Attn: Maico experts

Konis with poppi bodies on the rear. To me, the swingarm does not look like the OEM GP 74.5 set up. A lot of 73-74 frames were modded to moved shocks before then, by owners and by Maico, and Maico was constantly making mid production changes. What looks like a little gusset under the airbox does not look stock. Tank definitely looks to be some thing other than a 74.5 tank.

It is a very cool bike, those 74.5 and earlier bikes are getting harder to find in any shape and that looks pretty good. I've got an late 72 400 radial project coming up and am loving those shouldered Akronts

I love those early "Ake" radials. My first real bike!

That tank is off a 75-1/2.

I've seen early 76 AW's with them too.

Like indy_maico said the tank looks like a '75-76. I had a '76 250 AW . I had a choice between aluminum or plastic tank. They were real close in looks but slightly different. I took the plastic because I believe it held a little more gas and I was running mostly hare scrambles back then. Nice bike, wish it was mine.

Looks like the ignition/chain side case is unbroken, so that good there. Pretty common for those early radials that had the shock's moved up to throw chains and break the case with the countershaft so far from the swingarm pivot, I can't recall if it was the off year 75 bike or the AW's when Maico began to get things a little more compact there.

Not until the brilliantly designed Magnum, one of Maico's best.

Actually Maico never used Monza fuel caps, tank is most likely (99%) an English "Homerlite" sold by Torsten Hallman back in the 70's

Regarding,

"The engine number is U405086, which points to the motor being a '73.

The frame number is something of a mystery. It looks like 389625, but I haven't been able to match this to anything yet. "

Here's where how Maico managed things back in the day gets interesting. The 387xxx frame series was, to my understanding, used for the 1972 250 and 400 square barrels and the 1972 400 radials. That run would be frames 387001-389999, used across these three models. In addition, the engine serial number format changed from square to radial bikes - square will be prefaced S or T, radial will be prefaced K or U, like you have for your radial.

So, one consequence is frame numbers are not going to match engine numbers. Apparently Maico grabbed a produced frame and grabbed a produced engine and stuck them together.

The list that I have seen show the 73 frame series starting 390xxx. My best guess given the high 389625 frame serial number you have is that you have a very early 73 engine (405086) with a late production 72 frame out of the factory. If you take the head off there likely will be a cylinder production date stamped on top of the barrel.



The bike that cylinder is from was titled in California as a 73, but has the 72 frame and engine numbers on title which do not match (3880XX on the frame - so frame 1,0XXth produced in the 72 run; U4039XX, the 9XXth radial engine produced in 1972). In other words, as originally sold and titled in 73, it had mismatching frame and engine numbers, but both from the 72 run. I expect the title reflects the first-sold date, and the fact that Maico model years were kind of a soft concept.