Vintage Dirt Bike Q & A

Hello,
I have a 74 cr250. Purchased it in a bike junk yard for $200. It fired up with a little starter fluid and I rode it around for quite a while. Motor seems to be sound (more power than expected for an older machine). I've started to restore it on a meek budget. Everything was great until I discovered someone had welded the drive sproket to the shaft. So I will ride it till it goes and rebuild the entire motor. I read that a lot of people fabricate thier own chain guides. Does anybody know where to get templates. I am working out of a farm shop so we have a lot of machining equipment available. I don't mean to take any business away from fabricators, but some simply don't have the money for the fancy stuff. I've had many motocross bikes in the past 20 years and none have captivated me more than this bike and the damn things older than I am (28). Any help would be appreciated. Thanks