250 Ninja engine into GPX250????

[bonester]

Anyone know for sure that a 08 Ninja 250 engine will bolt in and wire into a 2000 or so GPX250????? Thanks!

[Wattie]

cant see it being too hard, its the same engine.

[bonester]

Nope it doesn't go straight in but I'm gonna make the fukker fit. Owner bought the engine off ebay from a wreckers in Tas and it was advertised as a 2008 GPX250 engine. Wish I saw the ad before he bought it- no gpxs were made in 08 and the pic is of a Ninja 250. So far differences- front upper right mount doesn't fit- grinder will fix that, different exhaust outlet on head, inlet manifolds, coolant plumbing top and bottom, kleen valve on top of valve cover, sparkplug wires, front sprocket and cover etc. Hope the electrics and carbs are compatible. Charging circuit will be, ignition circuit I sure hope so....

[bluebirdnate]

As long as the pickup coil is compatible, then the ignition should come close? My bet is if the the stator checks out OK, with similar resistances and the same wiring setup then the ignition should work fine.

It may not run 100% due to the timing in the CDI but it should still run. The coils shouldn't matter so much as long as you can fit the plug caps to the plugs. If you can plug in the CDI from the Ninja 250 then it may be worth a shot. Keep in mind this may be a good way to fry the Ninja CDI, depending if they use the same internal setup as the GPX. I'm guessing you already know this, but you can always check where the wires go on both bikes, and if it's the same then there's a fair chance it will be fine, ignition timing aside.

Then again, I'm not a mechanic and I am more used to motocross bikes and cars so I may be wrong...

As far as I know, the carbs are slightly smaller and jetted down on the Ninja 250 - the GPX & ZZR had slightly more power and was supposed to rev harder. Well, on paper anyway...