I dropped my 250S in a few feet of water a couple weeks back and despite a furious draining protocol I was never able to get it running. It passed a compression test (per the manual) but soundly failed a leakdown with 50% loss out the exhaust port. So, off came the head , cylinder and piston. The left exhaust valve immediately failed the leak test while everything else passed.

Turns out I ingested enough junk into the upper end to gum up the exhaust valve stems/seats and that had the exhaust valves closing slowly. Also, found that, at 20K miles, the exhaust valves were beginning to pit. The rest of the head looked good and no damage to the cylinder but it is ready for a touchup to reestablish crosshatching. Piston is fine and bathing in Pine-Sol even as I type.

So I'd like to replace at least the exhaust valves. I have new viton valve seals, ring kit and base/head gasket ordered.

Is there any real advantage to Vesrah or Kibblewhite valves on our little guys or are the OEM valves the ticket here? IIRC, you can install new OEM valves with nothing but a mild lapping whereas aftermarket valves require a full on professional grind.

Any thoughts from the more experienced wrenches?

 

As much trouble as it is to crack open the top end...at least as compared to an oil change or valve check...I'd freshen up the whole head with all four valves, seals, etc. Now if you're just repairing it to sell, then maybe just do the exhaust. That said, the Kibblewhite valves are about as good as it gets. Again, if I'm keeping my bike, I'd go with the K's over OEM. Just wondering, how are the prices of OEM compared to K's?

 

I installed Kibblewhite valves and K spring kit. They work fine and don't cost much more than OEM. No grinding required.

 

There's not a huge diff in $$ as the K's are about $30 versus $23 for OEM and $22 for Vesrah's.

Just had it stuck in my head that other than OEM valves had to be cut into the seats. That was the job I wasn't in for.

 

dj, I notice that the Suncup KLX guy who is really knowledgeable...can't recall his name right now because of oldtimer's disease...used K's in his KLX and just lapped them in carefully with excellent results from what I read. He is fairly demanding on his results, and he was very satisfied with the results from what I remember. If your seats are bad, you should be able to see this as you go through the lapping process.