Hi all,
I'm in Australia and purchased a 2014 Stohr F1000 earlier this year and have been working through it refreshing what's needed as I learn more about the car. It's got a GDRE built 2008 GSXR1000 motor with Geartronics shifter and dry sump. I've been rallying/circuit racing cars for a while (10+ years) but this is my first foray into this type of car, so motorbike engines and formula series are very new to me.
I'm currently stuck on two things:
1) The rear sprocket studs/nuts constantly come loose. I torque them to spec (3/8's bolt tightened to 28ft/lbs from memory, what ever was spec'd in the Stohr race prep pages, which now appear to be offline) and after a single ~850m sprint lap when I get back into the pits 3 to 4 of the nuts can be half to full turn loose. I've run a straight edge between the drive and rear sprocket, whilst having the rear raised and spinning the wheels, and both sprockets seems aligned, I've removed the sprocket, degreased it then locktite the studs back in, and then the nuts, but they still loosen. At this point I'm concerned if I do a multi-lap session I'll lose the rear sprocket. Do I torque them more, should I get a laser to align/shim them? Am i a muppet (yes) that is missing something simple/obvious (probably)?
2) The engine stutters/surges around the 5k-8k rev range when on constant velocity corners. I've replaced the Throttle Position Sensor as the previous one wasn't reading in spec, new one is in spec, and was good for two laps, but then went back to stuttering/surging although voltage remains still in spec (to the volt range from the factory service manual that is). It's got a custom loom so I can't get a stock dash to read fault codes. Any pointers on what to check next? My next play is to sit down with the service manual and multimeter every sensor I can, but that's a lot of effort and I'm sure someone's seem something similar that can point me in the right direction. Only thing I haven't replaced yet are the vacuum hoses, but all seem supple and seated properly (although who can say how old they are).
Any input appreciated.
Cheers