Rob brought his Banshee into Re-Do Banshee's shop because it just wasn’t running right. Virgil cleaned the carbs, adjusted the jetting, and chased down the usual suspects — but the problem needed deeper investigation.

Then Rob hit us with a PLOT TWIST 🔀 and decided it was the perfect time to freshen up the engine with a full rebuild. Upgrading to a +4-mil crankshaft (a stroke increase over stock) only added about $120, so it was an easy choice. After checking the piston size with a bore scope and choosing the next size up, Rob ended up with 65 mm pistons paired with a +4-mil crank. That combination puts the engine right at 385 cc.

Click here for more info on Engine Displacement.

With the +4-mil build complete, Virgil went back to diagnosing why the Banshee didn’t want to rev at the top of the powerband. Once the real issues were found and fixed, the engine absolutely came alive. (Watch the videos to see what was holding it back!) At this point, Rob might need an extended swingarm just to keep all that new power under control.

Rob picked up his Banshee and took it straight to the Oregon coast — and he said it ran AWESOME. That’s exactly what we love to hear. 👍🙂

For more info on Rob's build: 

• Watch the video. 👀
• Scroll down ⬇️ for the link to watch the build's whole playlist on Youtube.
• (NOTE: As of 11/19/2025 - We are still publishing the final videos to Youtube.)
• Keep scrolling down ⬇️ to see the build specs below the video.

We are flexible and will work with you. We can: 

• Help you select the parts for your DIY build and ship them to you. - OR -
• Build your engine and ship it to you to install. - OR -
• Complete the whole build for you and install in your Banshee.

Rob's Engine Specs

• BUILD NAME:  Rob's 385 4-Mil Build
• DISPLACEMENT:  385 cc
• CYLINDERS:  Stock Cylinders Bored to 65 mm
• PORTING:  None 
• PISTONS:  Wiseco 65 mm 795 Pistons (795M06500)
• CYLINDER HEAD:  Pro Design Cool Head
• DOMES:  21 cc Redline Racing
• CRANKSHAFT:  HotRods 58 mm stroke. This is +4 mil over the stock stroke of 54 mm. Crankshaft was trued and welded.
• COMPRESSION:  150 / 150 psi
• REEDS / CAGE:  Mototassinari V-Force 4 Reeds and Cage
• CARBS:  OEM Mikuni. Came in needing cleaned, re-jetted, and adjusted. 
• CARB JETTING:  Started with 320 main jets and 30 pilot jets at our shop. 
• NEEDLES:  5N7U
• AIR SCREW ADJUSTMENT:  1 turn out
• FUEL RECOMMENDATION:  Premium Non-Ethanol (91-94 Octane)
• CLUTCH:  OEM with 3 Stock Springs and 3 Heavy Duty Springs
• EXHAUST:  Toomey T5 Pipes with Toomey Stingers and Silencers. It had spark arrestors that Rob might change out to regular silencer tips.
• TIMING:  Set to 4 degrees advanced