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Lack of deceleration?? Aero 50
Posted: Fri Jun 07, 2019 2:29 am
by Edoggd
Long time since on here (couldn’t remember any of old account info).
Have a 1985 Aero 50 which had been sitting since 2011. Finally decided to tackle the many issues with it and after new carb/byatarter, gaskets, electrical work, and new tires...it’s running!
Performance is about the same as I remeber, but there is an issue of lack of “engine braking”, or decelerating when I release the throttle. It takes a lot of time to decelerate after letting off the throttle. Going open throttle to close throttle just doesn’t have that desired affect that I’m use to on these things and need to really use the brakes. Kind of sketchy actually.
When I do apply brakes to come to a stop, it seems to take a few seconds for engine to get back to a normal idle.
Planning to replace the throttle cable line, but other than that any suggestions? I was thinking maybe the carb slide is sticky (maybe need to grease it up?). Air leak or mixture issue? Just want to get these panels put back on for the first time in 8 years. I’m so close.
Re: Lack of deceleration?? Aero 50
Posted: Fri Jun 07, 2019 2:40 am
by Edoggd
thinking about it more, bystarter could be an issue. Going to try unplugging that and seeing if it’s doing weird things.
Re: Lack of deceleration?? Aero 50
Posted: Fri Jun 07, 2019 9:24 am
by bonesv
Could be the non-oem carburetor and/or an air leak/lean fuel condition. The bystarter would not be causing that. What gaskets did you replace?
Re: Lack of deceleration?? Aero 50
Posted: Fri Jun 07, 2019 11:44 am
by Edoggd
I replaced the two intake manifold gaskets (reed valve + intake), along with the o-ring plate between carb and intake manifold. I was thinking about going back to the OEM carb, but I have used the non-oem carbs on other scooters in the past with no issues.
Re: Lack of deceleration?? Aero 50
Posted: Fri Jun 07, 2019 12:47 pm
by bonesv
Try cleaning the original carb using compressed air to clear passages and blow dry interior area. Be sure you get all parts back in order especially the air/fuel adjustment screw with spring/washer/small black o-ring also testing pilot jet circuit by spraying carb cleaner thru center pipe and observe that it exits out of the pin hole in throat of carb. It’s also important to unscrew the main jet and remove the emulsion tube for cleaning. You can carefully tap it out from above. The Keihin carbs are superior to the ones made for sale on eBay. Be sure there are no leaky gaskets by installing with a sealant also and proper torque. Use a new ngk spark plug and check the color after riding to be sure of correct jetting. I think they use an 85 or 88. It is stamped on the side of main jet.
Re: Lack of deceleration?? Aero 50
Posted: Fri Jun 07, 2019 2:02 pm
by Edoggd
Okay thanks! Sounds like I will go the full carb rebuild route.
Regarding the intake gaskets...
Standard OEM gaskets but they did have a skinny rubber o-ring type seal on one side of the gasket. I placed this side against the metal mating surfaces. Not sure if it matters.
http://www.2wheelpros.com/oem-parts/hon ... -part.html
Also, I did not use any gasket sealant when installing, but have another set of new gaskets on the way. Is this needed and/or what type is recommended? I have not had issues with not using sealant before, but I guess the mating surface on the crank cases was a bit scratched (looks like previous owner had used a razor as some minor gouges and scratches were present.
Re: Lack of deceleration?? Aero 50
Posted: Fri Jun 07, 2019 2:37 pm
by bonesv
I was not sure how well the surfaces were cleaned so I suggested using the sealant to be sure. There is a service manual available here....
http://hondaspree.net/wiki/index.php5?title=Main_Page
Re: Lack of deceleration?? Aero 50
Posted: Sat Jun 08, 2019 2:17 am
by motormike
I, too, have used cheapo Chinese carbs with some success, and some being crap.
The OEM is always better, and can almost always be rebuilt.
The hardest part is always clearing the pilot once it has become completely blocked and solidified.
A cheap set of jet files(so they're called) is essential tool in my kit.
Guitar.strings can work too. I recently used one to clear a pilot on a 49cc carb.
bonesv makes a good point about the mixture screw arrangement being important.
Also, the method of checking ALL passages with spray carb-kleen is a MUST-do before re-assembly.
Don't forget the teeny orifice at the bottom of the bystarter "bowl".
Re: Lack of deceleration?? Aero 50
Posted: Mon Nov 25, 2019 1:25 pm
by beech190
I have this same issue on my 85 nb50. Did you rebuild the carb and if so, any luck?