GS450 - Idles but can't give it any gas

[tthayer]

O-rings arrived today and a dremel tool assisted in getting the stuck screws removed. The dip proceeds tomorrow and maybe if I'm extra lucky the bike will start the first time.

[tthayer]

So I dipped the carbs, replaced the o-rings, and replaced the big gasket in the bowls. No change. I did noticed, however, that the right-side cylinder doesn't appear to be firing. I think this is the root of my problem. The coil gets just as warm to the touch as the left side and the spark plug is firing, but that side of the head doesn't heat up and the exhaust is cold. Any ideas?

[pete]

Have you checked your spark plug cap? I know mine were a bit dodgy and I replaced them with NGK plug caps and they're great now. Have you checked the primary and secondary resistance on your coils?

If they both get warm evenly, I'd expect you'll find both primary resistances ok, secondary may measure dodgy which could be the plug cap.

[94ta]

not 100% sure if its been asked yet, but have you checked your points gap?

[tthayer]

not 100% sure if its been asked yet, but have you checked your points gap?

This bike doesn't have points, but there are some resistance tests I can run. The clymer manual doesn't give much help other than "swap the working coil over to the other side and see if the problem changes sides too," so it's worth a shot.

[tthayer]

Swapping the coils from one side to the other actually did make it run worse, but still no change. I'll see if I can find some good used ones from one of the bike shops nearby.

[JStones]

tthayer - I am not a guru like the rest of these guys but I can say I just had this exact issue. I mean your post reads my issue to a tee. I followed Nessisms guide and cleaned the carbs properly and the problems gone. Just thought I'd throw that out there.

[tthayer]

I thought I had, but I suspect the carb dip I used was already depleted. I'll go through it again now that I have a can of carb cleaner handy.

[tthayer]

OK, big progress was made today. I think the right-side intake boot wasn't sealing properly. I took it off and took a file to the mating surface and cleaned out the channel for the ring and the bike now runs and revs BUT BUT BUT only with the tank set to prime. It runs great but there is fuel pouring out of the drain on the airbox so I think that is probably going to harm my mileage a little bit. The bike runs for a short period with the tank set to reserve or on (with several gallons of fuel in the tank), but it won't stay on for more than a few seconds that way. I think there might be something preventing the carbs from creating enough vacuum to force the petcock to open or the petcock is faulty. Any ideas?

[tthayer]

I'm going to make a wild leap here and guess that one or both of my floats aren't working, which is why I'm getting fuel out of the airbox. As previously mentioned: I've checked the float heights and replaced the o-rings for the fuel inlet.

[rlong74]

Needle valve? I'm still a noob but I think if the floats aren't working that means they are filling up with fuel causing the needle valve to stay open, therefore causing overflow. But i'm pretty sure that overflow would come out of the overflow lines and not the airbox.

[tthayer]

I'm starting to think that I'm an idiot of all things mechanical.
I think I have the overflow lines plugged into the vacuum port on the petcock and the ****** ************ ******* ********* *** ******* overflow plugged into the *** ***** ** **** vacuum port for the petcock.

**Edit for clarity**
Basically the fuel overflow is pushing against the petcock, preventing it from opening when in run or reserve. The overflow is blocked and fuel backs up over the floats and into the intakes. So very disappointed that I can't run out and fix it right now. Damn the darkness.

[rlong74]

I'm starting to think that I'm an idiot of all things mechanical.
I think I have the overflow lines plugged into the vacuum port on the petcock and the ****** ************ ******* ********* *** ******* overflow plugged into the *** ***** ** **** vacuum port for the petcock.

**Edit for clarity**
Basically the fuel overflow is pushing against the petcock, preventing it from opening when in run or reserve. The overflow is blocked and fuel backs up over the floats and into the intakes. So very disappointed that I can't run out and fix it right now. Damn the darkness.

That would certainly do it. Your vacuum nipple? should be just about directly below the petcock off the side of carb #1. If it's coming from anywhere else it's more than likely wrong.
Hope this helps some.

[tthayer]

The petcock is brand new, and the vacuum nipple is on the right-hand carb. The carbs on this bike more resemble the BS36's in Nessisim'. tutorial than the BS34's I've seen in most of the other write-ups (including the Clymer manual).

[rlong74]

The petcock is brand new, and the vacuum nipple is on the right-hand carb. The carbs on this bike more resemble the BS36's in Nessisim'. tutorial than the BS34's I've seen in most of the other write-ups (including the Clymer manual).

It's not down in front of the choke lever? Looking at your pictures your carbs look a lot like mine and the nip should be on the left under the petcock. I could probably put my thumb on the petcock and my pinky on the carb nip, that's how close they are.
Check picture 149 in your photobucket. Directly above the choke lever as it sits there.