Screwball – SFV Racer Project – Part 3

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Every project has a few forks in the road. I had 2 roads to take, the short one where the goal was to just get the bike on the race track or the long road where the build would be “complete”. The short road was taken because my excitement to get this machine on the track overcame the desire to just have a neat project. This is a race bike after all, not a show machine.

We are not using a SFV motor or wire harness. The bike is powered by a 03-06 SV650 ecu/harness/motor with DL1000 throttle bodies. The SFV uses different coils so finding a nice place to mount the SV coils was needed. There was a perfect mounting spot for the front coil but the rear coil needed a mount made. sv650 ignition coil on SFV
sv coil on sfv

The bike is running a total loss charging system so finding a place to mount the R/R was not an issue. With only the ECU and Power Commander needing a place to mount, the wiring on the bike was simple and not very problematic. The computer and PCIII would be tucked under the tail and out of site thanks to the under tail.

One of the final obstacles was the clutch. The SFV frame gets in the way of the standard SV clutch cable routing and finding the SFV actuator system wasn’t the easiest. What about a hydraulic clutch? Why in the world would you put one on a race bike? Well we did. Ducati 848 clutch master paid with the SV1000 slave cylinder turned out to work like charm. Two modifications were needed to have the system work with the SV’s powerplant. First is getting the slave mounted on the SV stator cover. A small amount of material was needed to be removed from the inner part of the mounting posts and the SV1k slave fit right in with mounting holes lined up perfectly. Second would be the push rod as the 650’s rod is too short, the 1000’s rod is too long. Take roughly ~10mm off the 1000 rod and you have a perfectly working hydraulic clutch on your SV650 or in this case SFV650. It’s by far the easiest pull of a clutch my hand has had the pleasure of pulling.

I had this vision of a mostly yellow bike; frame, tank tail but finding the correct yellow that fit into my now limited budget became more difficult and under the new time crunch some cheaper paint was purchased and used. The scheme went to black/grey which is something I was not thrilled about but after it met my eyes for the first time I fell in love.

The final unknown about the SFV (for me) is suspension set up. I know the linkage ratio is much different from the SV. Stock shock (317mm) being much shorter than both of the SVs (330mm 2g, 337mm 1g). Adding 15mm of length to the SVs shocks worked out perfectly for those machines but I didn’t want to go so drastic on the first outing and with the front end on this bike being so short (485mm), we set the Racetech shock (from 2009 GSXR600) to 320mm. In future testing different lengths will be applied.

But now has come time to get it on the race track. April 9th CCS/ASRA would make it’s annual stop at CMP (Carolina Motorsports Park) and this became goal to get this SFV racer ready by. While with what preparation I had done to get the SFV ready for the track it was not enough. First practice stopped on lap 1 due to the machine cutting in and out which was not something I had run into in all my little test rides on the streets. Changed the spark plugs and took another practice laps prior to a race and it felt like it was ready to rock. Even on this single lap something went through me that this bike could handle and handle amazing. Race time came and the hydraulic clutch did not fail me on the start. Good start with some havoc taking place but once I was able to hit the corners my mind was blown away with this bike. The brakes were perfect, the handling was perfect, and even with old tires it felt like a dream. Sadly the power delivery issues continued right away as the bike stuttered when trying to climb through the RPM range. Sadly the fuel delivery was not the only issue, with the bike sitting so low the front of the belly pan would make contact with the ground under the hard CMP braking conditions. After a few times the pan would get ripped off the bike. I had to stay out for the entirety of the race to get a better feel for the new machine. Managed a 4th place at the line. Once we get this machine on the dyno to iron out the fuel delivery issues, there is no doubt in my mind this chassis will be damn near perfect. The SFV weighed in at 340lbs with roughly 2.5 litres of fuel. 320lbs is the goal for weight now that I know the state of it’s weigh in. Stay tuned for the next round for the SFV “Screwball” race project.

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1 Response

  1. Benjamin Loyle says:

    *photo credit by Benjamin Loyle*

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