Some Minor Mods

Water in the air cleaner
housing

Since colder temperatures arrived, the Ural has been running rough upon returning home in the evening. Really similar to the way the BMW was running last winter at colder temperatures. Upon arriving home today, the carb bowls were checked for water using the handy drain on the bottom of the bowls but didn't find any evidence of water. The airbox branch pipes that run from the air cleaner to the carb inlet were removed and the left one had a lot of water drops in it just like when they were checked a couple of weeks ago. The air cleaner housing also had a puddle of water with a trail of moisture from the breather hose which is attached to the left side of the air cleaner housing. The right side of the air cleaner housing and the right airbox branch pipe was completely dry. Seems like a good time to add some of the pieces and parts I picked up in Salem.

This is the solution sold by Raceway Ural in Salem, OR. A nicely machined, anodized aluminum canister with two hose fittings on top and a drain valve with a hose fitting on the bottom. In the old days, the crankcase vent would simply have been a hose aimed towards the ground. Sometime in the '60s this was no longer allowed and venting the crankcase into the air cleaner housing became the norm. The aluminum canister is mounted to the frame by a nicely machined clamp.

After removing the stock hose, the original crankcase vent fitting is turned up and a new hose is run into the top of the aluminum canister. A small diameter hose is attached to a valve on the bottom of the cylinder to drain the contents. The folks at Raceway suggested draining after every tank of fuel and that it depends on the temperature, humidity and if you have ethanol in the gas. (Alaska has none!)

Horizontal twins aka boxer twins and singles move a lot of air through the crankcase vent. With a boxer twin, the pistons both move in and out at the same time so the entire engine displacement of air is moved in and out of the breather hose with every revolution. Similarly, a thumper will move the entire displacement in and out as the piston moves up and down through the cylinder. Other engine configurations don't have this "issue" as when one piston moves up another is moving down balancing things out. For the Ural, that's 106 ft³ of air per minute while running down the highway.

The second hose runs from the top of the canister, along the top of the engine to a small air filter. The suggested location for the air filter is above the battery and below the seat but can be anywhere where it is somewhat protected from moisture. The air filter is the only shiny part of the whole system.

If this makes a difference, I may have stumbled into a solution for the rough running on the Beemer in cold weather. As it also has a boxer engine and the crankcase vent runs directly into the "air horns" inside the air cleaner housing.

I also picked up replacement airbox branch pipes from Raceway at the recommendation of ChrisL of EverydayRiding.org. The stock parts are made up two rubber 90° hoses, a short metal coupler and 4 hose clamps. Getting all of these pieces lined up correctly and the hose clamps tightened seemed to be a real hassle. Not an issue with these new one piece parts. BTW, these are not aftermarket but sold by Ural as a replacement part. I'm not sure if the lower hose clamp is even needed as everything fits together so well.

I had installed this earlier but figured that I may as well show it installed. This is the quick disconnect that fits into the fuel tank crossover hose. You simply push the round button and the two pieces pop apart and both sides seal. No more fuel leaking out when the gas tank needs to be removed. The hose above the quick disconnect is the one from the top of the canister to the small air filter under the seat. Given the amount of air that needs to move through this hose, it seems undersized.

There is still a lot of snow and ice on the road and the Ural is even more "sure footed" than the BMW especially with the GripStuds installed. I think that there is more weight on the rear tire and having brakes on all three wheels makes a huge difference. With the BMW, just touching the rear brake will lock up the wheel in these conditions. Possibly due to a lot of weight transfer to the front when braking. The leading link front suspension design on the Ural seems to eliminate the front end "dive". As you can see, there aren't that many studs installed. I just alternated from side to side so there is a lot of room to add more if needed.

Update - Upon returning home today, there was no rough running, no rich smelling exhaust and no moisture in the left airbox branch pipe. I didn't bother to check the right one.

Posted with Blogsy