1980 GS 550 no power after 60mph

[bodcherokee]

That might help some. If the ignition is still stock you'll have to cut or drill some new holes or slots to advance the timing I think. I'm betting more on carbs.



That's not likely to help in the short term (or, probably, the long term either). Three bits of advice you'll see frequently about Pod filters and CV carbs:

1) Only use good quality Pod filters (read: APE or K&N, no Emgos).
2) Don't do it until you get your bike running well with the stock airbox.
3) If you go with pods, get a Dynojet kit.



To me, you really need to establish a base line before you go much further. Some thoughts:

1) You said you cleaned the carbs - was that a full 24-hour soak per carb as per the GSR guide? Generally we recommend that, and an overall o-ring replacement. Don't bother with rebuild kits; the machining of their parts is generally inferior to what you find in the stock parts. Sometimes people need to dip 'em twice before they're really clean. Spray carb cleaner just isn't going to cut it. You also need to verify the proper float level, and make sure the slide diaphragms are completely free of leaks.

2) Have you verified the adjustment of the valves yet?

3) These GSes are set lean from the factory, and are VERY sensitive to any intake leaks. The O-rings on the carb boots are common culprits. The boots themselves may be over 30 years old. Before the carbs the boots need to be in good shape and the airbox well sealed.

4) I take it you've verified spark on all four plugs? Try a resistance check with your ohmmeter between the plug caps on 1-4 and 2-3.

If you start the bike up and idle, do all four pipes get hot?

Just to start with an answer to this one, i dont know nearly as much about this bike as i wish i did lol. I cleaned the carbs by hand on my bench with cleaner and soaked them for a day in gasoline and carb cleaner. Also put on new bowl gaskets, o-rings, and ran thin wire and compressed air through them. All four plugs are sparking, the exhaust is not clogged, all 4 pipes get hot, and the intake manifolds are good (the reason i bought the donor was because it had mint manifolds and good carbs) the barn bike had no manifolds or carbs when i got it. No clue how to check the adjustment on the valves.

[bodcherokee]

Steer away from aftermarket stuff for the head and base gaskets. Why does the engine need to come apart? Does it have low compression?

i honestly havent done a compression test, i just know it is seeping oil everywhere so i figured it'd be a good idea to check into some kind of rebuild while i was at it.

[tkent02]

Fine and dandy, but it would suck to do a rebuild and find it sill runs the same way. I would highly recommend finding and correcting the problem before you tear it apart.
How does it run at 9,000 rpm in the lower gears?

[bodcherokee]

Fine and dandy, but it would suck to do a rebuild and find it sill runs the same way. I would highly recommend finding and correcting the problem before you tear it apart.
How does it run at 9,000 rpm in the lower gears?

Thats the only reason i still ride it as is. In the city 1st, 2nd, and 3rd gear work as if nothing is wrong. Lacking a little power maybe but i have no reference. This is the first motorcycle i've ever rode.

[tkent02]

Thats the only reason i still ride it as is. In the city 1st, 2nd, and 3rd gear work as if nothing is wrong. Lacking a little power maybe but i have no reference. This is the first motorcycle i've ever rode.

The 550s have almost no low end grunt. Power should be very weak below 3,000 rpm...
getting fairly strong at 4,000 - 6,000 gradually increasing through 7,000.
and take off like a rocket at about 8,000 - 10,000. In the first couple gears at 8,000 rpm, it will take a strong grip to hang on to the bars. These are very short stroke engines, it does not hurt them at all to go to the high rpms and stay there all day. Ridden well and kept in the power band, it will smoke all but the fastest of cars up to 100 mph or so.

Usually just opening the throttle in sixth from a low speed it will top out at about 75 or so mph, but if you wind out fourth, take fifth to the red line and hit sixth it will accelerate right on up to red line in sixth gear.

These bikes are great if you like to wind things out. If you would rather open the throttle and chug on out, not so much.

If you have never ridden at all you really need some local help, post a location, there are people on this forum in your area who would be happy to help out.

Unless you have near zero compression, the problems you are having is not caused by anything internal in the engine.

[pete]

I still say make sure the advance mechanism is actually advancing...

[bodcherokee]

The 550s have almost no low end grunt. Power should be very weak below 3,000 rpm...
getting fairly strong at 4,000 - 6,000 gradually increasing through 7,000.
and take off like a rocket at about 8,000 - 10,000. In the first couple gears at 8,000 rpm, it will take a strong grip to hang on to the bars. These are very short stroke engines, it does not hurt them at all to go to the high rpms and stay there all day. Ridden well and kept in the power band, it will smoke all but the fastest of cars up to 100 mph or so.

Usually just opening the throttle in sixth from a low speed it will top out at about 75 or so mph, but if you wind out fourth, take fifth to the red line and hit sixth it will accelerate right on up to red line in sixth gear.

These bikes are great if you like to wind things out. If you would rather open the throttle and chug on out, not so much.

If you have never ridden at all you really need some local help, post a location, there are people on this forum in your area who would be happy to help out.

Unless you have near zero compression, the problems you are having is not caused by anything internal in the engine.

It wont even rev up past 4500 rpms in 4th 5th and 6th. I wish it would rev to 10000. It will sitting in neutral but not on the road. as far as being sure about the exhaust not being clogged, i mean the tail pipe pushes it out at a good pressure on both pipes. i guess i could pop the pipes off but i dont wanna mess with the gasket yet. Also figured i'd throw in a picture of her. I'm located in springfield, ma by the way.

[bodcherokee]

I still say make sure the advance mechanism is actually advancing...

i honest have no idea how to do that lol

[barnbiketom]

I honestly think that you need to re do your carb cleaning. you need to completely tear them apart, making sure the jets and emulsion tubes etc are spotless. unless you do this you are barking up the wrong tree. Theres a link how to do it properly on Bass Cliff's site and other places.

[tkent02]

The clogged exhaust thing, I have had this on two GSes now. One of them, a 1979 GS1000E, would only get up to 50 mph on a long down hill. It started fine, idled nice, ran OK at low rpm but got worse at it wound up, seriously 50 mph needed a hill. I noticed it was running very rich, and also very quiet, with a Vance and Hines 4-1 pipe and stock jets this didn't make sense. I poked a coat hanger down the pipe and started pulling out steel wool, the PO had been stuffing steel wool down into the pipe to make it quiet. Pulled out about six big handfuls from down in the collector. After that it was fast.
The other had mouse nesting materials in the pipe, it was slow as a dog too but not as bad as that one.
Just something for you to check.
You should definitely check the spark advance, that will kill high RPM as well.
As far as carb cleaning, the wide open throttle circuits in the carbs are the least likely to be clogged, they are larger and they don't have to be as perfect as the low speed stuff to run somewhat correctly. IF it idles nice with good low throttle and mid throttle response it's not so likely to be the carburetors causing the problems. Possible, but not so likely.
Unless your main jets are not the right size.

[pete]

i honest have no idea how to do that lol

Take off the ignition/timing cover (the round one with the Suzuki emblem on the right side held on by 3 screws).

Under there, you'll see a round plate with two boxes mounted on it 180 degrees apart, and these are the ignition pickups. In the centre is a rotor.

You should be able to grab the rotor with your fingers and turn it maybe 90 degrees clockwise fairly easily *without* the crankshaft turning.

When you let it go it should spring back to the original position by itself.

This photo is how it looks on my 450. I think yours will look a bit different but the components are essentially the same. Just ignore the Dynatek I'm holding in my hand and look at the left side of the photo.



Don't turn it by the nut on top of the rotor, turn it by the rotor lobes.

[Big T]

Thanks for all the info everyone. I have heard from a few people to pop the side cover and advance the timing. It has the stock air box on it and i'm thinking of getting a set of cones. It doesn't rev past 4500rpms just like you said too. I'm also looking on advice on rebuilding a my 550 engine. I have the one off my donor and i have rebuilt car engines but never a motorcycle one. Anyone know where i can get parts and gasket sets? Thanks again, love these kinds of forums, i build jeeps and i use those forums all the time. Better than any haynes or chilton book you can buy and this is free.

The timing is preset, so if the advancer unit works - don't ever get advice from them again

You do not need "more" air, again this is backwards thinking. You need the correct air/fuel mixture at the higher RPMs. If it's not running rich, you don't need more air

What do your spark plugs look like?

What are your compression readings?

Why would you rebuild a perfectly good engine?

[bodcherokee]

The timing is preset, so if the advancer unit works - don't ever get advice from them again

You do not need "more" air, again this is backwards thinking. You need the correct air/fuel mixture at the higher RPMs. If it's not running rich, you don't need more air

What do your spark plugs look like?

What are your compression readings?

Why would you rebuild a perfectly good engine?

Spark plugs are the ones it came with out of the barn and they are a little dark. Havent done any compression tests. Im thinking of rebuilding the engine because i bought a donor bike and i have a spare everything and i live in the northeast so i have all winter to work on the bike. In the end im trying to get this bike to at least be able to ride with the new gsxr that my buddy is buying in the spring. I know he'll smoke me no matter what i do, i'd just like to at least hit the highways.

[Big T]

Spark plugs are the ones it came with out of the barn and they are a little dark. Havent done any compression tests. Im thinking of rebuilding the engine because i bought a donor bike and i have a spare everything and i live in the northeast so i have all winter to work on the bike. In the end im trying to get this bike to at least be able to ride with the new gsxr that my buddy is buying in the spring. I know he'll smoke me no matter what i do, i'd just like to at least hit the highways.

Well, you're going about the "reviving the barn find" backwards

You need to do all the deferred maintenance first, then fix whatever else is wrong. See the "ten Common things" and go from there. Anything you need (other than tools) is on BassCliffs site

There are any number of probable causes for the problem you posted about

Clogged gas tank vent
Clogged petcock
Clogged carbs
Valves need adjusting
Torn carb diaphragm
Carbs out of sync

It is common to not get the carbs clean enough. See the tutorial on this

[bodcherokee]

ok so over the weekend i popped the round cover and the timing turns about 90 degrees then snaps back. also spins just fine when running. I'm thinking more and more that i'm going to have to have someone do my carb work because now after sitting for a month it runs worse now. Sitting in neutral it will idle fine but when i try to rev it up it goes to like 7500 then bogs back down to idle with the throttle open. If anyone knows of any shops that are good in western mass, please let me know.