PROJECT ATV: Banshee Back to Life!

On Nov 22, 2015

Throughout ATVing’s history, there have been a handful of machines that have earned legendary status. Among them are the famed Honda 250R, Suzuki’s LT500 Quadzilla and Yamaha’s screaming Banshee 350 twin. Yes, they are all two-strokes, and yes, they all spanned fanatic followings that can rival your favorite rock band. Head to any dune big enough to drag race up and you’ll find the three littered about. However, the Banshee will dwarf the other two in sheer numbers drastically. Why? Because Yamaha sold literally hundreds of thousands of them, and a great number are still in running condition today.

We picked up an old beater Banshee off of an Internet website for just over $2500 and set to work renovating it from the frame up. With the help of Jay Clark and many aftermarket suppliers, we have a super-fast, wicked-sounding, reliable duner that turns heads everywhere we go. The frame was powdercoated a hammered metallic blue finish, and the rest of the bike was built to match that color scheme, with many parts sourced from garage sales, Internet-sales websites (e.g., Craigslist and eBay) and even some word-of-mouth transactions through friends.

Slinging roost, coupled with twin cylinders of two-stroke glory; it’s about as good as duning gets.

ALL MOTOR
The Banshee already starts off with an advantage—its liquid-cooled, 347cc, parallel-twin, two-stroke reed-induction motor puts out power in the low 40s in completely stock trim, and we’ve seen dyno charts with a good set of pipes and an intake alone adding 15 horsepower to the Banshee’s belt. In that form, the Banshee will walk past most 450s in the dunes and belt out a brain-melting soprano scream from the silencers that is unmistakably Banshee. Simply put, there is no other sound like it out there. If you haven’t heard one, you’re missing out.

Banshees have earned a cult following for their pump-gas power potential, with a 75-horsepower motor running around in the dunes all year. And if you really want to get crazy with alternative fuels, huge stroke numbers and lots of money, you can get your Banshee up over 150 horsepower. If you don’t believe us, spend an hour on YouTube.

The controls were rounded out with Renthal 7/8 bars and Works Connection accessories, like this awesome Elite clutch perch.

The AC Racing nerf bars give a more comfortable, safe feel to the quad. We like having a solid foothold on something this fast!

One of the Banshee’s most redeeming qualities is its low-cost engine rebuilds—unless something goes terribly wrong. A set of pistons will cost you less than $200, and a head gasket is $20 at the dealership. For a skilled mechanic, a Banshee top-end rebuild is a 35-minute job, and we’ve seen plenty of them done in the dunes during a long weekend. There’s just no beating the simplicity of two-stroke repairs. No valves, no cams, no timing chains—just two pistons and a chunk of aluminum to compress against in the top end. Sounds easy, right?

This Banshee started off all stock, but after the top end gave out, we decided to give it a swift kick in the behind. We went with Hot Rods’ complete OEM stroker crank, which adds 4 mm of stroke to the Banshee’s 54mm stock measurement (yes, that’s a total of 58mm for you math whizzes out there). The kit comes with rods that are 5mm oversized, so a spec piston must be used to offset the longer rod. Vertex set us up with a set of 65.5mm pistons (stock is 64mm) to add a little more pep. To top it all off, the head was replaced with a Phatheads billet cylinder head. Banshee heads and stock cylinders have a maximum bore diameter of 66.5mm; anything more than that is pushing the reliability limits of the stock parts. Phatheads has many cc ratings and colors to choose from with the heads, so call them and let them know what kind of motor you’re building before you order. Once it was all buttoned up, our motor made an almost-perfect 390cc of displacement and much more arm-stretching power.

The Race Tech fronts we used weren’t quite stiff enough for our liking (not Race Tech’s fault), so we sent them back and had them rebuilt. When you get the spec right, it makes all the difference in the world!

Out back, Race Tech revalved the stock shock to deal with the increased speed, and Renthal supplied the drive accessories to hold up to the extra power.

TYING IT ALL TOGETHER
To complement the big motor, we set up a set of Race Tech front shocks and a rear revalve, which we didn’t quite nail on the first try, to allow us to ride it faster than the stock stuff can handle. Race Tech has many solutions—from budget to blowout—and can have your ATV riding better than you ever thought possible, so give them a call and let them know what you’re looking for. We found a slightly used Full Bore Race plastic set online, plus a billet grill and some AC Racing nerf bars, which added the security we were looking for when duning the Banshee hard. To finish it all off, Renthal came in with bars, grips, sprockets and a chain, and Works Connection supplied some bling to make it stand out.

LIKE RIDING A NOS BOTTLE
With the motor mods done, we headed to Pismo Beach for some summertime dune riding. After giving the motor a brief one-tank break-in (fuel mileage is the Banshee’s achilles heel), we let ‘er rip—and wow, what a difference.

With the Hot Cranks 4mm, long-rod, stroker kit, the Banshee really came to life. Bottom-mid power is insanely good.

The FMF Gnarly pipes are tuned for bottom-end grunt, which made the Banshee a handful off the line. Without a stretched swingarm, the power would come on like a NOS bottle with the valve stuck open. Huge wheelstands, a ton of roost and a lot of quick shifting and we were hooked. We actually ran into the problem of not having enough traction with the big eight-paddle tires we were using, as the Banshee routinely spun the tires all the way through the bottom and midrange until it leveled out on top and was time to shift. This motor would only work in the sand; in the dirt or the woods, it would just be too much. Not bad considering we spent less than $1000 on motor parts.

Having adjustable shocks on the Banshee was a big plus, as it wanted to literally throw itself into the face of every dune in Pismo thanks to its tremendous power. To say this Banshee is quick would be a huge understatement. It’s like bottled lightning; it’s fast, abrupt, somewhat violent and addicting, and like Jon Bon Jovi said, “Bad medicine is what I need.”

Jumping a Banshee can be tricky, but with all this newfound bottom end, it’s a breeze.

If you lug the Banshee a gear or two high, you can get away with cruising it through the dunes at a slow pace, but that’s not what it was built for. Slip the clutch, stab the throttle and wring it out because thrills like this don’t usually come cheap!

FINAL THOUGHTS
After spending a few days with it in the dunes, we grew very tired of the stock Banshee’s thumb throttle. We know it’s safer than a twist, but lifting the slides and springs of two carburetors with your right thumb for hours on end is just downright painful. We ordered up a Motion Pro twist throttle kit, which we will show you how to install next month. And if you’re going to beef up the motor on your Banshee, do us a favor and do the suspension as well to match the speed—you’ll thank us when you can’t stop fast enough and roll into that G-out off the throttle! If you’re a speed freak, throttle junkie or just enjoy going fast, pick up a beater Banshee and have some fun restoring yours. We’ve proven here that good times can be had well below the asking price of a new 450 or 700 sport quad!

CONTACTS
COMPANY WEBSITE PHONE NUMBER PART & PRICE
Parapros www.paraprosracing.com 951-544-0882 All motor assembly, Jetting etc. and sync carbs
Vertex Pistons www.vertexpistons.com .515-270-2302 Pro Replica racing pistons at 65.5mm: $119.84 each
Millennium Tech www.mt-llc.com 920-893-5595 Bore stock cylinders: $59.95 per cylinder
Cometic Gasket www.cometic.com 800-752-9850 Top-end engine gasket kit: $30.68
Bottom-end gasket kit: $33.97
Hot Rods Products www.hotrodsproducts.com 515-402-8100 OEM complete long-rod stroker crank +4mm: $650.88
Moto Tassinari www.mototassinari.com 603-298-6646 VForce 3 reed valve: $258
FMF Racing www.fmfracing.com 310-631-4363 Fatty pipes: $349.99
Powercore 2 silencers: $165.99
Phathead Racing www.phatheadracing.com 734-648-0103 Billet head: $289
CV4 www.cv4.net 800-874-1223 Formed silicone coolant hoses in red: $148.55
High-temp radiator cap: $22.72
Works Connection www.worksconnection.com 530-642-9488 Parking brake block-off plate: $19.95
Elite clutch perch: $149.95
Brake cover: $29.95
Renthal www.renthal.com 877-736-8425 ATV bars: $89.95
Kevlar grips: $19.95
Front and rear chain wheels: $25.95 (f)/$64.95 (r)
O-ring chain: $89.95 (104 links)
Motoseat www.motoseat.com 951-677-8325 Custom seat cover: $49.95
Race Tech www.racetech.com 951-279-6655 Rebuilt & revalved stock rear shock for heavier weight
Pivot Works www.pivotworks.com 515-402-8000 Rear-axle carrier bearings: $28.99
Front wheel bearing: $25.31
Uni www.unifilter.com 714-535-6933 Air filter (NU-4135ST): $28.95
AC Racing www.acracing.com 951-245-4040 Nerf bars: $187.00
VP Fuel www.vpracingfuels.com
Mixed 1/2 C12 and pump gas
Bel-Ray www.belray.com 732-938-2421 Oil and all grease/lubricants

Jetting:
• Per Parapros Racing: 330 main/45 pilot/VETO needle in third position
Fuel:
• Mixed 1/2 VP C12 and pump gas with Bel Ray oil
• Stock displacement – 347.44cc
• Bore and stroke to displacement:
Bore (mm) Stroke (mm) # of cylinders Displacement (cc)
64.00 54.00 2 347.44
• Bigger bore +1.5 with long-rod stroker +4mm
• Bore and stroke to displacement:
Bore (mm) Stroke (mm) # of cylinders Displacement (cc)
65.50 58 2 390.9

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