You defiantly have to much crank case pressure, most likely poor ring seal, how ever when modifying one of these engines a good venting system is a must. I give my advice on this thread https://4cycle.com/karting/threads/crankcase-venting.106737/Hello all I have vented engine via : New block with billet sidecover & valve cover four ports In total mild build billet rod +.20 , billet flywheel , 292 cam , 27/25 milled 50 head, 24mm flat slide, F&B header, Ect.
Starts runs great blows case seals on either the Pto shaft side or the flywheel side over and over I’ve changed both same thing I looked around no info on this issue I need help!
No . It is one that you would add .You keep talking about a Crankcase Vent Mine only has one and its in the valve cover. Is that what you mean when you say Crankcase vent. Or is there another one on the side cover I dont see or have. Thanks
a multi cylinder automobile engine and a single cylinder racing engine are completely different things. one piston rising while another piston is falling the crankcase is at equilibrium. if you create a vacuum in a single, the piston has to overcome the vacuum in the crankcase on the upstroke robbing you power. you want it to both expel and suck in air so the piston is fighting nothing while doing 2 times the RPM of your automobile.There is plenty of info out there why you should use a PCV valve but its not completely necessary. They are used in most automotive engines and I'm guessing they have a good reason.
Why do you want to fill the crankcase full of air on the up stroke if you don't have to? It then has to push more out.
With two holes in the sidecover it's probably less of an issue.
Paul at Paul's karts talks about this and sells the valves as well.
if you get to much vacuum it will cause a whistle like a tea kettle.I personally don't believe the seals on the shaft would hold a vacuum .
Wrong design .