new member - new bike - no spark! xj650

Hi!
Am new to this site - Hoping to get some help!
Have purchased a 1981 XJ650 as a non-runner.
There was no starter fitted to the bike.
I rebuilt one out of a box of bits and now have a bike that turns over but has no spark whatsoever.
Have had out the plugs and tried them all (to proove one side of coil system), but no spark at all.
Have fitted a set of brand new plugs to rule them out.
I was assured the bike was a good runner before being 'laidup' for a year or so (which in this case, i do believe).

The bike has been modified ('chopped').
The loom has been modified to suit aftermarket ignition switch etc, but not
very neatly.
I have good mechanical skills,but only minimal electrical knowledge!
I've read several posts on no spark, but was hoping for a guide on the most common causes and a 1.check this, 2. check that, 3. check the other etc type of thing.

CAN ANYBODY PLEASE HELP MEEEEEEEEEEEE???!!!!!

Thank you in advance

 

Checking the plugs was a good start. I'd check the stop run switch on the right handle.

Check the fuse block, you may have a bad fuse. But with age it's probably due for replacement and can be cause for a number of problems.

 

ignition switch, start / stop switch, or possibly pickup coil.. so here is the main question ... do you get voltage to the coil leads when trying to start..... if not are you passign voltage to the ignition from the start stop switch? if so ckeck your pick up coil for continuity...... also dont forget that notorious issue with the kick stand switch.

 

If you have a meter, you should check the voltage between black and red/white on the four-pin connector of the TCI module while cranking. It should be at least 10V.

Voltage to the red/white wire comes through the start/stop switch and originally from the ignition fuse. So, if the voltage is 0, those are the two main places it may be interrupted.

If it's more than 0 but less than 10, while cranking, you may have a bad battery, or you may still have bad fuse contacts in the fuse box.

It's also possible, though less likely, that you have a bad TCI box, but measurements will help narrow down whether that's the case.

 

Rollover with out spark on these guys can also be a simple weak battery. System does not generate electricity below 2k rpm. Every thing runs of battery below that. Often, battery will be low and turn bike over, but not enough juice to make the spark. Sometimes when this happens, you will get an attempt to fire right when you take your finger off the switch.

 

Hi guys,

Thanks for the responses so far...
I haven't been out to the garage to try any of your suggestions yet.

But...
As previously mentioned, the bike has been customised, so i dont know what remains of the original loom, and what is 'homemade'.
I haven't yet seen ANY fusebox or stop switches.
The right hand control MAY not be XJ - the lights work off the direction indicator switch - no indicators fitted - there is the possibility of the 'stop switch' being worked off of the original light switch perhaps???


Thanks again, and keep the suggestions coming please!!