Help! Coughing,sputtering,cutting out at mid/hi rpms

So about 5 minutes into a ride today, the WR started coughing and cutting out just a little at about quarter throttle, then started getting worse at various rpms to the point where I had to hear home, coasting with the clutch in as much as possible. It definitely got progressively worse as time went on. I was able to accelerate, but steady throttle just did not work. The bike idled just fine. I took it out again after letting it cool and once again, about 5 minutes in the coughing/surging/cutting out started, and I had to limp home. It seemed like it was running out of gas, but my tank was basically full. I had just had the bike out for a 200 mile ride on Sunday and was buzzing around town earlier in the week with no issues, in fact it was running great. The bike has full FMF and power commander V.


The manual says it could be clogged fuel, clogged air, bad ECU, bad fuel pump, or bad throttle body. Anyone had this happen or know the best plan of attack?

After looking around the frum more, it looks like this is pretty common. But, it doesn't seem like there is once definitive answer....

I would not say it's common, and certainly not for somebody using a PCV.

What year is your bike? Not a 2008 is it?

So - quick things I'd try.

1) download different map to PCV

2) drain/siphon as much gas from tank as possible and fill up with fresh, high octane from highly traveled and very popular station (fresh gas because of hi turnover due to increased traffic)

3) Check for a loose vacuum connection

4) check airbox, and all air intake connections (ie snorkle where flapper is) (have you done flapper mod?)

5) possibly try a fuel injector cleaner


Also - list all your mods you've done to bike, year of manufacture

Gundy wrote:

After looking around the frum more, it looks like this is pretty common. But, it doesn't seem like there is once definitive answer....

Well that's the weird part; it's a 2009. Seems like the fuel pump was a 2008 issue.

Things I did in the last two weeks in this order:
Repacked the Q4
Turned the key one day wouldn't turn over at all, just buzzed and clicked once. Resolved by removing seat, poking a few wires. Bike has started fine since.
Rode 200+ miles with a map for a LEO Vince, no spark arrestor, with no air lid (closest option available to my full fmf with opened air box). Ran well, but a little rich judging by how much I smelled of gas afterwards.
Washed the bike thoroughly. Rode it briefly back t where I store it.
Went out the next day, topped off the tank at one of my usual stations, and rode with the Q4 insert removed to see if the map matched that better (it did! Great power and throttle response. Too loud though:( )
Went out yesterday and twice encountered the sputtering coughing condition about 5 minutes into the ride (basically once the engine was warmed up fully) and had to limp home. Tried with and without inserts, made no difference.

Mods (mostly done by previous owner):

Flapper removed & box opened up a little more but door still on
Megabomb & Q4
Powercommander V. Have tried a few maps. Current one seems to work best.
Drd speedo healer
13/47 gearing
Edge taillight
Integrated turn signals front and rear
Lots of Zeta bling

Gundy wrote:

Turned the key one day wouldn't turn over at all, just buzzed and clicked once. Resolved by removing seat, poking a few wires.

This sticks out to me.

Wonder if certain rpm range and vibration + heat starts causing a strange electrical issue for you?????

From what I understand, all the "bad fuel pump issues" are only on 2008 models. Never heard of a 2009 having that issue.

Gundy wrote:

Rode 200+ miles with a map for a LEO Vince, no spark arrestor, with no air lid (closest option available to my full fmf with opened air box). Ran well, but a little rich judging by how much I smelled of gas afterwards.

This is suspect too.....

AS much of a pain in the as this might sound like.....once you get home from a sputtering episode - you could quickly try to get spark plug out and see if it's soaking wet with gas.

That's a big PITA though.... but a weekend of wrenching is never a bad thing if it reveals a problem.
WHile you're under the tank you can check the vacuum lines.

Thanks for the suggestions! In general it's a very modded bike with lots of wires going every which way. I'm thinking there are electrical connections that need some attention, especially because I washed it recently and some moisture may have gotten in to certain places. The starter issue also occurred after a washing after a muddy offroad session.

Check the battery too, loose connection and shit like that !

Pretty sure it's an electrical issue. Tonight finally got a chance to mess around a little.

First attempt to start, the fuel pump made its usual noise, but then the starter just made a quick buzz noise and that was it. Nothing. Turned key off and on again, this time it started. Let the bike warmup up a little and headed to a nearby parking lot to try to get the bike to cough again. While sitting in neutral and idling, it just stopped and the panel went blank briefly. I was able to restart after hitting the starter. I had no problem riding back to the garage. There was maybe one hiccup. Tested the battery and it had about 12.7 volts. There is a gremlin somewhere in the system....arg. Will try more riding tomorrow to see if I can induce the serious coughing.

I know people have had issues with the the starter button.
There's also the connector by the radiator.
I'd check the battery terminal connections too.

Just to start.

If you find issue please report back what it was.

Time will be the judge but I think I fixed it.

What I did:

Unplugged power commander
Removed battery then reinstalled after cleaning terminals with WD-40
Checked torque on header bolts


Rode around town for a while with no issues (bike ran fairly well this way btw)
Reinstalled power commander after spraying all plugs with WD-40
Downloaded the "zero map"
Rode around, again with no issues
Installed my small diameter insert and downloaded map #2 (stock exhaust, with no air lid)
Again bike ran with no issues

Will continue testing the rest of the week. Unfortunately I can't pinpoint what the cause was. Certainly possible that after an aggressive, several hour supermoto ride, some wires got loosened. The true test will be going back to the problem map, and if that ends up working like it did before the problem arose, it probably was a bad connection somewhere in the wiring.