The Thumper: Sandi Piper’s Yamaha SR400

Yamaha SR400 Custom

A Maltese Thumper from Sandi Piper / Choppershack… 

The Yamaha SR400 is one of those bikes that riders seem to bond strongly with. Perhaps it’s the heartbeat-like thump of the short-stroke single-cylinder engine, the classic lines, or the sheer timelessness of a bike that’s been produced nearly unchanged from 1978 to 2021. Although the SR400 became fuel-injected in 2010 for emissions reasons, the bike remained twin-shocked, air-cooled, and kept the same classic silhouette throughout its 43-year production run.

Yamaha SR400 Custom

Certainly the simplicity was one of the attractions that drew Sandi Piper (@__sandi__p) of Malta to the machine — a woman who’s owned a whole stable of bikes over the last 15 years, including four Sportsters, a Ducati, a Honda Nighthawk, two Mash commuters, and more.

“I was looking for an older model that was mechanically simple yet reliable, so nothing with water cooling, fuel injected, or loads of cylinders! A couple years back, I had a ride on a good friend’s Suzuki 400 Tempter, and it convinced me a big single was the way forward.”

Yamaha SR400 Custom

Of course, Sandi wasn’t likely to keep her 1994 SR400 stock for long.

“I bought it with a view to creating a flat track scrambler style custom. After cutting off a load of weight, we were left with the engine and modified frame. I’ve always loved the Gulf livery colours, so wanted to have these on my bike! I also love tigers too! So I wanted to incorporate that with some cool font also.”

Yamaha SR400 Custom

With the help of Malta’s Choppershack, the modifications were extensive, including a full engine rebuild, shortened subframe with one-off seat, rebuilt wheels with Avon rubber, louvered side panels, lots of one-off brackets and pieces, and of course the custom paint, carried out by Flakey’s Custom Paint. Sandi was heavily involved in the process:

“I learned a lot with this build from assisting with the assembly of the rolling chassis, installing the rebuilt engine, and so on.”

Yamaha SR400 Custom

Of course, having so much sweat equity in a build makes it that much more satisfying to ride, and the weight savings, modern rubber, and performance tweaks make this one fun single on the road:

“The bike weighs less than a 125cc, performs better than a 400cc, and is just such a joy to ride!”

Yamaha SR400 Custom

Aptly nicknamed “The Thumper,” this is one bike that Sandi doesn’t plan to let go:

“This Yamaha, out of all of them, this really is the one I will keep forever (she says) — nope I mean it!”

Yamaha SR400 Custom

Below, we talk to Sandi for the full story behind “The Thumper.”

Yamaha SR400 Custom: Owner Interview

Yamaha SR400 Custom

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

I was always mesmerized by motorcycles, especially when I used to visit family in India when I was younger. I remember fondly being pillion with an older cousin riding a Royal Enfield, but back then girls/women sat sideways, and looking back as a kid, I never really questioned it, as this clearly isn’t the ideal way for a pillion to sit! I.e cornering, bends etc! What a nightmare it must have been for him! Later on I found out it was a bit of a stigma for women to sit with their legs to either side. If I go back someday, I shall be riding myself!

Yamaha SR400 Custom

Fast forward to my early twenties, I met someone who was a custom bike builder and motorcycle fanatic and I was hooked from then on! I’ve had a few bikes. My first bike was a Suzuki Marauder, and it wasn’t the fastest of bikes, but it was a good learning base to get more confident before moving onto something faster! After that, I got a Harley. In fact, I’ve had four Harley Sportsters over the years with various types of customisation done on them. One also became a donor bike for a chopper, which I had for a short period. A Triumph Bonneville also featured throughout my years of riding. I have also owned a Ducati and two Mash Motorcycles, which were mainly for commuting. And Kawasaki 440L, which is the next project! I also owned a Honda Nighthawk, which was my commuter for a short time in the UK. I wish I had kept that because that would have been a great donor bike! So all in all, I’ve had a few bikes over the last 15 years. However, this Yamaha, out of all of them, this really is the one I will keep forever (she says) — nope I mean it!

Yamaha SR400 Custom

How did you decide on a Yamaha SR400 as the donor bike?

I was looking for an older model that was mechanically simple yet reliable, so nothing with water cooling, fuel injected, or loads of cylinders! A couple years back, I had a ride on a good friend’s Suzuki 400 Tempter, and it convinced me a big single was the way forward.

Yamaha SR400 Custom

Can you tell us what it’s like / how it feels to ride the finished bike?

The bike is so much fun to ride! It’s mechanically very simple and is kickstart only with drum brakes front and back. During the custom building process we managed to lose so much weight from the standard bike that it weighs little more than a modern 125cc.

Yamaha SR400 Custom

The light weight and pokey 400cc single engine makes it a pretty lively performer and great fun to ride. Plus, thanks to the Avon tyres, it handles really well too. Avon’s all the way!

Yamaha SR400 Custom

Tell us about your bike.

This is my 1994 Yamaha SR400. It’s a Japanese import that I purchased from the UK and shipped to Malta. I named it “The Thumper” because of how it thump thumps away due to the lovely sounding single cylinder engine!

Yamaha SR400 Custom

The SR400 was released in Japan in 1978, but was restricted to the Japanese market only to comply with Japanese Motorcycle licensing regulations. It was a standard bike when I shipped it to Malta, and some small adjustments were made to begin with, but I always brought it with a view to creating a flat track scrambler style custom. After cutting off a load of weight, we were left with the engine and modified frame.

Yamaha SR400 Custom

I’ve always loved the Gulf livery colours, so wanted to have these on my bike! I also love tigers too! So I wanted to incorporate that with some cool font also. I learned a lot with this build from assisting with the assembly of the rolling chassis, installing the rebuilt engine, and so on.

Yamaha SR400 Custom

Work done was as follows:

  • Complete engine rebuild.
  • Rear frame section removed and new shorter seat loop welded in.
  • Rear footrest hangars and all extra brackets removed.
  • Billet yokes and risers with Triumph US-spec handlebars.
  • Bates headlight.
  • Wheels rebuilt with ally rims and stainless spokes and fitted with Avon tyres.
  • Short stainless mudguards fitted front and rear.
  • Triumph Lucas style tail light and mini bullet indicators.
  • Finned engine covers and polished cases.
  • Peashooter style exhaust and K&N air filter.
  • New billet aluminium swingarm and brake torque arm.
  • Louvered side panels.
  • One-off seat.
  • Mini speedo on one-off bracket.
  • Stainless side stand.
  • One-off polished chain guard and chrome rear shocks.

The bike weighs less than a 125cc, performs better than a 400cc, and is just such a joy to ride!

I’m super happy with how it turned out. Cost a bit more than I had budgeted for but it’s tailored to me and thats the most important thing.

Yamaha SR400 Custom

Credit to Choppershack Malta (Phil), who did the fabrication, engine rebuild, and assembly. Thank you for your patience when I was learning!
Paint job by Flakeys Custom Paint UK
Pictures by Matthew from ROTTA Malta

Follow Sandi on IG: @__sandi__p

One Comment

  1. That’s a cool bike.

Leave a Reply to fabian Cancel

Your email address will not be published. Required fields are marked *

*