Thursday, September 17, 2009

Power Valve

So now I'm back to the exhaust flange repair on the KTM. I should have done a little more research before I started taking things apart, but in the end it's probably just as well. I removed the side covers to expose the ends of the flange and found this power valve contraption.

I wasn't sure if any of this would interfere with the flange, so to be on the safe side I started disconnecting things. Turns out I could've left it all alone. Except that once I did get the flange off, the power valve looked like it was ready for a thorough decarbonization, which meant pulling it off anyway. The guy thats repairing my flange, Ken Breda, was kind enough to send me the info I need to set up the power valve, so I continued with the disassembly until I got to the 4 screws that hold the side plates that lock the power valve in place. They're 5mm countersunk screws with a 3mm hex drive, held in with loctite and a few years worth of heating/cooling cycles. (number 1 in the diagram above)
After stripping the heads with a number of different 3mm allen keys, I determined that I would need some other extraction method. I was able to drill 3 of the screws out with no drama, the 4th put up a fight but I got some help and managed to get it out with a tap-in easy out.
Then it was just a matter of cleaning things up and putting it all back together, which went pretty well thanks to the instructions Ken sent.

Here's the right side with the cover off, showing the linkage arm etc.

The new flange, which is definitely beefier. Super-sano weld by Ken Breda.

I finally got it all back together today, gave it a test ride and everything works. Hannah and her friend Andy from Binghamton and I rode the home track today, Andy rode my bike and I had Seamus's 400. Got in many laps, had fun.

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