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· Registered
35 Posts
Discussion Starter · #1 ·
Hi everyone,

I recently adopted an SP2 with a blown head (It had been sitting for 2 years). Fixed it and took it out for a trackday last month. The bike is AMAZING. Faster you go, the better it acts. But there was one issue. Twice during the day the bike died on me. Both cases were identical.. Chopping the throttle from high RPMs and getting on the brakes preparing to enter a corner.

The first time it happened, I thought it might be the very weak battery in the bike, so I bought an 8 cell "superlight" battery at the track. Same thing happened again in the next session.

So, I dug into the bike this last weekend to address the problem. My buddy who runs the service department here in Santa Cruz told me to check that the throttles where synced, and idle at running temp. I get the air box off and start looking for vacuum lines and notice the front TB looks to be mounted differently that the rear. Start playing with it, and the front TB isn't mounted to the cylinder, it is being held in place by the rear mount. I can't believe the bike would even run. I remounted the TB and took it for another trackday at Laguna Seca on Wednesday.

Bummer. The seating of the TB was not the problem. The bike died on me several times at Laguna. In every case I am able to instantly flip on the on/off switch and restart in all situations (in traffic!)

Here is more background:

I bought a used head off of Ebay, repaired, reshimmed the valves, and that is about it. I did not sync the TBs.

No power commander (but I working on getting one)

Someone suggested checking the fuel pressure regulator, which I have not done yet.

Basically a stock bike but it has a fender eliminator kit on it. The wiring within tail section was just flopping around in the tail for the most part. I have attached all the relays to the subframe.

The ECU also looks like it was taped to something. It has a lot of foiled tape on it with thick black rubbery adhesive. The connections to the ECU look ok, but???

On my last trackday, I had the idle set in the 1750 range. The stall seem to come when I would chop the throttle from High RPMs, get hard on the breaks in preparation for a corner. When I when to get back on the throttle, nothing. But, I think the bike died prior to actually getting into the corner.

I started to role the throttle off later in the day, which seemed to help, but I was also riding less aggressively.

Any thoughts? My gut feeling is that it is an electrical issue. Kick stand switch? Tip Over Switch? Something else? Any ideas?

Looking for ideas. Thanks.

· Registered
2,606 Posts
Start from simple stuff: I would personally run a fuel flow/pressure test. I had similar issues (though not as bad) and they were caused by a clogged fuel filter. If you bought the bike used (like myself) you never what crap previous owners put in the tank... :rolleyes:

· Registered
226 Posts
I had a plug under the seat (near the battery) come loose - over bumps I'd momentarily lose power. Finding and reconnecting it cured the problem.

You need to first find out if it's a fueling, or ignition problem I think.
Most likely electrical by the sounds of it...
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