Originally Posted by
CosworthDriver
Looks great Storydude!
Have you considered using a carb from a .21 two-stroke?
I just got a little more runtime with my project last weekend. Unfortunately the weather is beginning to be so bad here in Denmark, that i'm not going to get much more runtime this year.
But I tried to change my clutch bell from 22 tooth to a 20 tooth, which was a big improvement! Better acceleration, lower temps and still ok topspeed. I'm still running the standard 48 tooth spur on my Hong Nor/Jammin' X2 CRT truggy, but I also have a 44 tooth spur from the X2 CR buggy. I'll try that later on, so I maybe can run a smaller clutch bell and also can mount the engine closer to the centerline.
I also have some plans to get more revs out of the engine (improving the flow through the intake manifold and mounting a fuel pressure regulator).
A friend of mine ran his Hobao Hyper 7 buggy with a 3 port .21 engine and as my 4 stroke truggy began reaching the optimum workingtemp I began to outrace him on topspeed! He was quite impressed and began to "feel the pressure" from the 4 stroke power!
I haven;t seen a .21 carb with a small enough throat. This isn't a converted Airplane engine, but an OS 40CX. It revs higher than any 4 stroke I've heard. Plus, with the carb being mounted on the head, a linear slide carb would be hard to hook up.
I'll try and get some pics with body and Aircleaner mounted.
I"ve found heat isn't that big of an issue with this motor. I've had it to well above 400* F with no loss of power, just hard starting if it flames....And not because it has no compression, but because it vapor locks due to the boiling fuel
I've run it hard like this for 5 tanks now, still blowing smoke and oil nicely and so much compression I cannot turn it over by hand...Hot or cold. Hot it seems to get MORE compression(probably due to iron liner expanding more than piston).
The big test will be next spring if it still runs good when it's 70F out...and not 50F.