18 August Points Race

What a contrast in weather we enjoyed this week.  Gone is the heat and humidity of July and we escaped the rain showers from last week.  Instead, mid to upper seventies with clear skies met us on race day.  Ideal for spending the day at the track!

Leading up to the race, I swapped in a 60 tooth rear sprocket.  This reverses the changes we we seeking earlier in the season.  During practice, the highest RPM Lian saw was 5220 but she was just as quick as ever and had no trouble keeping pace with the rest.  This confirms that even though a bigger rear sprocket will give you a higher RPM, the power drops off at that RPM and the engine stops pushing as hard.  Most likely, it just can't flow enough air through that small restrictor plate to make the power.

Another recent adjustment was to Lian's seat.  She has complained that her upper arm has been banging into the tall rib support - mostly on her right side, while making the tighter turns.  I couldn't really add padding to this as it would make contact with her arm earlier in the turn so instead, I added two pads in the seat.  One on the seat back to move her slightly forward, and another on the seat bottom to move her slightly up.  I hoped that this combination of 1/2" padding would move her arm further away from this rib support "wing" that has been bothering her.  Here is a picture of the modified seat with some toolbox foam added.

This hasn't completely resolved the issue for her so we may be looking for a new seat.  That can also change the dynamics of the chassis so we will look at re-weighing and making adjustments if we go that way.

I'm also a little concerned that there may be some corner weights that are off after the damage repairs I made last week.  To change this, I can either install an adjustable bearing cassette on the rear axle (this raises or lowers one end of the rear axle) or I can twist the chassis (carefully) to get the cross weight where we want it.

Looking back at where this all started, we realized that Lian may have been predisposed to this sport.  Here are a few pics of her motoring around the yard in the neighbor's toy Gator...

Three years old and jammin' gears...

Here is a picture of her working on her own toy Corvette with her dad's tools.  She told Mom "I'm fixing my Corvette so it will go faster!"

"You are going to put all those tools back where you found them, right?"

Lian started the Heats in 6th and 2nd, finishing 6th and 3rd respectively.  She started the Feature in 6th and was overtaken at the start by one kart and never found the chance to make a pass.  She finished 6th out of 7.  Her best lap time was 23.07 sec, a few ticks short of her best.  I guess everyone in the class was just getting better.  Lap times like that would have earned her a top three earlier in the season.

The crew chief is thinking about re-jetting the carb and a few other adjustments.  I'll keep you posted.  Next race is Sept 9th.

Last night race of the season

This week's race was the last night race on the schedule and the day did not start out promising.  There had been rain showers through the area all night and the morning was marked with even more.  The club president posted on the forum that the weather was dry at the track and that we were a go for racing until otherwise notified.

It drizzled on us while we were setting-up our canopy and equipment.  Drag racing at the track next door was curtailed and eventually cancelled.  The practice session was interrupted twice by rain.  After  the second time the track was soaked and the club brought out the wheeled leaf blower to try to dry the track. Eventually, the senior karts were sent out to practice and finish the drying process.  Drizzle came and went during the heats but it was always very light so it didn't impact the program.  With dark clouds in the area, the club decided to have no intermission and go straight to the Features before rain fell again.  Here she is during the Heat 1 when we had a glimmer of sunlight peek through.

Lian started 7th in Heat 1 and 5th in Heat 2 out of 11 racers.  Again a crowded track but mostly clean racing.  One competitor hit Lian while passing and backed her up a couple of spots.  The same racer hit a few of the other karts as well and after warning, was shown the full black flag.  The disqualification was a tough penalty and kept him out of the Feature but he will be more courteous next race.

Here is a shot of the new front end numbers as required by WKA.  The club informed everyone that they were going to start to enforce this rule this week.

Lian started 9th in the Feature race and moved up to 8th in the first turn traffic.  One kart passed her a couple laps later putting her back to 9th.  Later, a few racers ahead of her had trouble and spun out.  The same thing happened again two laps later.  The difference this week as opposed to the last race was that she was able to pass cleanly.  That luck combined with her very consistent laps to allow her to move up to 5th at the checker flag!

Although I was happy about not needing to do more repairs, I was very proud of Lian's cool hand on the wheel.  She managed track conditions that changed every lap with the intermittent drizzle, droplets on her helmet visor and 10 other very competitive racers sharing the track.  Through it all she never got frustrated and always showed good sportsmanship.  If I can make her kart the best it can be, she will probably win a race soon.  Now it is time for the Crew Chief to step it up!

Drizzle became heavy after her race and after a few false starts, lightning was spotted.  In the end, only one other class finished their Feature race.  We were lucky indeed!  The drive home was through some pretty heavy showers at times but with the prospect of future races looking bright and the confidence of two fresh-new tires on the trailer, I wasn't stressed at all on the highway - just pondering where I can find more track speed.

We race next week so I plan to go to a 60 tooth axle sprocket to see if I can advantage her with more top-end speed.  I'm also looking at leaning the carb a little but don't want to play that until I can get the Cylinder Head Temp (CHT) sensor working.  I'm working with Digatron right now to see if I can get the right sensor.  I've already adjusted the valve lash to 0.002" on intake and exhaust so it will flow as much as possible.  I'll let you know how we do...

Hard hit last race

Well, after the contact on the track last race, I found significant damage to the nose bodywork on the kart.  I knew this needed my attention before next race but I kind of put off repairing the cracks.  I finally got the nose off the kart to fix it on August 7th and made an important discovery.  There was some significant structural damage to the left front spindle and mount.  Here is a picture of the right front.  This is the way it is supposed to look:

Notice that the mating surfaces are flat and there is a bolt in the middle of the spindle carrier that goes into the frame in the center.  That acts as a pivot point when adjusting the caster.

Here are some pictures of the damaged left side:

Notice the separation between the parts.  The second photo shows the bottom bolt with the damaged washer, and the last photo shows where the middle bolt should have been.  In addition, I rotated the king pin (the large vertical bolt the black spindle pivots around) by hand and could see that it has a slight bend in it.

Well, fixing this consisted of disassembling, hammering the frame mount flat, and replacing the washer and the center bolt (after using an extractor on the remains).  I should eventually replace the spindle bracket and king pin but it will work for the next few races.

After working on this, I had little time to do the body repairs I planned.  As a result, my fiberglass work was a little hasty but there are no longer any open cracks apparent.  I'm declaring victory and re-assembling everything.  Next post will be after the last night race on Saturday, August 11.