ignition questions

[rjl250]

I really need some info on this one guys. I have a 2001 RM 250 and I need to know what exactly a regulator/rectifier does and how a CDI affects the voltage going into the ignition coil. I have no spark right now. If you disconnect the ignition coil and read what's coming from the CDI you get about 460VAC but only .5mA. My book says to look for anything over 200VAC. I've all ready tried replacing the spark plug,ignition coil, stator, and pickup coil with no results. I'm afraid if I spend too much more money on this thing without fixing it my wife will start pressuring me to get rid of it. I've also missed out on about 2 months of riding so far. If anyone knows anything, or even a site that might have this info, it would be greatly appreciated. :bang:

 

[reelrazor]

A regulator/rectifer turns AC into DC and then limits voltage (pressure). Your RM shouldn't have a reg/rec as it has nothing that needs to run on DC voltage(unless you have electric start and/or a battery in it)

Have you checked for AC output from the stator? At kicking speed you should be able to see 15VAC or more. You might need a meter that reads peaks to get this.

Some CDI's collapse the field at the spark coil(stop current to make spark), some send a trigger signal/pulse(induce current to spark).

About the only thing you haven't changed is the flywheel/rotor. Have you checked it over well? Does the magnetic field 'grab' a wrench if you put it in the cavity? Is there any sign that the magnets have slipped around the circumference? Look closely. Sometimes crashes or seizures can bring the flywheel to a halt hard enough that the magnets try to keep turning. This has teh same effect as a sheared flywheel key and throws the ingition out of phase.

Good luck.

 

[rjl250]

Thanks for the reply. My bike does have a regulator/rectifier. It's listed both in the troubleshooting page in my Suzuki book, and on the parts page in the Suzuki schematics at the shop. If the flywheel was damaged wouldn't I be missing voltage at the ignition coil? Even if the magnets slipped I should still get a spark, it would just be out of timing right? I am getting the right voltage out of the stator, so that would also imply that the flywheel is OK, it's still magnetized.

 

[Phydeaux]

This is probably a dumb question, but have you disconnected your kill switch from the system and tried it? Kill buttons can short out and drive you crazy. The newer styles are better but they aren't immune to failure. Just a thought.

Also, Regulator/Rectifier on an MX bike? I thought the Suz only had a stator & rotor, a cdi unit, an ignition coil and the plug. Even the pulse coil is incorporated into the stator these days, isn't it? Maybe I'm just confused.

 

[kuritaro9]

This is probably a dumb question, but have you disconnected your kill switch from the system and tried it? Kill buttons can short out and drive you crazy. The newer styles are better but they aren't immune to failure. Just a thought.

Also, Regulator/Rectifier on an MX bike? I thought the Suz only had a stator & rotor, a cdi unit, an ignition coil and the plug. Even the pulse coil is incorporated into the stator these days, isn't it? Maybe I'm just confused.

im also confused... :think: the only zooks i have seen with a reg,/rec. are the japanese versions of the rmx250sr which looked exactly like rm's.only with street legal equpment and oil injection.im not sure if any of those bikes made it to the states though...a few guys i know that were stationed here shipped a few of those bikes back.is it possible that you got of those.does your bike have a steel tank or is it plastic???

 

[reelrazor]

Hey Phy, that's what I thought too. I went and looked at the fiche for his bike, though, and sure enough, part #32800-37F00 is listed as 'rectifier assy.' There is a sub-note, ' Model K1'(2001) on that part. The wiring harness and cdi are specific to that year also. Over on the magneto page, the stator and rotor are also '01 specific.

It doesn't explicitly state that the rectifier is also a regulator. All I can think is that Suzuki had some idea about a DC ignition in '01 and dropped it again afterwards( '02 and '03 don't have that rectifier).

As far as the magnets slipping? No, you would not necessarily be getting an out of time spark. The trigger(pulse) coil is voltage dependent (hall effect sensor). Even though yours apparently is a dc ignition, the trigger coil is 'upstream' of the rectifier and being voltage dependent needs to be on a 'crest' of the AC wave from the stator to properly sense the timing bump on the outside of the flywheel. The chip in the cdi is also looking for signal in a certain time/voltage range.

That bump can't move. It is welded to the flywheel. The magnets can and do move. A few degrees and the ac wave will be in a null right when the trigger needs voltage. It is not real common, but it does happen. At this point(if you HAVE isolated the kill circuit like Phydeaux suggested), you need to check on the rare causes of ignition failure like this.