Will not start, fuel flow? vacuum issue? who knows...?
Bike will fire up when using starter fluid, but dies after. Checked petcock and fuel flow no issues. Fresh fuel and carb was rebuilt and cleaned out. Must be issue between the fuel valve and carb intake to cylinder. Or could it be something else. I want to say its not getting fuel to the carb, but when i disconnect the fuel lines from tank, they have fuel in them. Is it at all possible they could be clogged? Thats a pretty big diameter.
And when testing the vacuum to the petcock for fuel flow, I got a proper size hose and connected it to the vacuum port and began to suck and it would initially open up and fuel would start to flow but would eventually stop. Does that suggest the diaphragm needs to be replaced? How exactly is that supposed to work? Also, how do I drain the fuel lines at the carb when I know the bike will sit for a while? Amy pictures would greatly help identify what it is as well. |
Originally Posted by whatthefnck
(Post 404494)
Also, how do I drain the fuel lines at the carb when I know the bike will sit for a while? Amy pictures would greatly help identify what it is as well.
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Here's the drain screw. You can connect a hose to the nipple to catch the fuel.
https://cimg5.ibsrv.net/gimg/www.sup...b8167a736c.png |
Originally Posted by whatthefnck
(Post 404494)
And when testing the vacuum to the petcock for fuel flow, I got a proper size hose and connected it to the vacuum port and began to suck and it would initially open up and fuel would start to flow but would eventually stop. Does that suggest the diaphragm needs to be replaced? How exactly is that supposed to work?
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Originally Posted by whatthefnck
(Post 404494)
Bike will fire up when using starter fluid, but dies after. Checked petcock and fuel flow no issues. Fresh fuel and carb was rebuilt and cleaned out. Must be issue between the fuel valve and carb intake to cylinder. Or could it be something else.
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Originally Posted by Wolverine
(Post 404499)
You need a consistent constant vacuum source, like a mightyvac with a gauge. Connect that to petcock vac and test flow. You may be loosing proper suck to keep it flowing.
Originally Posted by Wolverine
(Post 404499)
I'd guess the lines on the petcock have been improperly connected.
**Did I incorrectly hook up the hoses under the tank maybe? A breather hose and drain hose to the tank itself? Was I supposed to use one of those for the petcock drain instead? Its been so long since I disconnected I'm not 100% certain how I disconnected them. |
Originally Posted by whatthefnck
(Post 404500)
**Did I incorrectly hook up the hoses under the tank maybe? A breather hose and drain hose to the tank itself? Was I supposed to use one of those for the petcock drain instead? Its been so long since I disconnected I'm not 100% certain how I disconnected them. |
The 10mm nipple and hose on the bottom of the tank is the fill overflow drain, the 4mm nipple and hose is the tank vent, both of which vent to the atmosphere. On CA bikes I believe these go to the charcoal canister. The nipple and line from the base of the rear carb goes to the small horizontal nipple on the left side of the petcock. The small nipple coming out of the bottom of the petcock is the diaphragm atmospheric vent.(no hose connected) The small nipple on the base of the front carb (RH) should be plugged.
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Originally Posted by CaryDG
(Post 404506)
The 10mm nipple and hose on the bottom of the tank is the fill overflow drain, the 4mm nipple and hose is the tank vent, both of which vent to the atmosphere. On CA bikes I believe these go to the charcoal canister. The nipple and line from the base of the rear carb goes to the small horizontal nipple on the left side of the petcock. The small nipple coming out of the bottom of the petcock is the diaphragm atmospheric vent.(no hose connected) The small nipple on the base of the front carb (RH) should be plugged.
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I'm still stumped. The carb has been pulled and cleaned. The fuel lines are clear. The gas valve and petcock is all hooked up properly, and diaphragm is functional. The fuel tank cleaned out and replaced old fuel with spruced up fresh fuel with a bit of octane booster and some stabil. But I still cannot get this thing going on anything other than starter fluid thru the airbox. WTF is wrong. Full battery too. I know someone out there has got to have an answer. I'm dying to go ride, but at this point I'm about ready to burn this fuker and buy a new bike grrrr
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"16/43" how much difference you think adding 2 teeth to your rear sprocket did? I'm debating on adding 2 in rear or dropping 1 in front..
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Won't feel any difference if the bike doesn't start...
Fuel, compression, spark. Pull the supply hoses to the carbs. Use a piece of hose and supply continuous vacuum to the petcock and confirm fuel flows. No guessing... If it flows, you have a carb issue and need to pull them to inspect float bowl needles. Are they stuck closed? If it doesn't, you have an issue in the petcock/tank. It sounds to me like you aren't getting proper vac to start the supply of fuel. |
Thx wolverine. I'll get back with that, but I've already done the constant vacuum and confirmed the petcock is good. Also pulled the carbs and hd them professionally cleaned. So I'm stumped. Maybe I'll pull em again and bring elsewhere.
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Originally Posted by whatthefnck
(Post 404713)
Thx wolverine. I'll get back with that, but I've already done the constant vacuum and confirmed the petcock is good. Also pulled the carbs and hd them professionally cleaned. So I'm stumped. Maybe I'll pull em again and bring elsewhere.
Also the quote in red is, to me, a red flag. |
Originally Posted by xeris
(Post 404728)
bypassing the petcock altogether?.
https://cimg2.ibsrv.net/gimg/www.sup...39c0fa2ec2.jpg As everyone is agreeing, fuel delivery is your issue. It's either petcock or carbs or lines in between. |
Push tubing onto both carb drain nipples, place in clear container, then open the drains on both carbs one at a time, apply a constant vacuum source, fuel should be flowing really easily and at a good rate from both drains...
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Originally Posted by Fastguy59
(Post 404764)
Push tubing onto both carb drain nipples, place in clear container, then open the drains on both carbs one at a time, apply a constant vacuum source, fuel should be flowing really easily and at a good rate from both drains...
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Originally Posted by whatthefnck
(Post 404881)
Ahh ok so if i open up the petcock then it should flow consistently out of the carb draining points... as if i opened up a faucet.
Just so it's a little more clear, the petcock has a mechanical On-Off lever, and it also has a vacuum actuated On-Off. |
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