Info 2fiftycc.com Quarter Mile Hall of Fame

Hi Linkin, I'm in Melbourne. I am planning to attend the Gunnedah 12th of August drags. I might be able to swing by Sydney on the way home and get those tyres off you. Is that Okay?

 

Well, another test day at Heathcote Park Raceway (HPR) ends in mixed results. I had prepped my bike for the drags in Gunnedah next week, but I wanted to test something a bit more radical before heading up. A few bikes at HPR today…2 busa’s, a GSXR750 and a HD that showed up late.

About a month ago, a drag racing mate and I were talking and I mentioned I wanted to try and run the bike without a flywheel. He said that idea was a “no brainer” as the reduced weight for the engine to spin would free up a few ponies and help the engine rev quicker. I removed the flywheel and the Stator and also the R/R as there wasn’t much need for any of those bits since the flywheel/stator & R/R all work together on my bike. I saved about 2kg of weight as well. I’d already converted the bike to Coil over Plug and the only thing left for me to do is change the Loom and TCI from the “C” unit it’s currently running to an “A” setup (since I’m now running an ZXR250A engine in the bike). I have a lithium battery that is rated at about 240CCA, so I was fairly confident I could make a few runs before I’d need to stick it on the charger. None the less, I wired a little Voltmeter with an on/off switch into the bike, so I could check the voltage at the end of each run.

Today, I show up at HPR feeling like there might be an 8-something in the offering if everything goes sweet. I ask the owner if I can steal some power from somewhere and he says yep, so I’m super happy now. I line up for my first run and everything turns to poo. Running without a flywheel on this bike is terrible. It launches like a 2-stroke…basically, it just dies off the line. My best 60-foot time for the entire day was a 2.18sec…and, as I said, that was my BEST 60ft time! Most of them were in the 2.2-2.3 range. Compare that to 2.02sec with a flywheel and it really is a “no brainer” as to what’s best!

Anyhoot, back to the run…I instantly realise I’m in trouble, but once the revs get to where they should be the bike starts to boogie. I’m changing through the gears and the bike is flying along. I race on 1/8 mile strips, so I’m never really chasing ¼ mile times, so I often change at 15-16k once I’ve gone past the 1/8 mile timers. Today, we had a tail wind at HPR. A rare occurrence that could help me set a PB for the ¼ mile. So, I figure the launch is cactus, but the bike starts to come on strong all the way down the strip…I mean, I’m actually going into top gear right at the lights!

So, without further ado, I submit my best run of the day. A 9.11 1/8 mile (which matches my PB with a flywheel) and a ¼ mile time/speed of 13.96 @ 108mph. But, since there was a strong tail wind, I will not claim the run even though in drag racing (as opposed to track and field) wind assisted just means “good for you”. I won’t get a chance to run the bike again until I get to Gunnedah, but I will be putting the flywheel back on as it’s just too hard to launch without one. I can understand why a circuit racer would make this mod as it just makes the bike rev so much quicker in the higher gears.

It’s a shame in some ways, because the .15 to .20sec I was wasting on the poor launches would have got me into the 8’s on the 1/8 mile, which is really what I’m chasing. Not to worry, we will push on and when the bike is back in Melbourne I’ll convert it to a ZXR250A TCI and see what that does.