08 senda xtreme project

I've just bought a 2008 derbi senda xtreme, and the guy before me put a 70cc big bore kit in it but hasn't done anything else to the bike. It has compression and spark but doesn't start, could anyone suggest why it wouldn't start, and what i should do to the bike to help it run with its new engine? The only things i can think of is rejetting and derestricting the exhaust (not that i know how to)

 

If he's put a 70 kit in it it will be de-restricted already.

Kick/turn the bike over with the plug in it. when you take the spark plug out is it wet? if not its a carb issue. strip it down and clear the jets and clean it all out.

 

i'll try that and let you know, but i think he just put the 70cc piston in and hasn't touched the carb of the exhaust, the exhaust especially looks very old

 

I've just tried to kick it over and the spark plug looks all good, however i noticed that there are loose wires everywhere. when i kicked it over, it sounded like absolutely nothing was happening, but then i plugged in a wire from the fuel tank by the looks of it and it started to sound like it was turning over a few times, it sounded pretty much like an owl but wouldn't start. should i look more into this wiring?

 

A video would be helpful but yes any dodgy wiring definitely look into it at the very least for the sake of safety.

Was the plug wet after turning over the engine a few times? If it's got fuel and it's sparking and has compression then that's very odd. Have you checked what PSI the compression is in the cylinder?

 

The spark plug looked clean, but it was completely black, and the black stuff seemed wet and came off on my fingers, but it did smell of fuel if that helps? I'll try get a video when i can

 

Yeah so it's getting fuel then. You did say the spark plug is actually sparking right?

Have you tested how much compression the cylinder is putting out? I know you said it has compression but how much?

You mentioned he fitted the 70 kit but never touched the carb. It would have needed a bigger jet or ideally a bigger carb so im wondering if the cylinder has low compression as a result of not enough oil perhaps

if you have fuel and you have spark the only real other thing it can be is compression.

 

Yeah, just checked the spark and that's alright, i'll look into the compression but we tried a new spark plug to get it to spark and it came out bone dry, so i'm guessing there's something wrong with the carb. After that we tried putting 2 stroke mix straight into the engine, and still nothing. The wiring for the check control timer is mangled aswell, and it needs to be replaced. I have a video but it won't let me upload it here..