Description

Honda 450, 500, 400 Service Manual – Clymer 1978-1987

I’ve seen more shade-tree mechanics ruin a good Honda twin because they trusted some online forum over a proper manual. The Honda 400, 500, and 450 twins from 1978 to 1987 share enough DNA that you need one source that covers all three without gaps. This 439-page Clymer Honda 450, 500, 400 Service Manual is that source. Is it OEM? No. Is it better than nothing? Absolutely. But you need to know where it came from and what it actually gives you before you crack a bolt.

Engine Overhaul: What the Manual Covers

Chapter Four is the engine chapter. It walks you through disassembly, inspection, and reassembly of the top end and bottom end. If you’re pulling the head on a CB400T, the torque sequence and valve adjustment specs are in that chapter. Page 4 is where you start. You’ll need a torque wrench that reads in ft-lb – Imperial, not metric. The manual calls out inch-lb for smaller fasteners. Do not skip the run-in procedure after a rebuild. Not all aftermarket manuals bother to include that. Trust the spec.

Troubleshooting Without Guessing

Chapter Two is the troubleshooting section. It lists symptoms – no start, rough idle, poor acceleration – and gives logical steps to isolate the problem. If you’ve ever chased an intermittent electrical fault on a Honda 500, you know how maddening it gets. The manual includes a systematic approach: check spark, fuel, compression in that order. That’s the correct sequence. I’ve seen too many people replace a carburetor only to find a dirty plug. According to the Automotive Industry Overview, systematic diagnosis is key to efficient repair.

Does This Manual Cover Both Manual and Automatic Transmissions?

Yes. And that’s rare for a single manual. Chapter Five covers the clutch and manual transmission. Chapter Six covers the torque converter and automatic transmission – that’s the Hondamatic models. If you have a 1978-1984 CM400A or similar, you need the specs from Chapter Six. The fluid capacities, shift points, and converter removal procedure are all there. Do not confuse the two. For a deeper dive into manual gearbox theory, see Manual Transmission resources.

Torque Values: Why You Need the Specs from This Book

Torque specs are the difference between a rebuild that holds and one that leaks or rattles loose. This manual includes each major torque value in the appropriate chapter. Cylinder head bolts, crankcase bolts, suspension pivot bolts – they’re all listed. But here’s the catch: because this is a Clymer manual, not a Honda factory service manual, cross-check critical engine torque values against a factory source if you can. I’ve seen small discrepancies in aftermarket specs on older models. For frame and suspension, the Clymer values are generally safe. The wiring diagrams alone are worth the price.

Fuel and Electrical Systems: Factory-Level Detail

Chapter Seven covers fuel and exhaust. Chapter Eight is the electrical system – wiring diagrams are at the back of the book. If you’re troubleshooting a no-charge condition on a 1982 CB450, the regulator/rectifier test is in Chapter Eight. The manual gives resistance readings and voltage checks. Note: the wiring diagrams are black-and-white and not the easiest to read, but they are accurate for the models listed. Compare with the actual harness colors on your bike – sometimes aftermarket manuals swap colors.

Who Should Use This Manual – and Who Shouldn’t

If you are a home garage enthusiast who owns one of these bikes and wants to do your own maintenance, this manual is adequate for tune-ups, carburetor rebuilds, brake jobs, and basic engine work. If you are a professional mechanic billing hours, I’d still recommend tracking down a factory OEM manual for critical steps, but this Clymer will get you through most jobs. Beginners: read Chapter One first. It explains how the manual is organized, what the CAUTION and WARNING boxes mean, and what tools you need. Don’t skip that. For a more recent model, consider Honda VT600C 1998 Service Manual – Factory OEM Repair Guide. The VFR800A is covered in Honda VFR800/A 2002 Service Manual – OEM Factory Repair Guide.

Source Authenticity: Clymer vs Honda OEM

This is a Clymer publication, third-party aftermarket. It’s not a reprint of the Honda factory service manual. Clymer uses experienced mechanics to write the procedures, but they sometimes simplify or omit steps. The upside: they include common troubleshooting tips and aftermarket part numbers. The downside: torque specs can be off by a few ft-lb. On a 1978 CB400T, check the cylinder head torque against a Honda dealer’s TSB if possible. For routine maintenance like oil changes and valve adjustments, the manual is reliable. For older models, see Clymer Honda 450 & 500cc Twins Repair Manual 1965-1977.

How many pages is this manual?

439 pages including wiring diagrams and index.

Can I use this manual for a 1977 Honda 400 twin?

The manual covers 1978-1987 models. The 1977 model year is not included. The engine and frame changed significantly in 1978. Using this manual for a 1977 could lead to incorrect torque specs and fitment issues. You need a manual specifically for 1973-1977 Honda twins. We carry that separately – check Clymer Honda 450 & 500cc Twins Repair Manual 1965-1977 for older models.

If you’re serious about keeping your Honda on the road, start with this 439-page Clymer. Then, when you need the last word on a critical spec, access the factory manual from our site as well.