My bike wasn't running like it should, so I should take apart my carbs and clean up. After I got everything apart, it looked really clean. I did what I could, but they were pretty good to begin with. While re-attaching them, I noticed that they never had the vacuum hose from the petcock attached. So I bought a new one and hooked it up. I thought this might fix my problems. After a few cranks, it started up but the bike would idle very high and if I adjusted the set screw lower, would not hold idle. No big deal though, I hadn't balanced the carbs yet. I built a vacuum gauge with some hose and a yard stick and adjusted the balance screw so that when it cranks, it appears to be pulling equally. The problem is that now that I've touched that screw, there's nothing I can do to get the bike started again. I've tried fiddling with the mixture screws, but nothing. Can anybody offer some advice?
If your choke is working, your pilot jets aren't clogged, and you have a good battery it should fire right up.
Check your plugs. They should let you know if the bike is running way too rich or lean. Also check for vaccuum leaks. Finally, check to make sure your pilot jets are clear.
If you can, I recommend taking the bike to a good local shop. $100 to get the carbs dialed in and the bike running right is a good deal.
The pilot jets were perfect when i took them off in the first place and I still cleaned them with ethanol. So I know they're not the problem. The battery is dead, but I've been jumping it so that shouldn't be the issue. I'm pretty sure the choke works.
I did get it running, but barely. It would not run without the choke on full, idled at 1k and died instantly when I gently touched the throttle. Something is very wrong. Now it won't start again. :dunno_black:
Juan, do you mean check the spark plugs to see if it's running rich or lean? I don't understand. I would take them to a shop, but I really want to learn how to fix my own bike...so that's last resort.
are you getting fuel now?
no, i don't think so. i'm pretty sure i'm getting spark, so something is borked with the fuel along the way. i still can't get it to start regularly and when it does, it runs very weakly and usually takes a good bit of engine cranking.
i guess i should pull the carbs off again, but they were spotless when i looked the first time. float levels is the only "regular" thing i haven't looked into yet.
turn your pet chicken to prime let it sit for a few seconds and try to start it.
well it's been on primary with gas for about a week now. i've been stuck for a while. :icon_confused:
if youve been on prime for that long your outta gas and or flooded
Quote from: dleemiller on March 10, 2009, 05:10:39 PM
no, i don't think so. i'm pretty sure i'm getting spark, so something is borked with the fuel along the way. i still can't get it to start regularly and when it does, it runs very weakly and usually takes a good bit of engine cranking.
i guess i should pull the carbs off again, but they were spotless when i looked the first time. float levels is the only "regular" thing i haven't looked into yet.
Before you pull the carbs off again, check your float heights. That will tell you if you have gas getting to your carbs as well as making sure the floats are set right. If the float heights are good, try checking for vacuum leaks quickly before you pull your carbs again. You said someone had removed the fuel vacuum hose, perhaps they did it because the petcock was creating a big vacuum leak. If it was missing a hose and running for any length of time, there is probably a reason the hose was gone. Probably not a good reason, but someone probably went through the effort of removing it at some point because they thought it might fix something... Just a thought.
Is any fuel getting to the carbs? You can crack open the float bowl screws and see if any fuel comes out (pop a hose on it and into a container). Also while you have a "clear hose" on it, you can check float bowl levels. You say the vacuum line was off the petcock. What setting were you running the petcock on when it ran normally? PRIME or ON?
Quote from: fred on March 10, 2009, 06:37:02 PM
Quote from: dleemiller on March 10, 2009, 05:10:39 PM
no, i don't think so. i'm pretty sure i'm getting spark, so something is borked with the fuel along the way. i still can't get it to start regularly and when it does, it runs very weakly and usually takes a good bit of engine cranking.
i guess i should pull the carbs off again, but they were spotless when i looked the first time. float levels is the only "regular" thing i haven't looked into yet.
Before you pull the carbs off again, check your float heights. That will tell you if you have gas getting to your carbs as well as making sure the floats are set right. If the float heights are good, try checking for vacuum leaks quickly before you pull your carbs again. You said someone had removed the fuel vacuum hose, perhaps they did it because the petcock was creating a big vacuum leak. If it was missing a hose and running for any length of time, there is probably a reason the hose was gone. Probably not a good reason, but someone probably went through the effort of removing it at some point because they thought it might fix something... Just a thought.
hm that's a good point.. i'll try checking the float height before i pull the carbs off again. i was thinking there might have been a reason for the lack of vacuum hose. it seems that whoever did the work on this bike before it got to me was pretty competent in the mods they've made. how does one check for vacuum leaks?
the setting from the petcock i've always had to use was PRI. it was never quite clear to me why, but i noticed it from the first day i bought it. :dunno_black:
Quote from: dleemiller on March 11, 2009, 07:39:20 AM
Quote from: fred on March 10, 2009, 06:37:02 PM
Quote from: dleemiller on March 10, 2009, 05:10:39 PM
no, i don't think so. i'm pretty sure i'm getting spark, so something is borked with the fuel along the way. i still can't get it to start regularly and when it does, it runs very weakly and usually takes a good bit of engine cranking.
i guess i should pull the carbs off again, but they were spotless when i looked the first time. float levels is the only "regular" thing i haven't looked into yet.
Before you pull the carbs off again, check your float heights. That will tell you if you have gas getting to your carbs as well as making sure the floats are set right. If the float heights are good, try checking for vacuum leaks quickly before you pull your carbs again. You said someone had removed the fuel vacuum hose, perhaps they did it because the petcock was creating a big vacuum leak. If it was missing a hose and running for any length of time, there is probably a reason the hose was gone. Probably not a good reason, but someone probably went through the effort of removing it at some point because they thought it might fix something... Just a thought.
hm that's a good point.. i'll try checking the float height before i pull the carbs off again. i was thinking there might have been a reason for the lack of vacuum hose. it seems that whoever did the work on this bike before it got to me was pretty competent in the mods they've made. how does one check for vacuum leaks?
the setting from the petcock i've always had to use was PRI. it was never quite clear to me why, but i noticed it from the first day i bought it. :dunno_black:
If you've always used prime on your petcock to run the bike, then it was not modified for non vacuum operation, it was just disconnected from the vacuum system. Was there a cap on the vacuum port that you connected the petcock to? If so, that is a really good indication that someone at some point thought the petcock was leaking...
As for checking for vacuum leaks, it is fun, just get a flammable aerosol and spray it on thing you think might be leaking while the bike is at idle. Just start from the intake tubes and work backwards. As soon as you spray the leaky part, the idle should increase and you've found a leak. Many people recommend using carb cleaner or WD-40, but both of these substances have been made to be far less flammable over the years, so a better bet is starting fluid. You can get it at any auto parts store and it is insanely flammable, so be careful and don't have too much fun.
mm yes i realized how cool ether was the day i tried to make a flamethrower out of it, like what you can do with WD-40...not a good idea! It is far far more flammable and the flame ran up the stream faster than the starting fluid came out of the can haha.
there wasn't any cap on the vacuum port of the petcock when i got it. i'll give this leak testing method a try once i figure out how to get it started.
Try capping off the vac port on the carb b4 using the aersol. My petcock has since been converted to a non-vacuum Honda CRF450 style to do away with vacuum issues and the engine didn't run well until the vac port was capped.
Good luck.
finally got this one figured out. i called a guy over to give me a hand with this thing and eventually we tracked it to the petcock. it seems the thing is partially clogged up so the carbs weren't getting a reliable stream of fuel. i yanked the petcock off and hooked the tank directly to the carbs. it starts fine and idles like a dream.
i was thinking of not buying a new petcock. other than the fact that i wont have access to my reserve, this is fine right?
If you have no petcock and your float needles do not seat or otherwise leak, you will have gasoline in the airbox and on the ground at best, or gasoline in the cylinder and crankcase at the worst.
I failed to notice something before, sorry. You're supposed to balance the carbs with the engine running at 1750 rpm, not by cranking. I'd put the screw back where it was and go from there. Hopefully you kept track of how much you turned it and in which direction.
you did remember to turn the petcock on on the tank back on after you reistalled the tank didnt you? if thats not it, you may not have as much fuel in it as you think. try running a gas line directly from the tank, to the carbs, and cap the other one at the petcock, and try that. if it runs like that, it would indicate a petcock problem
Quote from: bill14224 on April 15, 2009, 04:23:25 PM
I failed to notice something before, sorry. You're supposed to balance the carbs with the engine running at 1750 rpm, not by cranking. I'd put the screw back where it was and go from there. Hopefully you kept track of how much you turned it and in which direction.
Why would it matter what the original setting was? Since you have it running now (congratulations :thumb:) just rebalance from where it is now.
Quote from: jeremy_nash on April 15, 2009, 05:26:33 PM
you did remember to turn the petcock on on the tank back on after you reistalled the tank didnt you? if thats not it, you may not have as much fuel in it as you think. try running a gas line directly from the tank, to the carbs, and cap the other one at the petcock, and try that. if it runs like that, it would indicate a petcock problem
yeah that's what i did. i actually just removed the petcock completely and ran a line directly from the tank to the carbs. i capped off the reserve on the tank and the vacuum port on the carbs. it runs fine in that configuration, so i'm quite certain that something is wrong with the petcock. how much do i need a petcock if it runs without?
Quote from: dleemiller on April 15, 2009, 05:49:06 PM
Quote from: jeremy_nash on April 15, 2009, 05:26:33 PM
you did remember to turn the petcock on on the tank back on after you reistalled the tank didnt you? if thats not it, you may not have as much fuel in it as you think. try running a gas line directly from the tank, to the carbs, and cap the other one at the petcock, and try that. if it runs like that, it would indicate a petcock problem
yeah that's what i did. i actually just removed the petcock completely and ran a line directly from the tank to the carbs. i capped off the reserve on the tank and the vacuum port on the carbs. it runs fine in that configuration, so i'm quite certain that something is wrong with the petcock. how much do i need a petcock if it runs without?
You need it. If you don't, gas will continue to flow to the carbs when the bike is off and could cause trouble. You could end up with a big mess like a crank case full of gas if anything ever goes wrong with your floats. Even tiny float height problems could cause a massive headache. My friend lent me his KLR250 one day that had been sitting with the petcock on reserve for a couple of weeks and I found out on the freeway that pretty much all the gas in the tank had slowly leaked from the carbs and evaporated, leaving me with so little gas I only got about 14 miles before it was time to start pushing. You'll also want a petcock so you can make use of the fuel reserve instead of just running all the way out of gas. I know you might now think that you'll just keep track of all the mileage and never run the tank down, but there will be some day that you'll be distracted and not fill the tank up all the way and then ride really hard and then try to make it that extra couple of miles where you know you've almost got no gas to make it to the cheaper gas station and then end up pushing the bike. Trust me, pushing my friend's KLR250 3/4 of a mile to the gas station took about a half hour and was very tiring and that bike weighs more than 100 pounds less than a GS, you don't want to push the GS if you can possibly avoid it. You need a petcock, it is a really handy thing.
Quote from: fred on April 15, 2009, 07:11:25 PM
Quote from: dleemiller on April 15, 2009, 05:49:06 PM
Quote from: jeremy_nash on April 15, 2009, 05:26:33 PM
you did remember to turn the petcock on on the tank back on after you reistalled the tank didnt you? if thats not it, you may not have as much fuel in it as you think. try running a gas line directly from the tank, to the carbs, and cap the other one at the petcock, and try that. if it runs like that, it would indicate a petcock problem
yeah that's what i did. i actually just removed the petcock completely and ran a line directly from the tank to the carbs. i capped off the reserve on the tank and the vacuum port on the carbs. it runs fine in that configuration, so i'm quite certain that something is wrong with the petcock. how much do i need a petcock if it runs without?
You need it. If you don't, gas will continue to flow to the carbs when the bike is off and could cause trouble. You could end up with a big mess like a crank case full of gas if anything ever goes wrong with your floats. Even tiny float height problems could cause a massive headache. My friend lent me his KLR250 one day that had been sitting with the petcock on reserve for a couple of weeks and I found out on the freeway that pretty much all the gas in the tank had slowly leaked from the carbs and evaporated, leaving me with so little gas I only got about 14 miles before it was time to start pushing. You'll also want a petcock so you can make use of the fuel reserve instead of just running all the way out of gas. I know you might now think that you'll just keep track of all the mileage and never run the tank down, but there will be some day that you'll be distracted and not fill the tank up all the way and then ride really hard and then try to make it that extra couple of miles where you know you've almost got no gas to make it to the cheaper gas station and then end up pushing the bike. Trust me, pushing my friend's KLR250 3/4 of a mile to the gas station took about a half hour and was very tiring and that bike weighs more than 100 pounds less than a GS, you don't want to push the GS if you can possibly avoid it. You need a petcock, it is a really handy thing.
thanks for the info. its only a $50 part, so i think i'll just go ahead and order a new one.
something has been wrong with this bike since i got it and i think the petcock was it. it wouldn't idle correctly and i was totally confused when i pulled apart the carbs to find that they were spotless... just before it stopped working all together it started surging really badly.
on to fixing the tach, kill switch and replacing the front springs! :thumb:
ok i'm still having problems >:(.. here's the state of things.
* only getting fuel into the left float bowl
* carbs have been fully cleaned, no blockages found and were pretty spotless when i opened them up
* brand new petcock is installed
* bike gets gas to both carbs and fires right up when i bypass the petcock and run the tank line directly to the carbs
i'm really confused....what would cause the bike to only pull gas into 1 carb? the right carb (side without vacuum hose attached) is almost bone dry and gas readily drips out of the other side.
That's kinda odd.
Three thoughts:
1-are your hoses routed properly?
http://gstwin.com/images/how_to/fuel%20hose/www_gs500_de_HoseRouting.jpg
2- floats not set right
3- some blockage in one of your hoses
i know all the hoses are connected right... except maybe the vacuum line. ive checked that picture several times, but i can't see where the vacuum hose goes and there wasn't one connected before i got a new petcock.
it connects to the inside left carb correct?
on a side note, are you an atlanta rider? i live in the city, so i was just curious.
Yes, inside of left carb to petcock.
Edit: Didn't read post all the way to the end. I'm in Lawrenceville actually. Will be heading towards the city tomorrow. What part of town you in.
if my bike had been converted to a gravity feed, there should be something plugged right? maybe it's not getting any vacuum... if all else fails, i'm going to buy a metal valve and take out the petcock. do you know off hand if the gas hoses 1/2" or 3/8"?
If you convert to manual petcock, you'd install a vacuum cap to the left side carb. Same place the vacuum hose goes now. I'm using 5/16" I.D. X 7/16" O.D. clear polyurethane hose. I like the clear hose cause I can always see if the fuel is getting to the carbs and if there's any rust or debris coming from the tank.
Edit: You can check the vacuum while the engine is running by pulling the vacuum line from the petcock and put your finger over the line to see if you can feel any suction.
If I remember correctly its actually some mm size. 1/4 or 3/8 will work though. 3/8 is a bit loose but will be fine as long as you tighten the hose clamp down tight and 1/4 is particulary tight and can be a pain to get on but would probably hold fine without a hose clamp if one were so inclined.
Quote from: woodchuck5515 on April 26, 2009, 06:24:13 PM
If I remember correctly its actually some mm size. 1/4 or 3/8 will work though. 3/8 is a bit loose but will be fine as long as you tighten the hose clamp down tight and 1/4 is particulary tight and can be a pain to get on but would probably hold fine without a hose clamp if one were so inclined.
IMHO, I think the 5/16" is a good compromise. It seems to fit just right.
Didn't like the 1/4" hose cause of the same issue of being a PITA to remove and I'm always tinkering around so didn't want to mess with that.
Ya now that I think about it I think that 5/16 might be the correct size it can just be a pain to find sometimes. I don't believe any of my local businesses stock it but if one does near you then its the better choice. Its just not worth making a special online order just for that.
Quote from: ATLRIDER on April 26, 2009, 06:23:42 PM
If you convert to manual petcock, you'd install a vacuum cap to the left side carb. Same place the vacuum hose goes now. I'm using 5/16" I.D. X 7/16" O.D. clear polyurethane hose. I like the clear hose cause I can always see if the fuel is getting to the carbs and if there's any rust or debris coming from the tank.
Edit: You can check the vacuum while the engine is running by pulling the vacuum line from the petcock and put your finger over the line to see if you can feel any suction.
ah good point. ill give that a shot first and see if im getting any pull. i think my bike was converted to manual because when i got it there was no vacuum line attached...but there also wasn't a cap on the inside left carb.
unless i'm just totally picking the wrong spot to attach.. i know the vacuum ports on the top of the left and right carbs (by the black plastic tops) that i used to check the vacuum. both of those are capped, but i thought from the picture i was another spot on the inside.
i live close to midtown in an apartment complex just off of peachtree and collier road if you know where that is.
Quote from: woodchuck5515 on April 26, 2009, 06:34:57 PM
Ya now that I think about it I think that 5/16 might be the correct size it can just be a pain to find sometimes. I don't believe any of my local businesses stock it but if one does near you then its the better choice. Its just not worth making a special online order just for that.
If you have a Cycle Gear near you, they'll have it. It's where I got it.
Quote from: dleemiller on April 26, 2009, 06:36:29 PMah good point. ill give that a shot first and see if im getting any pull. i think my bike was converted to manual because when i got it there was no vacuum line attached...but there also wasn't a cap on the inside left carb.
unless i'm just totally picking the wrong spot to attach.. i know the vacuum ports on the top of the left and right carbs (by the black plastic tops) that i used to check the vacuum. both of those are capped, but i thought from the picture i was another spot on the inside.
i live close to midtown in an apartment complex just off of peachtree and collier road if you know where that is.
If there wasn't a cap on the left carb (not top plastic of carb, below there should be a metal nipple) the engine would have a pretty good vacuum leak and would probably run kinda crappy. Also, if you ever tried to sync the carbs with a leak that big, it'd be way off.
Quote from: ATLRIDER on April 26, 2009, 06:42:02 PM
Quote from: woodchuck5515 on April 26, 2009, 06:34:57 PM
Ya now that I think about it I think that 5/16 might be the correct size it can just be a pain to find sometimes. I don't believe any of my local businesses stock it but if one does near you then its the better choice. Its just not worth making a special online order just for that.
If you have a Cycle Gear near you, they'll have it. It's where I got it.
Well only kinda near. Its about 45min to an hour away but i've been meaning to go there to check out some new riding gear (mostly pants) in person since my couple of local dealers hardly stock anything and one didn't even have a single pair of pants