Banshee Bob is a long-time Re-Do Banshee customer who has purchased several Banshee engines from us over the years, as well as many other parts. Bob decided to ship us this tired engine for a rebuild to freshen it up. He knew he wanted a +4-mil stroker engine. Once Virgil started the tear down, he found the cylinders had a really terrible port job. Those cylinders were replaced with a good used set of stock cylinders with a mild port job. Going up one bore size on the cylinders brought the engine up to 397 cc.
After building the engine in Re-Do's shop, Virgil did a leak down test and ran it through several heat cycles in our shop's test stand. It sounded great. You can listen to it in one of the videos in the playlist below. Bob installed the engine in his Banshee, finished the break-in procedure, and it ran great. He then sold the Banshee for a nice profit. The new buyer loved the way it ran and is very happy with it. We love that!
Watch the Build
Want to watch how this project came together?
- 👀 Watch the video below.
- ⬇️Scroll down for the link to watch the project's whole playlist on Youtube.
- ⬇️Keep scrolling to see the Project Specs below the video.
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Q- QUESTIONS About Your Project? Whether you're restoring a vintage ATV, upgrading your suspension, or planning an engine build, we're happy to help. We specialize in Yamaha Banshees. If you have a different project in mind, contact us and we will let you know if we can take it on and what you can expect. We are flexible and will work with you. We offer a range of services. We can:
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Project Specs
- BUILD NAME: Banshee Bob's 397 4-mil Build.
- EXPECTED RIDING CONDITIONS: Recreational dune & trail riding
- DISPLACEMENT: 397 cc
- ENGINE CASES (CASE HALVES): Stock Cases
- CYLINDERS: Stock - Bored to 66 mm
- PORTED: Mild Porting
- PISTONS: Wiseco 66 mm - 795 Long Rod
- CYLINDER HEAD: Pro Design Cool Head
- DOMES: 22 cc 13 degree
- CRANKSHAFT: HotRods 58 mm long rod (4 mm over stock), trued and welded
- COMPRESSION: 130psi (determines fuel recommendation)
- TRANSMISSION: Stock
- REEDS / CAGE: Moto Tassinari VForce4 Reed Valve System
- CARBS: Stock Mikuni
- CARB JETTING: (varies based upon engine build and elevation)
- NEEDLES: 5N7U needles for Stock Mikuni.
- NEEDLE CLIP SETTING: Center Groove on Slide Needle
- AIR SCREW ADJUSTMENT: 3/4-1 turn out
- FUEL RECOMMENDATION: Premium Non-Ethanol (91-94 Octane) for 125-150 psi
- WATER PUMP IMPELLER: Stock
- CLUTCH: Stock Clutch
- CLUTCH BASKET: Stock
- CLUTCH SPRINGS: 3 Stock & 3 Heavy Duty Springs
- EXHAUST: TBD
- STATOR: Stock with Used Aftermarket Timing Plate, Cast Aluminum
- TIMING: Set to 4 degrees advanced