[GriffinKnox]

Ok, so I thought I got this great deal on a 78 GS1000. The bike had been sitting in someones shed for 16 years, it looked to be in great condition. So I get it home all jittery with excitment and began to tear her down and clean her up to see what I was working with.

I got all the bodywork off, the rear tire and swingarm, the Carbs and the exahust. I figured all she would need was a thorough cleaning and the carbs rebuilt. So today I am waiting on my carb kit and decide to do a compression check. Now mind you there is nothing but motor at this point, no exhaust carbs etc.... I start on the number 4 cylinder because that plug looked a little more crispy than the others. I hit the starter button and bam there it was 50 psi max. I still have a lump in my throat from holding back the tears.

So I start down the line Number 3 Cylinder 150psi, Number 2 60-75 psi, Number 1 150 psi. So, 2 and 4 are ****, I took a bit of oil and wiped away my tears so I could see the plug hole and dripped it in. Boom, 175 PSI in the number 4 and 150 in Number 3.

So give it to me straight guys, the least i am going to need is Rings right? Bore it too I would imagine. Right?

I am just a simple kid on College budget, no make that a Junior College budget, who loves the GS1000. So am I going to escape this for less than 200 or 300 dollars? Is this something I can do myself? I have moderate mechaincal knowledge, never tore down a motor before but I am sure with a deatiled instruction manual and a six pack or two or 12 I could figure it out.

So lay it on me boys, where do I stand. Hopefully you dont say "in a pile of *S#%T"

 

[bpe]

Doubtful you could escape for under $300 even if you had a confirmed perfect engine. Tires alone will probably run that much. 16 years in a shed you would need those, plus a few other items.

 

[stevesearles]

Slow down and don't freak out yet. Rings may be stuck in grooves from sitting so long. Yes the oil will seal during compression reading. Maybe just clean the carbs and fire it up and see if the rings will free themselves. (Try marvel mystery oil a little in gas and oil) If not, start by tearing the top end off and inspect the rings to see if they are stuck in the ring groove. Take rings off, clean groove and reinsert rings with oil. While off, check bore of cylinders and piston scroring. Could take ID measurements of cylinder and OD of piston. It may just free itself up after running. Change oil right away. Medium difficulty due to cam chain timing.
Bottom line is that the GS1000 is an awesome machine making 90 HP and smooth. I have a GS1000C and a GS1000E. Next on those is that the stator and regulator, rectifier are a weak link. (Charging system needs to give 13.5-14 Volts to the battery.) Need a new stator and upgraded reg/rec next to have a reliable machine. signed, Vintage Japanese motorcycle mechanic, collector and restorer.

 

[Critter]

You had the carbs off so the intakes were wide open correct? You didn't have rags in there to keep anything from getting in the engine? Compression tests need a wide open throttle

 

[SemiFast]

all jittery with excitment and began to tear her down and clean her up to see what I was working with.

She's a Beauty But.....

She'll age you long before She lets you ride Her And Her ride costs A Lot More than 300

S F

 

[OldVet66]

Ok, so I thought I got this great deal on a 78 GS1000. The bike had been sitting in someones shed for 16 years, it looked to be in great condition. So I get it home all jittery with excitment and began to tear her down and clean her up to see what I was working with.So lay it on me boys, where do I stand. Hopefully you dont say "in a pile of *S#%T"

 

[OldVet66]

The Bike above my screen name is a '78GS1000E. The GS series of motorcycles are tough as nails. The rings are probably stuck, Marvel Mystery oil soaking in the cylinders works wonders. It will be a lot of work and a bit of money, but it can be well worth it. Send the carb kits back, they are GARBAGE!!! All you need are O-rings, gaskets and a proper soak for 24 hrs. in carburetor dip. VM carburetors require a complete tear down so all the tiny passages get cleaned. Get your factory repair manual and carburetor rebuild tutorials here: (http://members.dslextreme.com/users/bikecliff/) Get the O-rings from: (O-rings for Suzuki GS850 Mikuni Carbs) very inexpensive. Gaskets are available at dealers but I would use Babbits Suzuki online parts for factory parts or Z1 Enterprises for aftermarket. Personally I use the factory gaskets. Z1 sells Pingel petcocks and adapters if you want to get away from fuel flow problems forever. Just put one on my bike. It sure Likes the high fuel flow.

 

[Scootertrash!!!]

Hi,
I have brought back quite a few bikes from the dead. And some of them had very low compression but after you run them and loosen things up, sometimes the compression comes back up.
Me and my grandson just got done with a 82 cx500c Honda.
It had been sitting a little over 30 years it was my grandson's other grandfather's bike that he parked back then, for an oil leak.
The motor was locked up, the starter was locked up, got them unlocked and had zero compression, would not even bump the Gage. Put fogging oil in the cylinders, and started spinning it, to help loosen things up. And then we started spraying ether in it. and it would pop from time to time in the more we did that the more compression we got. The more compression it got the more it would try to run on ether for a second.
Now it runs like a sewing machine.
The best part was when he fired it up, and drove it around the yard in front of his other grandfather( who had had a bad stroke and could not communicate) and his other grandfather got a big smile. The first one that they have seen, in quite a while. THANK YOU LORD ???
If I were you I would try that to see if you could get the compression to come up and maybe you might look at the valve clearance. That can lower the compression also. And if you do adjust the valve put them on the fat side of the clearance it will give you more power.
Have a good one
Hope this helps you ???

 

[OldVet66]

Valve clearance could also be a problem. The GS1000 is overhead cam adjusted with shims. The valves get tighter as the miles rack up instead of looser and can get to a point where a valve stays opened and reduces compression. Electrics are also a problem that can be totally fixed with a new stator if it needs it, removing the stator loop that goes through the light switch and installing a modern series R/R like the SH-775. I replaced mine with a Compufire 55402 buth they are expensive compared to the SH-775.

 

[SemiFast]

And if you do adjust the valve put them on the fat side of the clearance it will give you more power.

What is the "fat side"?
I would guess you are talking about setting them at the minimum clearance spec for more power.

S F

 

[Scootertrash!!!]

No actually putting them on the tight side will take your horsepower away.
I learned this the hard way on my 93 GSXR 1100 that was built up pretty hot. The first time I set the valves on it. the local dealer said to put them on the tight side and it would give me more power. They are supposed to be set on the intake 4 to 8 thousands, and on the exhaust eight to twelve thousands is what the book cost for.
When I took it apart all of the intakes were on 8 thousands in all of the exhaust where on 12 thousands. it was running real good but way overdue to be adjusted. So I put them on the tight side 4 on the intake and 8 on the exhaust. And then I went for a ride and it lost 30% of its power. It run like a stock bike with a jet kit, no second gear wheelies no first gear wheelies ? come back and was really pissed off and took it apart immediately. and I run a compression test. it had 145 to 160. And then I tore it down and put them back on the fat side, (8 thousands on the intake, and 12 thousands on the exhuast. ) with it cold, and before I put the plugs in I run a compression test and, it had 190 to 210 pounds of compression. And then I went and rode it, and I had my big GSXR back.?
It's what I call free horsepower just adjust the valves on the fat side. It takes more work than just checking and saying it is okay, it is in between the tolerances. I take them all apart and put them on the fat side and try to get more horsepower, it is not a perfect science, but works 90% of the time.
Another example, I was adjusting the valves on a 1981 or so 1100 Suzuki with the 8-valve engine.(the shims are on the top of the bucket. ) I could change the shim on top of the bucket and then run a compression test. With 3 thousands of clearance it had 90 lb of compression, and with 5 thousands of clearance it had a 140 lb of compression.
If and when you adjust your valves. run a compression test before and after you adjust them, and put them on the fat side, and you will see the difference, and when you ride it you will feel the difference.
Hope this helps you all!!!
Have a good one ???

 

[SemiFast]

No actually putting them on the tight side will take your horsepower away

My experience, education and logic makes me disagree.
As long as you stay within the factory clearance specs it does not make sense that setting the clearance at max would improve horsepower or increase compression a measurable amount.

.In the early days my two valve per cylinder KZ650 needed the valve lash adjusted every 6000 miles. It constantly lost clearance so I would set them near max. It never lost power after a valve lash adjustment. (But that bike was old tech).
Fast foreword to roadracing five valve FZR Yamahas. (26,000 mile lash adjustment intervals).
Using the "it's gonna lose clearance" logic of old I checked and found the clearance at minimum on the new FZR so I set all 20 of them at max/near max. The result was a BIG loss of power that was easy to feel seat of the pants.
When I checked my four valve Yamaha R-6 I found clearances near minimum. Lesson learned, no need to experiment. It was way fast as it came from Yamaha and would, and did, go well over 26,000 miles without needing adjustment as did the FZR's.

The reason for an increase or loss of power with different clearances are simple.
When you run at or near factory spec minimum clearances you effectively have more lift and duration than you would if you run with maximum factory spec clearances.
Something is way wrong if you lose a bunch of compression at any correct factory spec clearance.
I believe something else was going on with your Suzy. (Possibly inept engineering or incorrect specs)? Wouldn't be the first.

S F

 

[OldVet66]

You can disagree all you want but the GS 8 valve motors run better and longer between maintenance intervals with the valves on the higher side of the factory specifications. The saying is "happy is slappy". They make a little more cam noise but eventually wear to a point where a happy medium is reached and adjustment intervals are much longer than factory recommendations. I need to install new valve seals, so I'll check mine when I have the valve covers off but the last time I was in there was probably 2011. Admittedly I wasn't riding as much as I used to, taking into consideration I was a caretaker for my wife for years before she died of Pick's disease, and then there was a knee replacement and then foot surgery. I'm 72 now and have been a widower going on three years. I'm getting in pretty good shape so I intend to do a lot of riding. It's maintenance time now and the bike runs great. The saying today is 70 is the new 50 so I fully intend to put that to the test.

 

[mike721]

I just saw this..still waiting for the OP to come back and tell us how the oil freed up the rings and it roared into life with super compression in all the cylinders...
Please...
The suspense is killing me...

 

[OldVet66]

The '79 motor I put in my bike, from a parts bike I bought that had 4.500 miles on it and had sat since 1985, had fairly low compression. I soaked the cylinders with Marvel Mystery oil and ran the **** out of it. Compression was within factory specs the next time I checked it. You may hear from him soon, it would take super high mileage and/or abuse to wear out the rings on a GS1000. Stuck rings from sitting for 16 years is almost to be expected.

 

[Scootertrash!!!]

My experience, education and logic makes me disagree.
As long as you stay within the factory clearance specs it does not make sense that setting the clearance at max would improve horsepower or increase compression a measurable amount.

.In the early days my two valve per cylinder KZ650 needed the valve lash adjusted every 6000 miles. It constantly lost clearance so I would set them near max. It never lost power after a valve lash adjustment. (But that bike was old tech).
Fast foreword to roadracing five valve FZR Yamahas. (26,000 mile lash adjustment intervals).
Using the "it's gonna lose clearance" logic of old I checked and found the clearance at minimum on the new FZR so I set all 20 of them at max/near max. The result was a BIG loss of power that was easy to feel seat of the pants.
When I checked my four valve Yamaha R-6 I found clearances near minimum. Lesson learned, no need to experiment. It was way fast as it came from Yamaha and would, and did, go well over 26,000 miles without needing adjustment as did the FZR's.

The reason for an increase or loss of power with different clearances are simple.
When you run at or near factory spec minimum clearances you effectively have more lift and duration than you would if you run with maximum factory spec clearances.
Something is way wrong if you lose a bunch of compression at any correct factory spec clearance.
I believe something else was going on with your Suzy. (Possibly inept engineering or incorrect specs)? Wouldn't be the first.

S F

I reckon I disagree with you. I have made probably 30 or 40 motorcycle run better by adjusting the valves on the fat side, ( did not help two of them like I said, it is not a perfect science.)
I don't do it for people no more I am retired. But I teach people how to do it, and we done one a month or so ago, a 2012 R1, and the intake valves were not that tight, maybe a couple thousands tight. but the exhaust valves were real tight. ( backwards from usual). And it also had good compression 180 to 185 before we started. We loosened up the intake by a couple thousands, and the exhaust by as much as 6 thousands to get them to the fat side. He said the bike would not start when it was cold, but once he got it started it would start the rest of the day just fine. ( that is a sure sign that the valves need adjusting) (the reason they start fine for the rest of the day is that the valves gained about 4 thousands of clearance when they get hot) He said he would have to put a heater in front of the motor and put a hairdryer up the exhaust to get it to warmed up enough to start. And after we got it back together he told me that it started right up, and had a lot more power. ?
Good luck with yours!!!
Have a good one ???

 

[Scootertrash!!!]

You can disagree all you want but the GS 8 valve motors run better and longer between maintenance intervals with the valves on the higher side of the factory specifications. The saying is "happy is slappy". They make a little more cam noise but eventually wear to a point where a happy medium is reached and adjustment intervals are much longer than factory recommendations. I need to install new valve seals, so I'll check mine when I have the valve covers off but the last time I was in there was probably 2011. Admittedly I wasn't riding as much as I used to, taking into consideration I was a caretaker for my wife for years before she died of Pick's disease, and then there was a knee replacement and then foot surgery. I'm 72 now and have been a widower going on three years. I'm getting in pretty good shape so I intend to do a lot of riding. It's maintenance time now and the bike runs great. The saying today is 70 is the new 50 so I fully intend to put that to the test.

You're right I have adjusted quite a few of them old bikes and the setting was 1.1 to 2.9 thousands is what the book called for if I remember right.
I would set them on a loose 3 or a tight 4 thousands. That is the type of motor where you can change the shim on top of the bucket, and I could run a compression test before and after and at 3 thousands it had 90 lb of compression, and it 5 thousands of Clarence it had 140 pounds of compression.?
I am 63 and still riding, and hope when I am 72 I can still ride?
Take care of yourself out there.
Hope all your rides are good ones ???

 

[SemiFast]

the GS 8 valve motors run better and longer between maintenance intervals with the valves on the higher side of the factory specifications.

They make a little more cam noise but eventually wear to a point where a happy medium is reached and adjustment intervals are much longer than factory recommendations.

.In the early days my two valve per cylinder KZ650 needed the valve lash adjusted every 6000 miles. It constantly lost clearance so I would set them near max

I think we agree, we just don't know it...

S F

 

[SemiFast]

a 2012 R1, and the intake valves were not that tight, maybe a couple thousands tight. but the exhaust valves were real tight.

What do you mean by "tight"?

Do you mean less than the Yamaha minimum clearance specification? If so that is a rarity but no surprise considering the lack of quality control in all industries these days.
When Yamaha first came out with the 26,000 mile interval for checking/adjusting the valve lash on certain models none of us believed they would go 26,000 miles, and more, before needing adjustment.
We were wrong, they'll do it even when subjected to the stress of racing.
Through the years I've checked a bunch of them at the 26,000+ mile mark. I can only remember one unit that was out of clearance.
That one bike had about 35,000 miles on it and had no valve lash clearance at all and I'm sure burned valves.
It's cams and all 20 lifter buckets were toast and the internal parts looked like it had never had an oil change. My guess is that along the way somebody didn't know that oil changes were important or that it would overheat if it sat running while the rider was in the house having breakfast, or whatever, every morning before his ride.
My recommendation was that It would not be cost efficient to repair. The owner agreed and took it away.

S F

 

[OldVet66]

I think we agree, we just don't know it...

S F

Reading over it again, I think I got confused somewhere between post 11 and 12. I think we do agree.