Differences between 79 and 81?

[01ps]

There is a guy in my area selling a 79 XS400 Special. I was thinking about picking it up, either to work on or use for parts.

I have an 81 Special, this is a 79. Are there any major differences? I am mainly wondering about the electrical and ignition, as mechanically I am pretty sure they are virtually identical.

 

[OliverB]

I am not an expert by far but my son owned an '81 and just recently acquired a '79. This is what I have seen:
-No oil level sight glass on his '79 engine, just dipstick on oil cap
-slightly different frame design on '79, especially at front bottom engine mount
-Carbs on his '81 were Keihin, Mikuni on his '79 but that may not be universally true
-Speedo & tach are different case design and wiring different on speedometers
-Stock mag wheels on '79 require tubes, not so on '80 or '81
-Headlight bucket is plastic on his '79 - if it is still stock, I don't know
-Tail/stop light different between the two
-Seat design different between the two, seems flatter on '79
-Some wiring differences between the two
-If the '79 has a rear mag wheel w/disc brake, rim size is 18" while it is 16" on '81 w/drum. Swing arm on '79 different w/rear disc and mounting tabs on frame of '79 for MC with different brake pedal shaft to actuate MC rod

That's a few differences I know off the top of my head w/o ever really getting into a '79.

 

[01ps]

Do you know if the 79 is CDI or points ignition?

 

[HoughMade]

The biggest difference (in my opinion) is just that- the '79 has points and the '81 has electronic ignition. '80 was the first year for electronic.

I have never seen a stock XS400 (SOHC) with a Keihin carb. May be out there, but the manual refers exclusively to a Mikuni BS34 for an XS400H ('81 model).

 

[WulfgartheBlack]

Near as I can tell '80 and later were CDI. Check Yamaha site: http://www.yamaha-motor.com/partviewer/default.aspx?ls=sport
Brit model numbers differ but there could be a YamCorp site for them too.

Do you know if the 79 is CDI or points ignition?

 

[eric123]

All years SOHC should be Mikuni carbs AFAIK