Monday, September 28, 2009

Natasha is better now....

Good news, Natasha is about 99% back to normal. Well, as normal as a Ural can be. : )

This recent experience was the result, apparently of contamination in the fuel system, near as I can figure it.

The initial issue of the engine not restarting reliably from either electric or kick starter is theorized to be "vapor lock" by Mike of Wagnerscycle.com. He was a very informative and helpful guru that I was passed onto by Felicia when I called them about parts for Natasha. The symptoms I was able to relate to Mike led to:
  • Resetting the fuel mixture screw on the carburetors to 1.5 turns from seat, 2.5 being too rich. Then re-doing the idle speed and another carburetor sync. (This tip came from Felicia; apparently one can't believe everything one reads in the owners manual)
  • Draining some fuel from the carburetor float bowls and checking for water or crud. None found.
  • Blowing compressed air through petcock into gas tank to clear any obstructions in that path, through the carburetor with a partially filled fuel bowl via the fuel intake and having it vent out. This to ensure fuel jets are cleared.
  • Putting back the old NGK BP7HS plugs vice the Autolites because they're too "hot". I am to always stick with the NGKs.
Took Natasha out for test run and she can accelerate just fine now! Some minor bogging which I don't think is related to the carbs but to too much freeplay in the throttle grip. More investigation to be done there but for now, she's about 99% back!

While it had its frustrating moments, I did learn a lot from this:
  • A simpler and easier way to sync the carbs. Start with free throttle cables, get fuel mixture equal first, then equalize the air settings, when that's balanced, then remount the throttle cables and recheck. Easy!
  • Learned how to drain the carbs without dismounting the fuel bowls. Good for checking for fuel contamination. It takes more effort to take the bowls of the Keihin carbs than the Bing carbs on an Airhead Beemer!
  • Learned what type of fuel petcock I have, that it needed cleaning and that there's a better version out there somewhere for me to search for. I wonder if I can use Beemer petcocks on the Ural tank? Sure, you have to shut them off when parked or they leak but I am used to them.
  • Learned where my ignition coil and control unit are located and how they work with each other and the spark plugs. Tomorrow, I do my first timing light check, learned that as well from a different source.
  • Learned a "quick" way to clear the fuel jets on a carburetor. A thorough cleaning is in order for the near future.
  • Learned from Felicia of a source of oil/fuel compatible hose for replacing the cracking intake boots on Natasha.
  • Finally, re-learned the lesson to check the basics first before diving headfirst into the deep end of the troubleshooting pool. Checking the spark plug cables first would have saved me some trouble. It was not the major contributor but a factor nonetheless.
I've new spark plug cables, replacement carb flanges, new spark plugs and clear fuel lines on order, they should be here on Wednesday I think. The old NGKs are black from too rich a fuel mixture in the past, hopefully the settings I have now will prevent that. The plugs are to remedy the mismatched cables on Natasha now. The flanges will replace the aging and cracked ones that Natasha came with. Finally the clear fuel lines is for me to detect crud in the gas hopefully.

My heartfelt thanks to Felicia and Mike of Wagner's Cycles, their willingness to help me gained them a new customer. My gratitude as well to Andre, my Russian friend who showed me the simpler way to sync carburetors and set them correctly.

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