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Old 09-01-2012, 11:44 AM   #1
jlpp OP
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Joined: Aug 2011
Location: DC
Oddometer: 61
On road, engine loses power and dies repeatedly

In rural Kyrgyzstan riding US 2009 F800GS with problem as outlined below. Please excuse brevity (typing on phone) and mechanical novice. Requesting any thoughts on troubleshooting or fixing this problem. Bishkek is 350 kms away and hoping to get bike there tomorrow.

Problem:
Two days in row, at end of day and after 300+ kms per day, engine loses power and stops running, much like being out of fuel. Able to start by start button or bump start but only after engine turns over many times more than usual. Engine stops again after several minutes. Repeat this until arrive at destination for evening. After first occurrence, the following morning and most of day no issues, until recurred at end of second day. Thought I had run out of gas about 2/3rds through second day ride as fuel gauge dropped to zero quickly and engine died while gas gauge read empty for 10+ kms. Used two liters emergency supply and got to station. When filling it only took 11 liters so 16 liter tank should have had 3 or more liters when I thought it was empty and engine died. After filling at station ran 100+ kms before engine stopped for second time that day.

Conditions:
  • Occurred first day at 3,200 meters, second day at 2,000 meters.
  • Both series of engine stoppages were near end of day after 200+ kms.
  • Outside temps both days at about 70 degrees F. Engine temps normal. Four out of eight bars. Fan running fine.
  • Both days have been dusty with a lot of bumpy off road.
  • Opening gas cap near end of day to fill tank there is a strong rush of air but not sure if tank has vacuum or is under pressure.
  • In Central Asia for the past two weeks. Lowest advertised gas: no more than 5 liters of 80 mixed with 92 already in tank, more than week ago. All other gas: 91+. Last two days only used 93 or 95.
  • Air filter is not new or clean but doesn't drop much dust when blowing on it or hitting it against something hard. Does not appear clogged but does have a lot of kms on it.
  • All reservoirs, hoses, cables, fasteners, clamps, etc appear ok except one hose that runs from right side of bike under seat then snakes down to hang just below bottom of bike. This hose is not connected to anything on either end. This hose doesn't exist on friend's German 2009 800GS. What's it for?
  • No rain but a few splashes from riding through small streams. No standing water in air box.

Tests (while stopped on center stand at destination at end of second day, a few minutes after series of engine stops while riding):
  1. Run engine - engine loses power (struggles) and stops within five minutes
  2. Start with button - engine loses power and stops within one minute
  3. Start with button again - engine loses power and stops within one minute
  4. Open gas cap and start with button again - engine runs without issue for more than ten minutes
  5. Close gas cap without stopping engine - engine continues to run without issue for five minutes until turned off normally with switch
  6. Wait 15 minutes
  7. Start engine with button again - engine loses power and stops within ten minutes
  8. Open gas cap and start with button again - engine runs fine for about 15 minutes BUT THEN loses power and stops even with gas cap open

Thoughts:
Seems very much like fueling issue. Suspect vacuum in fuel supply preventing sufficient amount of gas from getting to engine. Maybe vacuum between canister and engine. Maybe fuel pump issue.

Next idea:
Check the fuel line vent to the very right and rear of bike, under seat. No issue on first look. Will remove from bike to have closer look and see if clogged.

Please let me know if you have other ideas. Maybe how to check fuel pump to see if it's working properly. Or how to get a fuel pump to Kyrgyzstan and get it installed in the next 4 days. Trying to meet visa and medical schedules and deal with bike issues.

Thank you,
Jeff

jlpp screwed with this post 09-01-2012 at 07:03 PM Reason: typos
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