what are compression releases for??? My local mechanic installs them. Check out the "services" section
http://www.queenscountycycles.com/#

Usually to make starting easier for the starter or for the kick start.

I used to have one on my BSA441 Victor...and thank goodness for it! I think I still have some scars from NOT using it! That was pre-electric start, btw!

Thanks, I kind of figured it had something to do with making it easier to start, maybe for a high compression engine. Are they a manually actuated valve, or automatic in some way?

There are both kinds. Not seen them on street bikes though. I'm sure those older v-twins needed them so you didn't break your leg. Older 4 stroke motocross bikes had a manual lever that you pulled before kicking. Anything within the last 3 or 4 years though are now auto. And by older i mean 1998 to about 2000 since that's when the 4 stroke moto-x bike started it's ressurection.

old xs650's had them you'd have to pull the lever before the starter would even turn the motor over

don't need them unless your going over 11-1 compression and using a kicker