worst case, a fire.

The Float Needle in the carb is supposed to prevent all that, but frequently it begins to leak. The manual-off or vac-operated shutoff is extra insurance. If you open your manual fuel valve and you get full-diameter fuel flow, don't worry about it. If you close it and it leaks more than a few initial drops, do worry about it.

Honda-san fitted most/all US-Market bikes with automatic shutoff valves, evidently believing lazy, dumb Americans wouldn't remember to do it themselves, or preferred not to touch icky mechanical things with their hands. JDM bikes mostly had manual valves for a while there. The vac ones fail occasionally too, especially if the bike sat for years with fuel in the tank.

jack1018 · Post by **jack1018** » Mon May 11, 2009 10:12 am

Hi, I have taken the carb apart and cleaned it as described. It still won't idle. It would only start with my hand covered the carb. Once it started, it would run for a few seconds. I have check the timing and it is dead on. I did noticed that there is fuel running down on the outside for the throttle valve. Also, the jet needle is not perfectly straight (off by about 5 degrees). Any ideas? How is the idle circuit work on this type of carbs, if there is an idle circuit? Thanks in advance.

Wheelman-111 · Post by **Wheelman-111** » Mon May 11, 2009 10:51 am

Greetings:

I have taken the carb apart and cleaned it as described. It still won't idle.

It's pretty hard to get that pilot jet pinhole open. Be sure you succeeded first. That's the idle circuit.

It would only start with my hand covered the carb. Once it started, it would run for a few seconds.

This would be the symptom of a blocked pilot. Also check the tiny bystarter insert for patency.

I have check the timing and it is dead on.

Is there a reason to believe the timing would spontaneously go "off"?

I did noticed that there is fuel running down on the outside for the throttle valve.

If the preceding steps were correctly performed, chasing down this symptom may give your answer.

Also, the jet needle is not perfectly straight (off by about 5 degrees). Any ideas?

Sounds like the throttle slide may need attention too. For sure you need a new, straight main jet needle. If you're idling and the needle isn't blocking the main jet as it is designed to do, you're going to have an awfully rich mixture.

How is the idle circuit work on this type of carbs, if there is an idle circuit?

See above.

Thanks in advance.

You're welcome. Hope this helps. Let us know?

jack1018 · Post by **jack1018** » Mon May 11, 2009 12:00 pm

Thanks again for the input. I have a few questions. Where is the pilot jet pinhole? Where is the bystarter insert (on the carb side or the bystarter side)? Thanks again.

Wheelman-111 · Post by **Wheelman-111** » Mon May 11, 2009 12:20 pm

Greetings:

Go Here:

http://www.hondaspree.net/phpBB2/viewtopic.php?t=8786

On the 3rd pic from the very bottom, you'll see the carb body and bowl.

The pilot jet corresponds to the brass standpipe alongside the main jet tower. In a dark room, put a flashlight under the carb casting. Block the mainjet tower with your finger and look down the throttle slide cylinder carefully for the little pinpoint of light next to the main jet. Someone had an excellent picture of this 3 months ago but I couldn't remember where it is. Maybe you'll get someone else to help.

The bowl has a pressed-in brass insert that corresponds to the bystarter's fuel supply. Both of these are so small, it takes next-to-nothing to block them and produce symptoms similar to yours.

jack1018 · Post by **jack1018** » Tue May 26, 2009 9:47 am

Thanks for all the input. I ended up buying a new carb and it runs go now. The previous owner did something to the brass tube for the pilot jet of the old carb and I think it is beyond repair.

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86 Aero 50

86 Aero 50

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