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ETZ 502!!

PostPosted: Fri Mar 13, 2020 4:52 am
by breakwellmz

Re: ETZ 502!!

PostPosted: Fri Mar 13, 2020 5:44 am
by Puffs
Yes, there are a few double-250's on Youtube too. Apparently it can be done:
https://www.youtube.com/watch?v=mUyMVp8lMWg
https://www.youtube.com/watch?v=R_PSGxOf6VY
https://www.youtube.com/watch?v=RZVo9AC0Uaw
https://www.youtube.com/watch?v=Coi_ybM2mIQ
https://www.youtube.com/watch?v=6C9gDT_n2SM (showing that's a 180° crankshaft - like the Jawa)

Making the pistons go up & down alternately (180°) can greatly reduce the vibrations, particularly if they are laterally close to each other. Similar to a flat twin (boxer, also 180°). But if the pistons are wide apart, you get another vicious vibration known as a 'rocking couple'.

Re: ETZ 502!!

PostPosted: Thu Mar 19, 2020 8:02 am
by breakwellmz
Hi

Quite common then!
I particularly like the mono-shock one.

Cheers.