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So I have been working on my bike for about 2 months now (when I find the time). I have pulled the carbs and gone through them completely. I installed some inline fuel filters. My question is when I turn it to prime I can clearly see the fuel going through the filter but when I put it to on and it is running I cant see it flowing any more. The bike stays running but when you roll on the throtle it sputters and dies. What could be some issues to look into?
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1980 Yamaha XS1100 Std
4 into 1 exhast, pod filters
2003 Triumph Thruxton -
carbs
After reading many threads in here I understand that prime is used for runnen your bike, "on" is for tuning and runnen bike as you work on it. Vacuum system I believe, must be in use for the "on" to work, could be wrong. Anyone else help out?At this time:
1985 Goldwing Innr.
1976 cb 750 cafe racer
2007 vtx 1300
81 sx 1100 s h
81 sx 400 special -
Possible kink, trace your line and make sure its not pinched. There are some diagrams some where on how to route them. Do a little search and it will keep you busy. Lots of other possibilities but start with the easiest... How well did you clean them? Browse through the tech tips on how to clean your carbs and you might find something that you missed..?'79 XS11 F
Stock except K&N
'79 XS11 SF
Stock, no title.
'84 Chevy K-10 "Big Blue"
GM 350, Muncie SM465, NP208, GM 10 Bolt with 3.42gears turnin 31x10.5 Baja Claws
"What they do have is an implacable, unrelenting presence and movement that bespeaks massive power lurking behind paint and chrome. They don't wail like a screeching ninja, the don't rumble like a harley. They just growl like a spactic, stressed out badger waiting to rip your face off and eat your soul." Trainzz~RIP~Comment
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PRI is only used to "prime" your carbs if you have ran out of fuel. It lets gas flow regardless if the bike is running or not. Our bikes have a vacuum operated system that is closed when the engine is off and 'opens' when the bike is running, when in the 'ON' position. I always use on while riding and/or tuning, no real other reason to use PRI other than stated above.'79 XS11 F
Stock except K&N
'79 XS11 SF
Stock, no title.
'84 Chevy K-10 "Big Blue"
GM 350, Muncie SM465, NP208, GM 10 Bolt with 3.42gears turnin 31x10.5 Baja Claws
"What they do have is an implacable, unrelenting presence and movement that bespeaks massive power lurking behind paint and chrome. They don't wail like a screeching ninja, the don't rumble like a harley. They just growl like a spactic, stressed out badger waiting to rip your face off and eat your soul." Trainzz~RIP~Comment
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Not really. "Prime" is used for tuning, or for filling the carbs after you've taken them out and emptied the fuel from them. It bypasses the vacuum diaphragm and allows fuel to flow without the engine turning. "On" is used for everyday use. The turning of the engine creates a vacuum that allows the fuel to flow.1980 XS850SG - Sold
1981 XS1100LH Midnight Special (Sold) - purchased 9/29/08
Fully Vetterized and Dynojet Kit added, Heated Grips, Truck-Lite LED headlight, Accel Coils, Irridium plugs, TKAT Fork Brace, XS850LH Final Drive & Black SS Brake lines from Chacal.
Here's my web page devoted to my bike! XS/XJ User's Manuals there, and the XJ1100 Service Manual and both XS1100 Service manuals (free download!).
Whether you think you can, or you think you cannot - You're right.
-H. FordComment
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carbs.....
Just tryen to get a handle on this item.......if you are not runnen a vacuum system and use straight fuel lines with filters is there still a vacuum?At this time:
1985 Goldwing Innr.
1976 cb 750 cafe racer
2007 vtx 1300
81 sx 1100 s h
81 sx 400 specialComment
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The vacuum system is part of the bike... If you have the stock petcocks, you connect a line from the petcock to the intake boots (the one used for sync'ing the carbs). Of course, if you choose NOT to connect things that way, you are forced to bypass the diaphragms by using "Prime" all the time.1980 XS850SG - Sold
1981 XS1100LH Midnight Special (Sold) - purchased 9/29/08
Fully Vetterized and Dynojet Kit added, Heated Grips, Truck-Lite LED headlight, Accel Coils, Irridium plugs, TKAT Fork Brace, XS850LH Final Drive & Black SS Brake lines from Chacal.
Here's my web page devoted to my bike! XS/XJ User's Manuals there, and the XJ1100 Service Manual and both XS1100 Service manuals (free download!).
Whether you think you can, or you think you cannot - You're right.
-H. FordComment
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I have taken the carbs apart a couple times now. The first time I thought they looked clean so I just did minor cleaning. Bad idea. This last time I took every thing off the carbs cleaned every thing with carb cleaner and blew every thing out. I still need to sync the carbs and do some final adjusting just thought I would see the fuel flowing more then I did.1980 Yamaha XS1100 Std
4 into 1 exhast, pod filters
2003 Triumph ThruxtonComment
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The only way your not using the vac in your fuel system is if:
1. you ditch the Octy, on the later models, or
2. go to full manual petcocks, for the earlier style that had the diaphram inside the petcock valve body
What size jets are you using, did you do a bench sync and check float height?'79 XS11 F
Stock except K&N
'79 XS11 SF
Stock, no title.
'84 Chevy K-10 "Big Blue"
GM 350, Muncie SM465, NP208, GM 10 Bolt with 3.42gears turnin 31x10.5 Baja Claws
"What they do have is an implacable, unrelenting presence and movement that bespeaks massive power lurking behind paint and chrome. They don't wail like a screeching ninja, the don't rumble like a harley. They just growl like a spactic, stressed out badger waiting to rip your face off and eat your soul." Trainzz~RIP~Comment
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Gravity does a lot of the action, but not all of it. There is a siphon effect once the lines are full of fuel. You might try filling the lines before attaching them, and get all the air out first. This might not be the issue, but it might be worth a shot...1980 XS850SG - Sold
1981 XS1100LH Midnight Special (Sold) - purchased 9/29/08
Fully Vetterized and Dynojet Kit added, Heated Grips, Truck-Lite LED headlight, Accel Coils, Irridium plugs, TKAT Fork Brace, XS850LH Final Drive & Black SS Brake lines from Chacal.
Here's my web page devoted to my bike! XS/XJ User's Manuals there, and the XJ1100 Service Manual and both XS1100 Service manuals (free download!).
Whether you think you can, or you think you cannot - You're right.
-H. FordComment
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So, you look to have a standard. This means you have vacuum operated petcocks in the ON and RESERVE positions. When in the PRIME position, as stated, you bypass the Vacuum valve inside your petcocks.
On the Special models, they use the OCTY or a separate single vacuum valve to control fuel in the ON and RESERVE functions. Again, it is also bypassed in the PRIME position.
You stated that your bike is running good in the PRIME position, this would indicate your carbs are not the issue, your petcocks are. If you forgot to hook up the vacuum lines, or your petcocks are not working properly, then you will starve for fuel when in the ON or RESERVE positions. What you describe is exactly what happens when the bike is fuel starved and it will slowly run out and die.
Basically, PRIME does as stated and bypasses the vacuum valve(s). It can be used to run the bike continuously. Thunderstruck was left on PRIME when I got it because the OCTY was shot and no one repiped or fixed it. Take note though, running on PRIME eliminates the reserve function, so when you sputter out of gas on PRIME, your done, wlecome to the walking brigade!!Life is what happens while your planning everything else!
When your work speaks for itself, don't interrupt.
81 XS1100 Special - Humpty Dumpty
80 XS1100 Special - Project Resurrection
Previously owned
93 GSX600F
80 XS1100 Special - Ruby
81 XS1100 Special
81 CB750 C
80 CB750 C
78 XS750Comment
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