Which Cylinders Do I Want?

Each engine build is different. Peak HP and power curves will vary depending on the amount of compression, timing, reeds, carburetors and exhaust that are being installed. Porting the cylinders changes the power curve. Here are some general considerations: 

Cast Precision Industries, Inc (CPI)

  • All CPI cylinders are Nikasil coated. 
  • Serval and Cheetah Cub cylinders have different port timing. Both are manufactured by Cast Precision Industries, Inc (CPI). 
  • Serval has more mid-range power band. Great for trail riding and dunes.
  • Cheetah Cub is more high-revving than the Serval. This makes it better for drag racing. It can also be ridden in the dunes. A serval would be a better option for dirt trail riding. 
  • Mono Cylinders - While stock Banshee cylinders are 2 separate pieces, CPI manufactures their cylinders as 1 piece with 2 cylinder bores
  • Cheetah Cub Line - The cylinder names "Cheetah" and "Cub" and "Cheetah Cub" are used somewhat interchangeably. 
    • Cheetah Cub, Super Cub, Cheetah DM, and Cheetah DMX cylinders are all the same line of cylinders. 
    • Engine builds with Cheetah Cub and Super Cub cylinders are sometimes referred to as just "Cub" builds. Examples are 421 Cub (instead of 421 Cheetah Cub), or 472 Cub (instead of 472 Super Cub or 472 Super Cheetah Cub). 
  • CPI's Wampus Cylinder Line is intended for the rider who wants a stock appearance with the performance of a Serval Cylinder.
    • Most of our customers opt for the Serval or Cheetah Cub cylinders, but this is an option we can order for you. We would have to check on availability and ETA for this option. 

Assassin-2 Cylinders

  • Manufactured by Driveline Performance. 
  • Assassin-2 cylinders have a mid-range power band. Great for trail riding and dunes.
  • Available with Nikasil coated OR steel sleeved cylinders.
    • Nikasil Coated Cylinders - if bored over in the future, these will need to be shipped off to be recoated in Nikasil. This can increase the time needed to complete your future engine rebuild.
    • Steel Sleeve Cylinders - are for people who do not want a Nikasil bore. On a future engine rebuild, you just bore these cylinders to the next size and skip the Nikasil replating process. 

Stock Cylinders

Banshee Stock Engine = 64mm and is 347cc.

Stock Engine Rebuild = If an engine has worn or damaged stock cylinders, the top end of the engine can be rebuilt or repaired by boring the cylinders slightly larger than stock and installing larger pistons. 

Stock cylinders are bored larger than the stock 64mm bore. Displacement varies depending on how large the stock cylinders are bored to and the stroke length of the crankshaft used. This engine build is often done as a rebuild to repair the stock engine when the cylinders are worn or damaged.

A stock engine rebuild can be done a few times over the years if needed. The engine will still perform as a stock engine or slightly better, and can still have a lot of life left in it. 

Crankshafts that Can Be Used with Stock Cylinders

Stock Stroke Crankshaft 

  • 350-375 cc. This is 64.25mm to 66.5mm bore with a stock stroke (54mm) crankshaft. 
  • A stock crankshaft or an aftermarket stock stroke crankshaft can be used. 

+4-Mil Stroke Crankshaft

  • 376-403 cc. This is a 64.25mm to 66.5mm bore with +4-Mil stroke (58mm) crankshaft. 
  • An aftermarket stock stroke crankshaft can be used.
  • A +4-Mil stroke (58mm) crankshaft is the largest crankshaft that we will build an engine using a stock engine case. This is because the engine case does not need to be trenched to make clearance for the swing of the crankshaft.

A stock engine case can be trenched to accept a +7 Mil crankshaft - BUT - there are tradeoffs with reliability and durability of the engine. 

The crank well and engine case thickness are reduced, which weakens the engine case. At the same time, you are adding engine components that create more power in the engine.

Before aftermarket engine cases were developed, builders would add epoxy or weld material to strengthen the cases. 

In our opinion, once you get to the point where you are trenching an engine case, it makes the most sense to trench an aftermarket, higher performance engine case from Driveline Performance. DP has added extra material to the design of these cases in all the places the stock cases were lacking. This allows for today's larger stroke cranks and aftermarket cylinders. You can trench these cases up to a 14mm stroke without any epoxy or welding. The top case can be bored and machined to fit a Cheetah Cub DM cylinder and not break through on the sides of the transfers. 

 

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Do You Have a Project?

If you have a Banshee to restore, want to upgrade your suspension, or are 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. 

CALL 📞📱 or message us at 541-419-6054. 

We offer a range of services. We can:

  1. Help you select parts for your DIY build.
  2. Help you Pack and Ship your Engine to us, build your engine, then ship it back to you to install.
  3. Complete the engine build for you and install in your Banshee.
  4. Inspect, repair and service the whole Banshee for you.
  5. Build or restore your Banshee.
  6. We may also be able to locate a local Banshee for you - then install your newly built engine in it.

Project References:

  • We calculate engine displacement based on the bore in the engine's cylinders and the stroke length of the crankshaft. Click here for more explanation in our Banshee Engine Displacement blog article. 
  • Click here for information about Banshee engine break-in procedures. This includes our recommendations for Fuel to Oil Ratios and Selecting the Correct Fuel.

About the Authors:

This project article was written by Janel with plenty of help from Virgil. Virgil is the Banshee mechanic, and I am the website mechanic. I do own and ride a Banshee, which helps. 

The Re-Do crew hopes sharing our project info and specs may help some with their own projects, or that you find it interesting. I want our technical info to be accurate and helpful.

Please do let us know if you like our project articles, or if you think I need to correct something. You can send an email to info@redo-parts.com - and your comments will be passed along to me. 

Thanks ~Janel 😉👌