The PolarFireplug CDI will be available again starting October 2021.  Our goal is to eventually phase in the single-coil configuration, Initially both styles will be available (no performance difference) until our small-coil stock runs out.  Pricing and warranty is same for either style.






Contact us by E-mail (e-mail for quickest reply) or by Phone: (810) 765-0820 (EST, limited phone availability) with any questions.

HewTech Electronics is offering A POLARFIRE Replacement FIREPLUG CDI for the 73~78 Ski-Doo & Moto-Ski’s ignitions.

The redesign was the result of issues found on 77/78 models.  We’ve determined the cause and changed the CDI design to cover all PolarFire years from 73-78 models.

NOTE:  The initial timing will require re-adjustment (advanced by 4*-5*) to match the timing mark to OEM specifications @ 5000 RPM.  This will be necessary to fully optimize engine performance.   This revised CDI design actually will advance about 4*-5* degrees initially, then pull back to match OEM marks above 5000 RPM.  This additional timing advance will add some lower RPM performance that wasn’t there with the OEM CDI.

If timing is not readjusted for the new CDI, the engine will run, but you are giving up significant performance gains.  This may not be critical on a show-sled, but any racers or serious trail rider will definitely want to optimize the timing to take full advantage of the performance gains. 

2 coil version includes 2 New Coils (limited to coil stock availability)
The Single-Coil model includes 2 spark plug wires.
CDI mounts in original factory location using original factory connector
Includes a separate Kill-Switch wire for common 2-wire tether switch connection (ground the wire through tether or kill-sw to stop spark).

NOTE:  Suggest using non-resistor B8ES-B9ES spark plugs for most spark energy transfer to the plugs.  However some Digital tach’s may require the use of a BR-resistor type to eliminate erratic display operation


  • 1973~1975 TNT-F/A & 75 Everest
  • 1975 RV245
  • 1976 RV250 & RV340 (RV345)
  • 1977 RV340
  • 1978 RV/Sonic models that use PolarFire CDI

NOTE: HewTech Electronics LLC cannot warranty the individual coils used in the ROTAX FIREPLUG CDI. We purchase these parts from PARTS-UNLIMITED, and test them prior to installation. We have absolutely no control over their quality or workmanship to warranty them. PARTS-UNLIMITED does not offer ANY warranty on electrical parts, therefore HewTech Electronics LLC cannot extend our warranty to cover the external coils. If a coil is found to have failed, HewTech Electronics LLC will warranty the labor at no cost to replace a coil, however cost of the coil & shipping is the responsibility of the CDI owner, and not HewTech Electronics LLC.

Uses original Factory 3-wire AND/OR any standard 2-wire kill-switch!


Verify that the chassis to engine (bonding) wire is connected & in good condition. Without this wire connection, the FIREPLUG CDI may not spark or operate correctly.

NOTE: The stock CDI may operate without this bonding wire, since it uses the aluminum case as a common ground. The FIREPLUG CDI case is isolated and no current passes through it, therefore the wire to connect the Chassis to Engine is necessary.

The Brown wire from the connector grounds to the engine crankcase internally at the stator plate. This wire often times breaks or corrodes over time. Verify your brown-wire does connect to engine ground coming from your engine, through the harness to the CDI.

Disconnect kill-switch harness, often times the kill switch & key-switch fail & short out the CDI box.

Verify Stator & Trigger resistance:

315-335 ohm Stator (RED to Brown)
55~60-ohm triggers (striped wires).

Additional information

Weight 2 lbs