I bought a helmet mounted camera from goprocamera.com and we used it last weekend at the race in Albuquerque. We ended up having a horrible bog at times and in the video you can see Tyler raise his right arm in frustration when the bog hits him.
When we got there for the practice only Friday sessions we did not change anything on our setup from our last race down here in the Valley. First session was just to set a baseline, knowing that our carb jetting would be way rich and that our gearing would not be right either.
After the first practice we leaned out the main jet from 175 to 165 and went back out. Engine ran better.
After the second session we changed the gearing. Went from an 18/22 to an 18/24. The third session seemed good.
Saturday morning we went out for first practice with the same setup we ended Friday on. Tyler came back in and I asked him what I needed to change or adjust. He said the kart was perfect. I did not have a transponder on the kart for that session but our MyChron Data logger showed a best lap time of 55.36.
For the second practice session I just checked the air in the tires. Tyler came to a stop on track which made me worry that maybe the air had gone bad and we had burned a piston by going too lean on our jetting. After the session I ran out with the stand to bring the kart in and he said it just quit on him. Back in the paddock the problem was quickly apparent. No gas.
For the qualifying session we thought we would not have any issues but as I was going over the kart one last time before putting it on the ground to get ready to head to grid I noted that the chain seemed “tight”. I loosened up the motor mounts to bring the motor rearward to put some slack in the chain and as I was tightening down the mounts I could see the chain going tight again.
Seems that one of the cross bolts that holds the motor to the mount had come loose and partially backed out. Got that pushed back through and fixed. Out he went for qualifying.
Tyler came back in complaining that the motor was jumping and the drive was really bad and that the kart had been bogging really bad coming out of the corners.
In my rush to get the chain issue fixed I had loosened up the bolts that held the rear sprocket together and they had worked loose and partially separated. Damn.
Fixed the gear but Tyler’s time in qualifying was not very good putting him toward the back of the grid for the race.
When it was time to head to grid for the race we could see a storm blowing in and we were getting some rain drops.
As the karts headed out onto track the front edge of the storm hit. Air temps dropped and there was a huge tailwind coming down the front straight just as the kart came through turns 3 & 4 of the oval onto the straight.
The air density went up 2,000 feet from when the karts rolled out onto track and by the time they came around to take the green. Anybody with good jetting was know marginal and anybody that was marginal was dead in their tracks.
We were way off on jetting with a huge rich bog. Tyler came in early it was so bad.
That night in the hotel room Benn and I reviewed the video from the race and from listening to the audio we decided that I needed to move our “Magic Can” (gravity fuel feed) further back on the seat and higher up.
Sunday morning I moved the Magic Can but the practice session was the same as the previous day. Rich bog coming off the corners. Showed the video to a few other guys and we decided that I should lean out the pilot jet. Did that (from a 52 to a 48) and went out for qualifying.
It was better but still not right. We were still gridded toward the back and behind karts we normally are gridded well in front of.
We discussed with Tyler that he was just going to have to drive around the problem. Like instead of being in 6th gear coming off the throttle into the oval he might want to be in 5th gear with the motor screaming so that the carb slide was open allowing in air so as to keep the carb from flooding.
As you can see in the video of that race as long as he did not have to come off the throttle he was able to run down karts with ease but as soon as he got into traffic and had to start playing with the throttle the engine would go into a bog.
Figure I will have to bite the bullet and invest in a pump around carb setup.