Rough Running Valk

[Elkfry]

My 99 I/S has been running very rough for a couple of weeks.  I can't figure it out.  Today I checked the timing and the timing belts, ALL fine.  But I did notice that the engine misses on all cylinders.  Any help would be greatly appreciated. 

[mario]

crappy ethenol gas ?

[stude31]

Elk,

Check for a vacuum leak... Make sure the spark plug wires are in good shape and are on the correct cylinder.   You might also do a leak down test on the petcock and make sure it is providing fuel to the carbs.   Looks like you are new to the club.  You might check out the "shoptalk"  tab at the top... www.valkyrieriders.com/shoptalk/

and you can download a free shop manual from dag's website here:
http://www.valkyrienorway.com/download.html
(kudos to Dag, great site bud!)

Elk you might share with us where you are located maybe someone in your area can come help you.  

Keep us posted!

[GOOSE]

elkfry.....get yourself a bottle of chevron techron, and put 5 or 6 ounces in your tank. alot of times its just bad gas/water/ethanol.

[Elkfry]

I'm out in Colorado where I try to ride whenever the roads are clear of ice.  When this problem started I tried the Tecron idea, one tank, no change.  My biggest issue is that the spark seems to be the miss, not the gas?  I've been doing some reading on the slow jets, maybe that is the answer.  Please keep up the ideas.  Thanks for all of your thoughts.  She sure doesn't purr very well right now.

[GOOSE]

elkfry......if when you are riding.... and you are below say 2500 rpm, pull the choke on...if it clears up it's prpbably the slow jets;   change the stock 35's out to 38's.

[Ricky-D]

It doesn't make sense, if the bike was running good before, to start changing out parts to correct the poor running now!

Bad gas is the most likely culprit! 

Draining the float bowls of a few ounces of gasoline may help. It could be water in the gas!

Occasionally, I get water mixed in the gas and on cold days there is always a chance the water will freeze in the float bowl and cause bad running. As soon as everything warms up, which can take more than an hour, the motor starts to run normally.

It does not take a lot of water in the float bowls to cause poor running. A few drops is all it takes to make trouble.

Drain each float bowl!

***

[old grouch]

elk--where in Colorado?  If you haven't done anything to the bike lately, it is probably bad gas or a vacuum leak.  Check all your vacuum lines for cracks, brittle, etc.  Vacuum leaks can happen all on their own, just from age.  How many miles on the bike?  Has it been de-smogged?  Does it have an OEM petcock?  Have you had the tank off recently?  If so, it could be a pinched tank vent or main fuel line. Like Ricky D said, don't start replacing parts until you have diagnosed the problem.  If you are close to the Springs, maybe I could take a look.  Stan

[Pete]

If the bike has been setting for some time, suspect slow jets.

Solution = clean them.

[Elkfry]

Hey Old Grouch, all good questions.  I haven't done any changes lately.  70K on the bike, not desmogged, it has original oem petcock, and I have not had the tank off for a year and a half.  If I were to check the vaccuum lines is there an easy way.  Yesterday I looked at everything and even snipped an inch off of #6 because it was turning burntish brown.  I was looking for the obvious, could see any problems.  Also, it was suggested to put in 38's for slow jets, wouldn't that cause more gas.  Here in Colorado she is already looking for MORE air.   I will drain all the bowls this AM.  Thanks Again!

[old grouch]

elk-- mine has been desmogged, so no lines to mess with.  If draining the bowls doesn't help, I guess I would just replace them all.  I think you have to remove the airbox to get at all the lines, but am not sure about that. I have a Pingel, with a DanMark electric shutoff, so no worries about the petcock.  There are some posts about how to check the petcock for proper functioning (search the old tech archives) and what to do if it is bad.  As was mentioned, it could be ignition related, but that doesn't happen very often with Valks.  I would suggest you exhaust all the fuel/vacuum possibilities before you start looking at ignition.  I have stock slow jets, K&N filter w/o the pre-filter and get 32 mpg +/- riding two up loaded in the mountains, slab, wherever & she is triked.  Don't think .038 slows would affect the mpg much.  Colorado is a big state.  Where are you at?  Stan

[old grouch]

elk--another thought just occurred.  Check the clamps on the rubber connector between the intake runners & the carbs.  Two on each one.  You will have to pull the pods to get at all of them, but if they are loose, they act like a bad vacuum leak.  Also check the tightness of the nuts that hold the runners to the head.  Stan

[stude31]

all good points by Old Grouch.

The more I think about it the more I think it is:

1. Bad Gas

2. loose intake clamps

3. Vacuum Lines brittle/leaking

 (If you have to take off the airbox, don't freak out it isn't as hard as you think.  I use zip ties to squeeze the intake runners on the airbox together and set the box back down through the frame and then cut the zip ties and your good to go.  Just make sure you get the lip of the runners around the tops of the carbs without the back side being pinched over.  Helps to look from the other side of the bike w/ a flash light to make sure the rubber tubes are on correctly. )