GS won't start! (video)

[queasy500]

Hello,

I picked up this 94 for $550 and before I spend anything making it look decent, I need to get it running! Something ain't right though. I bought it with the top end redone up to the cam cover being put back on, so I installed that, fixed the carb floats (one was loose inside the bowl), new plugs, new battery, and filled up the tank but she just won't go. There is fuel getting to the bowls and the jets are clear, but I don't smell any gas in the cylinders. When it cranks it pushes fine white smoke out of the exhaust like something is burning but it does not fully combust and start. I've been fiddling with it since I got it off the trailer and its a bust! Any ideas?

Here is a short video of the sound it makes. https://www.youtube.com/watch?v=RX4wpuugZe4

[Suzuki Stevo]

I bought it with the top end redone up to the cam cover being put back on, so I installed that,

Timing, are the cams indexed correctly 

[W201028]

Do you know why the top end was redone?

First things first, you should put the pipes on if you have them, back-pressure is somewhat important even on a four stroke.

Im not sure about that gulping sound, but it may be overlap in the valves. How many miles has she got?

Based on what you posted about not smelling fuel, I would check the carb boots for sealing first, then check the valves for clearance. With the pipes off like it is, you should smell raw fuel coming out of the ports.

Also, pull a spark plug out, connect it to the wire, and hold it next to the head. Run the starter, you should see spark across the plug.
It seems silly to mention, since you seem to have some mechanical ability, but these bikes have several "safety" switches at the kickstand and such that will kill the spark if they are not closed.

[queasy500]

Do you know why the top end was redone?

First things first, you should put the pipes on if you have them, back-pressure is somewhat important even on a four stroke.

Im not sure about that gulping sound, but it may be overlap in the valves. How many miles has she got?

Based on what you posted about not smelling fuel, I would check the carb boots for sealing first, then check the valves for clearance. With the pipes off like it is, you should smell raw fuel coming out of the ports.

Also, pull a spark plug out, connect it to the wire, and hold it next to the head. Run the starter, you should see spark across the plug.
It seems silly to mention, since you seem to have some mechanical ability, but these bikes have several "safety" switches at the kickstand and such that will kill the spark if they are not closed.

PO had it apart to change the head gasket and redid the top end while he was inside.

I've cranked it with and without the headers on. I left them off in the video so the exhaust valves could be heard to give a better idea of the timing.

11,000 miles

carb boots are tight but i haven't checked valve clearances

both plugs are in working order

I've cranked it both with the kickstand up and down

[queasy500]

I bought it with the top end redone up to the cam cover being put back on, so I installed that,

Timing, are the cams indexed correctly 

good question   

[queasy500]

I bought it with the top end redone up to the cam cover being put back on, so I installed that,

Timing, are the cams indexed correctly 

If you're talking about the relationship between the arrow and numbers on the cam sprockets and the timing chain then yes those are correct.

[W201028]

If you have spark on both plugs, then its not the kickstand switch or neutral/clutch switches.

I suppose my next step would be to check the compression, if you havnt already.

If I remember, I had to have a fitting made for mine, since the plugs are fine thread metric. A fellow machinist spun one up on the lathe for me when I was pretty green. I suggest taking a plug with if you are going to buy a compression gauge.

Beyond that, if the plugs arent wet and you cannot smell fuel, I would go back to the carbs, in particular the slow (pilot) jets.

If you havent already try cranking the motor with throttle. Its possible the idle adjustment is so far out of whack that it wont even run. If it will start with part or full throttle then you have your answer.

You said the bowls are full, so I would expect the motor to pull fuel out of them if it is in working order.

Edit; Do check the valves for clearance, even with the low miles (if they are correct) the exhaust seats do go away, but I would expect you to smell fuel from the ports if the valves were full open.

[Janx101]

The gulping sound mentioned earlier... pretty sure that's just the airflow out the exhaust manifold from the pistons pumping up and down.

And I think also as mentioned above that the exhaust pipes should be installed even if it's just pinch tight... you are changing the standard characteristics of fuel/air flow, back pressure and possibly compression (if the valves are worn?) by not having the pipes on...

Best to start checking with "system as normal/standard as possible" or you may create sub-issues that confuse diagnosis of the main issues!?

[queasy500]

The gulping sound mentioned earlier... pretty sure that's just the airflow out the exhaust manifold from the pistons pumping up and down.

And I think also as mentioned above that the exhaust pipes should be installed even if it's just pinch tight... you are changing the standard characteristics of fuel/air flow, back pressure and possibly compression (if the valves are worn?) by not having the pipes on...

Best to start checking with "system as normal/standard as possible" or you may create sub-issues that confuse diagnosis of the main issues!?

Understood. I'll put the pipes back on and give it another shot while giving it full throttle as suggested before. Since fuel is getting to the bowls but not the cylinders, I'm thinking the carb is gummed inside.

[sledge]

Fact is you don't know what the PO has done. What you are being told may not be the whole story. He may not have known what he was doing and f%&ked things up or created or overlooked faults.

I would take the cams out, the head back off and start all over. Examine all components, recheck the timing, reset the clearances. Then, if you are still having problems it's safe to rule out the head and suspect something else.

Another tip......buy a manual.

[Janx101]

Always buy a Manual!

[queasy500]

Manual is on its way! I've learned to diagnose a no start buy changing easy stuff first, so I want to work with the carb more first. If that isn't it then she's coming apart.

[gsJack]

Compression, ignition, carburation in that order is the way I learned it 68 years ago when diagnosing an unknown vehicle. Have you checked compression yet?  No need to pull it apart unless it's assembled wrong, check that first:

[queasy500]

Thank you gsJack for the visual. That's the clearest depiction of the cam timing I've seen yet and I'll be using that if she comes apart again. New piece of info as well..I was out trying to start it just now while spraying carb cleaner down the throat with the throttle fully open in an attempt to get SOMETHING combustible into the cylinders but it spit it right back into my eyes. To me that says the intake valves are opening either too early or too late. Yes?

[barry905]

When I tried to get my bike going after winterizing it wouldn't start, so I sprayed quick start (which i believe is ether based) into the carb inlets and it started fine. In you case I would check the compression and spark first (take the plug out, connect it to the HT lead and ground it, then put my finger over the plug hole and check that the spark appears roughly when the compression peaks).

If that seems OK then I would spray quick start into the carb inlets. If it runs for a few seconds and then dies then you have a fuel problem. If it doesn't then you need to check the compression, ignition and ignition timing.

Good luck.

[Suzuki Stevo]

First off...Don't believe a word the PO told you 

[Janx101]

Hmm Stevo?!?

[Suzuki Stevo]

Hmm Stevo?!?

Yes, people will tell you anything to make a sale, including flat out lying about the condition of a rig, including telling you that the top end has just been redone.

[queasy500]

For $550 I wasn't expecting much.

[Suzuki Stevo]

For $550 I wasn't expecting much.

Exactly, chances are you will sort it out, there is also a remote chance you can't.