Henshao, I guess you live in a cave. Motor companies survive in an international environment. Nobody makes every component of their end product. If their chosen suppliers use the metric system, guess what......you go with the flow. Even HD is slowly migrating to metric. They have to. I'm an inch guy, but I have had to become metric familiar as well for the same reason. This includes the huge investment of metric tooling. The conversion bothered me 25 yrs. ago, but I am equally conversant in both systems now. I still believe that there are engineering reasons for both systems, so I use both as the application demands. What issue?
I can see both sides. If I bought a new American vehicle, I would want it to be metric. It's just a more usable system.
But if you are making a prominently "Made in USA" product, advertising everything in metric is kind of ruining your message. Kind of like going for a very expensive gourmet meal and watching them make your steak in a microwave. Even if it is the best damn steak you have ever had, the whole experience is kind of ruined.
And reporting things like weight and horsepower only in metric units, something even the metric companies generally don't do, is just weird.
But all just fluff. They will be good bikes or not, and I'm happy to see anyone in the US giving it a go with as much domestic content as they can manage.
(Up to a point. If they are sewing made in USA labels.. on non USA made shirts... using the logic "the label was made in the USA" so its OK, then, well screw you, you are trying to mislead me.)
I do agree it is odd they didn't include the inferior imperial measurement in parentheses for the senior citizens (hell they did it for the rear suspension specs!)
I can't wait for imperial measurements to finally kick the bucket, no longer will I have to deal with the agony of trying to figure out which socket to use. Oh the 4/7 didn't fit? Do you try the 1/9 or the 3/37? Nah you can't have it be easy in order like 9, 10, 11, 12, etc.
As far as mechanics are concerned I really don't have a problem with metric tools. The Japs use 10, 12, and 14 a lot. The Euro's use 10, 13, and 15 a lot. I've worked on a lot of metric bikes and cars. It's just when I have to machine something that's 8mm I prefer to call it 5/16"! But don't worry, I did get 8mm stock when I made the throttle body shafts! The 8mm is .0025" larger! Or in technical terms a BCH!
Again both systems are useful in their own way. For instance, when machining something to correct size, dealing in "thousands" is easier as opposed to the metric equivalent. When dealing with thread pitches, the inch systems have more available standard threads than the metric system and there are legitimate reasons for both fine and course threads. The other side of the coin is that in many cases the standard "M" pitch, being in between the standard NC and NF pitches is adequate for a given fastener diameter. When dealing in small dimensions smaller than .001", the metric system is easier. My preference is therefore application specific.
When it comes to threads I will admit that knowing the tap drill size is easier to figure out with metric. Subtract the pitch from the diameter of the tap and you have it. In SAE you either memorize the tap drill size or look at the chart. SAE uses threads per inch where metric uses threads per millimeter. So an 8mm-1.25 thread would require a 6.75mm hole. What's funny is you end up using SAE drills to attain many of the sizes for metric taps.
BTW, SAE got us to the moon first and won 2 world wars!