no formal tests Yoshinkan

I don't think I would want to do away with formal tests. It's a good way to form group cohesion, whether you're testing at the same time as your uke or whether you're helping out a junior or being helped by a senior. It also focuses the mind with a degree of intensity and urgency that regular training doesn't always do. Gives you a reason to celebrate when it's done, and gives an overall sense of rhythm to the dojo year.

Not sure if you are asking how you keep motivated or how you keep the club as a whole motivated.In either case this is a very common problem which to be honest there is no good solution.  It would be nice if formal tests where done with, and we awarded rank based on performance in class.  That way you don't have that rising then falling felling you get for working hard before a test. Awarding rank based on merit would be great but it would lead to its own headaches.I have a few of recommendation that might help though since no one else seems to be offering:

1. create a demo team and continue to practice hard

2. invite a senior instructor to your school and ask them to demo specific techniques and the continue to work on them after he or she leaves.

3. NEVER TAKE THE SUMMER OFF

Not that they had the best solution, but in Aikikai, it was mandatory for anyone wanting to test for Dan ranking to attend summer camp AND people testing had to have their "passports" checked that they attended x number of seminars prior to testing. X would vary depending on the rank for which you were testing. It was their way of (a) ensuring people attended seminars put on by senior instructors and (b) ensuring that they had a good turnout for summer camp. The dojo I attended also had attendance cards. So even if your techniques were spot on and even if you were technically a student for the prescribed number of months or years for a rank, you had to have attended a specific number of classes. Funny thing how attendance picked up when people who wanted to get promoted realized they were short on hours! And of course the hours requirements increased with rank.