Testing the “new” 125 – 4/2/2007
Yesterday was our first day to take out Tyler’s new 125cc Shifter kart to give it a run.
While the picture “seems” to make the new kart look bigger then the old kart it is not. The bodywork and chassis are the same size. The double-decker stand that the new kart is on is just taller and closer to the camera.
The old chassis with the 80cc shifter engine on it is blue so Tyler decided he wanted the bodywork to mimic the Williams F1 team colors. The new kart has a purple frame so we had to find a color combination that would not “clash” with the purple and yet be acceptable. We decided to mimic the Crown Royal Grand-Am prototype car. Sam at SummitWest did a great job.
The Kart was a bare rolling chassis (wheels, brakes and radiator) on Thursday night and by Friday afternoon we had the motor mounted (and test fired) and the seat fitted. I then spent the rest of Friday night getting the bodywork, steering, data system and fuel lines mounted.
On Saturday I was working on the balance of the final prep on the kart before we would put it on the ground to see if the thing ran and was having a hell of a time trying to get the brakes to bleed (an important item on a 120 mph racing kart). So I swapped out the master cylinders from the old blue kart. Still could not get the brakes to bleed fully. After having spent from 8am to 7:30pm working on the kart I had to go laydown and rest. Told Tyler we would work on it again the next morning (race morning) since the schedule was for practice at 10a, qualifying at 12:30p, Qualifying race at 4:10p and Race at 5:00p.
Got up at 7am, cleaned the brakes, switched to a shorter rod that connects the brake pedal to the balance bar on the master cylinders and viola. We had good solid brakes.
After a run to Ace hardware to get some additional fasteners we put the kart on the ground to give it a maiden voyage.
Tyler made a handful of runs into the cul-de-sac and then pulled up to try a standing start. Held the clutch, wound the motor up and roared off with kart basically sideways from all the power. He came back around and was looking down trying not to split his face open from the grin when I asked him if he could feel the difference between the 80 and the 125.
We loaded up and headed out just before 11am.
Got to the track about 20 minutes before the qualifying session so without any time to setup our paddock space Tyler got into his gear while I ran to registration to get up signed in.
Since we would be breaking in a newly rebuilt motor I told Tyler to take it easy and not run it full throttle. We would just qualify toward the back and see how the kart behaved. Tyler circulated around the track about 2 seconds per lap slower than the rest of the 125 shifters just running the kart through the gears and listening to it.
After the session I pulled the plug to see what out mixture was looking like and while the plug was wet as if it was running too rich the electrode was darker and dryer then it should be. At that point noticed that our engine builder had put in a hotter plug than any of us run. after consulting some of the other guys we figured that was the cause for the strange plug reading (we had somehow lost our EGT probe the last time we were out and I had not noticed that until I was switching the data system from the old kart to the new kart so I was unable to get realtime readings of exhaust temps from Tyler’s first run)
Swapped out that hot #8 plug for a much cooler #10, swapped out the old worn tires that the first run was done on for some brand new rubber and Told Tyler to go for it in the qualifying race.
For some reason when the grid sheet was posted for the qualifying race Tyler was not on it. Benn for some reason had not seen that Tyler had posted a time so asked if it would be a problem for him to just start from the back. I figured that would not be a problem as if would give Tyler some practice passing all the Challenge and TaG class karts and we could see how many Shifters he could then catch.
At the drop of the green flag the karts screamed off into what is nominally the turn 8-9 (the start had been moved to the straight between turn 7 and 8) complex and as the leaders came into the tight right hand Turn 11 when the there was a significant incident at the front that saw at least five karts off tracks and in the dirt including two that flipped and were upside down. If Tyler had taken the grid spot that he should have been placed in he would have been placed somewhere between the two karts that flipped. As it was since he started at the back he was slowed down and had plenty of warning from the waving yellow flags.
He circulated for about another five laps under a full course caution before the race was red-flagged and brought to a halt while the track was cleaned up.
Just before the Red Flag came out Tyler said the motor sounded funny and did not have any power. He reached over to adjust the choke when it quit on him. He cot pulled back to our paddock space and checking the engine we saw that we had no compression. The plug was dry. Looking down into the cylinder I could see the piston moving up and down. Fortunately I did not hear any “noise” coming from inside like a broken rod or anything. Probably sucked a ring or burned the piston.
The carb we are currently running (and was suspect to start with) is what came standard with these motors but is not what everyone else is running. I’ll get the kart/engine back over to our engine builder to take a look at the motor to get it fixed and I have a new carb on order that is what everyone else is running.
Next event is a Double Header at Firebird. East Track on Saturday, May 5 and then Main Track on Sunday, May 6.