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Recent Transplant
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2,664 Posts
Discussion Starter · #1 ·
God damn bike.

Without going into too much yelling at my bike (or myself for putting something back together wrong), here's the issue. Bike starts and runs fine at first, drive it out of my neighbourhood and onto the main road in heavy traffic, and it proceeds to sputter and die. Get it pulled over, try to start it again, and it starts.... but then just dies again. Eventually my battery started sounding weak, so I opted to just push it back up the hill to my garage in traffic (that sucked).

Here's the play by play:
Start bike with choke on, let it warm up while I toss on all my gear.
Rev it a little and drop the choke, it idles fine, so I back it out and set off.
Make it down the road, out of the neighborhood and stop at the stoplight at the main road, and have to wait at a red. Still idling fine.
Turn onto the road, and immediately it bucks and sputters, I figure, 'shit I must have just stalled it by letting out too much clutch too fast, rookie move,' but manage to keep it alive by pulling the clutch and try again.
AGAIN, I rev it up a little and let out the clutch slowly, but as soon as it catches, the engine just flops and dies. Coasting, I start up again, and it starts, but barely.
Try to accelerate into traffic and yet again, it coughs and dies. pull it over a final time and sit there in traffic trying to start it. It just doesn't start.
I manage to push it back to my place and call a buddy, who brings over some jumper cables because I'm thinking it might be the battery somehow? So we hook it to his car, but it just doesnt want to jump. Got it started one time with full choke, but it died on its own a minute later. Seemed like the jumper cables weren't doing too much either, still sounded weak even when it was hooked up.

I'm going to take it apart again and double check everything I played with when I tore it down. It seems like a fueling issue to me, as if it's not getting enough gas. Gotta check all the fuel lines, I may have pinched one playing with the wiring. I have plenty of fuel in the tank, but I don't know which way to turn the stopcock. horizontal is off, but I don't know which is main, which is reserve. In the process of fiddling with it trying to get it to start, I also managed to pull out my idle adjuster valve... ugh.

Anyway, I know I should be down there working on it, but just needed to vent at my first big(ish) roadblock on the road to fighterdom. Today just isnt my day.

P.S.: Does it make a difference running 91 octane vs. 87? My car takes premium, so I think I tanked it premium last time without thinking. This might be contributing to it running poorly, if it's not able to detonate properly. hmm... troubleshooting.
 

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the mad doctor
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3,399 Posts
does it have a vacuum petcock? make sure the vacuum line is hooked up and not leaking. you can also pop off the fuel line, turn the petcock on (and put a vacuum on the vacuum line if it has one) and see if it flows fuel. there's a filter on the petcock (inside the tank) if there's a bunch of crap in it, it may just be limiting fuel flow.

it'll run on "on" or "reserve" if it's got plenty of gas. but if you leave it on reserve and run out of gas, well, then you're gonna have to push it to the gas station.

the float valves could be sticking too. if there's any build up gunk on the sides of the needle, they could have gotten hung up and just not letting fuel into the float bowls. sometimes tapping on the carb bodies with a screwdriver handle will free them up.

it does sound like it's starving for fuel due to something though. like it just ran long enough off the gas that was in the bowls, but it's not letting any more in. if you unscrew the float bowl drain screws, i bet they're empty. just have to figure out why.
 

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Recent Transplant
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2,664 Posts
Discussion Starter · #4 ·
Good call guys, I'm gonna tear it back down tomorrow and see what's up. Got the day completely off, so that's the only thing on my agenda. (besides maybe studying for my 2 finals on friday, but priorities, priorities, priorities!)

Edit: The fuel tanks vent tube and drain tube were also dangling so I cut them shorter... would that have any impact on fuel flow? The service manual quotes "clogged fuel tank vent tube" as a problem source if fuel isn't reaching the carburator.
 

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Recent Transplant
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2,664 Posts
Discussion Starter · #6 ·
well hey effin' presto, there was a huge kink in the stopcock vacuum hose, it was pressed up against the top shock mount. Fixed it, but to no avail. Still won't start, don't know if the battery is too dead at this point to crank it, or if theres still an issue in fueling.

If that hose was kinked like that and it ran until it died, what would I have to do to prime the system again or whatever? I'm bad at carburated things...
 

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the mad doctor
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3,399 Posts
if the vent line was pinched, then the carbs ran dry, might have to crank it over for a bit before they fill back up. or, just pop the vacuum line off and suck on it (eeeeww) for a second to let fuel flow thru the petcock and fill the carbs
 

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the mad doctor
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3,399 Posts
haelo said:
Man $200 for cleaning carbs that are off the bike is a lot.

seriously, i charge $100 on the bike, and i tune and sync them while i have it.
 

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Eff Tee Pee
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29,722 Posts
haelo said:
Bout the same for me. Cleaning carbs is easy if you have someone show you what all the parts are and the correct way to remove/replace them.

yes :D that sounds like THE way to do it. haa.
 

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Recent Transplant
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2,664 Posts
Discussion Starter · #13 ·
Well if I can every get it started, I can bring it over to my gf's dad's house, he knows all about carbs and can help me get these things cleaned, synced, and put back together. I have the service manuals, but they are pretty worthless when giving tips and advice.

working on it today, we'll see what happens. I need jumper cables or a battery charger.
 

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Recent Transplant
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2,664 Posts
Discussion Starter · #14 ·
LUCKILY it wasn't the carbs, tried to jump it today and it wouldnt start. Choke closed, same thing. Gave it a little throttle and turned it over, and it started right up though! hmmm.... throttle closes, engine dies. So not enough air is getting in.

I strip it down to the carbs, everything looks nice and clean in the airbox and intakes, but my throttle stop adjust was too low, letting the throttle close too far and killing the engine. Adjust the throttle stop, wire the tach signal for my gauges into the coil spade connector while I'm in there, put everything back together.... and she fires right up!

took it for a test drive for a few miles to test it out and charge the battery, runs like a champ. Idles a little rough still (but it always did) and I got what sounded and felt like a misfire when accelerating down a hill. Gotta check the plugs and see what's up. Anyway, she's mostly fixed now and I can start riding and doing some cosmetic work. woo!
 

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the mad doctor
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3,399 Posts
sync the carbs and play with the mixture screws and i bet you'll smooth out that idle. glad to hear it's running again!
 

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KNUCKLE UP
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209 Posts
I had the same problem with my bike. My float height was way off on my 1&2 flooding and eventually fouling the plugs. I pulled my plugs to see what was going on. Pulled the carbs off 3 times before getting it right.
 
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