RM250 rm 250 no spark. need help

Got a 91 rm 250 that is getting no spark. There is resistance on my coil. Wires have continuity. Fly wheel is clean. New stator plug cap and wire. Im out of options. I need help or a manual lol
 
Did you check the CDI box? Youve checked everything but that. Is the stator set up correctly (ie timing?) I have to ask these types of questions as I dont know you and can only assume that your not a mechanic. PLEASE get yourself a manual. It is your best friend when it comes to working on your bike. www.Rockymountainatv.com Will have one for your year make model. Be it a Haynes, Chilton, or the OEM manual that would have come with your bike new. You need one.
 

SRAD97750

Moderator
Staff member
There is no test for a CDI as far as I know.
Also never seen one fail. Never suspect the CDI...

FIRST, Change your spark plug with a new one and try again.
Then change that new one with another new one. I have had NGK spark plugs bad, out of the box.

You need to take 4-5 measurements, whether these components are new or not.
1. Resistance through the secondary coil (Ground to plug cap)
2. Resistance through the primary coil (Input terminal to ground)
3. Pickup coil resistance and continuity
4. Killswitch continuity when set to KILL, no continuity when set to RUN.
5.Verify the CDI/pickup coil/ignition coil has good grounds. (You will need a wiring diagram for finding the CDI grounds.)

Report back and we'll see where you stand.
Good luck!
-BIG DAN:thumb:
 
Thanks alot for all the help and quick responses. I work some hectic hours so its difficult getting online or wrenchin on my bikes. Il get out there and check resistance tomorrow after work. My email address is mrpizzlestick@gmail.com . Feel free to shoot me a email. A manual would help out alot.
 

SRAD97750

Moderator
Staff member
OK, here's your wiring diagram. Took forever to find.
wiringLarge.jpg

-BIG DAN:thumb:
 
I got .7 through the primary. 8130 through my secondary and 111 through my pick up. Tried several good known plugs. Grounds are good. Kill switch is fine still nothing
 

SRAD97750

Moderator
Staff member
Hows the plug wire itself? Have you cut back a 1/4 inch to get to fresh wires screwed onto the screws?
Lemmie think for a bit.... Troubleshooting electronics is tough over the internet... -BIG DAN:thumb:
 
Yes. All the electrical is new from the previois owner. Im no mech but I have several 2 strokes and am quite handy. The plug wire is good. I have cut a quater inch off. Ive tried everything I possibly can think of. However the gap from the tab on the flywheel and the pick up is rather larger more around a quarter inch. The pick up itself was pretty dirty, I cleaned it up a little but still nothing. The stator looks brand new. Allnew wires tthat ive checked continuity.
 

SRAD97750

Moderator
Staff member
What resistance do you get through the stator coil? Maybe the system isn't getting power at all? Just throwing out ideas, tracing the system backwards... -BIG DAN:thumb:
 
I can check tomorrow. Its tough without a manual. Not having the factory specs to be testing for.

I will check through my books. Once i find them. I don't know if i have one for a 91. I i think each year around there has different specs for each year. And i'm not much help with electrical.



Disconnect kill switch
New plug... (Check plug on another motorized machine to check firing)
Remove coil and sand the mounting spot.
Check all connections.
 
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