I have a 2.0L in my '75 right now and we just took the tin off a couple weeks ago. Does the tin really affect cooling? Does it help to keep the temp down if the tin is on the motor? Please let me know. Thanks
-Chris

Then engine tin is critical for the cooling, otherwise, there is nothing to separate fresh air from the top and hot air from the heat exchangers. The cooling fan takes whatever air it has so if there is no tin, it will try to cool the engine with hot air coming from lower part of the engine compartment.

Even an air-cooled aircraft engine has a cowling to direct air to cool the cylinders...

Wanna burn the engine up is a short second......leave the tin off.

So if I cut a couple of air holes on either side of the passenger seat on my trike and fabricated a couple of ducts for cooler air to the engine, where should I direct that air exactly..........

DTM.........down the middle Jake Raby......

Anyway, air would be directed between the cylinders with baffles to split it over the barrels & heads, with the baffle plate underneath the barrels to try to get an even airflow around the barrels.

Aircraft don't really do this as I remember, but they have a 100+ wind coming thru the holes and they fly in cool air too.

Ok thanks for the advice I appreciate it. Thanks
-Chris

Just another reminder that a CHT (head temp) gauge is a very good investment. Not very expensive (I think I paid <$70 for my VDO) and you'll KNOW where you're at. Easy to install... drop a ring under #3 sparkplug and run wires to the gauge.

Knowing if it gets too hot will save you a LOT of money.

The peace of mind of knowing it's running within spec... priceless.

Thanks I will definetly look into that
-Chris