What a great idea - next time I get a chance I will test it. You just helped me think I could also use a cyl, leak down tester through the spark plug. The beauty of your test is not special tools needed, thanks again !!! Denis
i have never used a cylinder leakdown tool but isnt that used to ck rings and valves???-this guy is testing to see if the crank seal is leaking-he didnt say where the piston was cause on a 2 stroke the piston has to bee down to where the intake reeds are open to let air/fuel misture into crankcase i think-im not sure exactly how the reed valves know when to open or if the just open after the fuel charge in the crankcase haswent into the cylinder creating a low pressure to suck in more moxture-anybody got any thoughts or lessons for me to learn???
@@storyoc It doesn't matter where the piston is nor whether you apply pressure from the intake, exhaust, or spark plug hole. The air will leak past the rings pretty easily and the entire engine will be evenly pressurized.
It's a good idea to also vacuum test it, I've read about a few that passed on pressure and leaked under vacuum. Most seals will have increased sealing pressure against the shaft when pressurized, and decreased pressure when under vacuum.
Not a bad method, but you definitely need to test each cylinder, moving your "apparatus" to the other cylinder and retesting. Also, I would verify your pressure. You could do this with a cheap tire gauge, in keeping with the "Yorkshire economy" approach. 😅 As long as you are in the 6-10 psi range, that should be close enough. You want to avoid being over pressurized and blowing out your seals. Finally, I would add the soapy water spray test to your pressurized engine to check for leaks. Bubbles are bad! It is ok to cobble up a home made test apparatus, but please do a complete pressure test and proof out your results. A two stroke seal failure can turn ugly fast. Then you are into big UK 💷 or US 💵 . Crank seals, gaskets, and case sealant are cheap. Yamaha RD's are very easy to work on. Your labor is free. Knowing your engine state exactly, is priceless. My two pence. Good Luck and Happy Motoring!😊
Hi, just cut the inner tube in a circle big enough to stretch over the exhaust stub. Any bathroom sealant is ok. Wait for it to set overnight! I should have mentioned that but assumed it was obvious? Maybe not 😂
You would do well to make that work on a lot of old two strokes. You can’t get to to seals when the engines running they’re usually behind the flywheel and clutch
Hi, what do you mean. It's best if the piston is at the bottom of the stroke so all ports are uncovered. Then the cylinder and crankcase are under pressure. Cheers
