Home » #252 SR400

#252 SR400

2022.7.5

Custom Bike

#252 SR400Custom Report

This order comes from Amu-san, who is active in hosting SR meetings and other events and on YOUTUBE “AMU Moto Blog ch“. Based on the “STD Hardtail Complete“, we created an old school long fork chopper style, and this time we used a lot of parts in a prototype position, such as “2° Rake Triple Tree”, “20cm Long Inner Tube”, “Mid Forward Jockey Shift Kit”, “Z Bar Handle”, “Battery Tray Kit for Hardtail”, “18cm Long Hardtail (for Long Fork)”, and so on, while trying out 2%ER’s new challenges.

All of the challenges this time were aimed at improving styling, better driving performance, and convenience.

【Vehicle Structure】

The bolt-on hardtail kit at the rear uses an 18cm long.

By bending the red circle part more than the regular product, the vehicle height is lowered, changing to a golden ratio silhouette of a chopper style with a lower seat height. A minimum ground clearance of 10cm is secured, and it is designed not to scrape unless there is a significant step. (The vehicle height is lowered to the best angle with a normal side stand)

With this bending process, the position of the crankshaft of the engine, which is the heaviest part of the total weight of the bike, is below the axle of the front and rear wheels. Lowering the center of gravity makes it feel much lighter when lifting or pushing and pulling the bike, reduces wobbling, greatly improves stability, and makes handling lighter and easier to handle.

The red line part indicates the trail value that determines the weight of the bike’s handling. When the rear is lowered and the fork is long, the trail width becomes longer and the handling becomes heavier, but this is corrected by the 2° rake triple tree to make the handle weight as light or lighter than normal. Even at high speeds, it remains stable and the handle can be turned with one hand.

※ The “2° Rake Triple Tree” has been decided to be commercialized because it produced good results in the prototype.

This is a chopper that has been extended by a total of 35cm with a 20cm long prototype inner tube. The styling is based on a 70’s style long fork chopper, with a mid-forward step (the jockey shift side is a prototype with mass production in mind) tailored to the owner AMU’s physique, a Z-bar handle (this is also a prototype), and a high-back seat with a backrest.

First, we set the handle, step, and seat positions in a comfortable position while having the owner actually straddle it, and by adding an inner frame to the inside of the backrest part of the high-back seat, we designed it so that the owner can ride with the entire upper body weight on it, which cannot be achieved with a seat made only of urethane. The steps are designed to bear the entire weight of the lower body, and the handle position is set without any strain, resulting in a tireless riding position.

【AMU Moto Blog ch】(Videos from the perspective of owner AMU)

“Movie from meeting to start of work”

“Positioning with Amu in a comfortable position”

【Click here for the STD Hardtail Complete sample car】

【Click here for over 70 hardtail production examples】

【Detailed explanation video about ride comfort and driving performance】

Cookie consent is required to display this video.

Cookie Settings

【Driving video】

Cookie consent is required to display this video.

Cookie Settings

“8/21 The vehicles planned to be exhibited at the Kobe New Order Chopper Show”

【Hokkaido Touring 2022 Digest】

Cookie consent is required to display this video.

Cookie Settings

Custom List

FrontHandlebars, F forks, headlights, etc.

●Assembled with a prototype triple tree from 2nd Lake, which is a long fork typical of a chopper, 35cm longer than the original.

【Front Fork Area】

“2%er 15cm long Joints for Front Fork (pair) [SR400/500]“

〇High-quality stainless steel fork joint

“20cm Long Inner Tube”

〇A fork tube kit that allows you to extend the front more safely

“2%er Tweak Bar (front stabilizer) [SR 400/500]“

〇A stabilizer that is extremely effective in correcting the handling that tends to lag one beat behind with extended forks

“2° Rake Triple Tree”

〇By offsetting the wheel position (shortening the trail width), it reduces the heavy handling that is common with long forks.

【Front Tire】

“SHINKO flute 3.00-18”

〇A street tire with a vertical groove design. It helps to lighten the handling that tends to become heavy when long forks are used. It is a small, rounded 3.00 size.

【Headlight】

“5.75 inch Bates Light Chrome General Purpose“

〇A headlight that fits well with the SR’s vehicle size and fork width, and can be installed without any discomfort.

“Bottom Mount Light Stay II“

〇A headlight stay that fits well with the chopper style due to its moderate height and protrusion.

【Handle/Handle Area】

“Diamond Grip Black 22.2mm 7/8“

“Amal type throttle holder, general purpose (for 7/8″)“

“Amal type slot wire 900mm ’88~’08“

“200mm Long Brake Cable“

〇The clutch lever has been eliminated by the jockey shift, and the change to the Amal throttle has made it even simpler than usual. Long cables are used for each.

“Z Bar Handle” (Prototype)

〇A chopper handle with a welded structure, also known as a robot handle.

【Switch】

“Mini Turn Signal Switch Coupler On Kit (’85~00)”

〇A mini turn signal switch that is easy to install with a coupler on

(It is installed with modifications on different year models and small headlights)

“Handle Lock Weld On Kit“

〇It is newly installed by welding to the lower part of the stem, which is inconspicuous and easy to operate.

“MOTOR ROCK Decompression lever“

A decompression lever directly attached to the engine to simplify the area around the handle.

【Front Blinker】

“Micro Blinker” (Discontinued ⇒ Now changed to Star Bean Blinkers, Set of 2, Black)

“Universal Blinker Stay 10A Type Steel”

〇The ultra-small micro blinker is installed on the front side of the lower part of the engine mount.

【Speedometer】

“Mechanical Speedometer 60mm Black Panel 1:4“

“Universal Speedometer Stay“

“Extension meter cable joint“

〇Mounted on the left front side of the gasoline tank where it is less noticeable and has high visibility. Additional welding of the switch plate to the meter stay has been done to consolidate the switches.

CenterTank, oil tank, seat, step, muffler etc.

●The Narrow Sports Star Tank is safely mounted with three rubber points. The frame under the seat is cut from the original part and rebuilt with thick steel pipes considering strength, precision, durability, and maintainability, according to the angle of the “Hardtail Kit” at the rear. A battery is installed, with a convenient USB under the left side of the seat, and ETC is installed under the seat.

【Muffler】

“Torque cone drag pipe muffler SR400/500“

It is a full exhaust muffler with a torque cone developed independently in the mouthpiece.

【Step/Shift】

“Mid-Forward Jockey Shift Kit/Chrome” (Prototype, decided to commercialize)

〇A jockey shift kit that maintains the comfortable riding posture of the mid-forward, focusing on touch and stroke operation.

※For the hand clutch “Mid-Forward Control Kit – Chrome – SR400/500“, click here

【Gasoline Tank】

“Narrow Sportster Tank for Production”

〇A tin ornament is semi-embedded on the top surface.

“Welding nut non-through M8 2p“

〇Drill a hole in the gasoline tank body and insert and weld. It’s non-penetrating, so it won’t leak. Used on both sides.

“Weld tab M size 4.5mm thickness 2p“

〇Enlarge the hole diameter and change to a rubber mount specification to hold the non-penetrating nut. Used on both sides.

“Weld tab L size 4.5mm thick steel 2p“

〇Used for the rear attachment of the gas tank. This also has an enlarged hole diameter and is used with a rubber mount.

【Carburetor】

“FCR carburetor 39φ SR400/500 single unit“

〇Your slow SR will dramatically change. It’s a carburetor that’s easy to handle with sharp and smooth acceleration.

“Manifold Kit for FCR39φ”

〇It’s a dedicated adapter to firmly fix the FCR carburetor to the SR400/500

“Net funnel set for FCR carburetor“

〇It’s a set of a change from a red plastic funnel to aluminum, and a stainless steel trash prevention net.

【Seat】

“High Back Seat” (One-off)

〇Designed with a backrest frame inside. You can entrust your entire upper body weight to it, making it easy to ride even over long distances.

【Electrical Equipment】

“SR400/500 Custom Electrical Plate #2%er Original #SR400/500“

〇All electrical components except the CDI are consolidated at the rear of the engine crankcase. It is easily accessible from either side of the vehicle and has good maintainability. There is no need to reassemble even if you return to the swing arm specification during vehicle inspection.

“IC blinker relay wide range specification“

〇A wide-range turn signal relay that can be used without difficulty even with LED turn signals. It can also be used as a replacement for the original relay.

“Battery Tray Kit for Hardtail” (Prototype, decided to be commercialized)

〇A tray kit for mounting a battery, which has been increasingly requested. It is also equipment for installing ETC after delivery.

【Engine Area】

“Breather filter SR400/500“

〇This is a filter kit needed when removing the original air cleaner.

【Drive System】

“Front sprocket SR400/500 428-19“

〇A durable replacement sprocket made of steel.

RearFenders, rear shocks, swingarms, etc.

●We finished it with an 18cm long hardtail kit, a normal 18-inch wheel, a flat fender with reinforcement on the back, an old-school tail lamp, and a one-off custom-made sissy bar.

【Hardtail】

『“Rigid Line” Bolt-On Hardtail Kit』(18cm long, for long forks, made-to-order)

〇As the name suggests, this is a detachable hardtail kit using bolts/nuts. It remodels the seat rail of the original frame to make it a rigid line. You can revert to the swing arm/rear shock specification when you have a vehicle inspection or want to change the style. (The hardtail of this vehicle is modified to lower the vehicle height more than usual to match the front long fork)

【Rear Tire】

“LOADSTAR TIRE 4.50-18“

〇A classic vintage style with a watermelon pattern. It’s a rear tire with height and volume.

【Sissy Bar】

“Stainless Steel Sissy Bar” (One-off)

〇A simple and slightly tall sissy bar. It is designed to withstand the vibration of the SR by sticking patches around the mounting area to distribute stress and prevent breaking.

“Lucas Large Tail Aluminum Number Base Set General Purpose“