No spark unless compression is removed
 

Hello everyone, im really hoping one of you guys can help as im really stuck now with this.
My bike dont have spark and wont fire up.
i did the test of removing the lead from the rear cylinder and connected it to a good known spark plug. (a previous one i removed from this bike when i bought it)
With a full charged battery it cranks fine but no spark.
If i remove the rear spark plug (and leave the good known one connected to the lead) I have spark.
Im truelly stumped on this i have replaced the coil packs. Checked the negative from the battery to the engine and that's fine.
I even got a new computer for the bike and that very briefly fired up but then the cold engine stalled straight away and not heard anything more since.

Any help would be greatly appreciated!

Reading between the lines, when the engine turns over with less resistance (plugs removed), you get a spark, but with plugs in place you don't? Sounds like a shortage of volts reaching the coils when the load on the starter is higher, so my suggestion would be to pull apart the connectors on the loom (especially the red one as all ignition power passes through) and look for corrosion or high resistance. Might also be in the solenoid or the adjacent 30A fuse holder too. I've also read that the starter lead connection can get corrosion.

I would also not discount blocked pilot jets in a no-start situation, or a damaged fuel petcock.

going to give that a go, i managed to start it with the help of jump leads and a car. charged my battery overnight and got a cough but didnt fire up. going to check all the connectors for corrosion now.

Are you sure the battery is not toast? They can develop an internal short so the current output is low, and even using a jumper cable can be partially unsuccessful. Before you do much else, try disconnecting the bike battery from the circuit and try the jump again (e.g. pull the bike battery positive cable off, and connect the jump positive to being careful not to contact any earthed point). Actually it would be safer (less chance of a short) to pull the negative off the battery and connect the jump crocodile clip to that. If the bike runs with just the jump start, the problem is isolated to the bike battery.

so :( still not any further along. There is nothing wrong with the battery itself, its new and i have swapped it with a second new battery. (I had a spare) wont fire up with 2 fully charged batterys connected. but it will off a car, i suspect that is because it boosts the voltage to 14v.
I have noticed that the Negative terminal on the back of the engine got oil spilt on it a while back from the cam chain tensioner, which if you remove the inspection nut has oil behind it. Iv just checked the connector and the connector is fine to the engine block. but the wire clamped onto that connector has soaked up the oil and its gone up the cable. Would this cause any issues?


https://cimg8.ibsrv.net/gimg/www.sup...6d1f41fa91.png
Also for the life of me i cannot find this ground point... and it seems to be the most important ground point for the wiring harness.
Where is this?