Maico 326

[Maicojames]

This cut and pasted from Firko's repsonse on the Maico board:

"Travis/James. This is a fairly common conversion here in Australia
and I believe South Africa. I've seen it done three ways. The first
is to use the complete 250 bottom end, modify the cylinder stud
spacing to fit a 400 cylinder. The second is to fit a 250 crank to a
complete 400 engine and machine the bottom flange of the cylinder to
allow for the shorter stroke/rod length. The third way is to fit a
400 liner to the 250 barrel but this method sometimes fails due to
there not being enough material in the casting. Some cylinders have
more 'meat'than others but I'm not sure which.

I actually race a factory 326 which is my factory '350' square
barrel. They were originally made for the old 350 ISDE class in the
late 60s and early 70s. If you have heard the old saying
that 'smaller is better' It's true. The engine revs like crazy and on
shorter courses will out accelerate 400 and 440 bikes. The only place
they fall short is very long straights. All over though, the 325 is a
brilliant bike to ride that feels so un Maico, maybe because it's the
only oversquare Maico engine. The factory actually bought the engine
back in the 90s with the blue bikes "

Firko, thanks a million. This gives me a start, another Maico board member indicates sending his engine to Eric at MO, and Eric said it needed a 78 cylinder to do the conversion-they must have more meat in the casting. ...just waiting for a few moto $ from polishing next month, and to ge tthe AW250 engine.

[firko]

Here's a cool 326 Maico that was uncovered in a deceased estate after laying dormant for years. The bike was originally owned by a Victorian racer named  Eldon Tucker back in the early 90s. Off memory it was built be a Port Pirie, South Australian racer whose name escapes me after Eldon had a ride on that blokes own 326. After a short while the bike was sold to ex A grader and then Aussie Sports Sedan Champion Bob Tindall. Unfortunately Bobs car racing committments and other activities saw the bike sit for 10 years.  Bob built other other bikes (mostly Maicos) to race as well after he retired from car racing but sadly, not long after retiring from car racing Bob got a nasty load of cancer and died before he had a chance to race the bike.
It's now owned by a Sydney racer whose name also escapes me (sorry mate) but is rarely seen at the races.
Note sand cast ignition cover with 326 cast into it.

[Maicojames]

Well, now I am to press on with it, though it will be a few months until I can start on it. I think the 400 cylinder will bolt on , but needs machining-I will try to find a suitable 250 cylinder-and put liner in. Thanks for that pic, i saw it on Maico board some time back-very cool.

[maicoman18]

I've seen it done three ways. The first
is to use the complete 250 bottom end, modify the cylinder stud
spacing to fit a 400 cylinder.

Getting a bit interested in this upgrade. Is there much involved in modifying the stud spacing?

Ed

[Maicojames]

No, they actually match, though you have to shorten the 400 cylinder. I am liking the idea of 400 liner in a 250 cylinder with enough meat to accept it. It looks to me like a 400 cylinder on the  bike pictued above...I am wondering if a 440 liner could be machined down to fit a 400 cylinder-or maybe a 250 cylinder. Gonna have to get a few cylinders and measurements.

[bigk]

250 cylinder has 7 fins and no decompressor, 400 cylinder has 8 fins and decompressor.
Cheers,
K