Ural Revs dropping slowly or not?

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Sergei
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Ural Revs dropping slowly or not?

Postby Sergei » Tue Feb 23, 2016 10:55 pm

Hi all! Have had my '05 Patrol for about a month now and have found this forum hugely helpful! This being my first Ural I'm trying to figure out if there's an issue with the revs dropping too slowly or if I'm just impatient. The reason I'm wondering is because it's difficult to get the up shifts right with the way it is right now. Also it was actually much worse before I did a tune up.

When I got the bike, it was running ok but not great. It would hesitate at lower RPMs, backfire/pop and then once warmed up the revs would hardly go down if you cranked the throttle.

the throttle cables move freely and throttles themselves don't stick. I've also given it an overall tune up including new plugs, checking valve clearance, cleaning air filter, draining carb bowls, setting the timing and tightening up the intake manifolds. I've sprayed WD40 around the manifolds and it doesn't spike the idle so I think they're good now.

My final suspicion is the carbs may be out of balance. But before I go messing with that, I wanted to see if the way it runs now seems normal to you all and if there's anything else I should be checking.

Quick video of blipping the throttle and waiting for revs to drop, once the bike has warmed up: http://youtu.be/UpHH8RXk1I0

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Re: Ural Revs dropping slowly or not?

Postby TerryG » Tue Feb 23, 2016 11:22 pm

Slow running down is sometimes an issue with the way the cables are adjusted. They may not have enough slack in one or the other. Pull on the outer part of the cable where it goes into the carb. There should be about 1/8 - 1/4" free play where you do not feel the carb opening. This of course also effects carb balance - so be prepared to do that also. You can get a close carb balance by adjusting the place where the cable goes into the carb so that both cables have the same amount of free play. If you get some improvement, you should either get someone to properly balance them or do it yourself with a meter such as a TwinMax. You will also need to balance them at idle.
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Re: Ural Revs dropping slowly or not?

Postby Brian Crean » Wed Feb 24, 2016 7:18 am

Agree with Terry on what he said. On top of that, you may want to make sure the throttle itself is rolling freely, the cables are lubed, and not hanging up, or jamming at the 1to2 splitter.Lastly, look closely, and make sure the cable linkages at the carbs are not rubbing on anything (had that happen, drove me nuts!) The cables should have gentle curves, and shouldn't be crammed in where they will bind.

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Re: Ural Revs dropping slowly or not?

Postby tx2sturgis » Wed Feb 24, 2016 10:33 am

It's not that far out of normal. These bikes have a heavy flywheel, and low compression, and drop RPM's much more slowly than what you may be used to. You didn't mention how many kms are on the bike...that will help us because a freshly broken in bike acts a bit differently than a bike with 20,000 kms...and the things we suggest can be related to age and mileage. Also are you in warm climate, or a really cold place with daytime temps still around freezing?

But going strictly by your description and your video, It sounds like the idle speed may be just a little bit too fast, and possibly, the idle mixture may be off just a bit.

Once its warmed up, and I mean, really warmed up good, try backing off on the idle screws a half turn or so.

Also, dont get in a hurry shifting these bikes, you have to wait until the RPMs drop (or rise) to get that next shift.

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Re: Ural Revs dropping slowly or not?

Postby Sergei » Wed Feb 24, 2016 11:54 am

Hey Brian - thanks for checking out the vid. Glad to hear it's not that far off from your experience. Just for reference that video was filmed in roughly 35 degree weather after the bike had a chance to warm up in my garage and then being driven around for 10-15 minutes. For what it's worth, I'm in Denver at roughly 5200 feet above sea level.

I'm not positive on the mileage - odometer reads 1,092 km but I was told the previous owner swapped in a new speedo after the old one broke. The bike is claimed to have a total of 7K km, but again I can't be sure, which is why I'm just going over everything.

Just based on the overall condition of the bike, I would say it's a lower mileage unit. Doesn't seem like it's been ridden much for the past 10 years.

I will triple check all the throttle cables and then read up on balancing the carbs. I feel like it's now very close to running well, but just need the idle to return a little faster so I can shift through the gears without grinding or waiting so long for the revs to drop that the bike starts to stall.

-Sergei

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Re: Ural Revs dropping slowly or not?

Postby Wildhorse Cafe » Wed Feb 24, 2016 12:08 pm

viewtopic.php?f=5&t=41773
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Re: Ural Revs dropping slowly or not?

Postby Sergei » Wed Feb 24, 2016 12:24 pm

^ Not ruling it out, but trying to get through all the easier stuff before taking the carbs apart. Could very well be improperly jetted as people LOVE messing with bike carbs here since we're at altitude and often times it causes more problems than benefits.

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Re: Ural Revs dropping slowly or not?

Postby rivers » Wed Feb 24, 2016 3:02 pm

Agreed, try the easy external tune procedures before diving into the carbs. Though a Twin max is a good sync tool, you can build a DIY manometer for <$10 that will work just as well. As previously mentioned these motors take a bit to spool down and shifting takes practice to get a nice clunk shift opposed to the dreaded buzz/grind/crash. The newer 07+ Herzog geared boxes shift somewhat better than the previous Russian gears but it's still an old design gearbox. You can't double clutch a Ural box but kinda sorta same principle.,,matching eng and gearbox speeds. Then shift like you mean it. NOT "stomp on the pedal" but shift firmly and deliberately with follow through. It is not a modern Jap snick, snick shifting box. Tune'r up and go practice, you'll get there.
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Re: Ural Revs dropping slowly or not?

Postby tx2sturgis » Wed Feb 24, 2016 7:46 pm

Sergei wrote:Hey Brian - thanks for checking out the vid. Glad to hear it's not that far off from your experience. Just for reference that video was filmed in roughly 35 degree weather after the bike had a chance to warm up in my garage and then being driven around for 10-15 minutes. For what it's worth, I'm in Denver at roughly 5200 feet above sea level.

I'm not positive on the mileage - odometer reads 1,092 km but I was told the previous owner swapped in a new speedo after the old one broke. The bike is claimed to have a total of 7K km, but again I can't be sure, which is why I'm just going over everything.

Just based on the overall condition of the bike, I would say it's a lower mileage unit. Doesn't seem like it's been ridden much for the past 10 years.

I will triple check all the throttle cables and then read up on balancing the carbs. I feel like it's now very close to running well, but just need the idle to return a little faster so I can shift through the gears without grinding or waiting so long for the revs to drop that the bike starts to stall.

-Sergei


Ok...now we kinda have a better idea about it. Yes, based on the temps and age it probably should drop RPM just a bit quicker than what I heard, but again, its not that far out from normal. Also, I cant stress it enough that you have to be patient when shifting...they will NOT shift quickly like a Japanese or even an American bike.

A side-of-the-road check for carb balancing is easy if you have a helper. With the motor warmed up and idling, lean over the bike with an arm on each side of the tank, and put a finger on the bottom of the bell-crank of each carb. Have your helper GENTLY begin to twist the throttle, to just barely increase the RPM. With your fingers, did you feel both cranks move at about the same time, and about the same amount? Or as the RPM increased, did you only feel one of them move?

This can be used to get them in the ballpark, until you can get it done correctly.

Once you get the idle speed reduced a bit, assuming you have the same carbs as mine, you can adjust the idle mixture screws which are in the very bottom of each carb, are brass colored, and slotted, not phillips. You can't see these from the side, you actually have to lay down under the bike and look UP at the bottom of each carb, maybe using a flashlight. These are your idle mixture screws.

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Re: Ural Revs dropping slowly or not?

Postby Sergei » Sat Feb 27, 2016 11:45 pm

Brian - used your technique and the throttles were definitely off! I adjusted them to open simultaneously and immediately noticed idle was smoother! Unfortunately the revs still take a while to drop once the bike is properly warmed up :-/

I also readjusted the idle mixture screws to 1.5 turns out per the manual.

Just to be clear a full turn = the mixture screw completing a full rotation like if a clock moved 24 hours. Correct?

The other challenge is I'm not sure the idle speed screws are set exactly the same on each side. Going to check this tomorrow when I have more light.

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Re: Ural Revs dropping slowly or not?

Postby rivers » Sun Feb 28, 2016 12:36 am

Sergei wrote:I also readjusted the idle mixture screws to 1.5 turns out per the manual.

Just to be clear a full turn = the mixture screw completing a full rotation like if a clock moved 24 hours. Correct?

Correct.
From "lightly" seated one full turn out is a full 360 degrees.Think minute hand not hour hand.
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Re: Ural Revs dropping slowly or not?

Postby Sergei » Sun Feb 28, 2016 1:01 am

Ok good, then I did it right. They were pretty close before but not even on both sides.

Any way to estimate or check RPM at idle on these bikes without a tach?


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