2006 Ural 750 will not idle

Are ya having a problem with your rig? We'll try to help. Share your tech tips and experiences here. Dr. Billy Glaser, author of the "Unofficial 750 Ural Service Manual" site myural.com, is moderating this section.
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LyleJade
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2006 Ural 750 will not idle

Post by LyleJade » Tue Nov 05, 2019 9:20 pm

I am working on my sons 2006 ural...here are some of my issues...now ...I've done all the usual things to get it to idle properly and run without stalling out...I've torn down the entire fuel system
2006 ural 750...new lines, cleaned out the tank completely with chemicals bc of corrosion...new lines...took both carbs off...broke them down and cleaned them up prestine... I even took a brand new glass Harley fuel filter n added to the fuel lines...so it has great filtration...I've adjusted the carbs...new plugs...followed the spark plug wires up to cam plate..removed it cleaned it...marked the plate so I reset the timing probably....put an additive in tank for fuel stabilizer...fuel is running great...diaphragms r good..carbs I've taking them off 3 times to fine clean them and used a air hose t make sure the jets r clean...so it still will not idle with the chokes off...it sputters out...I've..today...taken the idling springs off and made ones where I could set the idle higher...still doesnt want to idle...I'm at a complete lost...I ran it down the road the last time i drove it and it stalled out n that's when I was giving it gas...it just acts like it's not getting fuel...or something is wrong...sometimes it can be hard to start but once i get it going its good... it starts good .cold but can be difficult to start when gets too hot....and I'm working on w my dad...he builds motorcycles n restores cars....we r just at a lost

We have addressed all the usual suspects here...air filter good n clean...if anybody knows any tricks about this bike....please help me!!! Thank u so very much....any and all suggestions welcomed

jeffsaline
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Re: 2006 Ural 750 will not idle

Post by jeffsaline » Tue Nov 05, 2019 10:27 pm

My suggestion is to spray carb cleaner (using the straw that comes with the can) into each carb passage. Maybe wear eye protection and keep your mouth closed. : ) Remove the jets and the mixture screw. Verify carb cleaner comes out all the connected holes of the idle circuit. There are four holes in the idle circuit that must be clear. One is on the air cleaner side of the carb body throat. Another is on the engine side of the carb body throat. The other two holes are the pilot jet and the idle mixture screw. If carb cleaner doesn't come out all the holes when sprayed into any one of them it suggests there is a clogged passage.

Using a magnifier, hold each jet to a light source and make sure the inside of the jet passage is round.

Blowing air at a hole/passage doesn't mean the passage is clear. Spraying carb cleaner will allow you to verify the passages are clear.

Do not have any rubber parts in the carb when you use the carb cleaner.

Best,

Jeff
Jeff Saline
2010 Gear Up
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LyleJade
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Re: 2006 Ural 750 will not idle

Post by LyleJade » Tue Nov 05, 2019 11:07 pm

How do I set the pilot and the jet screws inside the carbs? Do i tighten them all the way in then give 1/4 turns backing them to a certain position? Also the 90° rubber elbows that go to the air filter t carbs...they are old but not worn...how sensitive is that system as far as carbs performing properly? There are no holes in them but do u recommend changing them anyway?

Taking the carbs back off tmr....I read about how to adjust them to get them insync... any helpful hints in adjusting them.properly is alw greatly appreciated!!

Thank u soo much 4 answering me...stay tuned...

jeffsaline
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Re: 2006 Ural 750 will not idle

Post by jeffsaline » Wed Nov 06, 2019 12:20 am

The main jet and pilot jet are located in the area cover by the float bowl. They are seated fully when correctly installed. The way a main or pilot jet is adjusted is by changing for a different size. The mixture screw located on the bottom of the engine side of the carb is adjusted for best but also leanest idle.

Not sure of what you are referencing abou the 90 degree elbows going to the air filter unless you mean the branch tubes which direct air from the air filter to the carb. If they are properly seated on the air filter housing and the carb they should be fine.

I recently posted how I adjust carbs like used on a Ural. I'll see if I can find the post and link it for you.

Edit addition: Here's the post that might be helpful.

viewtopic.php?f=5&t=55630&p=710134#p710134

For CV carb tuning you start with the main jet, then do the needle jet/needle position and then the pilot/idle jet and mixture. That gets you really close and then you can fine tune by doing it one more time.

For main jet I usually go wide open throttle in a lower gear like maybe 3rd on the Ural. Then I slowly close the throttle and observe what happens with rpms. If they go down with the throttle closing it suggests the main jetting is about right or could be a tad rich. If the rpms go up and then down is suggests the main jet is lean and by closing the throttle it reduces air which richens the mixture. Correct the main jet if needed.

Needle jet/needle position is used from about 20-80% throttle position. Some folks will say 25-75% throttle position and that is about right too. The needle jet/needle gets fuel from the main jet. So if the main jet is changed it also changes the fuel that is delivered using the needle jet/needle position. To get an idea of how the needle jet/needle position is set up... In a mid gear (2nd or 3rd) at mid throttle briskly roll on the throttle. This is a roll on and not a crack it wide open movement. All the right wrist is doing is requesting more fuel, the vacuum in the carb is raising the slide and needle which allows more fuel delivery. If you crack the throttle wide open it provides a huge amount of air but the carb can't provide fuel as quickly and it results in a lean condition for a second or two until the carb can catch up. If there is a lag when you roll on more throttle it suggests there is a lean condition and the needle should be raised. If the engine responds smoothly and without lag it suggests the needle position is about right. If there is surging at a steady throttle position it suggests the needle position is maybe a tad lean.

For idle/pilot jet have the engine at operating temperature. Set the idle rpm using the idle speed screw on the side of the carb. Don't confuse idle speed screw on the side of the carb with the idle mixture screw on the bottom of the carb. Set the idle speed at about 1,000 rpm. Make sure you have about 1/32" play in the throttle cable at the adjusting ferrule on the carb. Turn in both idle mixture screws one screwdriver blade width at a time until the engine barely idles because it is too lean. Stop the engine and let it cool for 20-30 minutes. Get ready to take a ride. Bring the screwdriver with you. From a standing start the engine will bog. Stop and turn each mixture screw out one screwdriver blade width. Start again. The engine will again bog and you again stop and open each mixture screw another screw driver blade width. Continue until the bog goes away. This is as lean as the engine will tolerate and still result in a smooth transition. Opening the mixture screw anymore is just a waste of fuel. Adjust the idle speed to whatever speed you like using the screw on the side of the carb. When the mixture is correctly set the engine will bog when cold but be fine at operating temperature.

Now resynch the carbs using your tool of choice and then do the entire jet check again. Remember to always start with the main jet, then the needle jet/needle position and finally the idle/pilot jet and mixture.

Best,

Jeff
Jeff Saline
2010 Gear Up
-Good, Fast, Cheap. Pick Two
-Just because something isn't true, no reason you can't believe it. Hub McCann Second Hand Lions
-Anything is possible if you don't know what you are talking about.

WEGUNTER
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Re: 2006 Ural 750 will not idle

Post by WEGUNTER » Wed Nov 06, 2019 4:28 am

Those L shaped elbows you mentioned are vent ports. Do not cap them. Bike will run like crap if you do.

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Lmo
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Re: 2006 Ural 750 will not idle

Post by Lmo » Wed Nov 06, 2019 4:55 am

Type V ignition interrupter might be loose. Pull the front cover and check it. The early rotors were made from two pieces of pressed steel and can come loose. When it does it creates all kinds of mischief.

Read > http://www.myural.com/interrupterreplacement.htm

Two-piece rotor (left), one-piece rotor (right).
Notice the joint on the left rotor.
Back side
Image
Front side
Image

Image
Lew Morris
Dnepr w/ '06 Ural Drive Train
C5 Power Arc
125/42 jets
Drilled slides/
.030" shims

1973 BMW R75/5 (original owner)
1947 HD FL (long gone, forever regretful)

LyleJade
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Re: 2006 Ural 750 will not idle

Post by LyleJade » Wed Nov 06, 2019 6:13 am

I checked and cleaned that yesterday...I'm got frustrated with it after that....so today is a new day....im.going to start over and check everything all over again....pulling carbs...removing gaskets, dipping them in carb cleaner to soak, blow out my jets make sure they're not clogged.....I know it isnt the gas tank but I might drain it again and pull it ....another small issue its had in the past ...so my son has said....is that it doesnt like to start up again once it's gotten hot....great cold starting...any ideas for that? Also the bike sat for 3 years out in the weather...fuel was left in it to corrode...so it's got all new lines, filters, plugs, cleaned the tank, cleaned the carbs and blew an air gun through the jets to make sure all the crud was out, and cleaned the petcock very well...and even added an extra HD glass fuel filter to the system so I can see the flow of clean fuel throught it...back to the drawing board today...thank u so much for your reply...keep em coming

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Snakeoil
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Re: 2006 Ural 750 will not idle

Post by Snakeoil » Wed Nov 06, 2019 6:07 pm

Do you have the jet positions swapped? This is possible on some carbs. Don't remember if possible on CVKs.
Regards,
Rob
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2000 Ural Tourist
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Lmo
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Re: 2006 Ural 750 will not idle

Post by Lmo » Wed Nov 06, 2019 11:51 pm

Do you have the jet positions swapped?
Yes, it is possible. And the needle jet can be installed upside down as well. The idle mixture jet o-ring is another easily damaged/lost item to keep in mind.

Image

Ref > http://www.myural.com/keihin_32cvk_disassembly.htm
Lew Morris
Dnepr w/ '06 Ural Drive Train
C5 Power Arc
125/42 jets
Drilled slides/
.030" shims

1973 BMW R75/5 (original owner)
1947 HD FL (long gone, forever regretful)

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