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Discussion Starter · #1 ·
Hello forum and thanks for having us!

Just bought a 81 gs450e suzuki.It appears to be in really great shape. Had a local mechanic take it to clean the carbs and he says that compression is low on the right cylinder. Left cylinder is around 175 and right cylinder is around 125. Mechanic says when they pulled the plug on the right cylinder it was full of gas. When they drained that gas out they could see surface rust on the inside of the cylinder.

The bike has been sitting in a garage for years. It hasnt been registered since 04. Previous owner supposedly had carbs rebuilt last summer. Thing started right up at time of purchase. I think maybe a valve is stuck or something.

Guess I'm gonna have lots and lots of questions but first wheres a good place to find parts for this oldie? Engine gaskets and the like I'm pretty sure I'm gonna need to rebuild the heads
 

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Just bought a 81 gs450e suzuki.It appears to be in really great shape.
Who constitutes "us" ?? :roll:

Then, there appears to be somewhat of a contradiction in your message.

And you left out a critical part of the story, which would tend to resolve that contradiction: does it run at all and if so, how good ??

Lastly, if it does run .........I think you are going WAY overboard thinking about stuck valves or head rebuilds. How did those ideas creep into your thinking ??
 

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Discussion Starter · #3 ·
Who constitutes "us" ?? :roll:

Then, there appears to be somewhat of a contradiction in your message.

And you left out a critical part of the story, which would tend to resolve that contradiction: does it run at all and if so, how good ??

Lastly, if it does run .........I think you are going WAY overboard thinking about stuck valves or head rebuilds. How did those ideas creep into your thinking ??

"us" would be the missus and I. That would constitute the "us". It is her first motorcycle.

Maybe I made an ommission and left out if the bike ran or not but I cannot find the contradiction that you repeatedly claim I make. IIRC isnt a contradiction, opposing statements?

I too like to hit the return key several times when posting, as it would appear so do you.

The bike does run but is having issues.

The mechanic says when he pulled the plug on the right cylinder it was full of gas and there was visible surface rust. That surface rust, the possiblities of damage to the cylinder walls, possible damage to the rings? Mouisture in a cylinder? Stuck rings?


Lets see when first purchased and started up it ran rough but ran. Now the heat from the cylinder with low compression has caused that sides exhaust pipe to crack. It wasnt cracket before. Thats a typical sign of trouble. IMO.

Or is there some other options to try? I'm all ears, well eyes in this case, and am open to any suggestions.

Thanks for the warm welcome and have a great day
 

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I guess it is way too late to tell you that you should never start an old bike that has been sitting until you have inspected the insides of the engine for rust, damage, etc. And it is way, way too late to tell you that you should have this inspection performed before you buy it, as absolutely nothing will destroy a piece of machinery like it just sitting around without being run or properly preserved to make it air tight and rust proof. Oh well, live and learn.

As you have found out, running it in this kind of shape will cause damage. The rings will have suffered damage or accelerated wear from the rusty and rough cylinder. You need to have the cylinders honed to remove the rust, then put in new rings. If the exhaust was cracked from briefly running it, just imagine what the insides of the motor might look like.

What makes you think it is a stuck valve? Does it tap badly from the top end and blow smoke? A stuck valve usually gives extremely low compression numbers, and rapid leak down of compression. You'll also get almost no difference between wet and dry test numbers, where as worn rings will give higher numbers with the oil test. Did you do an oil test, or just test the compression dry? Did you test it hot and cold, or just cold?

No matter, really, as if the inside of the motor is rusted then you really need to rebuild it. So you need an engine rebuild kit...but the problem is that there is no such animal for your Suzuki GS450. You'll have to buy each and every part individually. Bikebandit.com can supply head gaskets, valve seals, engine gaskets, rings, etc. These parts will add up quickly, and if you have to pay someone to do the mechanical work and machine work it will rapidly exceed the value of the bike. The carbs are also gummed up, as a stuck float or needle will flow liquid gas into the cylinder, which is apparently not firing either. So chances are, if the insides of the motor are rusty, you bought a really pretty looking, motorcycle-shaped paper weight. Bummer.

Fix the carb (stuck needle or float will let liquid gas into the cylinder) and make sure it is firing on both, then run it till it blows up or starts smoking so bad you can't ride it anymore. Might be next week, might be next month, or next year. When it does, part it out or buy a used motor from a salvage yard or wrecked bike, making darn sure you give the motor a good inspection before you buy, though personally I would not trust a 30 year old used motor, let alone sink more money into a 30 year old bike.

If funds allow and you don't mind sinking money into it that you will never get back, forget it as a driver, take it apart, and teach yourself to be a motorcycle mechanic as you restore it as time allows.
 

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"Maybe I made an ommission and left out if the bike ran or not but I cannot find the contradiction that you repeatedly claim I make. IIRC isnt a contradiction, opposing statements?
You started out by saying "It appears to be in really great shape." and then went on to describe things that indicate it might be on it's last legs, engine wise. An obvious contradiction to me.

I have total respect for DrBob but I would like to propose a different tact in dealing with this machine.
Do as little as possible.

IF......you can get the excess gas in the cylinder problem solved, carb likely, then I think it is possible you might be able to ride it for a fairly long time without a major rebuild.

125 lbs of compression isn't THAT bad. The rust might just be surface discoloration. The main problem might just be stuck rings.

Once the gas problem is fixed, I'd suggest putting a couple of ounces of Marvel Mystery Oil directly in through the plug hole (won't hurt to do this to both sides), put the plugs back in, rotate the engine about one revolution and then let it sit for a couple of days.

The way you decide to go depends on what your motivation is.......and how much time, money and expertise you have.

You might get a lot of miles out of it without doing much.........or it might blow up after only a few.
OTOH, the money you put in to do it "right" might not really be worth it.
 

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Discussion Starter · #6 ·
Another thing I should have mentioned is that there is 5879 miles on the odometer. Everything is super clean with the only noticable damage being maybe what I have done unknowingly. We paid $300 for it. Even if we had to put another $500 into it we would still be happy with the bike.

Thanks very much for the advise.

As far as the carbs go I'm thinking of breaking them down and soaking them in a parts cleaner solution for a couple of days to hopefully get the fuel flow issues solved. Then I'll try the magic mystery oil in the cylinder for a few days. I have had a few people tell me to try this trick.
 

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Hello forum and thanks for having us!

Just bought a 81 gs450e suzuki.It appears to be in really great shape. Had a local mechanic take it to clean the carbs and he says that compression is low on the right cylinder. Left cylinder is around 175 and right cylinder is around 125. Mechanic says when they pulled the plug on the right cylinder it was full of gas. When they drained that gas out they could see surface rust on the inside of the cylinder.

The bike has been sitting in a garage for years. It hasnt been registered since 04. Previous owner supposedly had carbs rebuilt last summer. Thing started right up at time of purchase. I think maybe a valve is stuck or something.

Guess I'm gonna have lots and lots of questions but first wheres a good place to find parts for this oldie? Engine gaskets and the like I'm pretty sure I'm gonna need to rebuild the heads
man I absolutely love mine it's not really a heavy bike and gaskets are pretty inexpensive for it I thought I ordered a stator gasket for mine when I bought stator for it off eBay gasket was only $11.25 and I had it within a few days free shipping I'm having an issue still getting mine to charge I bought all new charging system and still isn't working guess I'ma have to take it to someone that knows electric ok
 

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I'm having an issue still getting mine to charge I bought all new charging system and still isn't working guess I'ma have to take it to someone that knows electric ok
Does "all new" include the battery itself ?
How do you know that it is "not charging" ??

Did you notice that there has been no activity in this thread for 10 years ?? ;)

P.S. I am deleting the other TWO posts that you made about this problem.
Please post your questions in only ONE place on here.
Having the discussion scattered around all over the place is not good.
Thanks.
 

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Does "all new" include the battery itself ?
How do you know that it is "not charging" ??

Did you notice that there has been no activity in this thread for 10 years ?? ;)

P.S. I am deleting the other TWO posts that you made about this problem.
Please post your questions in only ONE place on here.
Having the discussion scattered around all over the place is not good.
Thanks.
I'm not to good w technology lol to answer your question though I hooked everything up the bike started fine but I have no juice going to the battery from charging system seems like it gets to the recitifer and stops but it's pushing great ac current from the stator that's what has me stumped!!!!
 

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I'm not to good w technology lol to answer your question though I hooked everything up the bike started fine but I have no juice going to the battery from charging system seems like it gets to the recitifer and stops but it's pushing great ac current from the stator that's what has me stumped!!!!
I used my multimeter to chk it and nothing is going to battery
 

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I used my multimeter to chk it and nothing is going to battery
How EXACTLY did you do that ?
Is the voltage at the battery exactly the same running as it is when the bike is OFF ?

In most designs, there is no fuse between the rectifier output and the battery post but the output wire from the rectifier often connects at the big + cable connection on the starter solenoid instead of going directly to the battery.

A good solid frame ground at the regulator/rectifier is important too.

AND.....you didn't say if the battery is new or not.
 
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