I was out on a HOT HOT ride today and about 4 hours into it my bike started acting up. Started just barely cutting out like it was out of gas. Got worse. Usually it does 6k at 60mph in 6th. As I limped it home I could only do 35-40mph and it was doing 8-9k rpm on the Vapor. I have the Vapor tied into the coil.
I'm thinking I need a new coil. What do you think? Please LMK ASAP.
And if it's the coil is it best to replace with a stock one or is there a better unit?
Thanks

 

Mine just did that a couple weeks ago. It was OK in the low end but anything over half throttle and it would sputter and not rev over like 5k. Felt just like it was running out of gas.

Pulled my main jet and there was a tiny sliver of wood clogging it. Blew all the jets out and cleaned the carb completely and it was running like a beast again

I'd check there if that sounds like what's happening to yours. Good luck

 

That's what I thought initially, but would that make the vapor tach shoot way up to 9k? That makes me think its the coil since that's where the vapor gets it's info from. It was just cutting out on the upper end (like fuel) but I was thinking the coil while it was under load.
I don't know?

 

Replace the spark plug first.

I chased a non starting/popping/sputtering problem by first r&r my carb then checked the valve clearance...what a waste of labor/time...

Hopefully its something really easy. good luck

 

That can be hard to diagnose without further searching, but something like that is usually a fuel issue...most often debris in the bowl or in a jet. On your tach reading, I'm not a fan of the tach wire wrap on the plug wire. I putzed with mine and could never get satisfactory, consistent results with it on my Vapor. I finally realized that I could just hook straight in to the old tach wire feed from the stock wiring harness, and it works perfectly.

 

I have an old KLX300, so no tach. I didn't wrap it around the plug, I tied it in with the wire on the coil.
I agree, it feels like a fuel issue, but that wouldn't make the tach max out.

I don't know of a way to test the coil? It only cuts out when I'm trying to give it more throttle.

 

There's usually a simple check listed in the service manual for most coils on most bikes, but even they're not always indicative of a weak coil. Most shops worth their salt have a coil tester. The tester has its own battery and puts a load on the coil by making a spark jump across an adjustable gap in the testing machine. If the coil achieves the minimum gap spark jump, then it should be good to go for your bike. This is more like a real world test, and it's pretty darned reliable. Check with your shop or some other local shop to see if they have a tester. Most shops require you to remove the coil.

 

Stick your tongue on the lead coming from the coil while cranking the bike over.

If your still concious afterwards your coil is probably bad.

 

I had the same thing happen to me yesterday on a long hot ride. Same deal but about 50mph in 6th.

The interesting thing... is when I opened up the throttle, it took off normally with no power problems. Only happens with very light throttle during cruise.

David

 

My bike has been doing this since I picked it up from the dealer.(09 250 SF) I have brought it back 2 times and still have the same studder/ miss in 6th gear crusing between 60 and 65 mph. I've had it in to the dealer 2 times now. The first time it went in they adjusted the needle positon to richen it up some. This seemed to help a bit under heavy throttle, it didn't seem to breakdown like it did before, but the miss or studder continued at 60 to 65 mph. The second time it went in for the tank recall and more carb work, they went with a larger pilot jet and sent me on my way. The problem still persists and the breaking down under heavy throttle seemed to return as well. I have swapped fuels(87 to 91), added K100 to the tank and the problem still comes and goes. Sometimes worse than others. I also noticed it seems to act up more with a full tank of fuel as opposed to almost empty. I don't know if this means anything, but I am trying to take notice of some potential factors that could be causing the issue.
Kawasaki contacted me 2 weeks ago and was looking into the problem but I have not heard from them since. I'm dragging my feet on bringing it back to the dealer, due to the fact we are seeing any improvement.
Kinda glad to see its not just my bike, but others are having similar issues....hope Kawasaki or someone figures it out soon! Sucks paying for a bike that has not run right from day one....
Its good to have a place to discuss and talk about these problems other than dealing with the dealer too. Thank you to all of you!