Why is this happening

C

C River Yamaha

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Dec 31, 2007
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44
Age
42
Location
Crooked river Michigan
I have a 97 v-max 500 and i just put a new topend in it and a new pto side crank seal it pressed in fine and snugg but when i start it up and run it and about 6000 rpm it pops that pto seal out??? What am i missing or doin wrong?? Thanks
 
I'm just curious here but are the cases for the 500 twin different than the triples in that there's no groove for the lip of the crank seals to fit into?I've never seen a twin crank case so I'm talking through my hat here (so to speak) but the cases of my SRX have this groove that keeps the seals in place so it may be why your seal is coming out the lip isn't in the groove.
 
Ya there is no grove on the case or the seal i got a new seal everytime it has poped out and the same thing happens.. When the motor roles over and the seal is out there is air coming out the hole you can feal it and here it i'm not sure if that correct or not..Thanks
 
a crank seal is designed to be "crushed" somewhat or squeezed by the 2 crankcase halves being compressed together on the seals outer surface, you cant install it correctly without splitting the cases. By just driving the seal in from the outside your cutting the outer surface of the seal(rubber)there by making the fit too loose. As stated before most have a lip that fits in the case, some older engines dont but cant be driven into place correctly because the "squeeze" from the case halves holds them into place. I also will use a thin smear of yamabond on the outside of the seals on those models.

Yes, you will hear/feel air with seal out, when the mixture is drawn into the cylinder, (you have a cylinder reed engine)it is compressed under the piston and crankcase, then forced up thru the transfer ports by the piston coming to BDC and onto the top of the piston.
 
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There is always the JB Weld method of putting it in, BUT DON'T do it, you will not be happy with the end resalt the next time you go to take it apart.
 
better off not to "try" anything but tearing it all down, splitting the cases, getting a NEW seal, and prepping it and installing it correctly. if you short cut now, it will cost you big time when it goes. and when it does go, hopefully you will be close to the truck, and not ruin anyone elses trip but your own.

there is no replacement for doing the job correctly the first time. like the old add used to say, you can pay me now, or pay me later. good luck, hope it all works out for you. ski
 
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