lean surge?

In reading through a few older threads it seems some FJR's are troubled by lean AFR surging at constant throttle (cruise) when the ECU is or should be in closed loop. Are all model years effected by lean surging or did Yamaha come up with a factory fix? I'm most interested in the problem if it applies to the 2010 model.

If my new to me 2010 has this problem I know what I'm going to do to fix it but hope I won't have to.

Thanks, Jim

It was only really a problem with the 06 & 07's

I have spare 08 with perfect fueling

The lean surging is a function of the stock ECU fuel map. It afflicted mostly 1st Gens, and to a lesser extent some early 2nd Gens. Somewhere along the line they mapped it out, and I can say with certainty that it doesn't affect 3rd Gens. The fix is a Power Commander with a good map.

Thanks Fred that's good to know.

If my FJR has the problem I'm going wth the Innovate Motor Sports wideband O2 sensor with LC-2 controller. I've had a lot of experience with this product on two oilheads. Just connect your laptop to the LC-2 and program whatever AFR you want. The ECU doesn't know or care what the AFR actually is so long as it gets the proper feedback signal from an O2 sensor. I settled on an AFR of 12.9:1 which completely eliminates any surging and noticeably increases low end torque on the flat twin. I also think the bikes run cooler which can't be a bad thing for longevity especially for an air/oil cooled engine.

Early on I tried a device similar to the PC called a Techlusion with mixed results. It worked by lengthening the turn on pulse length to the throttle bodies. You had to unplug the O2 sensor or else the ECU would just commence to lean out the AFR based on input from the O2 sensor. Same thing happens when you try and fudge the air input temperature sensor. The beemer ECU has several fueling maps which can be selected by changing a code plug which was just a set of jumpers. Problem was when you disconnected the O2 sensor the ECU would go into a default or what some call a limp home map which for me resulted in erratic operation with some backfiring. On the beemer the ECU has an adaptive characteristic and it literally learns over time and modifies the open loop fueling based on info learned from closed loop operation.

There, all you never wanted to know about an oilhead and most of which I would just as soon forget after years of dinking around.

Jim

jammess said:

In reading through a few older threads it seems some FJR's are troubled by lean AFR surging at constant throttle (cruise) when the ECU is or should be in closed loop. Are all model years effected by lean surging or did Yamaha come up with a factory fix? I'm most interested in the problem if it applies to the 2010 model.
If my new to me 2010 has this problem I know what I'm going to do to fix it but hope I won't have to.

Thanks, Jim

Click to expand...

My 2010 had a lean surge. I got a power commander PCFC and had the bike custom tuned. Super smooth and NO lean surge.

https://www.solomotoparts.com/Dynojet-Power-Commander-Fuel-Controller-for-FJR1300-06-12/

J's 2010 is a heck of a lot smoother than my '10'. We switched bikes after he had it remapped the second time and it is awesome.

But, being a cheap ass, not enough that I'm willing to spend the bucks.

I'm guessing my '08 and a '10 are the same. I run a PCIII with a merged and tweaked map after not being happy with the available maps. At one point 'just to see', I bypassed the PCIII and ran the bike in stock trim. Not un-ridable but no where near as smooth as with the PCIII. The trade off to me was about 2-3 mpg but well worth it in my book.

No lean surge on my '07.

What is this lean surge you speak of? My 2009 has always been smooth as can be. I've never even for a moment considered any aftermarket fueling system.

FJRLoonie said:

What is this lean surge you speak of? My 2009 has always been smooth as can be. I've never even for a moment considered any aftermarket fueling system.

Click to expand...

That is a good question, one that many people seem to get confused about. What lean surging is, is when you are cruising at a steady speed there is some subtle surging in power delivery. It feels the same as if you are riding into a gusty headwind. It happens because the fueling is too lean, most likely a result of the design engineers' efforts to meet emissions requirements. Adding fuel to the mixture during the cruising condition is always the fix. On a fuel injected bike that generally means disconnecting the O2 sensor, or otherwise tricking the ECU into reading a leaner mixture from the sensor. Adding fuel when cruising will always decrease your fuel mileage somewhat.

HotRodZilla said:

No lean surge on my '07.

Click to expand...

I'll bet it does, and that you are just not "sensitive" to it. I've ridden several OP's bikes that thought they were fueling fine and they surged. It's another one of those "not a big deal" things that only bothers you if you are sensitive to it and it annoys you. Unlike the abrupt Off/On throttle response of some years FJR, the surging doesn't cause any ride-ability concerns. Some people just want engine power to be delivered perfectly.

I became sensitized to surging issues on motorcycles long before I ever sat on an FJR. My stock 1994 BMW R1100RS has fuel injection surging in spades. This was one of BMWs first attempts at FI on a motorcycle, and the fueling was a bit crude. The fix was the same as on an FJR: Add a Fuel Injection module (Techlusion in that case) to add more fuel.

Both my 2000 Aprilia Pegaso and 2001 Kawasaki Concours came with surging from the factory, and those were carburetted bikes. Both required fatter pilot jets to eliminate the surging during cruise. I am sure that many owners of the BMW, Kawasaki, and Aprilias thought nothing of it and just rode them the way they were. I p[referred to fix them and then enjoyed them even more.

YMMV

Typically only seen at around 20 to 30 mph in steady traffic where you just toodle along in traffic on level ground.

I've e-mailed the owner of the 2010 FJR I'm buying about my concerns with surging and he assures me it doesn't surge. He also has always used non-ethanol premium fuel in the bike which I definitely believe in at least for winter storage. I'm pretty sure this guy would recognize any tendency to surge as he is tech savvy and been around the barn a few times and he knows about surging in early FJR's.

Fred, Do you still have your '94RS? That's a great bike. I'll never part with mine. Yours no doubt also has the M93 transmission. Couple weeks ago I filled the tranny on my '93RSL with Redline Shockproof Heavy gear lube and it quieted things down while idling in neutral. Shifts from 1st to 2nd were smoother as well. The stuff doesn't have a GL rating which kind of bothers me a little but it certainly seems to work noticeably well.

Going to leave tomorrow to pick up the FJR, can't wait! Even got my '04RT sold.

I leaned and surged once. It felt good.