Search for King of the Baggers engine numbers and you will find a lot of confident horsepower claims with nothing behind them. This post sticks to what can be checked: the MotoAmerica rulebook, the factory press material, and race coverage. Where nobody publishes a number, we say so.
Class rules: what the engine rules actually say
The class is governed by section 2.7 of the 2026 MotoAmerica Technical Regulations (August 14, 2026 edition). Key points for the engine bay:
- Harley-Davidson FL Touring (all years) and Indian Bagger or Touring (all years) are the eligible platforms, and the bike and its engine need MotoAmerica homologation.
- Harley engines: an originally equipped Milwaukee-Eight or air-cooled pushrod V-twin, up to 131.95 ci, normally aspirated. S&S or Jim's air-cooled Twin Cam or twin-cooled engines with MSO are also allowed up to 131.95 ci. Forced induction is allowed only on air-cooled pushrod engines, capped at 107 ci.
- Indian engines: an originally equipped water-cooled V-twin up to 112 ci, normally aspirated. Forced induction air-cooled pushrods are capped at 111 ci.
- Bore and stroke: maximum bore is 4.330 in (110.00 mm). On the Indian Challenger the stroke must stay as homologated.
- Minimum weight: 281.23 kg (620 lbs) with fuel, with ballast allowed.
- Rev limits: the edition we read lists 7,000 rpm for Harley and 7,700 rpm for the Indian Challenger. Australian Motorcycle News reported in May that MotoAmerica raised the Harley limit by 200 rpm to 7,200 to balance the two brands, so check the current bulletin before you quote a limit.
- Control parts: VP T4+ fuel, Dunlop slicks, and a controlled MotoAmerica-spec ECU (a MAXX Race unit) with no traction control or lift control strategies.
The rulebook also says the fuel pump and pressure regulator must stay stock, and the cylinder head must be the original part, though porting, valves, springs, cams, pistons, rods, crank and intake are open to modification within limits. We did not find a dry-sump rule either way, so we are not going to make one up.
Harley-Davidson's engine: a Screamin' Eagle crate motor, modified
For 2026, the Harley-Davidson x Dynojet Factory Race Team fields race-prepared Road Glides powered by modified Screamin' Eagle Milwaukee-Eight 131 Performance Crate Engines, according to Harley's release as published by Cycle News. That lines up with the 131.95 ci ceiling above. Kyle Wyman, who won the 2025 title, is named in that release.
Harley has also said it will end factory support in the class after 2026 and move resources to the Bagger World Cup; Motorcycle.com carried MotoAmerica's response, which said it is exploring options to keep supporting the class.
What Harley has not published is the output of these engines. We found no official horsepower or torque figure for the factory Road Glide, so teams don't publish exact output, and any number you see attached to one is a guess.
Indian's engine: the liquid-cooled PowerPlus, built by Vance & Hines
Indian's factory squad runs the Challenger. Rider Magazine reports a multi-year deal under which Vance & Hines oversees the factory team and builds an all-new Challenger around the liquid-cooled PowerPlus engine. Autoevolution describes the title-winning bike as using a Vance & Hines version of the liquid-cooled, overhead-cam 112 ci PowerPlus. The 112 ci figure matches the rulebook cap for water-cooled engines; Australian Motorcycle News put it at 1,835.35 cc.
So the two brands are chasing the same lap time from different directions: Harley with a big air-and-oil-cooled pushrod twin at up to 131.95 ci and a lower rev limit, Indian with a smaller, water-cooled overhead-cam engine that is allowed to spin higher. The balancing rules exist to keep that fair, and they get adjusted mid-season. Indian has not published output numbers for the race engine either.
What privateers run
The rulebook is the best evidence of what a privateer can build. A Harley team can start from a Milwaukee-Eight and take it to the displacement cap, or use an S&S or Jim's engine where eligible. Cylinders, pistons, rods, cams, valves, springs and the crank can all be replaced within the rules, and the crank weight can only be changed by up to 10 percent. Suspension is tightly controlled: only approved and listed units, with price caps of $6,000 for forks and $2,000 for shocks. We did not find a published list of privateer engine specs or dyno results from the series, so we are not going to guess at them.
The same goes for dyno claims on aftermarket pages. Output depends on dyno type, correction and fuel, so treat any single number with suspicion unless the maker shows the sheet.
What this means for a street-to-track build
The takeaway from the rulebook is where the freedom is. Race teams get big gains from airflow, tuning, displacement, and keeping the suspension and brakes consistent lap after lap, within a tightly controlled package. If you are taking a Road Glide or Street Glide to a closed course, the same order of operations makes sense: tune and breathe first, then displacement, then chassis. These are the kinds of parts we stock for Milwaukee-Eight touring bikes. We are not affiliated with any team and none of these are official or race-spec parts for the series, so confirm fitment on each listing against your model year.
Start with King of the Baggers parts, Road Glide parts, and Road Glide exhaust.
FAQ
How much horsepower does a King of the Baggers bike make?
Nobody official says. We found no published horsepower figure from MotoAmerica, Harley-Davidson, Indian or Vance & Hines, so teams don't publish exact output. The rulebook caps displacement, rev limits and weight, but not power.
How big are the engines?
Per the 2026 rulebook, Harley engines are capped at 131.95 ci normally aspirated, and water-cooled Indian engines at 112 ci.
Are your parts what the factory teams use?
No. We are not affiliated with any team or the series, and our parts are not official or spec parts. They are aftermarket parts sold for off-road and closed-course use only.
Related collections: King of the Baggers parts | Road Glide parts | Road Glide exhaust
Note: V-Twin Bikers parts and upgrades are sold for off-road / closed-course race use only and are not intended for street or road use.