Top end swap

[Guest]

Any known fitment issues when doing a top end cylinder/head swap from same years? In this instance a 1979 GS1000?

Reason- Keep bike going, but build a fresh top end (spare motor) bored/pistons etc. and then swap when ready. This keeps the same numbers on the title. Any dowel variations etc. encountered (like vintage Ducatis) or is it a clean swap?

[LAB3]

I'd start by comparing part numbers of your current head with the number from your perspective replacement. If they're the same there shouldn't be any issues.

[GregT]

The only differences amount to the extra bolt in the center at the front of the camchain tunnel on later 1000 engines. It's only between the head and barrel - and I've done engines with the extra bolt in the head onto a barrel without it.
Given a good gasket there's usually no problems.
The barrel stud spacing and oil galleries didn't change.

[bwringer]

On Suzukis, the engine number has nothing to do with the VIN. Is the engine serial recorded separately on CA titles for some reason?

Anyway, in general the answer is very often "yes". Without exact specifics of what you're trying to swap to what, that's all we can say right now. Suzuki's engineering "style" is to re-use parts and dimensions as long as they possibly can, so goofy undocumented mid-year stuff like you see on Euro bikes is pretty rare.

There are also many instances where part numbers changed for some minor reason, but still fit and function identically. Part numbers are a start, but you can't always count on that 100%. And tracing this through superceded and merged part numbers can be challenging.

I do like the idea of stashing a spare top end for later! I have a spare engine fogged and wrapped in plastic lurking under my workbench. I plan to keep my GS long past the point where fossil fuels become a rare specialty item.

[Nessism]

CA does have the engine number on the title (typically.)

When looking for a head be sure to stay with 1978 or 1979. Those early heads have intake ports/boot flanges that mate to the early type VM carbs. The later type CV carbs have different flanges with a wider bolt spacing pattern. Any of the 1000 cylinders will work, including those on the shaft drive 1000 bikes. You may as well target the early type cylinders though, the version without the extra bolt in the front center.

BTW, you may want to look up Tkent02's for sale thread. He was practically giving away engine parts a while back. He's got some good big bore parts he may be persuaded to part with too.

https://www.thegsresources.com/_forum/showthread.php?256873-Cylinders-heads