Yellow Addiction: Yamaha R5 Street Tracker

Scott Pickett’s “Classic American Street Tracker”…  

Introduced in 1970, the Yamaha R5 350 was the predecessor of the storied RD twins that smoked their way into the hearts of a generation. While the RD series would add six-speed transmissions and reed induction, the R5 paved the way, cementing Yamaha’s reputation for producing two-stroke giant-killers.

“The Yamaha R5 350 was in many respects the crown jewel of Yamaha’s continuing 2-stroke program. While it put out the same 36hp as the previous year’s twin, an increase in torque and other refinements meant it easily boasted the best performance of any 2-stroke Yamaha had ever made.” –Motorcycle Classics

The R5 was much less peaky than its predecessors, with Cycle World claiming that “the R5 pulls like a 500 when you twist the grip in fifth.” As you might imagine, this smoother power delivery was especially appreciated on dirt tracks around the country, where a light-switch powerband is no friend to traction.

Recently, we heard from Scott Pickett of Colorado, who literally grew up in his father’s Yamaha shop in Kankakee, Illinois, which opened in 1963 — the same year Scott was born! As you might imagine, Scott got an early start on two wheels.

“I built my first custom motorcycle at 15, when I stuffed a CS5 200cc engine in a LS2 100CC frame! I used an RD60 tank and a TY175 trials bike seat and made some clip-on bars for it!”

Since leaving Illinois in the early 80s, Scott has continued working on bikes out of his home garage, doing everything he can himself.

“I do all of my own fabrication and welding and even all of the sewing of upholstery. I did send the cylinders out to be bored, but it pains me to do it since I have the ability to do it myself, just not the equipment!”

Having raced flat track on Yamaha XS650/750s and a Trackmaster-framed TT500, Scott picked up this ’70 R5 as a “very rough original barn find” and set out to create his vision of the “classic American Street Tracker”…with a focus that would be more Tracker and less Street.

“The goal was to build a bike as close to an actual period-correct flat tracker while still meeting minimum street legal requirements.”

Aptly nicknamed “Yellow Addiction,” this two-stroke street tracker features an XS650 front end — resprung for the R5’s lighter weight with gold cartridge emulators — and a modified ’86 Yamaha Fazer swingarm. The bike is rolling on a pair of Yamaha 19-inch front wheels, with quick-change rear wheel adapters for easy gearing changes and an oversize rear disc to compensate for the two-stroke’s lack of engine braking.

The engine was rebuilt with a new crank and top end, but Scott kept the stock porting for a more dirt track-friendly power curve. It now breathes through a set of Mikuni carbs with UFO-style “flow optimizers” that Scott made himself, as they don’t make them in the 28mm size he needed.

“They draw so much more fuel up the needle that I went from #25 pilot jets down to #12.5s and I had to lower the needle to its lowest setting! It went from a bit sluggish to a ‘lift the front wheel’ kinda snap off idle!”

The bikes looks properly track-ready with the XR750-style Gopher Glass bodywork and speed-block livery, as if it’s just escaped the nearest dirt oval for a rip through town — just as intended. While Scott did 99% of the work himself, he credits his old man for teaching him the way of two wheels:

“I’d like to thank my dad for teaching me to love motorcycles and trust my ability to build anything. He has an ear for carb tuning that I will likely never have, but I am still learning from him at 85!”‘

Below, we talk to Scott for the full details on this “classic American street tracker.”

Yamaha 350 Street Tracker: Builder Interview

• Please tell us a bit about yourself, your history with motorcycles, and your workshop.

I grew up in a Yamaha shop in Kankakee, Illinois. My father opened the shop in 1963, which is the year I was born, so my entire childhood was in and around the motorcycle shop. I built my first custom motorcycle at 15, when I stuffed a CS5 200cc engine in a LS2 100CC frame! I used an RD60 tank and a TY175 trials bike seat and made some clip-on bars for it!

I started working summers and Saturdays in the shop just cleaning bikes and toilets and windows, then moved into the parts department at 14 and then into service at 16. By the time I graduated high school my dad had sold the shop and I was the only mechanic in the shop under the new owner.

I moved to Tallahassee, Florida in 1982 and spent 35 years there before moving to Northern Colorado in 2019. I’ve built a few XS650-based street trackers and raced flat track on XS650/750s and a Trackmaster TT500. Since leaving Illinois I have just worked out of my home garage and done as much work myself as possible.

On this most recent R5 Tracker build I either painted or powder-coated everything myself except for powder-coating of the frame, which was just too big for my kitchen oven! I do all of my own fabrication and welding and even all of the sewing of upholstery. I did send the cylinders out to be bored but it pains me to do it since I have the ability to do it myself, just not the equipment!

• Tell us about your Bike…

This project started as a very rough original barn find, but was transformed over the past year and a half into my vision of the classic American Street Tracker. As I said, all work was done by me in my home garage except powder coating of the frame (which was just too big for my oven) and boring of the cylinders!

 

The goal was to build a bike as close to an actual period-correct flat tracker while still meeting minimum street legal requirements. I feel like the style should be more Tracker and less Street.

The front end was swapped for a mid-70s Yamaha XS650 front end and the steering stem shortened to fit the R5 frame. The swingarm is borrowed from a 1986 Yamaha FZX 700 Fazer and has been narrowed and shortened to match the stock R5 frame and wheelbase.

The tank and tail are fiberglass in the XR750 style from Gopher Glass and painted in traditional “Molly Stripe” Yamaha competition yellow.

The engine was rebuilt with new crank and fresh top end and all new seals and bearings, but stock porting retained to favor a more dirt track friendly power curve.

New 28mm Mikuni carburetors with custom-made UFOs deliver the fuel through a single K&N filter for much improved throttle response through the low to mid ranges.

Wheels are Yamaha 19” cast front mags with quick-change knock-off rear wheel adapters to make gearing changes at the track easy. Hydraulic disc brake in front and an oversized rear disc provide the stopping, as there is almost no engine braking on the two stroke twin. Hydraulic clutch with FZR1000 friction plates and heavy clutch springs puts all the power to the rear wheel!

Nods to reliability are new vape electronic ignition and charging system with Dewalt-style Lithium Ion battery and LED lighting.

All switches are hidden except for the kill button and horn button so as not to spoil the clean flat tracker look of the bars. The single vintage-style electronic/analog tachometer is also in keeping with the flat tracker look. I find that a few minutes with a GPS and you can tell what speed you are going in top gear at the different RPM.

• Can you tell us what your R5 is like to ride?

This thing is a ball to ride! It still has stock porting, because I had initially intended to race it at the local flat track. I didn’t want the power band to come on like a light switch in the dirt, so the stock porting makes power from pretty low and pulls really smoothly from 4-8,000 RPM.

The suspension took a while to work out because the forks, being from an XS650, were too stiff for the lightweight R5. I finally found a good spring rate and used gold cartridge emulators for easy dampening adjustment. The brakes are amazing on this light bike and have that “just right” feel!

Finding a matching set of master cylinders for the hydraulic clutch and brake took a bit of trial and error, but in the end, I really like the way they turned out. The UFOs in the carburetors made a huge difference in throttle response too. The company that invented them, Thunder Products, doesn’t make them for the 28MM Mikuni VMs, so I made a set using epoxy putty!

They draw so much more fuel up the needle that I went from #25 Pilot jets down to #12.5s and I had to lower the needle to its lowest setting! It went from a bit sluggish to a “lift the front wheel” kinda snap off idle!

• Is there anyone you’d like to thank?

I’d like to thank my Dad for teaching me to love motorcycles and trust my ability to build anything. He has an ear for carb tuning that I will likely never have, but I am still learning from him at 85!