85 honda aero, bogs badly after cleaning carb

tominos · Post by **tominos** » Wed Jul 13, 2005 12:37 am

hi, here's the story..

bought an 85 aero about two weeks ago. i was going to ride it to the store but it died right when i was going in the intersection but realized my scooter had died. so i tried to crank it back up, and it didn't go. so i decided to walk it home, after a few minutes i tried to crank it back up and it cranked back up. so i rode it home and decided to check out why it died.

i turned some screws on the carburetor and it wouldn't start back up.

i figured it was a plugged main jet or something from debris in the gas tank, so i took apart the carburetor and cleaned it with carb cleaner, and put it back together and now it idles, but it's kinda rough.

so heres whats happening now, it starts right up, but i don't know what the settings are for the carburetor. its an 85 aero 50 cc engine. also, when i give it gas, it bogs really bad and when i ride it, and give it gas it will bog and want to die. what giveS? is it just the settings on the carburetor? i don't know what to set the air mixture screw or the idle screw at. someone help me out please. thanks!

tominos · Post by **tominos** » Wed Jul 13, 2005 1:11 am

the tube above the main jet that falls out when the main jet is out only goes in one way right? and the main jet doesn't look clogged, i blew compressed air through it and i can see through it. it's supposed to be a tiny hole right?

Post by **noiseguy** » Wed Jul 13, 2005 10:46 am

That's why you don't mess with the carb settings unless you know what you're doing (i.e. what they're supposed to be.)

Small tube that falls out? No idea, no "tube" should be falling out of anything in the carb.

The service manual for that scooter is posted in Tech Docs. Go there and take a look. It will have your settings for the carb.

tominos · Post by **tominos** » Wed Jul 13, 2005 3:40 pm

well, it's not necessarily a tube per se, but it goes in before the main jet does, and it has tiny holes on the sides of it for the fuel to mist out of.

Post by **noiseguy** » Wed Jul 13, 2005 5:31 pm

Got it. I forget what those are called (venturi tubes?). They only go in one way.

Stock setting on that carb is 1 1/4 turn out from full in. That's the top screw. The bottom sets idle speed. Bike has to run to set that.

I'm guessing this is somehow related to your idle jet, which is probably plugged. How close was the store, < 1 minute away? That would just be getting off the choke assembly.

tominos · Post by **tominos** » Wed Jul 13, 2005 9:53 pm

um, i was only about two blocks away from my house when it died. but it idles pretty well right now, it own't die but it's not real smooth, but i don't know how smooth it's supposed to be given that it's a two stroke.

thing is when i give it gas, it will bog for the first second then rev up.

but when i give it tons of gas in the beginning it will die.

if i ride it, no matter how much gas i give it, it'll bog out and when i let off the gas it'll idle or die.

so you're saying from top to bottom on the carburetor, the screws are the float drain, the idle speed, then the air screw is the highest out of the three?

tominos · Post by **tominos** » Wed Jul 13, 2005 11:25 pm

i looked in the service manual and it says the top is the throttle stop screw, and the middle is the air screw, and the bottom is the drain screw.

is that right? it's an 85 honda aero 50cc engine.

i tested the coil, secondary coil and they are a little bit higher than spec, and it sparks a bright orange if that means anything. it idles fine i think still, but i pulled the cdi and tested it and i can't get any readings off of it. does this mean it's bad? or is it just my equipment, using a digital multimeter.

the bike runs, would it run if the cdi was bad? would the bike idle but bog when on the throttle if the cdi was bad?

thanks for the replies.

tominos · Post by **tominos** » Wed Jul 13, 2005 11:30 pm

one more thing, if i just rev it to a certain rpm, it'll bog down then jump back up, bog down then jump back up, and if i ride it it'll do the same thing.

go bog go bog go bog go.....

vette76 · Post by **vette76** » Wed Jul 13, 2005 11:32 pm

more then likely if it runs it is carb related. not spark. if the cdi was bad it would not run. its the volt meter.

tominos · Post by **tominos** » Thu Jul 14, 2005 12:17 am

more info.

if i ride it around, and give it gas while riding it, say full throttle, it'll bog for about 3-4 seconds, then it'll ride as if nothing was wrong at full throttle.

what is the verdict on that?

burnt_toast · Post by **burnt_toast** » Thu Jul 14, 2005 10:27 am

it should be a bright blue spark! change out ur spark plug.

I've actually had exactly what your describing happen on the spree, just because of an old/bad sparkplug, so change it out and see what happens.

tominos · Post by **tominos** » Fri Jul 15, 2005 12:56 am

ok, got the new plug, has a blue spark now, and seems to run a little better.

i'm beginning to think the problem lies in the ignition, it seems to miss at idle and when riding, hence the intermittent bogging. it gets fuel, it gets good spark when cranking, and starts right up and idles.

this is frustrating the heck out of me... ahhhhh

sometimes it rides fine for about ten seconds, most of the time it just bogs out. it no longer goes 33-35 like it used to, if i full throttle it, it goes about 30 tops.

how can you tell if the air fuel mixture is correct? so you can know which way to turn the air screw? the manual just says correct it.

maybe the coil/ plug wires went.. can somebody let me borrow theirs so i can troubleshoot mine? lol

hondaman · Post by **hondaman** » Fri Jul 15, 2005 1:13 am

First set your air screw to the factory setting that it says in the manual.
Then when your bike is running adjust your idle screw until it idles good . Set your idle high but not high enough to turn your rear wheel. Then adjust your air screw either in or out until you can hear your idle raise to its highest rpm. Keep your air screw set there and then readjust your idle screw until you have it where you want it.

tominos · Post by **tominos** » Fri Jul 15, 2005 1:18 am

done and done.

i've followed the steps in the service manual, however i can't really tell if it's idling higher or lower if i turn the air screw a 1/4 turn in either direction of the 1 1/4 turn out from all the way in(factory setting).

it sounds like it's missing at idle also, but i'm not sure.

if i leave it on the center stand and rev it(twist the throttle slightly and hold it) the scooter will not rev at a constant rpm, sounds like it goes up and down and misses a little bit.

i rechecked the carb again, everything is clean in there.

would the aero bog go bog go if the coil was bad, it only does this after it's been ridden.

if i start it up when it's been sitting overnight, it'll ride fine for about twenty seconds, good power, speed. but after that it's downhill.

so many problems, i just wanna ride it!! thanks for the help guys

ferchja · Post by **ferchja** » Fri Jul 15, 2005 8:09 am

If has an auto-bystarter, that is your problem, electrical rarely causes an idle that goes up and down. Look at trouble shooting the by starter. What you describe is more related to vacuum leak causing it to go from rich to lean to rich...etc.

Either the bystarter is warn out and not sealing off completely, or the oring around the bystarter sealing outside air is failing causing the rich/lean running.

Check my post here on how to troubleshoot the bystarter. If the test makes a difference in idle and full throttle. You need a new bystarter, or used eBay.

http://www.hondaspree.net/modules.php?n ... =bystarter

These carbs have nearly no adjustment on full throttle (needle position is it). Everything else at full throttle is mechanical , ie. vacuum leakes, carb jet plugged, fuel delivery issues, lack of air filter, exhaust plugged, compression etc.

As mentioned on here dozens of times. (mostly by noiseguy) These carbs, and I am finding with other carbs, the statement "cleanliness is next to running-ness" holds true. Carbs are controlled by their porting, and sealing. In other words, the ports need to be free of debris and obstructions/restrictions, and air needs to be sealed from leaking into the carb, especially at fuel jet points (bystarter and throttle needle) Air passing by at fuel entry points need a certain vacuum to pull the right amount of fuel, anything that causes that air to not be set at the right vacuum or the inverse pressure, the carb will not work/work well.

The nice thing about these carbs is that they are so simple that you really have only a few adjustments. If you set the screws to the starting point (spec) then it will start and run near perfectly if the carb is sealed and the jetting is clear.

good luck