Two Stroke Motocross
Two Stroke Motocross Forum => Photos & Videos => Topic started by: opfermanmotors on November 13, 2010, 12:16:16 AM
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Maicos.
1983 Maico 490 Spider Rebuild Part 3 (http://www.youtube.com/watch?v=74QQ7rcnIEA#ws)
One thing about the metal used on Maicos, stuff is tough. My 82 I had a hell of a time with it, heating it up. Got to get it real hot to expand. Unlike metal on a Honda, expands real easy. I just recently pressed one of my cranks because the rod was going bad. I asked the guy how bad he thought it was and he looked at how pitted it was and said if it was a Japanese bike prolly 2 more rides, but with this European metal who knows, prolly last forever :)
BTW, ya I used a propane torch instead of the oven. This is a Maico, it's in the manual, I know the Honda manual says not to :)
(http://www.maicowerk.com//Images/Maico/Manuals/1982Manual/1982_manual_page50.jpg)
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Funny, one of my dad's manuals for the old motor (pre-75) specifically says to use an oven rather than a torch. I think it's safe to say they made a change in material when they reinvented the engine in '78.
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A friend has a small engine machine shop (he even does replating) and he said that Maicos have by far the strongest cranks of any single cylinder engine he has worked on. When he has to re & re a rod on a Maico crank all his employees hide.
Maico cases,like the old Spanish and British bikes, are pure sandcast aluminum. The Japanese cases are diecast and are "thinned" with impurities like zinc.This is why Japanese cases are always painted - to prevent corrosion.
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Yes, the older manuals I have say do not use a torch, now, there's a difference between using a welding or setaline torch and a propane torch. Using one of those seatline torches will surely melt your cases. I think a propane torch is a little bit weaker and is what is pictured in the Maico manual above. Perhaps a hand held propane torch just wasn't invented in the early 70s :)
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See? It's even safe on your face.
Ryan Stock Puts A Blowtorch Out On His Tongue (http://www.youtube.com/watch?v=9nZT0UntdO8#)
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TM's have sand cast cases as well.