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Old 02-14-2013, 04:46 AM   #143
roger 04 rt OP
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Joined: Nov 2011
Location: Massachusetts
Oddometer: 2,272
Originally Posted by wallyging
Here's an update on the LC-1 on my 2001 R1150 GS:

The fuel injectors I had sent off for cleaning (RC Engineering) came back today. The report showed they had flow rates of 315 and 294 cc/min before cleaning; and 321 and 319 cc/min respectively after cleaning. The 21 cc/min difference between cylinders before cleaning seems like a lot, which I believe could account for the slight surge I still had after installing the RC-1.

So I installed the cleaned injectors and went for a ride, syncing the TBs after the engine was fully warmed up. The surging is now gone! I had forgotten just how smooth and torquey the GS is with the richer fueling. The LC-1 transformed the bike. I rode like a hooligan coming home big smile on my face, 30 degree weather notwithstanding.

Thanks Roger for your help every step of the way. For me, this is a modification well worth doing.
That is a fairly large injector mismatch for a lean-fueled engine as yours was with the stock O2 sensor installed. When using the stock sensor I see AFRs move between 14.3:1 and 15.1. Since your cylinders had a 7% fueling imbalance so taking half that amount and adding another 3.5% to the 15.1:1 your leanest cylinder was at times in the vicinity of 15.6:1, a very lean mixture.

Also, around stoic, the fuel is converted to power at about half the difference of 7%, so one cylinder was producing 3-4% more or less power than the other. Your engine should be somewhat smoother now.

As you richened the mixture with your LC-1 but before you cleaned the injectors, you adding fuel and consuming the excess oxygen. As you do that your bike became less sensitive to the injector imbalance because once you've consumed all the oxygen the excess fuel can't be burned and the power differences diminish.

Glad it is working out for you.
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