Description

Yamaha DS7, RD250, R5C, RD350 1972 Service Manual

If you’re wrenching on one of these 1970s Yamahas and you don’t have the factory binder on the bench, you’re asking for a headache. I’ve seen guys try to rebuild an RD350 top end using a Chilton or some forum screenshot – those are good for starting a campfire, not for getting the ring gap right. This Yamaha DS7, RD250, R5C, RD350 1972 Service Manual is the real deal: 113 pages of Japanese engineering documentation, printed September 1972, straight from Yamaha Motor Co. It covers the DS7 (1972), RD250 (1973), R5C (1972), and RD350 (1973). The R5C and RD350 share the same bore increase, so the major parts differences boil down to overbore-related stuff and a different primary ratio plus a larger rear tire. You get the full story – not some aftermarket reprint that left out the torque sequence.

YAMAHA Autolube System – Not Optional

Chapter 1 dives into the separate automatic lubrication system. You might think you can mix your own premix and bypass the oil pump – don’t. The Autolube system is designed to meter oil precisely at different throttle openings. Page 1 covers handling of the oil pump, and if you skip that you’ll smoke a piston. The manual explains the features and why Yamaha went with this system. I’ve seen guys disconnect it and then wonder why the exhaust side of the cylinder looks like a burnt marshmallow. Follow the factory procedure. No shortcuts.

Cylinder Porting – 5-Port vs. 7-Port Reed Valve

Chapter 2 is where a lot of backyard builders get lost. The DS7 and RD250 use a 5-port cylinder; the R5C and RD350 get the Torque Induction System with a 7-port cylinder and reed valve. Page 9 details the operation of that reed valve. If you’re porting or replacing the cylinder, you need the factory port dimensions and timing. This manual gives you the construction features and the theory behind the torque induction. Don’t rely on a YouTube video that tells you to “just grind a little here.” The spec is in the book.

Engine Removal and Reassembly – Torque Values Matter

Chapter 3 is the meat: removing the engine, cylinder head, cylinder, pistons, rings, clutch, primary drive, crankcase split, crankshaft, transmission, kick starter, shifter, and carburetor. You get step-by-step procedures for each. The cylinder head torque sequence? It’s in the specifications section. Need the clutch disassembly order? Page 23. The manual covers bearing removal notes on page 48 – pay attention because a pressed bearing installed wrong can seize. Every torque specification is listed in ft-lbs (imperial). I’ve seen one guy strip a crankcase cover bolt because he used a guess-torque. Don’t be that guy. The manual tells you the exact value.

Chassis and Disc Brake Procedures (RD350)

Chapter 4 covers front wheel differences between the models, rear wheel, and the disc brake system on the RD350. Page 73 walks through the entire disc brake overhaul – caliper, master cylinder, pads. If you’re doing a brake job on an RD350, you need the torque spec for the caliper bolts and the bleed procedure. The manual also covers tire inflation pressures, front fork rebuild (page 77), rear cushion, fuel tank, swing arm, and steering head. Page 84 has the steering head bearing adjustment – too loose and it wobbles, too tight and it binds. The factory specs are there.

Electrical and Wiring – Charging and Ignition

Chapter 5 gives you the charging system and ignition system. Page 86 has the charging circuit; page 97 the ignition. You’ll find voltage readings, coil resistances, and point gap specs. The appendix includes circuit diagrams and cable routing diagrams – if you’re rewiring a rat’s nest, those diagrams save hours. No guessing which wire goes where. The appendix also has conversion tables and IBM parts order system info.

Source Validity – OEM vs. Aftermarket

I’ve seen third-party manuals that claim to cover the RD350 but leave out the reed valve section or use generic torque values. This is the original Japanese service manual, compiled by Yamaha’s engineering and service department, September 1972. It’s scanned from the factory binder, not a reprint from some data aggregator. The torque specs, clearances, and wiring colors are what the engineers intended. If you’re serious about keeping these bikes on the road, you need the real document. Don’t trust a $9.99 CD that says “universal.”

Who Should Buy This Manual

Home garage guys restoring a DS7 or RD250? Yes. Professionals who need to verify a torque spec during a rebuild? Absolutely. Beginners who’ve never split a crankcase? This manual will walk you through it – but read each step before touching a tool. The 113 pages cover everything from the autolube pump to the wiring diagram. If you own any of these models, this is the reference you keep on the bench, not in a drawer.

Related Manuals

• Yamaha XT350 1985 Service Manual – Factory Specs & Torque Data
• Yamaha YZF600RJ 1996 Service Manual – Factory Specs & Repairs
• Yamaha YZF-R1S YZF-R1SC 2003 Service Manual – Factory Torque Specs

For broader context on motorcycle drivetrains, read about the Manual Transmission on Wikipedia to understand how your Yamaha’s gearbox works. For an overview of the automotive industry’s shift to factory documentation standards, see the Automotive Industry Overview page.

Frequently Asked Questions

Does this manual cover both the 250 and 350 models?

Yes. It’s a combination manual for DS7 (1972), RD250 (1973), R5C (1972), and RD350 (1973). The R5C and RD350 share the same 347cc engine with a larger bore; the DS7 and RD250 are 247cc. All differences are noted in the specifications and relevant chapters.

Are torque values in ft-lbs or Nm?

Imperial (ft-lbs). The appendix also includes conversion tables to metric if you need them. Every critical fastener – cylinder head, clutch hub, crankshaft nut – has its specification in the corresponding chapter.

Where are the wiring diagrams?

In the appendix after Chapter 5. Circuit diagrams cover the charging system and ignition system. Cable routing diagrams are also included. Page references are in the table of contents.

Does this manual include the disc brake overhaul for the RD350?

Yes – Chapter 4, section 4-4 on page 73 walks through the disc brakes: caliper removal, pad replacement, master cylinder service. Torque specs and bleed procedure are included. No guesswork.

Stop chasing incomplete forum threads and aftermarket knockoffs. Access the Factory Manual now and get the OEM specifications Yamaha intended for your DS7, RD250, R5C, or RD350. Have it on your tablet, phone, or printed at the bench – you’ll never have to guess a torque value again.