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Discussion Starter · #1 ·
I am working on rebuilding my 340 kawi, i have a winderosa prof set, and 6 new orings on their way, my question is that the center seal on the crankshaft, the one that has two o-rings on it, should this be very tight like a traditional rubber seal, or is this designed to be a metal seal with a bit of play/looseness?
thanks!
 

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Your engine has the labrynth type seal. It doesn't fit tight on the shaft. If you could see inside there are a series of grooves that retain a small amount of oil. With the crankshaft spinning it creates a swirling effect with the oil which seals the air from side to side. Sorry if I'm giving information you already know. Long story short - yes it should fit loose.
 

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Discussion Starter · #3 ·
No i didnt know that, Thanks for the help thats quite a releif, i never even intended on tearing this engine apart then it got worse and worse. It began missing spark on one side, so i figured pull the flywheel clean the points and reset, i pull the flywheel and theres traces of oil all on the stator and points, which i figure is the mag oil seal getting my points all dirty so they dont work. So i order the gasket set and split the case, well it turns out my o-rings are shot, a little looking on ebay and ive got 7 on their way, then i notice the center seal is a little loose and thankfully it ends there....i hope.
sorry for writing a novel, THANKS for the help
 

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I need to confess I learned the hard way how these seals work. I just rebuilt my 340 Kawi. The first twin cylinders were built with a rubber center seal which would wear out. I replaced it with an aftermarket two-piece labby seal. After I got my engine all together it wouldn't start. I'm thinking: .....hmmm, it acts just like a bad center seal. After talking to many different people what my problem could be one asked me, "did you oil the center seal before you put it together?" To which responded: "....uh, no." Then it was explained to me that oil is what seals it, information which I will surely never forget! Surprise, surprise, afer a generous application of oil it starts and runs fine now!

The reason for MY novel is my round-about way of reminding you to squirt some oil down in that center seal before you assemble the two crankcase halves. Any motor oil is fine. This hopefully will save you the aggravation I went through. Good luck with it, and please let me know how it runs when you're done.
 
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