New F1000 owner

[Rexxus]

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

[Marty Nygard]

1) What type of nuts are you using? I used to use metal on metal lock nuts and discarded them with every use.
2) You know, you can get in touch with George Dean.

[10rmotor]

Are the studs backing out, or are the nuts loosening on the studs? its easy to determine, just put some witness marks with a sharpie on both ends of the stud and see who is moving around. That said, I use metal jet nuts for the sprocket.

[alangbaker]

All metal jet nuts are a good answer, but if you can find them, I'd also look into Spiralock nuts.

https://www.stanleyengineeredfasteni...ing-Resistance

[Rexxus]

Thanks all,

I was using studs with nuts, but replaced them the last round with bolts. With the studs it was the nuts loosening off the studs, the bolts they work themselves loose. So am i right in thinking i'm just using the wrong fastener and it's not an alignment issue?

I'll get some jet nuts and treat them as a disposable.

I'll hit up George and see if he's heard of the stuttering issue.

Cheers