username23
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« on: April 11, 2010, 03:55:23 PM » |
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Hi all,
My '97 Valk with 43k miles started lacking power. I've changed the air filter and spark plugs, but to no avail. (Started noticing bike lacks power most obvious at highway speeds, almost as if it's starved for fuel.) Any suggestions?
Thanks.
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RTaz
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Posts: 1319
Michigan...Home of InZane X -XI
Oscoda, Michigan
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« Reply #1 on: April 11, 2010, 03:57:09 PM » |
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maybe rebuild the fuel petcock...and replace the screen in the tank 
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 RTaz
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SANDMAN5
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Posts: 2176
Mileage 65875
East TN
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« Reply #2 on: April 11, 2010, 04:00:02 PM » |
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Check the simple stuff first. Vac lines been replaced? Had the gas tank off and pinched the vent line? Did it start all at once or come on gradually?
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"Evolution" is a dying religion being kept alive with tax dollars. 
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username23
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« Reply #3 on: April 11, 2010, 04:04:19 PM » |
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Definitely started suddenly. I hadn't had the tank off before it started acting up. Will check for pinched lines and I think I'll pull the petcock and clean that fuel screen, too, even if it ends up being something else that's causing my "performance anxiety".
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fudgie
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Posts: 10613
Better to be judged by 12, then carried by 6.
Huntington Indiana
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« Reply #4 on: April 11, 2010, 04:23:51 PM » |
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If its a black one then this is to be expected.
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 Now you're in the world of the wolves... And we welcome all you sheep... VRCC-#7196 VRCCDS-#0175 DTR PGR
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Willow
Administrator
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Posts: 16632
Excessive comfort breeds weakness. PttP
Olathe, KS
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« Reply #5 on: April 11, 2010, 05:25:35 PM » |
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Check your vacuum line to the petcock first.
Reach around behind the carb runner and feel the vacuum line. See if the line feels cracked or deformed.
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Rio Wil
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« Reply #6 on: April 11, 2010, 07:01:15 PM » |
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Might try a few other things also, when it is exhibiting the lack of power on the highway, turn off the petcock and see how long it takes to significantly reduce power. At 60 mph in 5th gear, it takes 67 seconds for mine to run out of gas. If yours is significantly less time, then you have a fuel flow issue. Also, pull the vac line on the petcock, replace with a line you can pull a moderate vacuum by mouth. There should be NO vac bleed off, if so the diaphragm is broken and needs to be replaced. If you don't have any leak off, pull the gas line on the output of the petcock, add a line going to a bleed container on the floor and apply the vac again. The petcock should flow about 100 ounces per minute. Significantly less than that and there is a fuel restriction somewhere, ie, the diaphram is not being retracted fully to allow flow, the filter screen is dirty......
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Dave Weaver
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« Reply #7 on: April 11, 2010, 07:13:26 PM » |
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Another thing to try is the venting of the fuel tank via the fuel lid. Place a spare key in the fuel lid and when the bike seems starving for fuel, reach down, turn the key to open the lid and see if performance improves. If it does, your problem is in the venting of the fuel tank.
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Do unto others as you would have them do unto you. 
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Ricky-D
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« Reply #8 on: April 12, 2010, 08:34:00 AM » |
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Try changing you source for gasoline!
Different gasoline!
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2000_Valkyrie_Interstate
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username23
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« Reply #10 on: April 15, 2010, 03:13:17 PM » |
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Has anyone had experience with a cover set from K&L? Is it worth using, or is it better to go with OEM?
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« Last Edit: April 17, 2010, 03:22:00 PM by username23 »
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Wago
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« Reply #11 on: May 02, 2010, 08:16:27 PM » |
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Hi all,
My '97 Valk with 43k miles started lacking power. I've changed the air filter and spark plugs, but to no avail. (Started noticing bike lacks power most obvious at highway speeds, almost as if it's starved for fuel.) Any suggestions?
Thanks.
Almost surely your petcock is not holding vacuum. Symptoms are identical to yours. See if you can pull and hold a vacuum using the vac line. If vac bleeds off quickly, repair or replace the petcock.
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