Parts for a 1985 Aero 50

[herman pahls]

Hello forum
For the last 25 years I have powered a mini sand car with a 1985 NB50M which the Honda dealer said is an Aero 50.
I found out from this forum that it was a mistake to remove and discard the original air box for best running results.
I also noticed that a possible fix to get the correct restriction with a Uni type air filter that the air box was intended to create, was drilling two 3/8's holes in a 2 Liter bottle cap and inserting into the intake tract.
I did not see where the the cap should be placed but assume before the carb since after the carb is a cast aluminum intake manifold.
Is this considered a viable fix or a bandage to get the engine jetted properly?
Are there posts the show this mod?
Would it be best to get the stock air box?
I am not looking for more power, but to improve how the engine runs, since it currently loads up if it idles too long and runs best at 3/4 throttle.
Honda says the stock main jet calls for a #80 mainjet and I have drilled it out to approx. 1.15 mm (millimeter) trying to get it to run better.
I assume an 80 mainjet refers to .80 mm ?
It appears that i have the non restricted exhaust header since it is larger in diameter several inches before the muffler.
Should I pull the exhaust off to see if the there is a restricting washer that could be drilled out near the cylinder?

Honda said they no longer have jets or variator belts for this engine.
Are parts still available for this engine in the after market?
I hope so since I hate to covert the engine to a lawnmower style engine and give up all the nice features of the scooter engine.

I appreciate what I have learned from this forum and hope you can advise me regarding optimizing how this engine should run.
Thanks
Herman Pahls
Coquille, Oregon

[Dr_Craw]

i usually just use electrical tape to restrict the intake (usually on the aftermarket filter) if i don't have the proper jets to get the jetting right
there are a couple folks on this forum that still have parts for that engine (even new ones like the malossi big bore kit)
the jets are fairly standard so you can always buy new ones at your local motorcycle/dirt bike shop or online