We were optimistic heading out to Circleville for this session. In post-test maintenance after last weekend's (see "Earlier Latest:", 022600) dismal outing we made several changes to remove the possibilities of fuel starvation due to slosh and/or foreign matter. The carb was meticulously cleaned and cleared out. We also found irregularities in the intake/cylinder and exhaust/cylinder mating surfaces which could have allowed leakage under certain circumstances. Additionally, inspection of the fuel pump revealed an actuating spring about a third taller than another one we compared it to. So combined, we figured our troubles were behind us.
Since karts have their engines mounted next to the driver you could say our troubles were more next to us than behind. It was definitely an improvement over last week but the engine still never really performed cleanly under load. The misfire, which manifested itself in various degrees of severity, seemed to worsen significantly under heavy-load corners, particularly right ones. It would then take the next straight or two to get back to being just a nuisance.
During the first session of 14 laps, only two laps were anywhere near full potential so badly did the misfire plague us. Also during that first session I managed to drive over some bumps in the racing line that will have me nursing my ribs for several days to come. On a typical lap these bumps cause the kart to bounce violently but this particular lap I was somehow in a slightly different position in the fiberglass seat and its wrap-around edge was forced into my side. My initial reaction was that I had cracked another rib (Eagle River, '79), the force and the pain was so intense. It was kind of like having a crash without leaving the racing line. Nevertheless, I stayed out for a few more laps playing with the fuel mixture to see if the misfire could be minimized or eliminated (it had no affect, adding to the mystery) and when I got back to the pits I made a painful note to order one of those vests that protect the ribs that are popular with the veteran karters.
Circleville Raceway Park
In the subsequent sessions, I drove the offending turn with my arm between my ribcage and the engine thereby not allowing my sore spot to come in contact with the edge of the seat again. Misfire and injuries aside, the kart seemed to handle very nicely. After a lap to warm up, the tires became fairly grippy and predictable. The chassis has no understeer and only moderate oversteer making it very much to my liking in almost every corner at CRP. Once we get the engine problems worked out, it'll be a blast to drive.
Despite the continuing frustrations we learned a lot once again. We gained important information on handling behavior, the maintenance and inspection routines we need to run through between sessions and generally mobilizing the troops to get ourselves and all our gear trackside. Next, I think I will query some karter bulletin boards with the symptoms we're facing just to see if there is something we've somehow missed. Assuming there are no revelations there, we will be turning our suspicions to flow problems in the carb or timing. When we find it, you'll be the first to know.