runs bad cobra pipes

[flcjr]

I bought my 99 tourer used has cobra pipes i didn't notice at first but now that i am used to the valk and ride more and more and maybe toofast sometimes i have noticed that in 5th gear cruising 80-85 open the throttle and it falls on its face sputters and goes nowhere if i accelerate hard all the way through 5th gear seems to run fine only acts up in 5th no other gear? any help would be great. i do have stock exhaust and was thinking about putting it on just to quiet it down...

[Ricky-D]

I think you have a battery going bad!

Could also be the alternator!

It's the result of low current, not enough!

***

[flcjr]

battery seems fine starts great every time and went for a night ride a few days ago and lights worked finr

[Rocketman]

I think you have a battery going bad!

Could also be the alternator!

It's the result of low current, not enough!

***

??????????????  Where did you get that????

I bought my 99 tourer used has cobra pipes i didn't notice at first but now that i am used to the valk and ride more and more and maybe toofast sometimes i have noticed that in 5th gear cruising 80-85 open the throttle and it falls on its face sputters and goes nowhere if i accelerate hard all the way through 5th gear seems to run fine only acts up in 5th no other gear? any help would be great. i do have stock exhaust and was thinking about putting it on just to quiet it down...

I believe it's necessary to rejet the carbs when using the Cobras (more free-flowing exhaust).  If that's true, and the previous owner did not do it, you would notice it most at more open throttle positions.  You're probably not opening the throttle up enough to hit 4-5k rpm in the lower gears, at least not cruising, therefore you're not noticing it.  Either rejet or use the stock exhaust.  That's my recommendation.

Mark

[Robert]

Im with Rocket on this one, it sounds about right 5 gear cruising is going to be the leanest the carbs get so if the mix is off it can show up here. Pull the plugs and check the color the rejet or check someone may have already put in a kit and all you have to do is richen the needle one groove. 

[9Ball]

sounds like a lean condition to me.....try a shim under each needle and see if that helps....quick and easy to do.

[Chrisj CMA]

First.......are you sure its not the rev limiter? 

Next, I dont think its electrical..........fuel most likely.  Id suspect the petcock.  The max flow of a healthy OEM petcock is so close to actual fuel need that if anything is wrong....leaky diaphram, vacuum line, it will not feed the bowls enough to thrive.

[9Ball]

First.......are you sure its not the rev limiter?  

Next, I dont think its electrical..........fuel most likely.  Id suspect the petcock.  The max flow of a healthy OEM petcock is so close to actual fuel need that if anything is wrong....leaky diaphram, vacuum line, it will not feed the bowls enough to thrive.

If he's hitting the rev limiter in 5th gear he's about to break the sound barrier.....

with the cobra pipes, it's more likely a lean fuel air mixture....carbs not set up right especially if it has the needle kit or hasn't been rejetted.  I agree that it's doubtful to be an electrical issue, especially if it only happens in 5th gear....weird advice.  Rocketman has some good advice.

I've been there with this setup and found that moving the clips out one notch fixed the stumble, etc.  Could be air leaks or fuel delivery, but I would check the needles first since it doesn't involve removing the tank to remove the petcock, or remove the air box and carbs.

[flcjr]

thanx for all the advice i think tonight i will check and see if the needles have been replaced with cobra kit or if there still stock. if they are still stock can i just shim the stock needles to correct this condition or would it be best to buy the cobra kit? If it has the cobra kit where should the clip be placed i see the instruction on there web site to put it in slot three. I live and do most of my riding at about 5000ft above sea level.

[Chrisj CMA]

First.......are you sure its not the rev limiter?  

Next, I dont think its electrical..........fuel most likely.  Id suspect the petcock.  The max flow of a healthy OEM petcock is so close to actual fuel need that if anything is wrong....leaky diaphram, vacuum line, it will not feed the bowls enough to thrive.

If he's hitting the rev limiter in 5th gear he's about to break the sound barrier.....

with the cobra pipes, it's more likely a lean fuel air mixture....carbs not set up right especially if it has the needle kit or hasn't been rejetted.  I agree that it's doubtful to be an electrical issue, especially if it only happens in 5th gear....weird advice.  Rocketman has some good advice.

I've been there with this setup and found that moving the clips out one notch fixed the stumble, etc.  Could be air leaks or fuel delivery, but I would check the needles first since it doesn't involve removing the tank to remove the petcock, or remove the air box and carbs.

weird huh.......well the percentage of OEM petcocks that have failed and caused this same problem is so high it would be weird not to investigate as a possible cause IMHO of course

[hubcapsc]

This article on servicing the petcock also has a good and easy test...

http://www.valkyrieriders.com/shoptalk/petcock.htm

-Mike

[9Ball]

First.......are you sure its not the rev limiter?  

Next, I dont think its electrical..........fuel most likely.  Id suspect the petcock.  The max flow of a healthy OEM petcock is so close to actual fuel need that if anything is wrong....leaky diaphram, vacuum line, it will not feed the bowls enough to thrive.

If he's hitting the rev limiter in 5th gear he's about to break the sound barrier.....

with the cobra pipes, it's more likely a lean fuel air mixture....carbs not set up right especially if it has the needle kit or hasn't been rejetted.  I agree that it's doubtful to be an electrical issue, especially if it only happens in 5th gear....weird advice.  Rocketman has some good advice.

I've been there with this setup and found that moving the clips out one notch fixed the stumble, etc.  Could be air leaks or fuel delivery, but I would check the needles first since it doesn't involve removing the tank to remove the petcock, or remove the air box and carbs.

weird huh.......well the percentage of OEM petcocks that have failed and caused this same problem is so high it would be weird not to investigate as a possible cause IMHO of course

Yes, I believe the electrical response regarding a bad battery was a bit on the weird side, not anything you said....my response had nothing to do with the known petcock issues and the petcock may very well be the problem.

here's what I said..."I agree that it's doubtful to be an electrical issue, especially if it only happens in 5th gear....weird advice. "

No offense was aimed at anyone suggesting a fuel related issue....please don't take it that way either....

[Chrisj CMA]

Yes, I believe the electrical response regarding a bad battery was a bit on the weird side, not anything you said....my response had nothing to do with the known petcock issues and the petcock may very well be the problem.

here's what I said..."I agree that it's doubtful to be an electrical issue, especially if it only happens in 5th gear....weird advice. "

No offense was aimed at anyone suggesting a fuel related issue....please don't take it that way either....
[/quote]

Ok, no problem.........FFR when you quote someone, it would be a normal assumption that whatever is said after the quoted statement is meant for that statement.  I understand completely your meaning, no harm no foul

[Tropic traveler]

Does sound fuel related for sure.
One thing that you may also check is the air filter. K&N without the pre-filter may cause a lean condition with Cobras as well. 

[Printer Mike]

Mine has Cobras and is stock jetted. Runs great.

[flcjr]

so i lied had to work late and do somethings around the house no time to work on the bike but did have a few minutes at lunch search around the website and found a reoccurring theme that the cobras will atcually loose hp. so i would it be best to make sure i have stock needles and just put the stock exhaust back on? the baffles are in the cobras and i do like the sound but gets a bit too much on long fast rides.

[9Ball]

"Ok, no problem.........FFR when you quote someone, it would be a normal assumption that whatever is said after the quoted statement is meant for that statement.  I understand completely your meaning, no harm no foul"

thanks for your blessing, FFR....

[roadmap]

i'm not going to comment on any answers that you got it might be that but here is what happened to me.
 i believe it fuel related. a couple of yrs ago the damn bike would just shut off in 5th gear. only at high speeds on the highway.. at high speeds not in the city stop and go. it was my petcocok. the first thing we and this board was the vac line under the tank check to see if clogged smashed bent any of the above that would shut it off. I always had trouble with that vac line so me i just took it off at the tank. no problems with a leak or smell. so that fixed one problem. that could off been it but was not. just one future problem fixed. next time for the old OEM petcock to be replaced. i know i had problems with it before, so i got a vacuum pingel for about 150 back then well that was it. i am not sure on cobras. just what happened to mine. all valks are getting old weather miles or not the rubber gets hard with time.
ok a bent line under the tank can cause this and i am 95% sure on a stock bike it is the OEM petcock.
  there has been so much talk about this over the yrs (petcock) i have a 1997 150,000 miles and what a bike it has been since OCT, 96 when i got it and it is stock so much of a bike i left it stock WOW!!!!

[roadmap]

Feels like i am running out of fuel?

Posted By: Bronxboy
Date: 4/4/2007 at 21:15:25


Not all the time, but lately i have noticed the bike seems to starve for fuel or so it feels.It seems to happen more when i am running thru the gears hard.I never feel it if i am just cruising?

Could this be a petcock problem? or is there more to it. My valk is a 97 standard, when i am cruising in top gear and i lay into it, sometimes i notice it bogs down a bit then accelerates? Any help would be great.

Regards
Nick

this problem has been around a while all came out to  be the petcock you can read on it for days seems like the petcock first thing whatever model or brand of petcock it could be it search the archives it is there

[roadmap]

petcock-- mine did that too try pingel

Posted By: roadmap
Date: 4/7/2007 at 08:57:18

In Response To: HELP, power loss and missing on full throttle (xlr8it)


it probably your petcock going bad either a clogged screen or your inside rubber is going bad. one check someone shared with me was to stick you finger on the underside drain spout put your finger over it it you feel vacuum(with it running) it probably not working right any fuel leaking around your rooster. mine would completly shut my bike off at highway speeds. when i got the new pingel all is well 1311CHV v is for vacuum. yes check your air flow could be.... but my dollar is on your petcock. maybe even a colapsed vacuum air line coming off #6 carb too. allot of things. just checking everything going through a list easy stuff first pull that tank. yes there is a repair kit for the oem petcock. it's just a problem going to return with oem i went through it over the yrs. had to finally spend the money on a good replacement (pingel)
this one is from April 1997

[flcjr]

could someone tell were to find the write up on replacing the petcock with a pingel i know i have seen it somewhere here but cannot find it now i need to remove tank and replace air filter anyway so i think i will replace petcock  while i am there and be done with it.

[flcjr]

just took a quick look at the valk found a split vacuum line at  bottom of #5 carb haven't had a chance to ride it yet but could this be my problem??

[CajunRider]

just took a quick look at the valk found a split vacuum line at  bottom of #5 carb haven't had a chance to ride it yet but could this be my problem??

Definitely a start... Take care of that, then take it for a spin and see how it does. 

While you're fixing that, you may as well change out all those vacuum hoses.

[Rocketman]

just took a quick look at the valk found a split vacuum line at  bottom of #5 carb haven't had a chance to ride it yet but could this be my problem??

The petcock is usually hooked up to the #6, but if it's hooked up to #5 instead, then I'd say it's definitely your problem.  But, as was said, replacing cracked vacuum lines never hurts, so replace 'em all while you're in there, and she'll run better even if it doesn't solve the problem.

[groundpounder01]

2001 valk with a pingle and cobras was doing the same thing so i knew it wasnt the petcock.Changed to the factory pipes and solved it. 

[flcjr]

line was split right at carb just trimmed line and reinstalled took out for a 30 mile ride runs much better now thanx everyone for your input still think i will change petcock out when tank is off,and replace all vacuum lines.

[2qmedic]

1st-very possibly the petcock diaphram, it's happened to me.

You memtion the sound being to loud on a trip.
Ok, I have a possible solution for you.
 
I have done this on my bike. I have the Cobras 6x with baffles.
 
1-Take out the baffle.
2-Use 2 stainless steel scouring pads. (got mine from the dollar store) They are
wound up in a coil.
3-Stretch two pads over each baffle (for the Cobra baffles).
4-Use some .032 or .040 wire (or some type of wire) and wrap it around the pads.
This will help compress the pads as to not be so puffy when reinstalling back
into the pipe. (learned from school of hard knocks)
5-Reinstall baffle. (If I did again, I would use some type of oil or lube in the
pipe to help get them in again. It will burn off.)
6-Take it out for a ride.
 
If not quiet enough for ya, go another step.
 
7-Take the baffle to an automotive store and buy freeze plugs that will fit over
the end of the baffle exhaust port.
8-Drill a 3/4 hole (same size as the orignal piggy) and then attach it with a
bolt, weld it or however.
Note: With the 3/4 inch hole, I know that I have not exceeded the stock mfg back
pressure. I did try a 1/2 inch hole, loss in pwr. 5/8 may be doable, didn't
try that size.
 
The volume at 50mph is now the volume at 75ish. Needless to say that the orignal
sound level at 75 was just way too loud. It was worth it for me. Will still wake up the neigbors, but not the whole town.

Hope this helps,
Cheers