EPIC 1985 aero 50/80 swap

[bc117]

Here we go! I have finally gotten ahold of an aero 80 engine (1983 3k miles) via PolarIce, so now i can finally make my super areo i'll be gathering most of my information from Workdog's ancient thread http://www.hondaspree.net/phpBB3/viewto ... 16&t=13021 which surprisingly looks really straight forward and easy
id kinda like to hear from bear and any other aero 80 owners out there on this, really looking to make it look as stock and sleeper as possible which at this point i know will require a custom exhaust to work
hey bear about how fast will a stock 80 go, and how fast will one with an upgraded main and exhaust go? ive heard claims of 40-45 stock while some claim anywhere from 45-60 with light modifications like carb,reeds,intake,tires, and exhaust how much of this is true? id be happy doing 45+ and really happy if i could do 50+

[Bear45-70]

Then why is it epic if it has been done?

[bc117]

sorry bear its epic to me i just put that in the title to make it sound better, but mine will actually look nice if ya catch my drift, no offense to workdog
but seriously how fast should i expect this to be with just a new main jet

[Bear45-70]

The stock Aero 80 tops out at about 43 to 45 mph. The stock carb restricts the * out of the top end being only 16 mm item.

[bc117]

could jetting fix this issue or do i need a new carb, how fast do you think the stock gearing will go once you solve the restrictions

[Bear45-70]

No, jetting will not increase the top speed. Jetting will cure the WOT stumble from being too lean from the factory only. The issue is the carb. The Spree has a 14 mm carb feeding 50cc while the Aero 80 has a 16 mm carb feeding 60% more cc. The motocross 80 cc engines have a 24 mm carb feeding them. You can install a CT manifold and and after market 24 mm carb but then you are into jetting issues which take some serious tuning to cure.

[bc117]

Bear I just read an article saying that the stock manifold opening is 19mm and if one could find a 19mm carb then it would increase the intake by 46%

[Bear45-70]

Bear I just read an article saying that the stock manifold opening is 19mm and if one could find a 19mm carb then it would increase the intake by 46%

19m does not refer to the opening at the back of the carb (the throttle bore) , but to the venturi size, which is the smallest restriction in the carb. The Aero 80 16mm carb has a 18.77mm throttle bore. A 19mm carb will have from a 22mm to a 25mm throttle bore depending on the brand.

[bc117]

would a aero 125 carb and manifold work

[Bear45-70]

would a aero 125 carb and manifold work

NO, the 125 manifold has a different bolt pattern (rectangular not square) and the 125 carb will not bolt to the Aero 80 manifold.

[eliteguy50]

Been out of the 80cc class for a year or two huh Bear. Any newer 80MX bike I've had is 26mm minimum on the carb.

I get a solid 45mph on the flats with no wind out of my '83 nh80 with 2700 miles on it. The guys claiming 60mph are running custom pipes that are not streetable for daily riding (stop and go). I agree with Bear, you really need a larger carb if you want more speed for daily riding. Reeds are more of a response issue than a top speed thing.

Bear-Have you tried the nh125 gears in an nh80 case?

[Bear45-70]

Been out of the 80cc class for a year or two huh Bear. Any newer 80MX bike I've had is 26mm minimum on the carb.

I get a solid 45mph on the flats with no wind out of my '83 nh80 with 2700 miles on it. The guys claiming 60mph are running custom pipes that are not streetable for daily riding (stop and go). I agree with Bear, you really need a larger carb if you want more speed for daily riding. Reeds are more of a response issue than a top speed thing.

Bear-Have you tried the nh125 gears in an nh80 case?

Try 2 or 3 decades, not years.

Boyesen makes 2 stage reeds for the Aero 80. I bought some and have a spare set in my goodie box which I will sell for cost plus shipping.

I am going to go the CT and 24 OKO route, mainly because I have the 24 on hand now. but I think I will eventually go with the a 21 because of the milder port in the Aero jug. I agree that the reeds are a throttle response thing, except the Boyesen reeds do not run the reed stops which will help the top end.

I have not tried the 125 gears in the Aero 80 but I have the spare pieces to do so.

[bc117]

just going thru threads and looking for performance ideas can't wait for the motor to get here so i can start working on it, some one said the ruckus variator may help, which i have, gave my aero an extra 5mph+ wouldn't that be nice if it gave the 80 an extra 5mph

[Bear45-70]

just going thru threads and looking for performance ideas can't wait for the motor to get here so i can start working on it, some one said the ruckus variator may help, which i have, gave my aero an extra 5mph+ wouldn't that be nice if it gave the 80 an extra 5mph

The Ruckus variator is not gonna help the Aero 80. It is smaller than the stock one.

Ruckus variator is 92mm.
Aero 80 variator is 98mm.

Th Ruckus variator helps the 50c scooters only.

However you can remove the rear cover off the stock Aero 80 variator and that should help the top speed. This is what I will be doing when I change weights in my variator and change the belt on the wife's Aero 80.

[bc117]

hmm taking the cover off might have a larger affect on the 80 then if the variator is that big, wow people should start modifying thier dio cases to fit those monsters

by the way i am making a custom exhaust to clear the aero50 plastics so i am needing to know the the diameter of the aero80's exhaust outlet pipe, since i am only receiving the header pipe, and do you know if there is more of the header in the bubble muffler thing or is it all baffles