RM250 weak spark

[JOHNOMCK]

Hi,
Any advice would be greatly appreciatied. Bike wont start unless I put a new plug in the bike. 1997 rm250, ignition coil checked out okay at the shop today, the stator was recently replaced by the previous owner within the last few months, I have a very weak spark, I can hold onto the plug while kicking the bike over. It seems there is not a CDI check that any local shop can do. Is the ohm meter check the manual suggests reliable, or do I have to spend 380 bucks for a new cdi and not really know if thats the problem.

Thanks

John

 

[SULLY]

I would start with the easiest items to check, also happens to be the source of the spark...IE your Stator Coil. In the manual you should have an ohmic value for the charge coils , disconnect all the wires from the stator to the CDI before measuring the coil/s resistance with a multimeter set on ohms, then follow the checkout procedure in the manual.It is not uncommon for the coils to go bad, and one result would be a weak spark.
There may also be a procedure for checking the CDI unit, but be very careful if you do this , be sure you have the right type of meter, set on the correct setting (diode) or you can damage the CDI.

 

[berno11]

Over the years I have been through 3 stators in my 250. You might want to look at yours again. Who knows, maybe it went bad already.....................

 

[JOHNOMCK]

Thanks Sully and Berno11,
Yes I did a resistance test on it and it was shy about 8 ohms. However I can put a new plug in it and it will kick right over after a few hours of riding, it wont kick over. Theory: the stator is a bit weak and once the plug starts to build up a little resistance the combination of the weak stator and used plug are too much for the ignition system to run the bike. Yea I'll put a new stator in it.

Any sugestions for an after market product that is better than the factory model?

Also has anyone ever run the $32.00 plug that the local shop says the RM250 97-2001 calls for?

Thanks

 

[SULLY]

8 Ohms is very little to be short, what was the total figure (100 ish?), so 8 is v little and would be unlikely to be enough to cause your pb.Make sure the HT lead is screwed into the plug cap, and CDI unit properly. If you have access to a similar bike, try to swap components over, starting with the HT lead, they can crack internally and weaken the spark, especially when it all warms up and the insulation on the plug lead gets more flexible allowing any cracks in the conductor to move around.

 

[shawnhitsman]

Thanks Sully and Berno11,
Yes I did a resistance test on it and it was shy about 8 ohms. However I can put a new plug in it and it will kick right over after a few hours of riding, it wont kick over. Theory: the stator is a bit weak and once the plug starts to build up a little resistance the combination of the weak stator and used plug are too much for the ignition system to run the bike. Yea I'll put a new stator in it.

Any sugestions for an after market product that is better than the factory model?

Also has anyone ever run the $32.00 plug that the local shop says the RM250 97-2001 calls for?

Thanks

i put the 32 dollar plug in mine

 

[JOHNOMCK]

weak spark

I bit the bullet and bought a new CDI from Electrex. Their box
eliminated the need for the stupid 32.00 plug... I was told early on that if I didn't use the 32.00 plug it would f--- uip my stock CDI and it did. After I put Electrex's new CDI in I could use any comparable plug..

Its worth the investment.

j

 

[berno11]

I know this is an old thread. But I have been using BR8ES plugs in my 97 rm250 for 9 and a half years and I am still on the original stock CDI