Engine lurching on freeway confusion

[mduhon]

I bought my bike 4 months ago and have been riding it a fair amount ever since. After the first week my bike did a thing where it would die while downshifting to 1st. It did this 5 times in two weeks and hasn't done it since. That part still puzzles me.
But there is something new happening that I don't understand either. When riding on the freeway occasionally the bike would "lose" power for a second and then go back to normal, this makes it feel like the bike is lurching forward. It did this a few times in december and hasn't bothered me in the past 1000 miles I rode until yesterday. I took 100 miles trip to visit a friend and about 3/4 of the way there it started this again. It would do it twice in a row then would wait again for anywhere from 2 miles to 20 miles before happening again. It did it at speeds anywhere from 60-75 mph. I have an 05 with higher miles and the only mod done is a slip on exhaust from the previous owner. All the fluid levels are fine.

 

[PipBoy]

Not sure about your freeway problem.
But the first day i had my bike it kept dying when I shifted from neutral to first gear. Couldn't even get it out of the driveway. Well it turns out I hadn't put the kickstand up and the kill senor was tripping. DUH!

 

[DownrangeFuture]

Intermittent problems are a PITA. And they tend to be electrical. Not always tho.

My first guess would be bad gas, but if you ride a lot and always get gas from different stations, then probably not. If you always get gas from the same station, try swapping for a different one next tank.

It could be an issue in the ECU, but I'd rule everything else out first. Loose connections, something rattling around in the airbox, cat getting gummed up, etc. Does the exhaust note change drastically when it loses power? What I mean is, does it change differently than if you just chopped the throttle normally? If you lose a cylinder or two it won't change pitch, it'll be more like it just got "rough" closer to how a v-twin sounds at speed. No backfires or pops when it lurches back to life?

Valves, timing, and spark plugs checked recently?

 

[macem29]

TPS was a known problem with those year bikes

 

[mduhon]

I get gas all over, not just at one station and in different towns so i don't think its the gas. Something in the airbox could be likely and I will check that asap. The sound doesn't sound drastically different, like no loud popping or sounding like a twin, it sounds like the bike basically dies but since its only a second it is really hard to tell. The valves were checked about 2k miles ago right before I bought the bike by a shop. they said it was all mechanically fine but I do not know if they checked the timing. I do want to check to see if the throttle bodies are synced but haven't had the time just yet and not sure if that would cause this problem or not.
There was a few recalls on this bike a few years ago and so I took the bike to the shop and they pulled up my bike and showed me that the recalls were done. The recalls were the kick stand switch and the throttle position sensor. Maybe the throttle sensor is going out again?

And I haven't checked the plugs, maybe they are a little fouled or something. I will check once i get home on that.

 

[DownrangeFuture]

Sounds like it dies? Try hitting the engine kill switch on the highway, then turning it back on. Does it feel like that?

Don't worry, you wont have to pull over and start the bike. Hitting the engine switch back to on with the ignition on will let your bike run, and going 70mph is the mother of all push starts.

And if you do find something in the airbox, let us know what it is. You get points if it's cooler than the dead squirrel my buddy found in his. Oh, and if they recently changed the kickstand switch, check that it isn't loose or mis-aligned. If it's right on the edge of being switched off, you might experience random issues with shifting into gear, and bumps on the highway, vibes getting just right, etc. may make it switch to off for a second or so.

 

[Topical]

I read somewhere on this forum (sorry i don't have the link) of other people having this problem. Most of them traced out back to dirty electrical connections in the kill switch. I'll look for that thread when I get home, I'm on my phone right now. Although I would try and search for that.

 

[FizzySix]

Hitting the engine switch back to on with the ignition on will let your bike run, and going 70mph is the mother of all push starts.

Threadjack: I've wondered what would happen if I accidentally hit the kill switch at speed, but I'm not crazy enough to do it.

If I ever accidentally hit it (or the power is cut due to some other reason) the rear won't lock up?

Just curious...

 

[mduhon]

Threadjack: I've wondered what would happen if I accidentally hit the kill switch at speed, but I'm not crazy enough to do it.

If I ever accidentally hit it (or the power is cut due to some other reason) the rear won't lock up?

Just curious...

I tried it on my way home from my original trip yesterday. My bike didn't act up for the first 117 miles then did the lurching again. However I did try the kill switch and no it does not lock up your rear wheel. It just keeps going and then when I flipped it back on the bike started without even pushing the start button. I did it 5 times. It was the exact same feeling I was having.

 

[DownrangeFuture]

So then you're probably getting one of those safety switches kicking on and off randomly. The prime suspect in my mind would be the kickstand switch. You can say for sure it's not the tip-over switch, cause then it would go with error 30 and you'd have to flip the key off and on before it'd start.

The neutral switch only affects the starter button.

The fuel pump, isn't likely cause it'd sputter off and sputter on, most likely. And it should, ideally, set off an error code that you'd have to cycle the ignition.

So you're left with the engine kill switch, or the kick stand switch.

And no, you won't lock up your rear wheel, but... if you twist the heck out of the throttle before you realize the engine is dead, then don't ease off the throttle and hit the switch... It's about the same as slipping the clutch.

 

[mduhon]

So after arriving home and getting some other stuff done I finally had a chance to look at the bike. I believe I found the culprit but wont know until I go for a ride again tomorrow or the next day. I believe it was the kick stand switch. I had never noticed it was lose before because when the stand was down it was tight. but when it was up it was super lose. the back nut on the top was almost off the bolt! The bottom was a little lose too. When I went to tighten them I found that both heads were stripped so I had to replace both. One I was able to get out with pliers but the other I had to cut the head off and punch it out. Now that is done i'm hoping no more issues.

And DownrangeFuture I did check my airbox and nothing exciting like a squirrel, just one tiny leaf.

As for the kill switch idea, i'm going to clean the connections and make sure they are good. If it continues to happen i'll try putting the jumper in and see what it does

 

[Caladin]

I did it 5 times. It was the exact same feeling I was having.

The kill switch is a good place to start. I had this problem with my bike while on a trip. I have bypassed the switch until I get around to replacing (or perhaps cleaning) it. You can see pictures of it here.

 

[killereef]

I am having the same problem with my 05 high mileage bike. My bike would do the same. I noticed that when my bike "lurch" or dies, if I dont flip the kill switch I can not start the bike by either hitting the push start button or roll start. When I hit the push start button, nothing will happen the starter would not even start. When flip the kill switch then I can do either hit the start button or roll start the bike. I will check my kill switch and kick stand switch.

 

[mduhon]

My bike has done the same where it wont start again once it dies until you flip the kill switch on and off. It has stopped after about 3 weeks of it happening and hasn't happened since. As you've probably read from the previous posts it now does the lurch thing instead but I'm guessing its a very similar problem.

 

[Razer]

I was told when I bought my '06 used from the dealer, to kill the engine with the kill switch all the time because the contacts oxidize if you don't. I guess there is more truth to that than I thought.
I also had to tighten the switch on my kickstand...after reading this thread...

 

[Pauly_V]

It's possessed. You need a priest.

 

[flash]

Check the Throttle Position Sensor.