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Bittersweet weekend.
Arrived Friday early and safety wired a few things. First session went well and I was running the same pace as the weekend prior (1.26's). I had dropped the front end of the bike another 5mm over the break to combat the larger circumference of the Dunlop slicks and it seemed to help turn in. Session two went well up until the last lap when the bike started stumbling coming out of 2. I nursed it around and pitted in. Power seemed to be down >50% until I got back to cold pit. Idled fine with both cylinders firing. Tried to go back out but as soon as I put the throttle to her coming out of T2 she fell flat on her face again. Thought I saw evidence of arcing on the front coil wire so I wrapped it in duct tape. Bike started, idled and ran fine around the pits. Went out for session three. First lap felt great (1.28). Coming out of T2 on the second lap the bike hesitated. By the time I had exited T3 it was again down 50%. Weird. Pitted in. Swapped out the front coil, plug wire, plug cap and both spark plugs. The plugs that came out were almond in color but the front showed evidence of some corrosion; almost as if it hadn't been tightened fully. Skipped the 4th session working on the bike. Mike Martire stopped by and we bounced the bike a bit. Front seemed planted. Rear needed a bit more rebound.
First session Saturday I had two new plugs, two new coils, all new wires and all new caps. I had driven the bike around substantially the night before and everything seemed great. Lap 1 on rain tires the bike again stutters coming into 3. By the time I hit T4 I was down 50% on power. WTF. Back to the pits, pull the plugs and they're both white. After consulting with countless people, I check the diaphragm on the tank (ok) and a few vacuum lines. Because both cylinders showed lean, we didn't think it had anything to do with a main jet in one cylinder or the other. I had placed a bit too much grease on the threads for the gas cap and it had blocked the ball bearings. We thought that maybe under wide open throttle a vacuum was being created inside the tank restricting the flow of fuel. I pulled the cap and mount and cleaned all the components and reassembled. Did a continuity check on all the wires going to the coils from the ECU shaking and moving the harness but didn't find any issues. Extensive testing ensued riding the bike all over the place. Idles great. Accelerates great. Throttle response is awesome. Maybe I figured this out?
Track dries out so I swap back to slicks. Race 6 I plug in the warmers. Race 8 I start to get dressed and rip the zipper off of one of my Sidi boots. Not just the tab.. the entire zipper. Thank god for Miles at Street and Comp... ~10 minutes later, new Sidi's on the feet. Race 10 arrives. 12 people on grid and I have a wicked case of the nerves. How's the bike going to run? Should I try for the holeshot or let someone lead me around and then try for a late pass? I'm about 2 seconds behind the fastest rider in times so maybe try to follow them? Warm up lap begins and I'm up into third coming in T1. Bike feels great. Awesome throttle response. Suspension feels planted. Flop for 2, roll on throttle.. wait.. did it hiccup? Flop for three back on the throttle and I'm down 50% on power. I had unenthusiastically tightened the gas cap back in the pits.. so I easily spun it off another 180 degrees to make sure it wasn't a vacuum build up in the tank. No change. I hold her to the boards simply trying to not get run over with my left hand up. Pit in running on one cylinder all the way back to the garage. DNS. For the first time in two days, restarting her yields only one cylinder.
Didn't bother troubleshooting just packed it in and came home. I'll pull it apart later in the week. Still trying to figure out which cylinder is the problem child and then go from there. Float bowls are next as well as a check on the internal tank screen. It's going to be hard to troubleshoot as it seems to require a good amount of wide open throttle to get the issue to occur. Idling, revving it in neutral, riding around normally don't seem to produce the issue. Definitely not heat related. Suggestions?
Huge thanks for all those who helped troubleshoot (Zip Tie Alley, the Tansey's, Todd Babcock, Bob, Mike, Neal, etc) and Mike from GMD for adjusting my rebound. I'll let you know how it turns out.
Fitz