Building History: HONDA CB900F Custom by SANCTUARY

SANCTUARY's CB900F

How is a complete custom made? The history of the bike is discovered by taking the machine apart to discern its current state. Then, each part is made almost new, customized specs are added to match the owner's wishes, and a new history is born. This process can also be applied to the CB-F series, of which owners tend to want to keep stock aspects intact. AC Sanctuary's complete custom RCMs (Radical Construction Manufacture), are a concrete example of this. Since this custom had just been built, we asked Mr. Nakamura at AC Sanctuary about the necessary elements to be taken into consideration when customizing a CB-F.

"This custom is serial number RCM-604, and at about the same time we were building another CB-F with the number RCM-609. Both were neither 750 nor 1100, but CB900Fs. And both owners have a passion for CBs, so they wanted clean-cut builds that didn't stray too far from the CB-F style. They knew about the lack of parts, etc., and that's why they ordered the customs now, while they were still possible. One other thing of note was that they were both certain that they wanted 17-inch specs. Although the Z series, which are common bases for RCMs, and the CB-F are very much different models, the main points for conversion to 17-inch are actually very similar: caster angle and fork offset settings to avoid insufficient trail, and use of a slightly longer swingarm than stock. Therefore, it is rather easy to decide on what to do for the chassis. The difficult part is the engine. Pistons can be selected from DiNx or other brands, and the crankshaft and other internal combustion parts can be modified, but the lack of a stock cam chain tensioner and other consumable parts makes it difficult. We look for usable reproductions and used parts to make sure that the bike will be able to hold up in the future," says Nakamura.

Getting back to the bike featured in this article, the chassis is made just right, as mentioned above, and the engine parts are all there and precision machined, so there is no concern for the foreseeable future. It looks like this custom was ordered just in time.

Handle

The front master cylinder is a NISSIN, and the handlebars are the DAYTONA RCM Concept Low Bar. The SCULPTURE φ43 SP Stem Kit Type-1 is originally for the Z and modified here, and the fork offset has been changed from 45 to 35mm to match the 17-inch wheel.

Bodyworks

The seat is based on a stock seat, with the seat base modified and padding removed by SANCTUARY, taking into consideration the connection after installation.

The exterior colors are based on the red and white of the '82 FC, arranged in a gradation pattern with black as the base color.

The gradation from black to red is applied from the front to middle of the fuel tank, the bottom of the side covers to the model logo, and from the center on the tail cowl to the front and rear. The front and rear turn signals have also been downsized to create a sleek impression.

Engine

The engine, finished in black with GUN-KOTE, was upgraded from stock 901 to 915cc with DiNx ø65mm forged pistons. Crank journal wrapping, dynamic balancing, decking, valve guide replacement and reaming, and valve seat cutting were also performed by DiNx, SANCTUARY's internal combustion machinery division.

The carburetor is a TMR-MJN φ36mm with YOSHIMURA dual stack funnels. The funnels match the body color with a red and black combination.

Chassis

The steps are by NITRO RACING. In addition to reinforcement of the seat rail base above the pivot, original frame reinforcement, and wide laydown reinforcement in the upper section of the rear shocks has been applied, and the chain line track has been secured. The drive chain is an EK530RCM (BK;GP).

The OHLINS RWU forks come as part of the Noblest ExM Package, along with the front fender. The front brakes are Brembo P4-40C Axial 4P calipers + SUNSTAR Premium Racing "RCM" Concept discs.

The rear brakes are composed of a Brembo P2-CR84 rear caliper and SUNSTAR 250mm disc. The exhaust system is a NITRO RACING 4in1 Weld Craft Titanium 3D EX Exhaust with half polished NITRO RACING Conical Titanium Silencer V-III.

The rear suspension uses a modified SCULPTURE R.C.M. Wide Swingarm for the Z + OHLINS Legend Twin shocks, and the wheels are forged aluminum OZ Racing GASS RS-A, in 3.50-17/5.50-17 sizes.

Gallery

Specifications

About SANCTUARY

SANCTUARY is a custom builder that is good at Vintage motorcycles like Z1,Ninja and KATANA. They sell special parts which were born from trial and error that mechanics had repeated mounting and testing

SANCTUARY brand page

Original Source of this Article

Heritage & Legends