GS850 Head Identification

[Big N daft]

I'm going to be rebuilding one of the engines I've got for the 850 and I've picked up a ported head, not sure which year engine it came off so I have a couple of questions.

I thought I'd seen the answer to this question somewhere here before but a search didn't find it. Can a head off any model 850 fit on any set of 850 barrels?

How do I determine the model of head so that I can get the correct head/rocker cover gaskets?

Hmmm I think I may have just answered the first question there, if the head gaskets are different from the older to newer models then that would indicate oil ways and possibly other stuff are different which would probably mean that the heads aren't interchangeable?

[bwringer]

The head gaskets are the same on all models of GS850. The valve cover gaskets are different on 82-83 models (19 bolts, asymmetric), but the head will interchange as long as you keep in mind which valve cover gasket you need. (79-81 GS850 valve cover gaskets have 16 bolts and are symmetric).

The 1979 model used slide carbs, so the intakes are slightly smaller. You can tell it's a '79 head because there are vacuum ports on each intake. (On later models, the vacuum ports are part of the intake boots.)

Let's put it another way -- the same top end gasket kit is used for all GS850 models, except that the valve cover gasket is different -- 16 bolts for 79-81, 19 bolts for '82-83. (The clutch cover and gasket is different, too -- it's angled on '82-83 models.)

If you have a '79 head, you also need the intakes, carbs, and airbox from a '79. But anything from '80-'83 will interchange.

There are some other details that can be important -- for example, the driveshaft mounting flanges are slightly different on 79-81 engines than '82-83.

Can you be more specific about what you're planning to do, or if you simply need to identify the part you have?

[bwringer]

A simpler chart:

Vacuum ports on intakes on cylinder head: 1979 only

No vacuum ports on intakes, 16 bolt valve cover: 1980 or 1981

19 bolt valve cover: 1982 or 1983

19 bolt valve cover, painted black at factory: 1983



Same head gasket for all...

[Big N daft]

A simpler chart:

Vacuum ports on intakes on cylinder head: 1979 only

No vacuum ports on intakes, 16 bolt valve cover: 1980 or 1981

19 bolt valve cover: 1982 or 1983

19 bolt valve cover, painted black at factory: 1983



Same head gasket for all...

Thats brilliant..........

I've picked this ported head up for a few bucks and I was already going to rebuild one of the engines I had so I thought well, why not stick this head on and see how it goes.