AFM 103 – Greg McCullough

Who knew?  There’s internet access at the track.

It’s been a very busy week of prepping the bike for the races this weekend.  There’s a list of technical requirements for the bike that far exceed the regular track day items like taping headlights, brakelights, etc.  Basically, no fluid should ever be able to spill on the track, so every bolt or cap needs to be safety wired so it cannot open, and every drain hose needs to be routed to a catch can.  The total effort was only about 4 hours, since much of this work had been done on my bike by the previous owner.  However I took my sweet time triple checking everything, since it’s my first time around at this.

Other items included

- Fixing my frame sliders, which were mounted in a less-than-safe/optimal way

- Rigging up my video camera in the front of the bike.  I won’t use this at race time, but I’ll run a session or two in practice today to have some footage of this track.

- Getting my subframe re-welded.  One of the seat mounts snapped off, and my zip tie arrangement probably wouldn’t have passed tech inspection.

-  Repacking my exhaust pipe.  When my pipe came apart last track day, I noticed the fiberglass inside was overdue for replacement.

This is where it got a little crazy.  An exhaust pipe is nothing more than a steel tube (the core) perforated with lots of 3 millimeter holes, wrapped with fiberglass padding, then stuffed inside the outside can, with 2 caps on the ends with holes in them.  Same concept as a gun silencer.

Well, when I repacked the exhaust,  the core was pretty sloppy.  It didn’t tightly fit in place with the 2 caps on.  I didn’t think much about it, and riveted it all back together.  When I got to the track today, I checked inside the pipe and noticed that the core had slipped off one end, and was very mis-aligned inside.  No good.  Bad airflow = badly running engine.

Given that no one was likely to have a spare core for my particular pipe just lying around, I borrowed a guy’s dremel tool, and hacked an inch off the outside can, causing the inside core to then fit tightly between the end caps.  A little drilling and re-assembly later, I have a one-of-a-kind slightly shortened M4 exhaust pipe.  Yeah baby.

And on with the day…  Today is all about suspension.  The bike is making great power, so I can really only find speed by going faster with the bike leaned over, which is where the suspension needs to help keep the tires on the ground.  It’s all a bit of black magic to me at the moment, and I’ve left setup to Dave Moss when he comes to trackdays.  That basic setup isn’t going to do much more for me though.  I need to feel what the bike’s doing, and know what different settings will do to adjust around quirks that I find.  As recommended by a few guys, I’m just going to start taking a few clicks out of the different rebound/compression settings and feel what happens to get an understanding of what adjustments are available to me.