Any help appriciated

You need to consider your bike a 500 with a smaller motor. Use the 500 shop manual.

Your bike is a Japanese Home Market model that was imported to NZ - along with many other 400 cc bikes - because they were considered obsolete in Japan , and available at a good price. 400 cc was the upper limit of the Japanese drivers licence rating , before you had to pay huge amounts to have a bigger bike.

The GL400 was made in a number if variants, ranging from a cX500 standard with smaller bore to something more like the CX650C (again with a smaller engine). If you post pictures of yours we may be able to help you figure out what it actually is.

BTW: I have heard rumours of some being put together from left over parts in '85 for sale in less developed places but I'm pretty sure production for major markets ended after the 1984 model year. Does New Zealand follow the UK practice of vehicle paperwork indicating the year first registered instead of the model year?
That system often causes confusion when changes were made between the year the vehicle was made for and the year it was registered so it is always best to figure out the actual model year.

Sidecar Bob said:

Does New Zealand follow the UP practice of vehicle paperwork indicating the year first registered instead of the model year?

Click to expand...

I've heard of the UK doing that, but not Michigan's Upper Peninsula.
Actually, I think that was a common clerical error in the US. My '78 Standard is mis-titled as a '79 Deluxe.

I meant UK (corrected).