What is interesting is the sucess of the 81 490 in VMX. I see more now than I did in 81, though I admit I saw a few still raced currently as late as 90. The clutch "woes" are largley due to lack of understanding of proper setup..or even worse misunderstanding. The small Maico clutch is very reliable, rugged and simple. One of the keys is to use factory sintered bronze fibers instead of Barnett.
Further, it is critical to follow procedures properly to not warp the plates-this is all too frequent. You must use a good quality cable, and Magura lever( though I have seen some late aftermarket lever used) to gain proper cable travel. My clutch never dragged, never slipped-and I slipped it often in slow speed turns in 2nd gear( due to the high 14/56 gearing I preferred). I also took the time to deburr, and even lightly polish clutch actuator, as well as basket( I do this on any vintage bike, though).
In fact, my old 77 had the original stock fibers and steels. Many of these bikes were ridden long after their asian contemporaries were put out to pasture-thereby wearing out more parts, corrsion etc..on top of far fewer bikes to begin with( unlikley to find an original 490 with few to no hrs on it). The trans was very tough, I frequently powershited on up shifts( full throttle-fan clutch), and at times up shifted w/o clutch full throttle. This was not really needed when the bike's power and tractability put my fat ass out in front anyway. The primary chain is the weak linkm though I did get a CZ chain from NW Maico-and it never stretched after 6 races. You will have to monitor this every season for a novice to intermediate, an likley twice a season for you fast riders. Personally, I ran Bel-Ray for two-three races once primary chain has seated in, along with a magnetic drain plug. Still, I know many who run automotive 20w-50 and forget to change with no consequence.
Where I found the "touchy" areas was air leaks, probably most VMX bikes develop some in a season of racing. The radial Maico seemed to me affected more by these than the asian bikes I've owned. Another area is the kicker, anyone who does not use the comp release is asking to break parts . Use it, do not "slap" at the kicker-get it up on TDC and spin it through fast after engine is primed. When hot, use comp release and starts fast. The Maicos are otherwise a tank, really take a beating to the trans, chassis, clutch and engine. if you are passionate about your bikes, you will learn the ticks to maintain a Maico-and be rewarded with excellent power and handling-as well as long service life of major components. Until the 490s prices went out of sight a few years back, they were comparitively priced to a YZ465. I have found that once you set up your euro bike, you actually get more hrs out of it than a comparable asian bike. That is, though only my experience.
The 490 was made to conquer the YZ465, and if the 465 were a pos, the 490 would not have been built. Here in the US, Yamaha parts are much more difficult to locate than Maico parts. Though I have purchased few YZ parts, I wished at the time, I was buying Maico parts-many of which costs comparable, but are much easier to obtain. Yamahas of the era were always durable machines-and great performers too. Perhaps the biggest Maico adavantage was hooking up that power in all kinds of terrain. BTW, the 495 KTM and CR480 are both faster with perfect traction.
As far the the championships, in 1971 most bikes were less than reliable at that level. By 1981, there was no way any euro company could possibly bankroll a fifth of what Honda, Kawasaki, Suzuki, or Yamaha could for development, or riders. Still records are records, and excuses are moot. I wonder how it might have been had Maico been as open minded, and sold enough foo-foo bikes for profit to budget a better field. In the end, the Japanese were determined to their goals and won-relegating the euros out of business, I think due to mainly US riders who wanted more and more advances each year with less maintenence-in my opinion an unwillingness to learn and practice simple maintenence on a bike. To me, the real pinnacle of the era was the single shock 83 CR480 Honda, along with the 81 and 83 490 Maicos. Given the prices of a 490 these days, one may easily consider dealing with locating parts for a YZ465-even if you prefer the 490.
Yawn...... ::)Vee Dub Beetles were also pretty popular once. I doubt I'd try and race one though.......