Sharing this information. Please note it only applies to Motor Trike "Adventure" conversion......
For some unexplained reason trike driveline components seem to take way more abuse then their two wheel versions do. I'm sure it's a combination of exsposed stress and maybe less then perfect engineering. Regardless of the cause I'm a bit uneasy to be heading out on long trips without a back up plan. I contacted Motor Tirke to get the replacement U-Joint numbers so I could carry spares. Seems the front yoke assembly is supplied to them complete and no part number was available. They did give me Precision 369 as the rear replacement joint.
Not believing a replacement U-Joint was unavailable I did some measuring with my calipers and then went online in search of a U-Joint to match the measurements. I found the Spicer 5-170X but to double check my measurements and research I also took the driveshaft in and had the Pros take a look. They came up with the same measurements and also verified the Spicer number.
The two U-Joints (front and rear) I bought are actually Neapco joints (1-0170 and 1-0153 respectively). Funny thing -- right down to the big "X" on the opposite side of the zert fitting and the number "15" stamped in each cap, the physical appearance of the new front joint is absolutly identical to the original one.
For those of you so inclined to do this sort of work youself, I hope this helps you out.