same prob as others - can't find thread...please help

[JunaryBunch]

I'm riding along and I start to notice my bike sorta jerking.  My throttle is constant.  As I increase my throttle my jerking increases...basically I lose power and then it suddenly jerks forward.  Finally, around 40mph the bike just dies on me.  I restart my bike and does the same thing.  Any ideas?

[ginoe]

sounds like fuel starvation

gas cap vent might be blocked (dirty) - pop open the gas cap & set the petcock to prime - see if that helps...

[scottpA_GS]

I am having the same problem I have posted everytime someone else has this problem... Do you have an inline fuel filter? after market fuel lines? I think that both are to blame on my bike.. I will find out today. I think I will finally have time to change them out and remove the insides of my petcock  Let me know what you find out on your bike..

I tried the gas cap thing.. nope

and I always run on prime.. still no

maybe together we can help put an end to starving carbs!  

[Slavik]

have the same problem......do you guys know, when running on prime, do you still have some fuels on reserve?  or if you run out you are out for good?

[Jazzzzz]

if you're running on prime, when you're out you're out

[scratch]

Just happened again (2nd time in 2 years) to me this morning. It was surging a little earlier than it usually does on my commute (there's a low spot in the expressway, heavily shaded and usually very cool in this area; I always thought it was colder, denser air causing my carbs to get a little lean (1 washer under clip)), and there was a fast approaching car in the carpool lane behind me, so I whipped it up to a hundred, still feeling the slight hesitation, and sure enough as soon as I started to roll off, the bike really started to buck, so I got over to the side of the road, still going 60mph, switched to Prime and away I went smoothly, but of course by now I'm under the high demand for fuel at the over 60mph speeds.

[Slavik]

if you're running on prime, when you're out you're out

how much worth is your gas milage get?  i am getting 55-60 now, can i at least hope for 40-45 mpg?  (just trying to estimate when my mandatory fuel stops need to be on the long hwy runs)

[JunaryBunch]

So what is the big difference between having your petcock on the "on" position and having it on "prime"?

If I put it on prime, will there be any long-term effect on the bike?

[goat]

the difference between "on" and "prime" is that you need vacuum from the carbs for fuel to flow for "on". in "prime" it just flows with gravity.

If you are just doing it for a little while, there is nothing wrong with using pri. If you want to be extra careful, just turn the petcock to ON when you're not riding.

If you find that you need to leave it on PRI in order to run well, there could be other problems like an improperly connected vacuum hose or a busted petcock diaphragm.

[Kerry]

Slavik -- are you asking whether running on PRIme will reduce your gas mileage?  The answer is NO.


Here are some old posts that may provide some useful background info for this thread:

What is PRIme for?

Fuel Starvation -- Possible Causes and Things To Try  (Be sure to read Ed89's excellent follow-ups!)[/list:u]

[Slavik]

very informative links......Thanks Kerry!

as far as my bike goes, since the problem only occurs after cruising at 80-85 for a while, i decided to just switch to PRI before hand, and switch back when I am off the hwy.....

[mondo27]

also, you may want to replace all those old fuel lines if you didn't already do that. it made a big difference when i cleaned my carbs.

[scratch]

Now, there's a good idea!

If and when you do replace the fuel lines, do me a favor and cut them lengthwise to see if the interior of the fuel lines are actually deteriorating, please?

I really doubt it's the vacuum line collapsing from the vacuum.

[mondo27]

f and when you do replace the fuel lines, do me a favor and cut them lengthwise to see if the interior of the fuel lines are actually deteriorating, please?

I really doubt it's the vacuum line collapsing from the vacuum.

i agree with scratch. but i think if they are deteriorating, tiny particles may be passing to your carbs and could clog them up. its easy to do, hardly costs anything and should be done if you have the same old lines that came w/ the bike. my fuel lines may have been blowing chunks instead of tiny particles since i had a really rusted tank. oh well, just my 2 cents.

[scottpA_GS]

I cant find good fuel line... The stuff the dealer has is alot thicker walled than what was on the bike factory. (seems much less fuel could travel) They said it is very tough to get the same line as factory!?!

Anyone use clear line? Or any other slim walled type line?

[Kerry]

I cant find good fuel line... The stuff the dealer has is alot thicker walled than what was on the bike factory. (seems much less fuel could travel)

Yeah, and harder to push onto the two side-by-side outlet tubes at the  tank-mounted petcock!  :x

They said it is very tough to get the same line as factory!?!

Hmmm.  Have they tried ordering OEM parts?  

I don't think I would recommend that route anyway, unless that fact that they are "pre-shaped" tips the scale for you.  Even from MrCycles (go to the FUEL chicken page) the 3 main fuel lines will run you a little over $20 ... before shipping!

Anyone use clear line? Or any other slim walled type line?

Check this old thread for a fairly comprehensive discussion of replacement fuel lines.  Don't miss the picture(s?) near the bottom.

[davipu]

i got 6mm clear fuel grade line from the stealer for a buck a foot,  I bought the ends of two rolls so if anyone needs any....