Answer to random bogging down stalls - Kawasaki KLR 650 Forum
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post #1 of 2 Old 06-12-2011, 12:15 PM Thread Starter
Join Date: May 2011
Posts: 1
Answer to random bogging down stalls

The following is broken into sections:
  • Introduction
  • Symptoms
  • Trouble-shooting
  • The fix
  • Observations

About a month ago I purchased a used 2009 KLR650 that the prior owner warned me had sat most of its life in his garage collecting dust (only had ~1,700 miles on it). He also stated that he had drained the float bowl to take care of a stalling problem and that it seemed to be ok now (he was guessing the issue was due to gas going bad/condensation).

What I soon discovered after getting the bike home:
  • Ride to work in the cool of the morning - no issues.
  • Mid-day ride to go get lunch (bike sitting in the sun) - stalls about 1/2 mile down the road and is very hard starting. Discovered it would start if I switched it over to reserve, and could then switch it back to the primary feed with no issues about a 1/2 mile later.
  • Ride home from work in the evening - seemed to be temperature dependent. Hot day? Stall. Cold day? No stall.

Read through the forums and ultimately installed a high-flow fuel filter so I could see if the issue was before the carb or in the carb. I highly recommend this low cost addition which will spare you a lot of head-scratching trying to diagnose what the heck is happening in a stalled state.
  • Normal riding state: Fuel clearly visible in fuel filter, no air/gas vapor visible (NOTICE - be sure to read observations section, as this is NOT normal on California smog models).
  • Stalled: No fuel visible in the fuel filter what-so-ever. Switching to reserve and cranking it over, fuel floods through the filter and I'm up and running (plenty of gas in the tank).

The Fix
In the middle of installing the Thermo-Bob (excellent upgrade by the way), I had to pull off the fuel tank and closely examined the smog lines. Sure enough, the two lines coming off the tank were reversed (!!!).

If you were sitting on the bike staring straight down at the tank, the tube on the right is the one that is referred to as 'red' in the chart on the inside of the rear side panel. My tank had a red dot sticker on the tank next to that line, but both rubber tubes were black with no markings, so I just followed the routing on the chart. Once I figured-out they were reversed, I added a band of red electrical tape to the end of the 'red' rubber tube to go with the red dot side to help make re-assembly in the future easier.

I also found a line that was just about pinched off at the rear of the bike where it makes a 180 degree loop back into the smog box. The loop was too tight and was bordering on kinking the line, so I pulled the line and added a little bit more slack at the 180 degree loop (there was enough length overall to do this), then wire tied the line in place to remove future concern.

Stalling problem is fixed..!!!

For California model bikes with all the smog equipment, you should see gas AND gas vapor in the fuel filter. The line that returns from the smog system to the back of the fuel/reserve switch is constantly dumping fuel return vapor back into that junction. So if the lines are switched on the fuel tank, you will get a huge burst of gas vapor(?) or air(?) (i.e. smog system fart) in the fuel line every once in a while. Nice...

Hope this helps some of you save a bunch of time.
- FlyingBlue09
FlyingBlue09 is offline  
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post #2 of 2 Old 06-14-2011, 09:51 PM
1st Gear
Join Date: Nov 2008
Posts: 21
Well said! I'm sure that will be helpful for future readers.
donavon is offline  
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bogging down, stalls, vapor lock

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