84 Aero 80 carb swap

Does your Spree/Elite already run great, and you're trying to make it quicker/faster? Need a monster motor swap? Discuss your ideas here.

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Rob406
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84 Aero 80 carb swap

Post by Rob406 »

Hey guys. I have a 1984 Aero NH 80 which I’ve owned for at least 6 years now. Nowadays I mainly only ride it when we take it with us on vacation, for about a week or so a year.

I want to go with a carb swap, mainly to have the use of a cable operated choke. I have been doing some homework but need some help.

If Im not mistaken, I think the Pollini 21mm is the carb of choice? I need some help building a kit, i will need the carb, intake boot, throttle and choke cable for starters. And maybe some baseline jetting if anyone can help with that.

I should mention that I am not looking to squeeze every last bit of power out of this. Just want something a little more simplified that starts easier, and a light performance boost would certainly be welcomed.

Lastly I am looking for an adequate shock to ride two people, so if anyone could point me in the right direction that would be awesome!
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motormike
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Re: 84 Aero 80 carb swap

Post by motormike »

Hey Mr. Rob406: Here's a notion. What if you retain your OEM carburetor,
and instead of replacing it, eliminate the octopus choke system ?
I've found that by eliminating the original cold-start system can be easily done
with some new fuel line and a simple inline fuel shut-off valve.
While i don't have personal experience with the Aero 80 specifically,
I have copied the method of converting the auto-choke to manual choke on the Honda Urban Express.
It seems the two models share that system of a bi-metal valve control.
I will include a crude drawing I made for the Urban Express.
Maybe you can get the idea of using the fuel shut-off valve as the choke OFF/ON valve.
Your access to the new valve will be limited due to your covers, so you will need to
route the new system for easy access.
You can also try the search feature for this page to research the posts that discuss the Aero 80 choke system
and the details of just how it was eliminated by the member Bear 45/70.
Hang around for more replies from member Breaze who has experience with your Aero 80, good luck sir...motor
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Rob406
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Re: 84 Aero 80 carb swap

Post by Rob406 »

motormike wrote: Mon Sep 11, 2023 1:45 pm Hey Mr. Rob406: Here's a notion. What if you retain your OEM carburetor,
Thanks for the reply! Well i actually pulled the trigger on a 21mm carb, intake and some other goodies. Knowing how hard it is to find parts I have kept all original pieces labelled and packaged neatly.

Does anyone know the stock carb size? It is a Keihin PB, that’s all I know. I measured approx 16mm but not sure if that is accurate.
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Re: 84 Aero 80 carb swap

Post by Rob406 »

I will answer my own above question. The carb is infact 16 mm, model number PB54D. I found this in the service manual on this site. So thanks for that!

New question. I am considering deleting the oil system and premixing my gas. Typically I trust factory oiling systems, and also I'm guessing that with this system the ratio is probably variable thru the rpm range. However as old as the system is I think it's inviting a failure.

Has anyone bypassed the oil system and is premixing their gas?
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Re: 84 Aero 80 carb swap

Post by Rex 80 »

Rob406 Did you ever end up deleting the oiling system I am interested as most carbs run pre mixed
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Re: 84 Aero 80 carb swap

Post by Rob406 »

Yes I did, i removed the pump entirely and used an expandable plug in the case hole, 3/4” if i remember correctly, the automotive type used as freeze plugs sometimes. I do believe the stock system to be reliable, i just wanted a cleaner set up. Stock oil system leaked everywhere and the choke didnt work. Starts much easier now. It does run richer as the stock system adjusts the ratio as needed. I kept all parts in case i ever want to change back.
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