Tecumseh Cam

#8
Intake port on HS-50 block is not round. Does anyone have link on using the epoxy to make the HS-50 intake port round?
I have done it and another OldMiniBikes member did it I think 125 crazy. I stole the idea from him. I doubt it is a performance improvement but just that I made a manifold from aluminum tube that was round so I did not want to go from round to whatever you call the hs50 shape, first pic is stock port next epoxy filled.
 

Attachments

cfh

Well-Known Member
#9
i would not recommend changing the hs50 port from D to O. i think a better approach is to just get rid of the cast flashings to make it flow better. less invasive and probably achieves the same end result. using epoxy on an air cooled motor, so close to the combustion chamber, just seems like a bad idea. i guess you could TIG aluminum fill it, but that's a lot of work. and the welding may (will) warp surfaces. meaning you may end up having to bore the cylinder. and to what end?
 
#10
I did the epoxy on one of my motors, i forget which epoxy i used but never had any issues.
I guarantee i could build up a TIG weld without warping anything, using some serious stickout and a gas lens.
The epoxied motor is my fastest Hs-50, but it could just be coincidence.
 
#11
I would be curious to know…I’ve built several and never worried about that shape…but if it in fact makes them go a .010 of a mile faster it maybe be worth it to try….
 

delray

Well-Known Member
#12
think we can all agree that nothing can flow good when air and fuel has to crash and bounce around in a port like this.  101.PNG
i been using a product that is made just for reshaping ports now for couple years. mostly on my clone stuff and depending on the motor and track i will see them spin from 7000-9000 rpms and the stuff has not failed on me yet. big thing is to make sure your metal is clean and another thing i am finding out that some buildings are drilling couple small holes into the area's where they are putting the epoxy in to help Achor it down better. Something I'm trying on my next project.
epoxy.jpg 96.jpg 98.PNG
Big problem with flatheads also are the bowls. they are cut out like a pop can. straight down. making it much harder for the air/fuel to ramp up and out. the air/fuel comes in from the left and right of the valve stem and then crashes into each other than tries to exit. not good if you're looking for power and we all know these little things need help when it comes to power...lol
 
Top