aero 50 will not start unless I hold the throttle wide open?

[radbrad]

I am a brand new scooter owner and a self proclaimed shade tree mechanic.

I have had motorcycles for years, but picked up a 1983 Honda aero 50 from craigslist.

It has been the most fun little bike I have owned in years and years.

For the first few weeks I could kick it one time and it would start. It was fast and responsive and fun.

The battery was dead, so I purchased a new one. I also filled the tank (.5 gallons ) with shell gasoline and purchased the two stroke motor oil they had at the station at the time.

That is when the trouble started.

The next day I ran the battery flat trying to get it started. Would not kick over either. Just refused to start.

I figured it was the carburetor (lots of carb problems on the forum here) so I pulled the carb off. Cleaned it and re-assembled it. Same thing no start.

I finally tried holding the throttle wide open while turning it over and it finally started after almost a minute of cranking. Let it warm up shut it off. Wont start again, unless I hold the throttle wide open.

Just for the heck of it I pulled the air cleaner off (faster than pulling the carb off again) and sprayed some starting fluid (just a whisp) in the carb. Fired right up.

So, does this sound like a choke issue? Or a vacuum issue?

There is spark.
The float bowl is full. ( I loosened the screw and checked.
Bike continues to run once started.
Idles just fine also.
I have cleaned the carb out once.

I am stumped. Can someone smarter than I am chime in here before I pull all my hair out.

Thank you,
Brad.

[sickelf]

Clean the carb again. Clean it 5 more times. I have a 87 aero 50. Not sure if its the same deal, but the pilot jet in the carb is a pin * hole(i think its called the pilot jet - its in the brass tube in middle. That thing gets clogged easily. You need to soak the whole thing, poke it with a small piece of wire, spray compressed air into it, whatever it takes over and over until you can see a dot of light if you hold it up. Hopefully someone with same bike can chime in.

[radbrad]

Thanks for the reply, but I just did that, when I took the carb apart.

I did not take the float bowl out and clean the valve there because the float bowl was staying full.

Like I say, once it starts it runs perfectly (fast, smooth idle), in general great.

Just getting it started is a PITA.

Brad

[swflcarl]

Trying to think about this... am thinking it is your by-starter.

http://www.youtube.com/watch?v=O2qRVOkfdaY

Test it by applying 12 volts. Make sure it is working and the seal and everything is kosher when mounted up.

If you idle fine then you should be clean on the pilot circuit.... but what the h3ll check this too. This is typically the unclean item that most folks don't get clean during their 5 attempts. Here is an old video that shows how you can verify.

http://www.youtube.com/watch?v=KbNzbwbuqL8

Take a look at your main needle and note the position of clip on the position rings... make sure it is where it should be per the service manual. Hopefully you already downloaded this tool.

We need to start crossing things off the list. Is your air filter clean and lubed with your air boxed cover and intake boot sealed up good?

Please report back.

[radbrad]

First of all thank you swflcarl. I appreciate the response.

Do the by-starter just drop out?

When the scooter had the old dead battery in installed, it would just kick right over first kick. I just figured, maybe wrongly that the scooter started right up with a dead battery, the by-starter would not be involved. Maybe now that is has power the by-starter is not choking or choking the engine at start?

I hope we can puzzle this one out, I am sure several people have the same issues.

Thanks,
Brad

[radbrad]

One more piece to this puzzle. I completely disconnected the bystarter and the scooter started right up. I am wondering if it is shorting and staying on, causing the no start condition.

I noticed that the battery I charged earlier in the day is flat. After I got it running I took a spin on it. Let it sit a few minutes and hit the starter again. I ground about 30 seconds, but finally started. I though I was going to have to call the wife with the truck to come and get me.

When I got home. I shut it down, then hit the starter again. Nothing, not even a click.

Dont know if this is a symptom or the problem. I am going to treat it as a second problem for now. Since it starts with the bystarter unplugged, I am going to leave it unplugged and enjoy riding for the next couple of days (after I charge the battery again).

Cheers,
Brad

[patthesoundguy]

http://www.hondaspree.net/phpBB3/viewtopic.php?t=26255
$3.50 bystarter tester

Check that thread out. By starters can still move but may not move enough. When you disconnect the by starter you are really just leaving the choke on all the time. So when you try to start out warm its too rich, hence the wot to start out. The pilot circuit in the bowl in the also the key to having the by starter circuit get its fuel. The vacuum test for the by starter will tell you for sure if the by starter is doing what its supposed to do. The manual will instruct you in the test. You need a vacuum tester ( I just got one half price for 25$) or the Baby aspirator trick I just came up with. I would strongly suggest getting a multimeter and test the by starter leads for voltage, with the engine running, no power the thing won't extend and the thing stays in enrich mode.
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[swflcarl]

Hello my friend... I am a noob myself, but somehow found five honda 50s in my garage? New home for many lost oil burners in the last 6 months.

Okay... the bystater needle and bronze body starts to push out as the bike runs. It has nothing to do with the battery - it works on that stator running circuit. When full retracted (cold position), it allows additional fuel /air into the carb into the intake for starting - hence the enrichment circuit. After a minute or so... it blocks the enriching passages of the carb (the bystarter circuit) after the bike is warmed up.

When you have your carb dailed in... all you do is tap the starter and viola. I like to ensure the main jet needle is in the correct position, all carb passages clear, by-stater is working, petcock is full tested, and air box houses a clean oiled filter and that is fulled sealed (at the box and on the intake side of the carb). Once you have all this done, you are going to start with ease.

Be careful not to over do the starter.... if she doesn't fire in 5 seconds (stop) and lets get back in the carb. My limited experience has proven that a clean carb properly functioning will bring back the most lost honda 50 oil burner (as long as there is proper compression in the motor).

There are so many knowledgable folks here waiting to help folks... if you stick with it your Aero will be running like did back in the mid-80s.

[patthesoundguy]

Oh and check to make sure the battery has enough water in it. My spree battery got weak once it was just half full. Topped it up with distilled water charged it and been decent ever since. Also go through the battery connections, and polish the connections with rough sandpaper and make sure the connections aren't loose. Then check the connection at the fuse make sure its clean and in good order.

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[radbrad]

Thank you guys. You are brilliant. I am now confident, that the bystarter had been disconnected from the previous owner. IT was tuned to run with out it. I am actually going to fix it though.

I have decided to do the test as outlined in the manual and suggested by you swfcarl. And I want to also thank you for your sage advice as well patthesoundguy.

I am going to order a gasket kit for the carb and if it comes, going to tackle it this weekend. I will let you know what happens as I progress.

I love working on these little scooters. Kind of therapeutic. Ha!

Cheers,
Brad

[swflcarl]

It will run fine without it... as it is just there to help the starting process - but it will not start easy.

Once warmed up... your bike should start right back up without the bystarter working.

My 85 Aero had a broken petcock and the main needle was jacked all the way to the rich side.... and my pilot circuit was clogged. Just take your time and go through the whole carb... it is really not that much time once you have all the passages clear.

If you need a new bystarter... here it is:

http://www.amazon.com/Scooter-Carbureto ... oter+choke

[patthesoundguy]

Order from abreen89 for the petcock he's gonna have waaaay faster shipping if the petcock is toast. And having a spare is never a bad idea for how cheap they are now.

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[patthesoundguy]

The engine won't really run fine without a by starter unless its stuck all the way out. It will run very rich all the time. The by starter in is enrichment mode when it is cold with no voltage running to it, when you start the motor voltage comes from the alternator and powers the heater inside forcing the needle into the passage blocking airflow that normally makes a small vacuum drawing in fuel from the bowl and spraying it into the carb. There have been tales of people blocking the passages off to remove the by starter completely, but why risk it when a by starter is so cheap.
Here is the link to the wikispreedia for the by starter its awesomely done it explains with cutaways and shows what passages get clogged
http://hondaspree.net/wiki/index.php5?t ... at_It_Does
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[radbrad]

You guys are so good.

One thing I have decided on. It seem to run pretty good with the bystarter unplugged. For about $29 I can buy a carb with a brand new bystarter on it.

For that kind of money, I may pull off my working, tuned carb and bolt the new one from ebay on and experiment with it.

I am guessing since I have a 1983, they should all be interchangeable. A carb is a carb on these honda 50's arn't they?
I am guessing the 84-86 should work shouldn't they?

I did notice that my carb has a plastic spacer between the carb and the manifold. I figured it was to make the bolts line up for the airbox in the back.

I just figured for $29.00 I would have a new carb with a new bystarter on it and go from there. Any opinions?

Again, I cant tell you how thankful I am for your help. I am just getting in to this as a hobby. This to me is fun, after a stressful day. Oh, and I get to tear around on my hobby in the neighborhood too...

[swflcarl]

I recommend going cleaning the quality Keihen carb... Chinese unit is not quality.

That is my honest opinion... you can go with the china bystarter.