90cc Piranha engine kit semi-auto

Piranha Engines

$533.60 $533.60

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PIRANHA 90cc Engine KIT includes 90cc Engine, 19mm Mikuni Carburetor, Wire Harness, CDI, and Ignition Coil.
This engine is a great update for any pit bike, Honda CRF50, Z50, Trail 70, and ATC70!

  • Big Valve E22 Performance Head
  • 4 Speed semi-auto transmission (4 gears Up)
  • Comes complete with Kicker, Intake Manifold, Gaskets, and Gear Shifter.


Displacement 86cc
Engine Type Air Cooled, Single-Cylinder, 2-valve, 4-stroke
Bore/Stroke 47mmx49.5mm
Final Drive Chain
Fuel Delivery no
Fuel Unleaded / 93 Octaine
Reccomended Engine Oil 10W-40 Petroleum Based (Nonsynthetic)


Kick Start Yes
Electric Start no
CDI no
Auxiliary Output Yes


Transmission 4-Speed Semi Auto (Four Up)
Shift-Pattern Four-speed Transmission: N-1-2-3-4
Semi auto (no hand clutch)

Type 4-Stroke single-cylinder OHC air cooledPiranha 90cc

Engine Specs

Bore: 47mm


Displacement: 86cc

Big Valve E22 Head

Gears:4 speed ,Bottom neutral

Carb: Mikuni 19

Ignition:CDI Flywheel type

Starting Tips

Starting pit bike engines will take some practice. All pit bike engines have relatively high compression ratios and require a "quality over quantity " approach in order to ensure quick start-ups and avoid mechanical mishaps. It is important to follow this routine the first few times when first attempting to start your bike. 

  1. Slowly kick the engine over until the kick start reaches a compression stroke (the point in which the kick start lever is hardest to push down.)
  2. Slowly continue to press the kick starter until the engine rotates slightly through the firmest point in the compression stroke.
  3. Allow the kick start lever to return back its top rest position
  4. With a quick and balanced motion - Move down forcefully on the kick lever. These motors need a strong, quick kick to get started.
  5. If you fail to follow this procedure, especially with longer stroke engines or 125cc + bores you can cause serious damage to your crankcase, clutch and transmissions assemblies!

Tips to Avoid kickback 

  1. Hold onto the crossbar pad with your throttle hand while kicking the bike over to avoid twisting the throttle open by accident
  2. Before start up - turn the idle screw on the carburetor in a turn or 2 (turn the screw back out to normal idle setting once running.)
  3. Use a digital CDI with variable ignition timing at start-up, this will help reduce kickback and allow the bike to start much easier compared to the stock CDI unit.
  4. If ignition timing is adjustable it should be adjusted to the minimum
  5. Furious, repeated kicking will not get the engine started - firm, full stroke kicks are the only way to get them to start first kick, every time "Quality over Quantity"
  6. The throttle must be completely closed when you kick the engine over or it will kick back EVERY TIME.
  7. A small blip of the throttle may be used when the engine is hot if required but NO more than 10 ° opening of the throttle in any case


Crate Engines are sold AS IS with no warranty whatsoever.