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Which engine do I have?

  • Thread starter Thread starter MrZig
  • Start date Start date
M

MrZig

Guest
I bought a GS400 the other day for $450 but it appears to be a frankenbike.

The previous owner said it was an '82, the registration says '80, yet I think I've narrowed it down to being a 1978 GS400.

However the engine does not match the engines from a 1978 GS400 as the cam covers are square instead of circle, and other details like the side cover being different, and saying "TSCC" on it.

Am I correct in thinking that it is from a 1980 GSX-400, giving me 44hp?

Here are some pictures:









http://img339.imageshack.us/my.php?image=gaugesdm6.jpg

http://img4.imageshack.us/my.php?image=small3bx0.jpg

http://img4.imageshack.us/my.php?image=small2kr1.jpg

http://img4.imageshack.us/my.php?image=ffefcf9b9cb1ba862785b77yz3.jpg

The reason I believe it's a 1978 is that it doesn't have spoked wheels, so it has to be above 1977, and that it has an 11 digit VIN, so it has to be before 1980. It also fits the general looks of that era.
You'll notice that the seat and mirrors do not come standard on the 1978, which is why it must also have parts interchanged from different years / aftermarket. That doesn't bother me. I just want to know what engine I have. The engine has an ID of "GS40X-128565". When you compare the appearence of the engine to the one featured on a 1980 GSX400 here:

http://www.suzukicycles.org/GSX-series/GSX400E.shtml

and

http://www.bikepics.com/suzuki/gsx400/80/pics.asp

You'll notice they are identical. However, apparently there's another identical looking one on this bike and it only has 27hp:

http://www.suzukicycles.org/GSX-series/GSX400L.shtml

Or is the 27hp only in Germany like I've heard?

So am I correct in thinking it's a 1978 GS400 with a 1980 GSX400 engine producing 44hp?
 
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well only the "elected by dogs" pics are visible, all the others require a sign on someplace and only come up as forbidden so without being able to see the rest of bike it is hard to say.

look at the data plate on the steering stem (where the forks pivot) and that will give you the answer.

that is for sure a 1980 or later GSX400 engine, you did not list where you are but those engines were never sold in America, they did get some in Canada and they were standard in the rest of the world.
here in America we got the 450cc 4 valve engine.
 
focus frenzy said:
well only the "elected by dogs" pics are visible, all the others require a sign on someplace and only come up as forbidden so without being able to see the rest of bike it is hard to say.

look at the data plate on the steering stem (where the forks pivot) and that will give you the answer.

that is for sure a 1980 or later GSX400 engine, you did not list where you are but those engines were never sold in America, they did get some in Canada and they were standard in the rest of the world.
here in America we got the 450cc 4 valve engine.
Click to expand...


I will rehost the images when I get back from work today. I am indeed from Canada so that would explain things.

Also all the numbers on my steering column are rubbed off. The only one that exists is the VIN.
 
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The orignal post is updated with working pictures of the bike.

Since I have to order a tachometer housing, I simply say its from a 1980 GSX400?

So does this mean I have 44hp?
 
MrZig said:
The orignal post is updated with working pictures of the bike.

Since I have to order a tachometer housing, I simply say its from a 1980 GSX400?

So does this mean I have 44hp?
Click to expand...

Not sure about 44 hp but that is a 8v engine so it should be well above the hp of an 8 valve 400.
 
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The rectangular valve cover caps indicate that this is a 4 valve head. These engines were made in 250, 300, 400, 450, and 500cc versions. If you look on the top right rear of the engine case above the cluth cover there should be a raised boss that has the engine number on it. That will include the displacement of the engine immediately following the GSX designation.
 
GSexpress said:
The rectangular valve cover caps indicate that this is a 4 valve head. These engines were made in 250, 300, 400, 450, and 500cc versions. If you look on the top right rear of the engine case above the cluth cover there should be a raised boss that has the engine number on it. That will include the displacement of the engine immediately following the GSX designation.
Click to expand...


So now I'm told it's either an 8 valve, 4 valve, or 16 valve. I've never heard anything about this range of engines having 16 valves. But 8 or 4.. Hm.

Also do you mean this? GS40X.

http://img4.imageshack.us/img4/4200/small2kr1.jpg
 
Yes, that's it. That means it's a 400cc 4 valve per cylender engine. Being a twin cylender engine, that means 8 total valves.
 
Okay awesome. So what is the 27hp vs 44hp model? On suzukicycles.org, it says that some GS400 engines were detuned to 27hp in Germany. On bikez.com specifications on the GS400, GSX400 etc, they all say 27hp.

Yet, again, on suzukicycles.org, all the models except germany have 30-50hp.

I'm fairly certain my bike frame is from a '78 or '79. The VIN starts out as GS400, so I don't think it's a 425 or 450 frame. And 80+ would have a 17 digit VIN, right?

It seems like it has a lot of mis matched parts. Probably been through a lot this poor old thing.
 
Thats what he ment GS40 = 400cc GS45 = 450cc.
They probably blew the original engine & replaced it.
Look on the registration, see if the engine # is listed here in Calif it is on the title/ Reg
 
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ok I have gone over all my reserch data and can say for sure that your bike is a franken bike.

the tank is a L tank, the tail piece might be from something else also.
17 digit vin numbers were not used in 1980.

the GSX400 8 valve engine makes 44hp unless it is a learner German bike.
the GS450 4 valve engine makes 43hp. Suzuki feeling we Americans like torque better gave up a bigger displacement engine but with the old style head. niether are related to the original GS400 as it used a roller bearing crank while the GS450 and GSX400 (and GS500 twin) use a plain bearing crank

there was not a 450cc version of the GSX twin but there is a very rare (possibly Germany only) 400cc version of the last generation GS (AKA: gs500) sold for one year along side the GS500 (4 valve)
Suzuki also has made a four cylinder GSX400 (16 valve)
 
To me that looks like an L model tank and seat on a E model frame. The tailpiece looks to be off a 4 valve E model, maybe a 78. The gauge cluster and controls also look to be off a 4 valve as do the signals.

The engine is definitely an 8-valve (4 per cylinder). The real question is whether the motor matches the frame for the year it was made. My guess would be a newer motor in an older frame. I didn't think that it would fit (looks like I'm wrong).

If it is a 400cc engine, the 8-valve model is much better than the 4-valve model IMO....more responsive and almost 10 hp more which makes a difference on smaller bikes, esp if you spend anytime on the freeway (I owned one of both at one time or another).

Also, I think the info on the page with the 27 hp is wrong. Looking through them, you will note that this is the only 400cc engine with that number. The older 4-valve 400cc engines make about 35, so I can't see how an 8-valve would make less. The 250 version of the conspicuously has ~27 hp, which is the model I believe this figure is for. If this engine did exist, it would be for a very specific market, and the odds of getting one unless you were in that market would be pretty close to nil (in other words, here in Canada it would be rare to find a German learner spec bike of any make or model. Odds are much better that you find an US model with a speedo that reads in mph).
 
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79 sh850 said:
The engine is definitely an 8-valve (4 per cylinder). The real question is whether the motor matches the frame for the year it was made. My guess would be a newer motor in an older frame. I didn't think that it would fit (looks like I'm wrong).
Click to expand...

thats one of the interesting oddities about Suzuki, they kept the motor mount positions the same on the 400, 425, 450, and 500 twins (the tempter twin likely is a drop in) you can go and get a brand new GS500 engine and it will bolt right up in a 1976 GS400 frame.
the only complication being Suzuki rotated the exhaust ports inward to clear the perimiter type frame used on the 500 twin so exhaust clearance in the early GS frame is a problem.
you need a custom exhaust.
 
Awesome, good to hear. I'm going to give it an oil change this weekend and fire it up with a fresh tank of gas and see what happens! hopefully the roads are dry enough to take it for a quick spin.
 
I'm installing new seals for the fuel petcock (mine was leaking) and was wondering what to lubricate them with before installing?

Just plain old gasoline?
 
I dunked them in gas and installed them and it doesn't leak anymore, awesome.

Another question, does the GS400/GS425/GSX400 have a low oil pressure light?

I can't find anything about one.
 
gsx400

gsx400

Hello, have you checked www.michaelsGS-classic.com use translater and book mark translated page,to keep eng or french. click on models. and you have almost every GS made articles to eng frame w/b etc i will go threw my mags CYCLE,C/W, etc if i find specs ill let you know.Let us know how she goes. keep an I on petcock, useally 50.00 new one is a good invest, petrol can still leak into eng, w/out being noticed. enjoy SAN.
 
How does gas leak into the engine?

I noticed that the petcock doesn't automatically shut 'off' when there's no vacuum. It'll still leak with the selector in any position. Could that be a problem? I don't want to spend $50 on a new petcock..

Does the problem happen by sucking fuel through the vacuum line? If so, I could just plug that off.
 
Seems I read on here somewhere that if the vacuum operated petcock is malfunctioning it will let fuel flow through the vacuum hose & you can end up with fuel in the crankcase which is not good! I could be way off because I am still learning so maybe someone else will elaborate soon & correct me if I am wrong. Seems like I read also that if you plug the vacuum line & run the petcock on prime it may be a temp fix, but like I said I am not 100% positive. Don't hold me to that I just wanted to let you know we are still out here. Good luck man!
 
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