Yamaha TRX850 Enthusiasts Forum

I have recently picked up a TRX850 cheaply.
The bike does not start, but if you take the plug out it sparks once when you turn the bike over and then does not spark again.
If you turn off and on the ignition it will only spark once again.
Does this sound like a knacked CDI/ignitor box ????
Any advice would be helpful.
Thanks.

It could be a number of things - what have you checked so far?

Have you got a manual? Do you know how to test an electrical system?

I've got a Haynes manual. So far I have checked the ignition switch, relay, clutch switch, side stand switch and kill switch and they all work correctly. And we have a brand new battery.
Any ideas ???

I would suspect the CDI, especially as you are getting a spark, even if it`s one!
The coils must be ok or you wouldn`t see any sparks, have you checked that both plugs spark just once?
Might also be the pick-up for the ignition system, it`s inside the alternator cover and picks up the magnetic pulse from the passing rotor as the motor turns.
It`s a process of elimination you need to go through to be honest.

I have had problems with losing ignition, turned out to be the pick up coil breaking down, would run for a while then stop. As mince says you need to do the fault finding methodicaly, making assumptions can be costly and may not fix the problem

I've got a xtz750 cdi which I could try in the bike. Would this work ????

I didn`t know the answer to this but one of our members happens to be an XTZ and TDM man too and I`ll refer you to this link:

http://www.xtz750.com/index.php/super-t ... hp?p=22225

See the post by tonydevil