well, yes, you'll need a custom engine mount, and a whole lot more.
you'll need the mount which offsets the engine to the left so the chain will clear the fat rear tire.
you'll need a custom exhaust (make one or buy one), you'll need about 8 more links of engine chain, you'll need to modify the rear sprocket to work (or buy a sprocket adapter). you may even want to drop to a 36 tooth rear sprocket because a 44 tooth is a bit too big and you won't get a whole lot of top end speed out of it. (i have a 41 tooth on mine and my top speed is right around 30 mph)
you'll need to modify the rear brake caliper and left side brake shoe to work. you might want to add a front brake because the occ caliper brakes are terrible.
you'll need to make a mount for the kit supplied gas tank or make a better looking tank with your own mount.
you'll want to put a different seat on the bike because the occ seat is the worst thing ever made. you'll have to make a better chain tensioner because the kit supplied ones are junk and it won't work well at all on the occ frame.
you'll want to invest in a set of rear wheel chain adjusters and you will have difficulty getting the pedal chain and the engine chain to both be adjusted right. one will be too tight, while the other will be too loose. (this is where a custom chain tensioner and the rear wheel chain adjusters will come in handy).
dissasemble the bike before you even start to put the engine on.
check, every bearing, clean the junk grease off of them and re-grease them with a high quality wheel bearing grease. the rear wheels on the occ bikes have been known to lock up due to lack of grease. you're better off removing the factory junk grease and packing the bearings with high quality grease.
you'll have to make something to limit the turning radius of the front forks so the handle bars don't hit the gas tank when they're turned all the way.
I know this sounds like a lot, but please don't expect to buy an engine kit and a custom mount, and throw the bike together in a few hours.
you WILL have to modify and make parts to make everything work and to make it work right.
Please, take your time, build it right and make it look good.
don't do what the majority of people do.....they just throw the thing together and expect it to work great and last (especially with an occ). almost every occ i;ve seen is a cookie cutter (they all look the same), so do something different and make it unique.
these bikes have the potential to look super slick when they are put together right, with the right parts.
invest in some blue loc-tite and use it. Invest in some better nuts & bolts while you're at it.
don't waste your time stripping down the engine (my opinion).
here's my occ...
