1976 Suzuki GT550 2 Stroke

ubergeez

ubergeez

Been Around the Block
Hi Everyone, I would like your suggestions on an issue Im having with my bike.

I cleaned the carbs, ultrasonic. All the electrics as far as I know work. Put it on the street, and within seconds it was running.

I was very happy, then a couple minutes later it died. Couldnt get it going again. It has good spark, Gas, compression, and timing.

Im thinking I could be some gum from the oil. even though its new. in the carbs. Thinking of taking them off again, and checking. Could be electrical. Maybe.

I got it going 1 time after then it went to idle and died. ;(

You can see it here : https://youtu.be/izVA9wCPPBI

Your suggestions on how to attack this problem are much appreciated.

Uber.
 
There are a few places you could start - carbs or electrics. Let's start with electrics. I would look at the points cam and see if it is loose or maybe moved. I was helping a buddy with a similar issue on his 550 and in his case the "propeller" had moved and was about 45 degrees out. In your case, the drive pin may have dropped out and allowed the cam to move relative to the shaft.

if you spin the motor over, does the points cam also rotate or is it static? If it's static, it could well be a broken drive gear. They always crack and sometimes they break up.
 
Thanks. All that looks to be good, I did check the spark, and gaps again, as thats what I was thinking. Im going to take the carbs of and blast them out again.

Hoping its just a jet issue. I do have inline gas filters to keep the shizzle out of the carbs. But you never know.

When you say propeller are you talking about the advancer, that rotates the spark gaps?

Uber
 
The "propeller" is the three bladed piece of flat steel that sits behind the points cam and indicates timing. There are lines for L, C, and R and are not exact but are a good way to see if timing is a mile off.

http://s791.photobucket.com/user/k-taylor56/media/GT380140_zpse3a106a5.jpg.html

http://s800.photobucket.com/user/Cragdoggy/media/Mobile%20Uploads/photo4_zps346c26e8.jpg.html

You can pull the heads and do it more accurately.
PB130009.JPG


An easy way to see when the points open is to use a small bulb. I use one in a housing pulled out of a speedo. I fitted alligator clips to both leads to make it easy to use. Clip one end to ground and one to the power side of the points you are working on. Turn on power and rotate the motor slowly with a wrench. At the instant the points open, the light bulb lights up.
 
I see what you did....

I am thinking it sounds like carbs, so it must be electrics and you did the opposite.

In reality, the carbs and electrics need to be checked, it's a question of which do you prefer to tackle first.
 
Ok so this morning, I got the bike to start again, I let it idle, then it died, I pulled the airbox, and it was full of gas. That cant be good. I took off the tank as well.

Been out all day, Just bought 2 Suzuki 83/86 Gl's parts bikes. Got them for a steal. Will be melding them to make one bike. The 650 preferably.

Anyways, Ill put gas in a squeeze bottle tomorrow and see if that works. Then Ill pull the carbs, and go through them again.

It was running, good until it died, and started as I said this morning, so I assume the points which I checked are good.

Ill go back to electrics after the carbs are throughly checked.

Thanks for your help. Ill probably need more soon.

Ill keep you posted.!

Uber
 
Either it's electrical or fuel.

Let's look at fuel for a moment. If you remove the drain plugs from each carb one at a time (outside and with a gas collection device in place) Do all three allow fuel to pour out at more or less the same rate with the petcock set to PRIme?

If so, when you stripped the carbs, did you spray air/cleaner/wd40 through the slow jets one at a time and did they all have similar spray patterns?

Did you spray through each drilled passageway in one carb at a time and compare the spray from that drilling to the other carbs? Without that comparison, we have no real idea what is right and what isn't.

Before re-fitting the carbs on the bike, check the FUEL levels.

When you are 110% sure the carbs are right, go back and look at the ignition timing with a bulb. If my previous instruction was confusing, let me know and I'll try again.
 
teazer said:
Either it's electrical or fuel.

Let's look at fuel for a moment. If you remove the drain plugs from each carb one at a time (outside and with a gas collection device in place) Do all three allow fuel to pour out at more or less the same rate with the petcock set to PRIme?

If so, when you stripped the carbs, did you spray air/cleaner/wd40 through the slow jets one at a time and did they all have similar spray patterns?

Did you spray through each drilled passageway in one carb at a time and compare the spray from that drilling to the other carbs? Without that comparison, we have no real idea what is right and what isn't.

Before re-fitting the carbs on the bike, check the FUEL levels.

When you are 110% sure the carbs are right, go back and look at the ignition timing with a bulb. If my previous instruction was confusing, let me know and I'll try again.
Click to expand...

I completely agree with Teazer. Pull the carbs and pull them apart completely. I did the soak in cleaner thing and thought my carbs were clean on on a RD350 and it turns out they were still plugged in several places, like the smaller drilled passages. Nothing beats a full tear down and clean.


Sent from my iPhone using Tapatalk
 
I did tear them down, and ultrasonically cleaned them, thats why it started right away. Now im dealing with something else. Here is another video from this morning.

I took off the carbs again, re-gapped the contacts put new plugs in yesterday as well.


Interesting situation.


https://www.youtube.com/watch?v=0yHXta-Ab9A

Uber
 
That's an awful lot of blowback. We expect some, but that looks like it's flooding. Are the plugs wet? Are the chokes ON?
 
Have you tried removing the fuel filters to make sure they are not the problem?

Did read the plugs, as Teazer said, see if they are wet?

Are the floats adjusted properly?
 
Go I think its timing.

Check the video.
https://www.youtube.com/watch?v=VnenwUEGw_Y

I need a gauge to show me top dead centre. Have to find one around here, I hope Canadian tire has one.
 
Totally off topic
But did you buy this gt550 off of kijiji not so long ago?
 
You appear to be jumping from one incomplete line of thought to another. just as an FYI, I use an industrial ultrasonic cleaner for carbs and it doesn't always get all the stuff out of some of the passageways. I have to check them for flow by blowing a spray can of carb cleaner or wd40 through one passageway in one carb and comparing that to the same drilling in the other two. All three should appear to be the same. It's not a measured flow test, but it certainly identifies any major issues in a way that a simple clean and inspect fails

Yes, check the timing and make sure it's correct on all three cylinders but it's also important to synch the carbs and set fuel levels. It doesn't matter much which sequence you approach that, but it's important to get the carbs right as well as timing.

How do you plan on setting timing? On a friend's GT550 he had set the timing to the best of his ability, so we pulled the head off and used a dial gauge bolted to the cylinder studs and found that all 3 were out and two of them were miles out. Point is that timing is really important to get right.
 
I bought 2 off Kajiji. The first was an orange Gt550, sold that, and bought this one. Much better shape. It was from Quebec!
 
teazer said:
You appear to be jumping from one incomplete line of thought to another. just as an FYI, I use an industrial ultrasonic cleaner for carbs and it doesn't always get all the stuff out of some of the passageways. I have to check them for flow by blowing a spray can of carb cleaner or wd40 through one passageway in one carb and comparing that to the same drilling in the other two. All three should appear to be the same. It's not a measured flow test, but it certainly identifies any major issues in a way that a simple clean and inspect fails

Yes, check the timing and make sure it's correct on all three cylinders but it's also important to synch the carbs and set fuel levels. It doesn't matter much which sequence you approach that, but it's important to get the carbs right as well as timing.

How do you plan on setting timing? On a friend's GT550 he had set the timing to the best of his ability, so we pulled the head off and used a dial gauge bolted to the cylinder studs and found that all 3 were out and two of them were miles out. Point is that timing is really important to get right.
Click to expand...

Thanks for that info. Im not jumping around thought patterns. #1. I cleaned every passage, took them all apart. They were seized and I replace the rubber boots as well. They were turning to goo.

The bike started right up. Then died.

As a mentioned I the carbs are clean. Yes I need to sync it with a manometer.
The carbs are bench synced for now.

I have a service manual. Need to hunt down a gauge that checks for TDC, and adjust it to the spec in the manual, for all 3 cylinders.

I havent done that yet
Ill let you know once I go to Canadian tire and get the job done.

Im pretty confident, its timing.

Ive got, great compression, spark, and gas... So timing is Key as you mentioned!

Again, thank you everyone for your information and interest.

Ill see how this bike turns out, might sell it, once everything is working properly.

Who knows. I have 2 more cb550s an Rd350 and a GL650 I need to build as well!

If you would like to see some of my bikes, this was taken at Freedom Machines this Year..

Enjoy.

Uber
 

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Ah, there was green one not so long ago for sale that was in nice shape
 
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