what is the motorcycle engine size for I-75 in michigan?

http://www.legislature.mi.gov/(S(przuvo550pkhhn45g...

In 1977, the definition of "motor-driven cycle" was deleted (Section 257.32) as was any speed laws with "motor-driven cycle" (Section 257.630.)

In Michigan, there is *NO* motorcycle engine size requirements.

However Michigan, you have a minimum speed on freeways of 55 mph. http://www.legislature.mi.gov/(S(wvhfgm55up1rug45p...

Federal interstate highway minimum is 150cc for a 'motorcycle' class license plate allowed on interstate- under 150cc means it is classed as 'motor driven cycle ' and the warning signs at entrance say not allowed as well as pedestrians, agricultural equipment.. and a secondary 15 hp from older highway pre1980 or so rules . States may have a higher kicker size for 'motorcycle license plates' Ohio seemed to have at one time a 15hp first requirement before the engine size and Texas posters note a 250 size for interstate use- but Texas also has a stretch of 85mph highway. Minor issue is the 150cc size law was proposed/made when speed limit was 55mph but minimal pollution and noise requirements- ad a 150cc 2stroke Yamaha would have 16hp so met the older suggested 15hp or over to go on state and national highways before interstate system. The older 350 Honda's were decent enough for solo highway use, I rode a BMW R50/2 a lot on highways when 55 mph was upper limit and had no concerns- but now with the 75mph speed common I would prefer a 40hp engine instead of a 25hp engine as minimum. Decent road work with a 500, minimum engine preferred for short runs a 250 like brother old Honda Rebel. Check Michigan DOT for actual law required size

There IS NO law that regulates the size engine you need to ride the Interstate highways in Michigan or anyplace else in the USA. There ARE some minimum speed laws that are enforced... If your bike cannot hold a steady speed of at least 45 MPH, then it should not be used on the Interstate highway.

Unlicensed vehicles like Mopeds and scooters are also prohibited.

Are you asking what the minimum size engine you can take on the interstate? It will be posted at entrances and on ramps. If your bike can comfortably do the the interstate speed limit plus a little more for a sustained period of time then I would say you are good. The main thing is you don't want to get out there and hinder traffic, then you put yourself and everyone else on the interstate in danger. In my state on ramps have minimum horsepower rating posted along with things not allowed.