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Mike
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« on: February 12, 2020, 04:26:00 AM » |
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Hi all,
Last fall I had an issue with the throttle response. She ran great while increasing throttle gradually. When up at highway speed and tried to snap the throttle to pass someone, there was alot of hesitation.
This only happened if I got onto the throttle fast and at higher speed.
Any help would be greatly appreciated.
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indybobm
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« Reply #1 on: February 12, 2020, 05:19:41 AM » |
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First thing that I would do is go to Walmart and get a can of Chemtool B-12 (less than $4). Put 1/2 can in a tank of gas and run that tank out. then repeat wi the other 1/2 can. B-12 is good stuff, just don't spill it on anything.
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So many roads, so little time
VRCC # 5258
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Steel cowboy
Member
Posts: 1284
Moving ahead so life won’t pass me by.
Spring Hill, Fl.
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« Reply #2 on: February 12, 2020, 05:33:18 AM » |
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Float level could be an issue. Have you had any carb work done. Check your tank vent too.
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2001 black interstate
2003 Jupiter Orange wing
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Avanti
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« Reply #3 on: February 12, 2020, 06:53:41 AM » |
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Both above responses are in regrades to a fuel flow issue, which I also believe is the problem.
If neither of the above issues are the cause, do you have a fuel line restriction which will slow the fuel delivery and starve the engine at higher RPMs.
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« Last Edit: February 12, 2020, 08:24:34 AM by Avanti »
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sandy
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« Reply #4 on: February 12, 2020, 08:46:18 AM » |
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Your symptoms could be caused by several things. too much fuel, too much air. Basically improper air/fuel ratio. Look for bad vacuum lines, leaks where the intake runners meet the heads. if a local shop has an air ratio meter, get them to check it out.
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98valk
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« Reply #5 on: February 12, 2020, 09:28:52 AM » |
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Pilot jet mixture screw adjustment affects throttle at higher rpms. open up idle mixture screws 2-3 turns open. half turns at a time test ride.
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1998 Std/Tourer, 2007 DR200SE, 1981 CB900C 10speed
1973 Duster 340 4-speed rare A/C, 2001 F250 4x4 7.3L, 6sp
"Our Constitution was made only for a Moral and Religious people. It is wholly inadequate to the goverment of any other."
John Adams 10/11/1798
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Chrisj CMA
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« Reply #6 on: February 12, 2020, 09:43:20 AM » |
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I suspect early symptom of impending petcock failure. Or at least a vacuum leak on the #6 line to the petcock
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old2soon
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« Reply #7 on: February 12, 2020, 10:07:41 AM » |
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Has it been desmogged? Those vacuum lines get brittle when old and leak. Let us know what ya find to be the culprit here. RIDE SAFE.
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Today is the tommorow you worried about yesterday. If at first you don't succeed screw it-save it for nite check. 1964 1968 U S Navy. Two cruises off Nam.
VRCCDS0240 2012 GL1800 Gold Wing Motor Trike conversion
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Ricky-D
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« Reply #8 on: February 12, 2020, 12:05:17 PM » |
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Your problem has nothing to do with the low speed circuit.
It would be foolish to try to correct your problem by starting there.
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2000_Valkyrie_Interstate
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98valk
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« Reply #9 on: February 12, 2020, 12:46:49 PM » |
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It runs well and passes most of the tests as provided on your tuning guide. It does, however, appear to be lean low down, as there is a "hole" when cracking the throttle wide open at below 2500rpm and at high rpm/part throttle, it shows some surging. I have though set the fuel screws, so that it idles correctly and returns to the correct rpm, when the idle is set below 1000rpm and the throttle is blipped. > To fix the lean patch, is it better to go the next step up in pilot jets, rather than adjust the fuel screw? > Will upsizing the pilot jet, require re-adjustment of the fuel screw and thus negating some of or all of the gains made by the larger pilot jet? (Using another "rule of thumb", if you have the correct pilot jet, the fuel screw will end up at between 1.5x and 3.0x when set for best idle.) Marc http://www.factorypro.com/ Motorcycle Tuning Tech |
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1998 Std/Tourer, 2007 DR200SE, 1981 CB900C 10speed
1973 Duster 340 4-speed rare A/C, 2001 F250 4x4 7.3L, 6sp
"Our Constitution was made only for a Moral and Religious people. It is wholly inadequate to the goverment of any other."
John Adams 10/11/1798
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hubcapsc
Member
Posts: 16773
upstate
South Carolina
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« Reply #10 on: February 12, 2020, 02:38:30 PM » |
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I suspect early symptom of impending petcock failure. Or at least a vacuum leak on the #6 line to the petcock
This. It is easy to fix and is a "normal" Valkyrie problem. -Mike |
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indybobm
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« Reply #11 on: February 13, 2020, 06:06:33 AM » |
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When i got my second Valkyrie years ago, it idled properly and low speed performance was great. The poblem I had was full throttle after a certain RPM. Chemtool B12 fixed it. Main jets can get partially clogged also.
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So many roads, so little time
VRCC # 5258
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Ricky-D
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« Reply #12 on: February 13, 2020, 08:41:23 AM » |
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Anytime an experience is observed being connected to the throttle, attempts to detail the experience and relate
the experience to speed (mph), gear, rpms, usually fails in accuracy when trying to analyze the problem.
The reason being is because they have only a reactive connection to the throttle. The only definitive throttle positions
that can be accurately described, off hand, would be idle or WOT.
So if you have a problem that is throttle related the only, and the best way to describe the problem would be to
index the throttle which would then allow an accurate and intelligent description of exactly what is transpiring.
How to index the throttle.
1) Put a permanent mark on the throttle that is easily visible and in your viewing area while riding.
2) With the bike not running, just sitting there, turn the throttle to where it is just engaging the carburetors and starting to turn the "wick".
3) Mark the exact position of the previous mark (you made on the throttle), correspondingly, on the throttle body.
4) Continue now, by turning the throttle to full open, all the way, and put another mark on the body corresponding to the throttle mark.
You have now marked on the throttle body two marks that indicate idle position and WOT.
5) Now and finally you can make another mark on the throttle body half way between the two which will represent "half throttle"
Make two more marks, one each between the three to represent 1/4 throttle and 3/4 throttle. And you're done
You have indexed your throttle.
Now, when you're out riding your Valkyrie, you can easily look at your throttle and see actually, the true throttle setting to which you are riding.
So, when and if you have a problem, and it is throttle related, you can most intelligently report at what throttle setting the problem is occurring.
Indexing the throttle is a very important step for the accurate solution to any throttle related problems.
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2000_Valkyrie_Interstate
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Mike
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« Reply #13 on: April 14, 2020, 11:49:21 AM » |
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I suspect early symptom of impending petcock failure. Or at least a vacuum leak on the #6 line to the petcock
Finally got a chance to do the petcock with a new cover set. With the weather we have been getting I've only been able to get out for a short 75km ride and she ran fine. Thanks for the advice. |
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Chrisj CMA
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« Reply #14 on: April 14, 2020, 12:32:55 PM » |
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I suspect early symptom of impending petcock failure. Or at least a vacuum leak on the #6 line to the petcock
Finally got a chance to do the petcock with a new cover set. With the weather we have been getting I've only been able to get out for a short 75km ride and she ran fine. Thanks for the advice. Absolutely. Been there done that. If the problem returns like it did on mine in a year or so after the cover set. Just get rid of the OE petcock. I went with Pingel and never regretted it |
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Mike
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« Reply #15 on: April 14, 2020, 04:00:41 PM » |
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I suspect early symptom of impending petcock failure. Or at least a vacuum leak on the #6 line to the petcock
Finally got a chance to do the petcock with a new cover set. With the weather we have been getting I've only been able to get out for a short 75km ride and she ran fine. Thanks for the advice. Thanks Chris, appreciate all your help. Stay safe. Absolutely. Been there done that. If the problem returns like it did on mine in a year or so after the cover set. Just get rid of the OE petcock. I went with Pingel and never regretted it |
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