I have had my SP1 parked up for a few years and although it was run out of petrol before being parked I cannot get it to start now. Is there an easy way to clean out the fuel system on these bikes as I am assuming that is the problem.
You gotta give a little more than that.
Does it fire?
Does the fuel pump prime?
Did anyone try to fire it with the old fuel still in it?
A likely reason it wont start, is part or all of your fuel system is gummed up.
Another big mistake is trying to start on an old battery that's been inactive for that long, then recharged. It may show the proper voltage on a meter, at least 12.75 or better, until you thumb the start button. If voltage drops below 11 or so, ECU wont function.
Sitting that long, with the ethanol in the gas these days, no doubt your injectors and fpr need attention. I would suspect the fuel filter too. Hopefully the fuel pump isn't gummed up.
Rust in the gas tank is a possibility.
And the SP1's were prone to a faulty weld that causes rust and leaking. At the rear tank bracket. Look for discoloration in the red paint at the hinge.
All that said, the easy way is to purge all the old fuel from the system, get fresh fuel, and a bottle of Seafoam. I haven't ever used it, but it gets good remarks on the forums.