Atc 90

[73 90]

Hello, I have what I believe is a 1973 ATC 90. It has a serial number of us90 203518, if I’m reading it correctly,I’m wondering if this unit would’ve originally had the balloon tires and I know it’s supposed to have a metal fender it has a headlight that’s not currently on it I do not have the engine number at this time. Can anybody verify exactly what year this ATC is. I would like restore it some what I have had a lot of fun riding this thing as you can see. I was not the person who painted it it was red and all the decals are under the paint any info would help thanks, steve261361

[coolpool]

You are correct in your assumption for your frame serial number. 1972/73 (K1 Models) had frame numbers US90-200001 and upwards. Things changed in 1974 as far as serial numbers go to an ATC90 prefix. Look down by the shifter and you should find the engine serial number. If it's US90E-1100001 and upwards then it's also a 1972/73 engine. Yes your model should have had the balloon tires on it but the upgrade is allowing you to ride guilt free. Check in the little pocket at the front of the seat between the fibreglass and seat material and you just might find a toolkit! And does it still have the tire pump on the right side of the frame, score if it does but most don't have it? I'd consult with an automotive body shop to see if you can remove the black paint, it appears to be spray bombed at the most.

[ps2fixer]

Any photos of the hubs/axle setup? The balloon style tires had a super small bolt pattern and the splines used were very corse, while the newer hubs was a larger bolt pattern and used a finer spline style. Just wondering if you have the stock axle with different hubs, or someone swapped the whole axle out.

As for year identification, the frame number starting with US90 2* indicates 72-73 as stated before. Another way to reference the model is that it's an ATC90 K1 as both years are the same.

For the engine, you could validate the year at my site below, with out looking at the code I'm pretty sure it runes off the same logic/rules. The site supports all Honda 3 wheelers, so you could validate the frame and engine numbers match on all of your machines.


https://atvmanual.com/honda/interactive-vin-decoder-atv-and-atc

[73 90]

No pics at the moment but there really tiny with some adapter plate to the larger rims the rear splines are quite course compared to the other machines I have I will snap some more pics when I can

[73 90]

I didn’t find the tool kit and I know I didn’t have a pump I would have kept it if I found that when I get things cleaned up in my shop I’m going to start working on it more and I’ll snap some more pics

[ps2fixer]

I see, makes sense then. Sounds like it has the original axle/hubs and the adapter plate on out is all that's changed. You could convert back if you really wanted at any time. The stock splines are huge, like 1/4in wide while the later ones are tiny, say 1/16in wide. Something like 6 spline vs 24 (just random numbers I pulled out of nowhere for an example).

[Joseph Farrow]

Has a fairly rare Hondaline rear rack......has 110 foot pegs.....

[73 90]

Has a fairly rare Hondaline rear rack......has 110 foot pegs.....

I have the original fold up foot pegs there not installed because of the 125m exhaust, I’m not sure what happened to the original exhaust pipe but the other interfered with the original foot pegs

[coolpool]

Has a fairly rare Hondaline rear rack......has 110 foot pegs.....

Good catch, I didn't even see the rear rack poking out!

[sledcrazyinCT]

Nice score on 90 73!.

What does it take to remove the original rear tires from the rear axle? There is a plastic cap does that pull off? Does it require a tool to not break it?

[ps2fixer]

Yep have to pop the rubber cap off to access the 3 wheel nuts. Also could remove the axle nut and pull the whole hub off with the tire. The cap is rubber, so it should flex off, but with age it gets brittle so it might require damaging it to remove. Not sure if there's something to apply to the rubber to soften it or not.

https://www.partzilla.com/catalog/honda/atv/models-with-no-year/atc90k1-a/rear-wheel-axle



Honda continued to use that basic idea/design in their lawn tractors from the late 1980's (I have a few of these mowers lol). Same setup except they have an actual rear diff (transmission is part of it, shaft drive!), and there's no lug nuts for the rim, the rim is also the splined hub. I'd dare to say the lawnmower rims would probably fit a lot of the 3 wheeler axles.

https://www.boats.net/catalog/honda/lawn-tractor/ht3813k1-sa-vin-ht3813-5100001-to-ht3813-5199999/wheel-tire

[73 90]

Nice score on 90 73!.

What does it take to remove the original rear tires from the rear axle? There is a plastic cap does that pull off? Does it require a tool to not break it?
I had the whole hubs off like ten years ago it’s funny because that’s how I wound up with it,the kid that owned it thought the axle was bent so I bought it super cheap and when I got home all I found was loose wheels and loose hubs I think I shimmed the hubs so the nut held tighter or something and tightened the wheel nuts and I’ve been abusing it ever since I honestly don’t know how the fenders haven’t broke on it,if I had know what it was I probably wouldn’t have ridden it so hard