Carbon build-up after throttle butterfly

Woe unto you that bought the first model year of a major remake, perhaps this section can help address any 2014 and later model Ural "imperfections". Here's a special section for folks with the latest rigs to discuss 2014 and later model-related topics such fuel injection, 3-wheel disc brakes, hydraulic steering dampers, spin-on oil filters and other anomalies that don't belong on true Russsian motorcycle ;-P We've gone from using big hammers and greasy wrenches to needing computers and Ouija boards in order to fix our rigs.
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Please keep this section specific to issues pertaining to 2014 and later models such as fuel injection, sidecar and rear disc brakes and so forth. Ask general or non-2014 and later specific questions in the main Hammerin' & Wrenchin' section.
AndyH
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Carbon build-up after throttle butterfly

Post by AndyH » Sat Jan 18, 2020 3:12 am

2015 Tourist 1WD with 30,000 kilometers on the clock.
Noticed this recently when I pulled the TB's and wondered if anyone else had something similar - a fix - or a just ignore?
Accumulation in the first picture is less than 1500 kilometers.
carbon1.jpg
Accumulation in the second picture is around 25,000 kilometers :)
dirty.JPG
Similar pattern on both sides mainly centered around the throttle cable side, or engine side of the TB.
Wipes off with a Qtip dipped in acetone.

Is it a reason for concern?
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Re: Carbon build-up after throttle butterfly

Post by Tomcatfixer » Sat Jan 18, 2020 12:53 pm

I was getting this quite heavily, enough that it fouled and ruined one of my MAP sensors. I rerouted my engine breather to vent to atmosphere, instead of the airbox, and I noticed a less accumulation. What appears now, I suspect, is blowback from the intake.
- Chad

Gordonsville, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 2001 Ural Patrol "Little Red Bear", 1999 Ural Tourist "The RPOC", Mid-Nineties Ural Tourist "The Heap", 1994 Honda VFR750F

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
Two different 1986 Yamaha FZX700S Fazers

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Re: Carbon build-up after throttle butterfly

Post by rivers » Sat Jan 18, 2020 1:08 pm

Just guessing here but thinking dirty oily air filter from the crankcase vent?
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Re: Carbon build-up after throttle butterfly

Post by AndyH » Sat Jan 18, 2020 4:28 pm

Tomcatfixer wrote:
Sat Jan 18, 2020 12:53 pm
I was getting this quite heavily, enough that it fouled and ruined one of my MAP sensors. I rerouted my engine breather to vent to atmosphere, instead of the airbox, and I noticed a less accumulation. What appears now, I suspect, is blowback from the intake.
Tomcatfixer - I had been considering a "catch" to maintained positive crank case pressure but hadn't got around to it. There is a smear of oil in the branch tubes, none on the air filter and none in the bottom of the filter box as well as a film on the inlet side of the TB.
Will check the posts here on re-routing the breather (edit found it here viewtopic.php?f=23&t=49981&hilit=breather+crankcase )- I suspect PCV is an environmental thing and the Ural doesn't actually require it? Van never did come back with the official story.
rivers wrote:
Sat Jan 18, 2020 1:08 pm
Just guessing here but thinking dirty oily air filter from the crankcase vent?
rivers - Nup.. brand new clean air filter - fitted when I first noticed the problem (see above) but thanks for the thought.
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Re: Carbon build-up after throttle butterfly

Post by Tomcatfixer » Sat Jan 18, 2020 5:16 pm

I had been considering a "catch" to maintained positive crank case pressure but hadn't got around to it.
Something like this?

2020-01-18 16.11.34.jpg
2020-01-18 16.12.02.jpg

I took Burt1713's idea and ran with it. It works... sort of. Some oil vapor still sneaks by and taints the air filter. My preferred solution is to simply vent to atmosphere.
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- Chad

Gordonsville, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 2001 Ural Patrol "Little Red Bear", 1999 Ural Tourist "The RPOC", Mid-Nineties Ural Tourist "The Heap", 1994 Honda VFR750F

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
Two different 1986 Yamaha FZX700S Fazers

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Re: Carbon build-up after throttle butterfly

Post by Mr Wazzock » Sat Jan 18, 2020 6:41 pm

Tomcatfixer wrote:
Sat Jan 18, 2020 12:53 pm
I was getting this quite heavily, enough that it fouled and ruined one of my MAP sensors. I rerouted my engine breather to vent to atmosphere, instead of the airbox, and I noticed a less accumulation. What appears now, I suspect, is blowback from the intake.
I've seen this on cars too. My old R80 had its carb atomizers completely clogged up wth the black stuff. I think you can clean it out, but maybe not entirely stop it.
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Re: Carbon build-up after throttle butterfly

Post by AndyH » Sat Jan 18, 2020 10:24 pm

Tomcatfixer wrote:
Sat Jan 18, 2020 5:16 pm
Something like this? download/file.php?id=120995&mode=view
Yes, I was thinking of something like that but since my air filter was clean and there was no froth in the air box, I decided against it.
Like Van said, there was a reason they vented the PCV through the box, unfortunately he didn't stick around long enough to tell us why...
If the branch tube distance pieces/spacers are positioned correctly oil won't/shouldn't foul the filter. Having said that if you twist the inlet pipe it will pull the left branch distance piece into the air box (talking from experience here.. lol). I notice on the picture of yours that the right hand "distance piece" is buckled on the front leg - shown in the picture in the original fix post:- download/file.php?id=100214&mode=view?

So back to the original issue, I wonder if the carbon buildup is due to oil misting or something else. I would have thought the inside of the TB wouldn't be hot enough to carbonize an oil film and since it is predominantly on the intake side of the TB, I was more worried about backfiring or ECU issues.
It seems balanced and doesn't show any issues when hooked up to OBDWiz or the dealer tool.

WWID? probably ignore it. So unless someone has any better ideas I might just do nothing.
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Re: Carbon build-up after throttle butterfly

Post by Mr Wazzock » Sun Jan 19, 2020 8:36 pm

Like Van said, there was a reason they vented the PCV through the box, unfortunately he didn't stick around long enough to tell us why...
Because we're not allowed to drop oil onto the roads anymore. :D

So it's redirected to the inlets so it can be burnt.

I think in California it came in in around 1980 because that's when the Meriden Triumphs changed to recycling their vented oil. Carburation had to be improved too.
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Re: Carbon build-up after throttle butterfly

Post by GHGoodwin » Thu Jan 23, 2020 8:07 pm

Carbon or fine particulate dust? Inefficient air filter coupled with oil vapor from CCV. Conical shape in TB going into butterfly would be the perfect place for impingement and trapping.
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Re: Carbon build-up after throttle butterfly

Post by windmill » Thu Jan 23, 2020 11:33 pm

I have no scientific evidence to back it up, but I believe its just from the carbon deposits in the oil.
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Re: Carbon build-up after throttle butterfly

Post by AndyH » Mon Jan 27, 2020 3:47 pm

Mr Wazzock wrote:
Sun Jan 19, 2020 8:36 pm
I think in California it came in in around 1980 because that's when the Meriden Triumphs changed to recycling their vented oil. Carburation had to be improved too.
My imported 76 Buick Riviera had PCV and an extra Cubic Inch to make up for it so it might have been the 70's, but I was interested in Vans take on it because the discussion was around how a boxer engine works and the benefits of the PCV.

Topic is exhausted, As Mr GHGoodwin said it is probably just the right spot for deposits and since no one has said omg mine has that too I will just put it down to "it a Ural".
Thanks for all the replies.
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Re: Carbon build-up after throttle butterfly

Post by Tomcatfixer » Mon Jan 27, 2020 5:04 pm

since no one has said omg mine has that too
I mean, sure, if you don't count the second post in the thread. :wink:
- Chad

Gordonsville, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 2001 Ural Patrol "Little Red Bear", 1999 Ural Tourist "The RPOC", Mid-Nineties Ural Tourist "The Heap", 1994 Honda VFR750F

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
Two different 1986 Yamaha FZX700S Fazers

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Re: Carbon build-up after throttle butterfly

Post by Lokiboy » Mon Jan 27, 2020 6:56 pm

AndyH wrote:
Sat Jan 18, 2020 10:24 pm
Tomcatfixer wrote:
Sat Jan 18, 2020 5:16 pm
Something like this? download/file.php?id=120995&mode=view
Like Van said, there was a reason they vented the PCV through the box, unfortunately he didn't stick around long enough to tell us why...
.
To paraphrase Van and a Ural mechanic, the breather into the air box is designed to do two things. 1. The pressure differential from the cylinders along with the incoming air helps pull the pressure out from the engine crankcase via the breather. 2. The atomized oil is there to provide oil to the front end of the piston and working parts in the carburetors (not sure if EFI have moving parts?)

Anyway, that’s how I remember two different conversations from folks vastly more qualified than me stating the same thing. Take it for what it’s worth.
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Re: Carbon build-up after throttle butterfly

Post by AndyH » Thu Feb 20, 2020 6:02 am

Tomcatfixer wrote:
Sat Jan 18, 2020 5:16 pm
I had been considering a "catch" to maintained positive crank case pressure but hadn't got around to it.
Something like this?
2020-01-18 16.11.34.jpg
2020-01-18 16.12.02.jpg
I took Burt1713's idea and ran with it. It works... sort of. Some oil vapor still sneaks by and taints the air filter. My preferred solution is to simply vent to atmosphere.
Seems Ural took Burt1713's idea and ran with it from 2017 onwards :)
EECS.PNG
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Re: Carbon build-up after throttle butterfly

Post by Tomcatfixer » Thu Feb 20, 2020 8:47 am

Would'ja look at that!
- Chad

Gordonsville, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 2001 Ural Patrol "Little Red Bear", 1999 Ural Tourist "The RPOC", Mid-Nineties Ural Tourist "The Heap", 1994 Honda VFR750F

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
Two different 1986 Yamaha FZX700S Fazers

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