Need help with my GS cant workout what it is.

[Black93GS]

Hi I have a 1993 GS500E Suzuki. I was riding home and gave it some throttle from a set of traffic lights and it cought and spluttered then lost power and was very sluggish. I checked the diaphragms in the carby. One had a very small hole. I checked the cams and they where slightly out of wack. Re-set the timing also checked the cam clearance on the valves. Then connected vacum gauges and the carby's are sinked but it looks like that they are saying i have a leak in the inlet side or late valve timing.

I have patched the small hole in the diaphram but still not idle on both cylinders properly. (have two new ones on the way).

I have cleaned the carby's. (every part)

Have a small leak on the head gasket.

The bike will start nearly first time every time.  But when its running it sound like it has a really lumpy and only running on one cylinder some of the time.

When i give it throttle you can hear it sucking air and then dies.

Could it be the diaphram? Have i dropped a valve (but there is no noise in the engine)
Could it be the pet  chicken valve? 

I also did a compression test at cold and i got 149 PSi on the left cylinder and 150 Psi on the right cylinder.

Please help!!!!!!!!!!!!!!

[the mole]

Hi I have a 1993 GS500E Suzuki. I was riding home and gave it some throttle from a set of traffic lights and it cought and spluttered then lost power and was very sluggish. I checked the diaphragms in the carby. One had a very small hole. I checked the cams and they where slightly out of wack. Re-set the timing also checked the cam clearance on the valves. Then connected vacum gauges and the carby's are sinked but it looks like that they are saying i have a leak in the inlet side or late valve timing.

I have patched the small hole in the diaphram but still not idle on both cylinders properly. (have two new ones on the way).

I have cleaned the carby's. (every part)

Have a small leak on the head gasket.

The bike will start nearly first time every time.  But when its running it sound like it has a really lumpy and only running on one cylinder some of the time.

When i give it throttle you can hear it sucking air and then dies.

Could it be the diaphram? Have i dropped a valve (but there is no noise in the engine)
Could it be the pet  chicken valve?  

I also did a compression test at cold and i got 149 PSi on the left cylinder and 150 Psi on the right cylinder.

Please help!!!!!!!!!!!!!!

Firstly, with compression at 149 and 150 there's nothing wrong with your head gasket (except maybe small oil leak?) or your valves. When you say "I checked the cams and they where slightly out of wack. Re-set the timing also checked the cam clearance on the valves.", did you alter the valve timing or just the valve clearance?
Start with the electrical side, how good is the spark, check plug gaps (how old are the plugs?), ignition timing, leads, coils.
Does it miss at idle or under load?
If all that checks out, try the carbs and make sure they're clean with good diaphragms, they're both getting good fuel supply (undo drains and set to 'prime', check for good flow out of both drains.). Then run it on 'prime'. If that works the problem could be the petcock.
Good luck!

[mister]

Um... how's your fuel? Don't just say "I looked in the tank and it'd fine". Are you 100% certain you have enough fuel for On and don't need to switch it to Res and go tank up?

Also, check the fuel line from the frame mounted petcock. Sometimes, when you lift the tank to do something and put it back down the main line can get a small Kink in it and the bike will Act like it's out of fuel, exactly like you're describing. It may have run fine for a while until all fuel in the carbs was used quicker than refilled. So do check the fuel line for kinks as well. This can make you think vacuum as it will work on res but not on.

Michael

[Black93GS]

The timing was re-set and the valve clearance where set to 3x 0.04mm and 1x 0.06m.  All valves are in tollarence.

It is missing when at idle, i cant open the throttle with out it sucking heaps of air (you can hear it) and then it dies.
I cant get the RPM over 1200 Idle.

The tank is about 90% full and its on the "prime" setting on the pet chicken.  I have re-placed the fuel lines.

The plugs are only 2 weeks old.  How do you test the leads coils and ignition timing?

Im new at this so sorry for asking.

[the mole]

You say the timing was re-set. If you mean the valve timing, why was it re-set?
It can't change or go out of adjustment, it only needs setting after a top end re-build, or if someone who doesn't know what they're doing has screwed with it. (I once had to do it to my Kombi van after a "qualified mechanic" set it wrong.) If it was OK before your problem started and its been changed, then its now wrong!
Its really hard to diagnose without being there, but from what you're saying it sounds like its running on one cylinder. As the two cylinders share the same camshafts that wouldn't be a valve timing problem, as that would affect both cylinders equally. Also if the valve timing was a little out it would still run OK on both cylinders but just be a little down on power (The Kombi was two teeth out on the valve timing and still ran fine, just even more gutless than normal!).

[lamoun]

Under the nipples, under the carb cover, you used to check your vacumm there should be one o-ring. It,s a common think to lose it. This could account for an air leak. Ah! also the things that are written on the vacumm gauges (late timming blah blah) are bullshit. They must be ok for cars, but motorcycles... 

Now about the timming issue. It is possible that your timming was "ok". On a KLX I had, I checked the timming when I bought it. The marks wouldn't align, so I adjust the chain a bit. The bike work fine, but then it hit me. I opened the cover and measured the chain links between the camshafts (as stated by the manual). The chain was so worn that when set right, the marks on the camshafts wouldn't align.

The same think could be happening to you. Measure the chain link as per manual and see whats going on.

[Gs/Gl500]

Try bypassing the frame mounted petcock. Sounds like your just not getting fuel. I spent two weeks trying to track down the same problem on my GL.

[mister]

I have re-placed the fuel lines.

Have you double checked to make sure they are not kinked? Do you still have that mesh netting on them?

Michael

[Black93GS]

Yeah have double checked the fuel lines ad they are fine no kinks.  They don't have the mesh netting on them.

[Black93GS]

I just worked out what the problem was.  It was a broken wire from the pulse generator.  The wire has been repaired and the bike is running again.