1100 cylinder head on 850?

[Guest]

Hi there, I just got my first gs. its a 82 gs850L. I am planning on builing it into a cafe/brat style bike. I was just wondering if an 1100 head would fit on the 850 motor for some extra power? I will be running a 4-1, pods, and proper jetting of course. What else could i do to wake it up while I am freshening up the engine?

[Steve]

It might fit, but I don't think you will gain any power.

The 1100 head has inlet ports sized for 34mm carbs, the 850 is sized for 32mm carbs. Since your displacement is not changing, the extra carb size will probably work against you.

If you want to "wake up" your 850, just swap the entire 1100 engine into it. It's a bolt-in swap, but you will have to use the engine mounts, airbox and driveshaft from the 1100.

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[Jedz123]

I agree with Steve and do more research on a swap. The 850 engine is based off the 8V 750 (chain drive) engine, from what I can gather that's the only other engine (cc wise) that is compatible with your 850cc motor, an 1100G 8V head may not fit correctly on your 850 (studs and deck will likely not line up) and if it did (by some miracle) your going to have lower compression ratio for your increasing the size of the combustion chamber. We use to do similar tricks with Subarus to make them turbo ready, put a 2.5 head on a 2.2 block and the compression would drop allowing for some boost... It will bring you the wrong way when running larger heads on smaller bores if you go Naturally Aspirated. To pop compression you could put a 750 head on the 850 but I'm damn sure that it will suffocate the 850 for the 8V 750 head doesn't breath well at all and breathes through 28mm VM carbs... I'm nearly 100% sure the big block motors (1000cc+) don't cross with the mid sized block (750cc and 850cc). Can swap some things but two totally different engines.

Look into a swap if you want more power... It's the only thing really you can do.

[JTGS850GL]

If you want to "wake up" your 850, just swap the entire 1100 engine into it. It's a bolt-in swap, but you will have to use the engine mounts, airbox and driveshaft from the 1100.

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Not exactly true... It's a straight bolt in swap as long as the 1100 engine is from a shaft drive 1100G. No need to change motor mounts or mounting bolts. His driveshaft may not need to be changed either depending on the specific model. In 82 it depends on what sub model you have. The "T" model used the older version while the "X" model used the larger version common to the 1000G and 1100G. You will have to change out the ignition signal generator if it's an 82 or newer 1100G engine with electronic advance but even then it's a straight swap between the 850 and the 1100. Everything may be a straight bolt up depending on the exact model he has.

[Steve]

OK, good points. I was assuming he would be asking about an 1100G head, only because he is trying to put in on a 850G (both shafties). My bad for assuming.

Did not know that the output shaft was upgraded on the 850s.

I am a bit confused, though, about your "T" and "X" 'sub-models'. I have always understood that the "T" and "X" were the year designations for 1980 and 1981, respectively.

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[JTGS850GL]

Sorry, my mistake as well. In 1981 there were two "sub models" T and X listed for the GS850G. I know I stated 1982 but it was actually 1981. By 1982 all the GS850Gs were using the later driveshaft that was on 1000G and 1100G's. Just look up the 1981 parts fiche and you'll see that two were offered that year designated as T and X models. By 1982 all 850 and up GS shafts carried the same mounts and driveline. Fresh in my head because I'm in the process of swapping and 1100G engine into my 1000 and looked into it for my 850.

[Steve]

I will still respectfully disagree with your "sub-model" theory, regardless of year.

I know that some fiche will show "T, X" on some of the parts because the '80 and '81 models were virtually identical. Some things were, indeed different, like the turn signals. The '80 (T) turn signals were round chrome items, the '81 (X) signals were rectangular and black. The fuel tank and frame covers (side covers) would only be different because of colors and striping, but again, would show on the same fiche as "T" or "X", depending on the year, not the "sub-model".

If you look at the '82 and '83 bikes, you will see similar things that you would think of as "sub-models", but they would be "GZ" and GD". Look at the valve cover. Same part, but has different number because the '83 is black.

The only "sub-model" possible would be the "L", as in "GL", but that was also in "GLT", "GLX", "GLZ" and "GLD" (including '82 and '83).

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[GSX1000E]

Time for me to jump into the foray and answer the original questions biggest problem. Yes it will bolt on. Yes the stud sizes are different.
NO, it will not work as the valves will hit the top of the 850 cylinder. < Hows that for a direct answer?

[bwringer]

And now to address the issue under the question: get the thing running right before farting around with engine swaps and suchlike. A bone-stock (stock airbox, stock carbs, stock jetting) GS850 that's running right is one of the more enjoyable engines you'll find on two wheels.

[GSX1000E]

And now to address the issue under the question: get the thing running right before farting around with engine swaps and suchlike. A bone-stock (stock airbox, stock carbs, stock jetting) GS850 that's running right is one of the more enjoyable engines you'll find on two wheels.

BINGO!!!
Even if you can't/don't want to modify them to make them any better, these GS models are some of the finest all around/do everything well bikes ever made.
Why do you think that the guys that know how to keep them alive are still riding them today? Others that fail/have failed have moved on to newer bikes.

"I have owned some great bikes over the years but honestly I don't think any of them are as much fun to ride on the street as my old GS." - Roland5color

[JTGS850GL]

I will still respectfully disagree with your "sub-model" theory, regardless of year.

I know that some fiche will show "T, X" on some of the parts because the '80 and '81 models were virtually identical. Some things were, indeed different, like the turn signals. The '80 (T) turn signals were round chrome items, the '81 (X) signals were rectangular and black. The fuel tank and frame covers (side covers) would only be different because of colors and striping, but again, would show on the same fiche as "T" or "X", depending on the year, not the "sub-model".

If you look at the '82 and '83 bikes, you will see similar things that you would think of as "sub-models", but they would be "GZ" and GD". Look at the valve cover. Same part, but has different number because the '83 is black.

The only "sub-model" possible would be the "L", as in "GL", but that was also in "GLT", "GLX", "GLZ" and "GLD" (including '82 and '83).

.

I'm going by this:

http://www.suzukipartshouse.com/oemparts/a/suz/50d4017bf8700230d8b4e4d4/propeller-shaft-final-drive-gear

So, as you can see they did define it as different "models". It may very well be a mid year change.

[Steve]

Funny, they have that same "mid-year change" for the 1980 models.

I tell ya, the "T" is for the '80 MODELS, the "X" is for the '81 MODELS.

EDIT: I just did a cross-reference on the part numbers. The first number (for the "T") is only used on the 1980 850G and 850GL. The second number (for the "X") is used on the '81 1000GL, '81-'83 850G and GL, and the '82-'84 1100G, GL and GK. If you read that list carefully, you might notice that the '80 1000G is missing. Yeah, it has its own number.

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[GSX1000E]

Hi there, I just got my first gs. its a 82 gs850L. I am planning on builing it into a cafe/brat style bike. I was just wondering if an 1100 head would fit on the 850 motor for some extra power? I will be running a 4-1, pods, and proper jetting of course. What else could i do to wake it up while I am freshening up the engine?

After market camshafts work a treat. Whether it is a T or X model.

[eil]

Yeah, T means 1980 model year and X means 1981.

When they made the parts diagrams for the GSes back in the day, some (most?) were made to cover multiple years and even models with a single set of fiches. Less expensive, less redundant, than producing one set of fiches for every similar model for every year.

The parts sites on the Internet (like partsoutlaw) organize their bikes in this heirarchy:

* make (e.g. Suzuki)
* type (e.g. Motorcycle)
* year
* model (e.g. GS850G)

Model comes below year because that's the easiest way to drill down through all the different bikes in the database. But one side effect of this is that if a fiche set covers multiple years, the same set of fiches has to be available in those two different years. You can check for yourself, compare the 1980 GS850G (model T) and 1981 GS850G (model X) fiches, they will be exactly the same, zero differences.

On top of that oddity, I've found myself that the parts sites are actually a pretty poor resource in terms of figuring out which models were available when. So far, this is the best thing I've found: http://thegsresources.com/gs_modelchart.htm

Aside from a bolt being added here or there, I'm not aware of any Suzuki GS mid-year model changes.

[Joe Garfield]

What about the 750T? I thought that was a specific model and not a year. It was like a cross between a G and a GL:

http://www.suzukicycles.org/GS-series/GS750T_articles.shtml