motopsycho87
New member
Ok, I'm a happy owner of my 2 stroke death machine, but as with every other 2 stroke out there, they are finicky bastards to say the least. So in response to a PM I got asking about my RM125 CDI, I want to write those to stop anyone having the same problems as myself.
So, your bike is running like a piece of poop. It didn't, but suddenly, it hates you...
1 - Spark plug, always start here, take it out, look at it, if it's black, it's rich, if it's white, it's lean, if it's perfectly clean, you may have a water leak, if there are bits missing or extra bits, it's pre-igniting. Anyway, change the bugger. ENSURE YOU ARE USING A RESISTOR TYPE SPARK PLUG AND CAP, THIS IS SO IMPORTANT IT HURTS!!!!
DO NOT REJET AT THIS POINT!
It's worth noting the KTM EXC/SX300 and 250's use a BR7ES plug, honestly, I think KTM are a little better at technicalities, so I went with an Iridium BR7EIX.
DOES YOUR BIKE RUN HOW IT USED TO? IF NOT CONTINUE...
2 - THE CHECKLIST
Reeds - take them out, if they're ****ed, you'll know
Ignition coil - check resistances (the specs are in your manual)
Kill switch - Disconnect, does it start?
Stator coil - check resistances (the specs are in your manual, NO CABLE SHOULD EARTH, THESE ARE CLOSED CIRCUITS) *sometimes stators can read correctly when cold, but when hot begin to break up, keep this in mind, use your mum's oven maybe?... i've only had 1 go like this, and 3 earth out (on different bikes.. not just my gasser!)
Power valve - is it moving correctly? freely?
Exhaust - some of the silencers have a habit of imploding, check!
Engine / carb breathers - just blow through them...
Crank seals - is there oil on the stator side? are you getting a much heavier blue smoke upon first start that smells a bit funky compared to your insanely expensive strawberry flavoured yum yum? is there ANY float in the rotor or crank?
Carb float height - doesn't often come out of whack dramatically, but perhaps you have a big off and it shocked it enough
Jets - DON'T change them, your bike ran right before, just check they are clear of dirt, and if you don't have a fuel filter fitted, FIT ONE YOU TIGHT ****ARD!
Electrical connections - Ok, get a wiring diagram out, everything seems fine so far, so now start checking the condition of all connections, check continuity (use the resistance setting) the close to 0 from one end of a wire to the other the better.
Piston rings - still got 'em right?
I don't think I've missed anything, but if you have anything to add, please chip in.
Chances are, if you've got this far, your CDI is shagged, and no-body wants to buy a new one, have a look at the image below, it will give you an idea of what you can fit.
Ok, so the RM125 CDI, if you go on electrex world, you can see how I came to this conclusion (attached image). The KTM CDI's will fit too.
I fitted the RM125 CDI because it looked the same, quite frankly that was it. It's important to note that the GASGAS has a shared earth with the lighting etc, take the earth's from the CDI, cut them, and make a new earth direct to the frame.
Literally, almost any kokusan cdi will fit as long as they use the same stator, make sure you get the wiring plug that goes into it, the wire colours are the same, but may fit the plug differently.
I've found RM125 CDI's from 1995 all the way to 2004 are almost identical, they have different part numbers, but the same plug, same wires, same stator.
Sorry this is quite fractal and rushed, I'm moving house today. I'll get everything neat and itemised and detailed as hell soon..
So, your bike is running like a piece of poop. It didn't, but suddenly, it hates you...
1 - Spark plug, always start here, take it out, look at it, if it's black, it's rich, if it's white, it's lean, if it's perfectly clean, you may have a water leak, if there are bits missing or extra bits, it's pre-igniting. Anyway, change the bugger. ENSURE YOU ARE USING A RESISTOR TYPE SPARK PLUG AND CAP, THIS IS SO IMPORTANT IT HURTS!!!!
DO NOT REJET AT THIS POINT!
It's worth noting the KTM EXC/SX300 and 250's use a BR7ES plug, honestly, I think KTM are a little better at technicalities, so I went with an Iridium BR7EIX.
DOES YOUR BIKE RUN HOW IT USED TO? IF NOT CONTINUE...
2 - THE CHECKLIST
Reeds - take them out, if they're ****ed, you'll know
Ignition coil - check resistances (the specs are in your manual)
Kill switch - Disconnect, does it start?
Stator coil - check resistances (the specs are in your manual, NO CABLE SHOULD EARTH, THESE ARE CLOSED CIRCUITS) *sometimes stators can read correctly when cold, but when hot begin to break up, keep this in mind, use your mum's oven maybe?... i've only had 1 go like this, and 3 earth out (on different bikes.. not just my gasser!)
Power valve - is it moving correctly? freely?
Exhaust - some of the silencers have a habit of imploding, check!
Engine / carb breathers - just blow through them...
Crank seals - is there oil on the stator side? are you getting a much heavier blue smoke upon first start that smells a bit funky compared to your insanely expensive strawberry flavoured yum yum? is there ANY float in the rotor or crank?
Carb float height - doesn't often come out of whack dramatically, but perhaps you have a big off and it shocked it enough
Jets - DON'T change them, your bike ran right before, just check they are clear of dirt, and if you don't have a fuel filter fitted, FIT ONE YOU TIGHT ****ARD!
Electrical connections - Ok, get a wiring diagram out, everything seems fine so far, so now start checking the condition of all connections, check continuity (use the resistance setting) the close to 0 from one end of a wire to the other the better.
Piston rings - still got 'em right?
I don't think I've missed anything, but if you have anything to add, please chip in.
Chances are, if you've got this far, your CDI is shagged, and no-body wants to buy a new one, have a look at the image below, it will give you an idea of what you can fit.
Ok, so the RM125 CDI, if you go on electrex world, you can see how I came to this conclusion (attached image). The KTM CDI's will fit too.
I fitted the RM125 CDI because it looked the same, quite frankly that was it. It's important to note that the GASGAS has a shared earth with the lighting etc, take the earth's from the CDI, cut them, and make a new earth direct to the frame.
Literally, almost any kokusan cdi will fit as long as they use the same stator, make sure you get the wiring plug that goes into it, the wire colours are the same, but may fit the plug differently.
I've found RM125 CDI's from 1995 all the way to 2004 are almost identical, they have different part numbers, but the same plug, same wires, same stator.
Sorry this is quite fractal and rushed, I'm moving house today. I'll get everything neat and itemised and detailed as hell soon..
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