Derbi GP1 running issues. Please help!!

[russed99]

Hi all.

Recently purchased a non running derbi gp1. The previous owner suspected the cdi unit tho i have since changed this to no avail. After some tinkering, new plug etc. It became apparent that we had a spark and the problem seemed to be fuel related. The bike simply turned over but only briefly 'fired' before cutting out.
I have changed the auto choke unit and the vacuum tap this evening and after many, many attempts at starting, she gradually began to come to life.
Finally i managed to get throttle response and the bike was revving freely before again losing response. Close but no cigar it would seem.

So as it stands the bike will start and rev for maybe 30 seconds to 1 minute before it loses throttle response and cuts out. For the time it is running, it regularly threatens to die before it picks up again. Eventually tho, it always dies a death.

I dunno what else to look at. We appear to have fuel air and spark. Any ideas?

[Nope.]

1) Have you cleaned out the jets and carb bowl?
2) Spray some WD40 on the manifold and if it revs up then you have an air leak.
3) Clean the air filter
4) Check that the engine has compression
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Former: Derbi GP1 50, Sachs XTC 125, Suzuki GSXR 400 GK73A, Kawasaki ZX7R, Suzuki DR250, Yamaha RD350
Current: 2011 Yamaha XT660Z Ténéré, 2003 Yamaha YZR-R1 5PW (In Build), 2009 Kawasaki ZZR1400

[russed99]

1) No i haven't
2) I'll give that a try
3) I've tried to run it without the filter on but i haven't cleaned it.
4) I've done a compression test and it was over 100 p.s.i.

Thanks for your help

[Nope.]

[russed99]

I'll give it a try tomorrow.