Shop manual question

[intothemystic]

I've got a 1983 CB450SC and recently picked up a "Honda Shop Manual CB/CM450's '82, '83, '85" off eBay.  The manual seems to be geared toward the CM450A, CM450C, CM450E and CB450T.  There is a short addendum in the back for the CB450SC with specs, and it says "Refer to the base shop manual for service information not included in this addendum." 

Can I follow the repair/maintenance procedures shown for the CM450C, CM450E, and CB450T for work on the CB450SC?  The CM450A is the Hondamatic, so I'm assuming that the info for that model won't apply.  From the photos the bikes appear similar if not identical, but I lack the knowledge and experience to know for sure. 

I've also got access to a Clymer manual, so I'll be able to cross-reference, but I'm just wondering if one manual is considered better than another.  Maybe the best way is to check various sources, including this fine site, to figure this all out?  Thanks so much for any thoughts and suggestions.

[Bumblebee]

Quite a few official manufacturers manuals have addendums like that for a particular subseries of the motorcycle that are nearly identical with minor changes.

The answer is yes and no and you have to do your homework before beginning.

The base manual has the main information on how to do something.
The addendums are supplementary to that information and anything in the addendum supersedes anything written in the base manual...and in previous model/year changes.

1. If a particular maintenance procedure is not covered in the addendum, then follow the procedure in the base manual.
2. If the maintenance procedure is covered in both the base manual and the addendum, it is essential to cross reference both sections while doing maintenance. Follow the base manual and when coming to any part or instruction that is in the addendum, ignore the base manual instruction and use the addendum instruction. When the addendum instructions run out, return to the previous instructions to continue.
3. Addendums are changes done for that year or addendum variation. Here's the catch; addendums can supersede addendums.

A good example is my 1982 CB650. The manual covers 1979-1982 since it's essentially the same motorcycle and engine with minor changes as the years changed. 1978 and before is another design, 1983 and after is a major redesign thus they are not listed. The base manual is specifically for the 1979 version. The addendums are for any and all changes done in 1980, 1981 and 1982 by year and by variation changes such as CB650 CB650C and CB650SC.
A classic addendum cross reference is the carburetors for my motorcycle. They are in the base manual (aka 1979 design) however they are not the same as the ones on the motorcycle. So I look at 1980 and there is a carburetor change there but it's still seriously different from what is on the motorcycle. Then there's a totally new carburetor design in the 1981 addendum and a minor change to that in the 1982 addendum. The 1981 instructions are indepth just like you'd expect to find in the base manual. The 1982 instructions are only bits and pieces of what is listed in 1981.
So I get to ignore the base manual and 1980 procedures entirely. I use the detailed 1981 carburetor procedures as the new base procedure and only ignore parts of that on details specifically listed in the 1982 addendum and use those. If I tried to use the 1982 addendum on the 1979 base or 1980 addendum without referencing the 1981 information, it wouldn't make a bit of sense.
There can also be other procedures that are listed in all 3 addendums or even skip an addendum. Inside each addendum by year on my manual can have more than one section for specific model changes such as the CB650 vs CB650SC for 1982.

It sounds messy at first however it's really very straightforward, rational and easy to follow. Always do your homework before picking up a wrench. Know what is covered in what addendums and what changes. Then open the tool box.


In your situation, you may have to follow the CM450A hondamatic instructions even though you don't have a hondamatic. It totally depends on whether there are changes after that year to those specific components. Always use the newest information available even if it's from the original base design.

[intothemystic]

Bumblebee,

This is incredibly helpful and kind of you to write all this up -- thank you very much.  You have a wonderful way of presenting information clearly and concisely.  I'm going to spend some time with the manual and the motorcycle later today and now have a basic approach to follow as I sort through the base info and addendums.  Much appreciated!

Here's a shot of the bike:

[roadrunner]

Nice looking bike you've got there !   

[intothemystic]

Thanks roadrunner!  It's been great fun learning to ride and doing minor maintenance.  And the people here have been nothing less than stellar.