I rejetted a week ago, and finally was able to take it for a test drive over this last weekend. After figuring out that the main and resevoir lines were backward on the tank petcock, I was able to get the float bowls to fill with prime. So on the test drive, I only made it about a couple houndred yards, then complete loss of power, then the engine shut off. I'm guessing that I ran out of gas, but the tank has gas in it. It's like I was running on what was just in the float bowls, then when that was used up, it quit. I could see that there was not gas in the line cause the clear fuel filter was empty. I put it on prime, but it didn't do anything, then after about 5 minutes, I was able to get prime to fill the float bowls back up, and I road it back home on prime. I don't know why prime didn't work imidiatly to fill the bowls, but I'm more concerned about why they aren't filling on 'on', or 'res' while the engine is on. I'm guessing it's a vacuum line or something, so I checked the line from the frame petcock to the left carb, and it wasn't obstructed. Anyone know what's going on?
You probably took care of this, but it has gotten me before. :oops:
Did you remember to turn the fuel-mounted petcock back on? (Slot vertical.)
(http://bbburma.net/MiscFotos/100_1485_TankPetcockInONPosition.jpg)
yeah, that's the first thing I thought of when on the side of the road, so I unbolted the tank and checked it. It was on, which I was hoping it wasn't, cause it would have been an easy fix. Any other ideas? It's realy got me stumped...I can't track it down anywhere, it just isn't making since why the gas wouldn't flow.
The petcock diaphragm might be torn, or the needle stuck. I don't believe there are replacement parts available, but someone else might know more.
Mine came with an aftermarked petcock, so I'm no help other than that. :dunno_white:
the diaphram on the frame petcock? that might make since if that itself is malfunctioning. That would explain why it wasn't wanting to fill on prime for a bit either. Maybe I'll tear that off and have a look. Any other ideas before I get into something that might not have anything to do with it?
The "Prime" setting bypasses the diaphragm (i.e. even if the diaphragm was stuck, fuel would still flow on "Prime").
Why not disconnect the fuel line going to the carbs, put it in a bucket and see if fuel flows out on "Prime" before tearing it apart? The petcock isn't meant to be dismantled, so if you take it apart there's a chance it won't go back together happily.
Quote from: quiktaco on November 05, 2007, 08:41:02 PM
After figuring out that the main and resevoir lines were backward on the tank petcock, I was able to get the float bowls to fill with prime.
Sorry if you've worked through all of this, but I don't know what
you know....
How did you figure out that the lines were backward on the tank petcock? Was it just by looking at parts fiche, or have you read some GStwin threads
on the topic, or ... ? Just in case you haven't seen them, here are some annotated
diagrams that capture the results of a LOT of research:
[From the Haynes manual (http://bbburma.net/Scans/Haynes_FuelSystem_CA_Specific_Annotated.jpg)]
[From the Clymer manual (http://bbburma.net/Scans/Clymer_FuelSystem.gif)]
[From one of the online parts catalogs (http://bbburma.net/ScreenShots/Fiche_FuelHoseRouting_2001AndUp.jpg)]
In general, if you're fairly certain the tank-mounted petcock has not been reversed by a previous owner, the fuel lines that go from the tank to the ON/RES/PRI switch should not "cross over" each other.
Quote from: quiktaco on November 05, 2007, 08:41:02 PMI'm guessing that I ran out of gas, but the tank has gas in it.
If it turns out that your lines weren't switched before (and now they
are :icon_rolleyes:) you could have a full gallon of fuel in the tank and not get it to come out on the PRI setting.
Even if everything is attached perfect, you might be surprised at the amount of fuel still in the tank when you truly "run out of gas".
Hope this helps!
Good idea, I probably won't get to testing it till this evening, so I'll try just putting it to a bucket first on prime to test it.
Kerry - I figured out that the PO had switched them, because prime didn't work before to fill them after the jetting, so I looked at a parts fitch, and it was backward. So I switched them and then prime worked. Assuming they are correct right now, would prime not work if I was down to the resevoir section of the tank? That would explain why prime didn't work and why 'on' didn't work. Assuming they are switched now, why would prime not have worked before, but it does (usually) now.
Also, depending on which fuel line you are using (I use Tygon which is very flexible) you could have kinked the line as you reinstalled the tank. Very little fuel would get through that way. Normal fuel line would not have this problem -- it's almost impossible to kink.
I don't think there's a kink, but I'll check that out too, thanks
Re-reading through some of this, I realized that I did match it to some parts fitch, I think it was the bike bandit one, so maybe I did switch it. But the only thing is, the prime didn't work when it was the other way, so I'm pretty sure it's correct now. I'm going to get a long lunch today, so I'll be working on it in a couple hours from now.
Kerry - you said "Even if everything is attached perfect, you might be surprised at the amount of fuel still in the tank when you truly "run out of gas"." Would the prime not fill the float bowls if I were down to the reservoir part of the tank? I think that would explain it all. I'd just need more gas in the tank. But I thought prime was supposed to work through 'on' and 'res'.
FIXED! went through a few things, first off, couldn't get it to start, so I expiremented with push starting for the first time (on flat ground). It's actually really easy once you have the key turned to on instead of off :oops:
So for the remedy. When I rejetted, the idle screw got seriously messed up. That was the root of my problems, but the real problem is that I was just low on gas. I got it to start in 'on', then let it sit for about 20 seconds in neutral, and, looking at the fuel filter, the gas started to gurgle inside, so I switched it to 'res' and it flowed back normally again. It still doesn't explain why 'prime' is acting up and not filling the bowls, but hopefully, the other problems will go away with more gas. Sorry for the stupid post, but hopefully it will help out some others that aren't quite familiar with their bikes yet like me.
Quote from: quiktaco on November 06, 2007, 10:41:28 AMI thought prime was supposed to work through 'on' and 'res'.
The only way things make sense to me is that the PRI setting pulls fuel from the RES hose (only).
Congrats for figuring it out! :thumb: