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.
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BinDerSmokDat
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Re: Carbon build-up after throttle butterfly

Post by BinDerSmokDat » Thu Feb 20, 2020 10:27 am

GHGoodwin wrote:
Thu Jan 23, 2020 8:07 pm
Carbon or fine particulate dust? Inefficient air filter coupled with oil vapor from CCV...
windmill wrote:
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.
I'll third this^^^^^^.

I don't have a fuelly bike but I have a direct injection turbo car engine.
There is a lot of evidence that under some conditions, even with a catcher, some fine particulates from the crankcase get through through the filter to the intake.
In direct injection cars the particulates and oil vapor hit hot intake valves and create carbon.
Because no fuel is going past the intake valves in direct injection or in butterflies or carbs of a Ural, there is no cleaning by the fuel and it's additives.
The fix in DI cars? Dealerships charge for very expensive intake cleanings to remove the carbon.
Not sure why there is buildup in a throttle body but not in carb bikes, it should be cool so it isn't cooking anything.
Maybe the oil/carbon mix is ideal for agglomerating to create build up.
It could be that the throttle body creates the perfect set of conditions of air flow/stalling that allows build-up where a carb doesn't.

I have always vented the crankcase to the airbox in my carb bike, no issues and never see any buildup in the carb bodies.
I'm against venting to the environment, as it is really a bad idea. There is enough fuel and oil that makes its way into waterways.

I'd look for any causes of excess blowback in the engine itself, put in an inline catcher and still vent to the box.
See if that helps.

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windmill
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Re: Carbon build-up after throttle butterfly

Post by windmill » Thu Feb 20, 2020 10:41 am

BinDerSmokDat wrote:
Thu Feb 20, 2020 10:27 am
Not sure why there is buildup in a throttle body but not in carb bikes, it should be cool so it isn't cooking anything.
On carbed bikes the breather just discharges directly into the airbox before the filter, what doesn't pool at the bottom is caught by the filter. On the EFI rigs the breather is routed through the airbox, past the filter, and splits to discharge directly into the throttle bodies.
Barry

"Take care, sir," cried Sancho. "Those over there are not giants but windmills".

2007 Patrol 100k km and counting,
2018/20 M70

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aduthie
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Re: Carbon build-up after throttle butterfly

Post by aduthie » Thu Feb 20, 2020 11:24 am

The evaporative emissions system is California-only (at least in the U.S.), and it’s for controlling the fuel vapors that otherwise emit from the fuel tank. That part is labeled “Kip valve”; I’m pretty sure it opens a vacuum line to allow fuel vapor from the charcoal canister to get pulled into the engine and burned.
Andrew Duthie / Nashville Motorcycle Repair / Nashville, TN

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BinDerSmokDat
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Re: Carbon build-up after throttle butterfly

Post by BinDerSmokDat » Thu Feb 20, 2020 5:45 pm

windmill wrote:
Thu Feb 20, 2020 10:41 am
BinDerSmokDat wrote:
Thu Feb 20, 2020 10:27 am
Not sure why there is buildup in a throttle body but not in carb bikes, it should be cool so it isn't cooking anything.
On carbed bikes the breather just discharges directly into the airbox before the filter, what doesn't pool at the bottom is caught by the filter. On the EFI rigs the breather is routed through the airbox, past the filter, and splits to discharge directly into the throttle bodies.
Anyway to tap a hole and route the breather to the "outside" of the filter box?
Weird that Ural would route the breather to the post-filter side. :?

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GHGoodwin
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Re: Carbon build-up after throttle butterfly

Post by GHGoodwin » Thu Feb 20, 2020 8:31 pm

Not weird at all. Some think the CCV enriches the air flow and provides some lubrication to intakes along with reducing ping. Some don't. It's still my thinking that oil vapor deposits on a smooth surface are a perfect place for fine particulates to stick.

FWIW - my '14 did this until I vented the CCV to atm.
Hal

2011/12 Tourist - "The Russian"
It's a long list.
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windmill
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Re: Carbon build-up after throttle butterfly

Post by windmill » Thu Feb 20, 2020 9:54 pm

Having upgraded it the 2019 centrifugal breather, I'll be watching how it does. This is typically the worst time of year for condensation, and it seems to have significantly reduced it, but not entirely eliminated it.
Installing a vapor trap has moved way down the to do list, but still not crossed off until further evaluated.
Barry

"Take care, sir," cried Sancho. "Those over there are not giants but windmills".

2007 Patrol 100k km and counting,
2018/20 M70

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