No fuel getting to carbs

[ty998]

Hey All,

Just finished cleaning the carbs on a '81 gs650gx. I have the starter working now, but the bike does not start. Based on my review of the fuel line after removal of tank, I don't think any fuel is getting to the carbs or even to the fuel line for that matter. I am not sure if it is an issue with petcock or fuel filter possibly. If you set the tank flat and turn the petcock to PRI fuel will run out. I am going to try to fill carb bowls by pouring fuel directly into the fuel line to make sure that is not a filter problem first. If bowls fill and bike starts then I will look at petcock as next possible issue. Also tank is only about 1/5 full. I have tried switching to RES as well thinking fuel may only be available from 1 side.

Any comments or ideas?
I have been working on this bike for 3 months and am painfully close to getting it to work.

[chuck hahn]

Hook up the fuel line and put the petcock on PRI for about 30 seconds..choke ( no throttle ) and crank it over...should fire if youve done the carbs correctly and you have spark. PRI stands for PRIME as in to PRIME the carbs if the bowls are dry. Once its running swing the lever down to ON. Be sure the vacuum from the carbs is hooked to the petcock as well. Remember to swing it back down to ON if you leave the bike and it hasnt started too..keeps the petcock from possibly overflowing gas into the cylinders and crankase.

[allojohn]

Hey All,

Just finished cleaning the carbs on a '81 gs650gx. I have the starter working now, but the bike does not start. Based on my review of the fuel line after removal of tank, I don't think any fuel is getting to the carbs or even to the fuel line for that matter. I am not sure if it is an issue with petcock or fuel filter possibly. If you set the tank flat and turn the petcock to PRI fuel will run out. I am going to try to fill carb bowls by pouring fuel directly into the fuel line to make sure that is not a filter problem first. If bowls fill and bike starts then I will look at petcock as next possible issue. Also tank is only about 1/5 full. I have tried switching to RES as well thinking fuel may only be available from 1 side.

Any comments or ideas?
I have been working on this bike for 3 months and am painfully close to getting it to work.

If fuel runs out when the petcock is set to PRI then it's getting to the carbs. Put another gallon in the tank to eliminate whether you should set the petcock to RES or ON.

Do what Chuck says.....

If it still won't start check the float heights. If it still won't start then there's still crap in the carbs.

[tom203]

Sure sounds like fuel is making it to carbs in PRI! This bike needs full "choke" (actually an enricher) applied and NO throttle whatsoever! Hold "choke" up all the way if it won't stay up, press starter button and away it will go-IF IF those carbs got cleaned.

[ty998]

Thanks for your comments. I will update this post after my next opportunity to work on bike

[ty998]

I poured fuel directly into fuel line and Vroooooommm! So fuel delivery is another issue I am working on. Unfortunately, my fun ended when I disengaged the choke and the bike died, over and over.
In my dismay over my carb cleaning I forgot that I left the vac port unplugged (since tank is off). Hopefully that will improve the situation. My idle jets are clean. So if plugging the vac port does not work then I am not sure what the issue is. We'll see.

[tom203]

I poured fuel directly into fuel line and Vroooooommm! So fuel delivery is another issue I am working on. Unfortunately, my fun ended when I disengaged the choke and the bike died, over and over.
In my dismay over my carb cleaning I forgot that I left the vac port unplugged (since tank is off). Hopefully that will improve the situation. My idle jets are clean. So if plugging the vac port does not work then I am not sure what the issue is. We'll see.

The good news is it came to life with "choke"- the bad news is that the "choke" system is sorta independent of the rest of carb . You very likely have gummed up passages in the slow speed portions of the carb- many folks have to clean them twice before total carb happiness.

[ty998]

I know the carbs are clean. Also the slow jets are spotless. After plugging vac port IT WORKS! WOOHOO! Needs an idle adjustment, but runs without choke or throttle. Hooray, now onto custom seat, tail, wheels and the fun stuff!

[ty998]

Well, first I actually need to figure out why no fuel was getting from petcock to fuel line first. So not so fun yet. I am guessing it is an issue with the vacuum. I don't think there is a good seal around fuel cap and the tank. I am assuming there is supposed to be something on the tank that the cap would fit down onto to create a seal. On the bike there is nothing around fuel cap hole to create an air-tight seal. All comments appreciated!

[tom203]

Well, first I actually need to figure out why no fuel was getting from petcock to fuel line first. So not so fun yet. I am guessing it is an issue with the vacuum. I don't think there is a good seal around fuel cap and the tank. I am assuming there is supposed to be something on the tank that the cap would fit down onto to create a seal. On the bike there is nothing around fuel cap hole to create an air-tight seal. All comments appreciated!

Before the WOOHOOs take total possession, you should do some reading at Basscliff's where many things will be explained, like the fact that you DON"T want a seal at gas tank cap or not much fuel will leave tank. Some other info there is pertinent to your issues. Good stuff, FREE!!!

[ty998]

tom203: Thanks for the correction. I will read those notes. However, i still support my previous "woohoo". lol