Polaris Trail Boss Spark Plug
GarageDex's powersports data shows the Polaris Trail Boss uses a BKR5E spark plug, gapped to 0.028", or upgrade to the BKR5EIX iridium plug.
Spark plug fitment by year
| Years | Standard plug | Iridium upgrade | Gap |
|---|---|---|---|
| 2002-2003 | BKR5E | BKR5EIX | 0.028" |
500cc atv. Match the exact part code, thread reach, and heat range. The iridium column is the same-fit upgrade for a longer service life.
Spark plugs for your Polaris Trail Boss
The recommended plug is a BKR5E. Match that code - spark plugs are thread-, reach-, and heat-range-specific, so the part number matters more than the brand. Worth considering: the BKR5EIX iridium upgrade - it fits the same port, fires cleaner, and lasts far longer between changes.
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Frequently asked
What spark plug does a Polaris Trail Boss take?
GarageDex's powersports data shows the Polaris Trail Boss uses a BKR5E spark plug, gapped to 0.028", or upgrade to the BKR5EIX iridium plug.
What is the spark plug gap on a Polaris Trail Boss?
The Polaris Trail Boss spark plug gap is 0.028". Set the gap with a feeler gauge before install - iridium plugs come pre-gapped but always verify, since a wrong gap causes misfires and hard starts.
Are iridium spark plugs worth it on a Polaris Trail Boss?
The BKR5EIX is the iridium upgrade for the standard BKR5E. It fits the same port and heat range, fires more reliably, and lasts far longer between changes - a worthwhile swap for most riders, though the standard plug is perfectly fine if you change plugs on schedule.
How often should I change the spark plugs on a atv?
Standard plugs typically want replacing every 8,000-12,000 miles (or per your service manual); iridium plugs go much longer. Fouled or worn plugs cause hard starts, misfires, and poor fuel economy - a cheap part that punches above its weight.