Teryl reached out to Re-Do Banshee after his engine suddenly started running poorly. Virgil’s first recommendation was simple: start with a compression test.

Teryl grabbed a tester from Harbor Freight (or a nearby store) and checked the numbers. One cylinder came in at 150 psi… but the other showed only 40 psi. A big drop — especially on just one side — is a clear sign of piston or cylinder damage.

Wanting to get it fixed right, Teryl ordered a shipping box from Re-Do Banshee and sent his engine in for a full diagnosis. When he bought his Banshee, he was told it had a 4-mil crankshaft, and Virgil was able to confirm that once it arrived.

After Virgil also confirmed damage to one of the pistons and cylinders, Teryl made the decision to upgrade to a full 421 Serval build. Virgil ordered up the parts and assembled the 421 Serval with no issues. Now both cylinders have about 150 psi compression.👌 He completed the heat-cycle process in the shop.

Then Teryl's fresh engine was shipped back to Ohio. After Teryl installed his new 421 in his Banshee, he went out for a ride and did a plug chop to dial in the jetting.

Not long after, Teryl called to share the good news: his Banshee RIPS. Tons of power. Runs amazing. He’s thrilled with his new 421 Serval build — and that’s what we love to hear! Woohoo!👍🙂 We hope Teryl will share a short video of him riding it soon. 🤞

For more info on Teryl's build: 

• Watch the video. 👀
• Scroll down ⬇️ for the link to watch the build's playlist on 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 your engine in your Banshee.

Teryl's Engine Specs

• BUILD NAME:  Teryl's 421 cc Serval Build
• DISPLACEMENT:  421 cc
• CYLINDERS:  68 mm Serval Cylinders - from Cast Precision Industries, or CPI. 
• PORTED:  As Cast. This means they are untouched from the casting at CPI. 
• PISTONS:  Wiseco 68mm
• CYLINDER HEAD:  Redline Racing Cool Head
• DOMES:  22 cc
• CRANKSHAFT:  Came with a HotRods 58 mm stroke. This is +4 mil over the stock stroke of 54 mm. Crankshaft was already trued and welded.
• COMPRESSION:  150 psi
• REEDS / CAGE:  Mototassinari V-Force 4 Reeds and Cage
• CARBS:  Keihin 35 mm PWK
• CARB JETTING:  Started with 170 main jets and 50 pilot jets at our shop. Teryl will do a plug chop to determine final jetting.
• NEEDLES:  CEL
• AIR SCREW ADJUSTMENT:  1.5 turns out
• FUEL RECOMMENDATION:  Premium Non-Ethanol Gas (91-94 Octane)
• WATER PUMP IMPELLER:  OEM
• CLUTCH:  Modquad Lockout Clutch with Cover
• EXHAUST:  Shearer Big Bore In-Frame pipes with Shearer silencers.
• TIMING:  Set to 4 degrees advanced