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Old May 4th, 2023, 05:21 PM   #1
motopreserve
ninjette.org newbie
 
Name: Scott
Location: Brooklyn
Join Date: Oct 2022

Motorcycle(s): Tiger 800, CB550, EX300, XL250

Posts: 3
Running on one cylinder...

First post here on the site, but I have gotten a ton of knowledge here in the past. So thanks! I searched a bunch, but did not find anything that dealt directly with the issue I am having.

Attended a track day where I intermittently lost and gained power over the course of several laps. I was able to ride through it by smacking the throttle. This would bring back power for a bit, then it would lose it again. Now at the shop it is consistently only running on cylinder #2 (haven't tried it again under load). After researching a bunch of tests to narrow down the issue - I am still coming up short.
  • So far I have tested and ruled out: compression, bad coils, battery, air filter.
  • Cleaned the fuel injectors, tested the FI resistance, FI power source and FI output voltage.
  • I have swapped cyl #2 parts to cyl #1: coils, fuel injectors.
  • I have spark when the plug is grounded to the engine.

All this has turned up the same thing - cylinder #2 runs regardless of which FI/coil etc are in it. And #1 does not, despite swapping known working parts. My thoughts are leaning toward fuel pump or throttle bodies. It's obviously getting fuel to cylinder #2. But is there a way that the pump would not produce enough pressure to push it to cyl #1 down the pipe? Or perhaps there is some reason that the healthy FI is not passing the needed fuel to the cylinder?

Tomorrow I will remove the throttle bodies and check to see if anything on TB #1 is acting different to the working side.

I'm looking for some guidance on what to check next. Any help is much appreciated.

Scott
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