700 crankshaft, possible problem

[jedw79]

Hi, I purchased a SBT crankshaft for my 700 polaris and installed it approximately 1.5 months ago. Everything seems to be working okay so far, however I'm concerned about one thing. Whenever I received the crankshaft I noticed that the surface of the crankshaft where the magneto seal rides was marred; it was basically not smooth like it should be. Upon inspection, I determined that a tool, possibly a vice or vee block, had made the marks. I went ahead and installed the crankshaft since I wasn't sure if the surface imperfections were on the actual sealing area of the crankshaft and since I've heard nothing but praise about SBT crankshafts. I tried to measure to make sure, but it was too close to call. I pressure tested after completing assembly and it held 9 psi for 10 min. without any noticeable drop in pressure, so I know it was sealing at this point. However, I theorize that if there is a problem, it will show up after use since the seal may possibly develop small tears in it. Should I be worried or is this a common occurance? I would think the crank would have something to protect it from this type of damage while it is being trued and assembled.

BTW, I've ran approximately 3 tanks of fuel through it so far (9.8 gal/tank) and have removed the magneto cover to install an oil block off plate. I didn't notice any fluid in the housing. I guess if it was leaking it would have had something there by now. However, there were some small metal shavings in the bottom, but they are likely from the teeth of the flywheel, bendix, and/or starter, no?
Thanks

[Technical Support]

The marks were most likely from corrosion, actually. Many used cranks look like that, however we do repair all the actual seal surfaces. Many receive collars and are turned down, some are not that bad and simply be cleaned up. Yes if you're holding pressure you're fine, and if the seal was going to go it would have done so almost immediately.

I don't like it to even be a question in the customer's mind however, and will see about changing a little procedure so this won't have to be asked again.

[jedw79]

That makes me feel better about it. I'm not sure if I'm still holding pressure in my crankcase since I haven't pressure tested since I first assembled it. Seems like it would be quite a bit of a hassle to do so in the jetski, requiring disassembly of exhaust and intake manifold. As far as a visual inspection, there is no fluid in the magneto housing as said before. I've also been keeping an eye on both spark plugs and from their appearance it seems apparent that both cylinders have pretty much the same AF ratio in them. I know this is a barbaric approach but it is the best I can do at the moment. I think I should be able to catch a problem before it happens this way since I'm using a single carburetor. as opposed to a dual setup. Thanks for recognizing the fact that this maybe a possible issue that warrants some type of attention in the future.
As far as the marks are concerned, they sure did look like they were stamped into the crankshaft. You could actually see little "x" patterns in the material. However there was a blackish in color circular wear mark on the crankshaft that was free from any marks. This is surely where the seal rides, so hopefully it will be alright. This is assuming that all 700 Polaris magneto housing are made the same (depth wise) and the seal is seated fully because the abrasions were very close to the mark.