Carb purge lines/Fuel Starvation?

[SpidyJ]

I did this job because after I installed the Dan MArc and a Pingel vac operated petcock I noticed two problems:
1. No reseve.....only about 5 gal usable fuel.
2. Fuel starvation at sustained high speeds.

Had the tank and airbox off yesterday to install a K&N and go back to the stock petcock that I rebuilt.
Upon disassembly I found that one of the purge lines was hooked up to the airbox and the other was hanging free.

In my shop manual I don't see where they are supposed to be hooked up so I installed a tee and connected them to the bottom of the air box.  Is this OK?

Now the bike starts and runs fine up till 4k.  I can blip almost to redline but she won't run at sustained speeds at much over 3500 rpm.

1. So, what are the carb purge lines supposed to be hooked up to?  If not the airbox then what is the third hole for?
2.  Seems like fuel starvation still occurring maybe even a little worse... have I created another problem.?


Tank vent seems fine.
Petcock shutoff works but runs for about 10 minutes at idle after shutoff.

Any further troubleshooting/testing ideas appreciated.

[BigMac (SoCal)]

Check to make sure that your fuel line is not kinking when you put on the tank. You have to shorten the line to make up for the length of the dan mark valve.  I did a carb job on a friends bike and it ran great until you got on it. I replace the fuel line and vent tube line from the tank and it runs great.

Dave

[SpidyJ]

Check to make sure that your fuel line is not kinking when you put on the tank. You have to shorten the line to make up for the length of the dan mark valve.  I did a carb job on a friends bike and it ran great until you got on it. I replace the fuel line and vent tube line from the tank and it runs great.

Dave

I replaced the fuel line and cut it to length.  I did not replace the vent tube though. I blew back with my mouth and it seemed clear.

[custom1]

I suspect that the problem has something to do with the "purge lines" you speak of. Maybe give us some more info about them and the three holes?  Maybe a picture? Are you sure one of them isn't a vacuum line? A vacuum line off will lean it out and act like starvation. When you say you had the airbox off do mean just the lid to change the filter or the whole box? Did you use the pre-filter with the K&N?

It seams you had the starvation like symptoms with both the Pingle and the stock petcock, so I would rule them out.

[Oklahoma_Valk]

The purge lines do not hook to anything. (i assume by purge, you mean the two hoses coming off of the carb bank)

On your carb bank bracket, you will see two holes toward the back. The purge lines poke down through there. Do not hook them to the air box. Regarding the holes in your air box (has your valk been desmogged?) Bottom of your AB has 3 holes. One hooks to drain tube. One hooks to Crank case breather, One hooks to SMOG system. If your valk has been desmogged, someone may have left the hole un-plugged. You should plug the one you do not need.





Im not sure if this is the source of your problem, but it can't be a good thing AT ALL.

Make sure you used 1/4'' hose barbs on the dan marc, to allow fuel to pass freely. Make sure your new fuel line is OEM diameter. Make sure there is no sagging/twisting in your fuel line under the tank. Make sure your vent hose is clear and not being pinched.

[SpidyJ]

The purge lines do not hook to anything. (i assume by purge, you mean the two hoses coming off of the carb bank)

On your carb bank bracket, you will see two holes toward the back. The purge lines poke down through there. Do not hook them to the air box. Regarding the holes in your air box (has your valk been desmogged?) Bottom of your AB has 3 holes. One hooks to drain tube. One hooks to Crank case breather, One hooks to SMOG system. If your valk has been desmogged, someone may have left the hole un-plugged. You should plug the one you do not need.





Im not sure if this is the source of your problem, but it can't be a good thing AT ALL.

Make sure you used 1/4'' hose barbs on the dan marc, to allow fuel to pass freely. Make sure your new fuel line is OEM diameter. Make sure there is no sagging/twisting in your fuel line under the tank. Make sure your vent hose is clear and not being pinched.

OK thanks!!  Those are the two lines, I couldn't imagine thery weren't hooked up to something.  The bike has not been desmogged that I know of.  I will disconnect these two lines now but I will have a third open port on the bottom of the air box.

I have a brass tee with barbed adapters on the end of the Dan Marc.

What is the purpose of the purge tubes?  SHould it take almost 10 minutes to run out of gas once I shut the petcock off?

Tanks comes off again this week end.  Dang I hate taking that air box off!!

[Oklahoma_Valk]

I've become pretty good at getting the air box off.....its putting the darn air box back on that I hate! Haha.

Those two lines keep the vacuum pressure behind the diaphragms equal. Important shannanigans that I really don't know how to explain. All I know is they do not hook to anything.

Yes it should take 10minutes at idle to run the fuel out of the carbs. Those carbs hold a lot of fuel. At highway speed, it runs out rather quick.

The brass tee is a great idea. That shouldn't be a problem. Lines can get lost in all of that mess, you aren't the first one to have an empty space in his air box. Take a picture of the underside of you box this weekend. Upload it to photo bucket, and post it on this thread. That will help us figure out the missing hose.

Where did you wire the Dan Marc valve to? Coil wires? Did you use a relay? High speed miss could be caused by incorrectly wiring that Dan Marc.

[SpidyJ]

Thanks guys...I hope I can get this straightened out this weekend.

The pollen is started to fall in SC......more and more Valk days comin' soon!

[SpidyJ]

Where did you wire the Dan Marc valve to? Coil wires? Did you use a relay? High speed miss could be caused by incorrectly wiring that Dan Marc.

I hooked the Dan Mark to a fused line off an acc spot at the fuse panel. I grounded it on the plate where the coil pak and Petcock dial are bolted on.

[Oklahoma_Valk]

OK. It should be OK then.

[SpidyJ]

OK.....finished except for a test ride. It's late and too cold.

I disconnected the carb purge lines, Plugged the xtra hole in the air box, installed the K&N and re-installed the stock petcock after rebuild.  Replaced vacuum line to the petcock and made sure there were no kinks or bellies in the fuel lines and the tank vent.

Let it run for about 1/2 hour to get to temp.  Revs and holds to red line w/o breaking up.  I held it at about 4k rpms for about a minute w/o a whimper.

So, those purge lines were prolly picking up the vacuum from the air box and starving the carbs somehow.

Can't wait to test drive.

Front wheel bearings/seals, rebuild calipers and replace pads are next on the list.

Should then be ready for the riding season.

Thanks so much for all the help fellas.  No fear with you guys here!

[Oklahoma_Valk]

Woohooooo!!!! glad you fixed it!!!

ps Pics or it didnt happen!!

[Red Diamond]

If the bike has not been desmogged, then you have an open orifice on the bottom of the pair valve. There should be three (3) hoses connected to the bottom of the airbox. 1) From the top of the crank case canister located just behind the ignition switch. 2) A clear piece of tygon tubing that T's into the tygon tubing coming from the bottom of the crank case canister. 3) From the bottom of the pair valve. None should be plugged.

[SpidyJ]

If the bike has not been desmogged, then you have an open orifice on the bottom of the pair valve. There should be three (3) hoses connected to the bottom of the airbox. 1) From the top of the crank case canister located just behind the ignition switch. 2) A clear piece of tygon tubing that T's into the tygon tubing coming from the bottom of the crank case canister. 3) From the bottom of the pair valve. None should be plugged.

Did not see @ 2 any where.........I didn't notice any clear tygon tubing. Me thinks I have parts missing.  Do not know if it was de-smogged.  Guess I should write the Original Owner.
 What bad things will happen now?

[Red Diamond]

Nothing, Just may not run good. The clear tygon tubing is the tubing at the bottom right of the bike with the plug in it. It should accumulate moisture and a little oil from the crank case, should be drained periodically.

[SpidyJ]

Nothing, Just may not run good.

This is a bad thing!  Who wants a bike.....a Valk no less that doesn't run good?!?!  That's why I bought it in the first place!

Test ride today..........

[Oklahoma_Valk]

Here's what a desmogged bike would look like


Here's what a smogged bike looks like.


Those images were taken from this thread in shoptalk:
http://www.valkyrieriders.com/shoptalk/desmog.htm


Which one does your bike look like?

[SpidyJ]

Here's what a desmogged bike would look like


Here's what a smogged bike looks like.


Those images were taken from this thread in shoptalk:
http://www.valkyrieriders.com/shoptalk/desmog.htm


Which one does your bike look like?

Thanks OK Valk........mine is desmogged.

Just test drove it.......wow......90-100 mph for 4-5 minutes sustained with 3 bars on the gas gauge.
I could never do that b4.  It even seems to have better throttle response  at low speeds but that's prolly just my magination.  Thanks so much......never coulda done this by myself.

[Oklahoma_Valk]

Great news. Enjoy the ride!