got a issue i hope yall can shed some light on i was out for a sunday ride and rode to get breakfast everything going fine. leaving out we got on the highway and about a mile later it started running ruff as crap and choppy and hesitant at highway speed, pulled off looked it over no smoke no leaks oil at acceptable level no lights on the dash cranked right up every time. but sounded like shit and im assuming not firing on all cylinders. if i would have thrown a rod or something wouldnt i hear more clanking knocking or popping? im going with my gut being a injector , a coil or a fouled plug but im no mechanic but i can twist some screws im good till you talk about going in the motor then i would take it to a shop..

2007 zx14 stock except slip ons
oil changed about 2k ago
plugs about 3.5k
17.5k miles

any ideas gentlemen?

exhaust header bolts?

Injectors seem to be relatively problem free compared to plugs and coil sticks unless the bike has sat for long periods and then only run a short while over and over.

If it runs you have fuel but the screen in the pump may be dirty and reduced flow. Get some shit crap gas recently

Pull plugs and post pics and check coil 1st and 2nd winding resistances per SM specs

Sounds like it cropped up all the sudden out of the blue. That would seem to point to an electrical problem.

There's been a couple threads in the past few months about dirty fuel filters. The last guy used a fuel system cleaner and it improved but only temporarily. The cure was to change the fuel filter which entails removing the fuel pump. I guess there are two filters and I know at least one of them is not meant to be replaced without replacing the whole pump. There's a way to do it though.

I'm leaning towards fuel/electrical just with what's there. I would follow both of Rudy's and Roook's advice in those steps.

If you're brave enough to start it, maybe setup a camera so you can record video and post it here. Might help determine issue a step further.

If it's ONLY running rough it's probably not mechanical. If there's any sort of knocking or abnormal sounds it's probably mechanical or at least partly mechanical failutre. If it's a quiet sound, might just be a spun bearing or something but will get worse quickly if continued to run, probably to the point of grenading the motor if you run it long enough.

I was on my way to Laguna a few years ago. Got to the bottom of my hill and the bike dropped a cylinder. Sounds rough. Tried to clear it out on the bridge in case it was a spark plug, no go.
Turned out a coil had failed. When an electrical item fails there is often no warning at all. It's fine then POOF, it's not. Try to locate the dead cylinder by checking the exhaust pipe temp. Then switch that coil for a different one. If the problem moves it's the coil.

Mad

Good advice on swapping the coils and checking the temp Mad!

so finally got around to dragging it to the shop and they pulled the far right plug and its been smashed in and it charred im assuming thats a bad thing at this point im sad but still optimistic is it cheaper to rebuild or swap .. im hoping to get it done for less than 2500 usd am i dreaming? (not including labor)

so finally got around to dragging it to the shop and they pulled the far right plug and its been smashed in and it charred im assuming thats a bad thing at this point im sad but still optimistic is it cheaper to rebuild or swap .. im hoping to get it done for less than 2500 usd am i dreaming? (not including labor)

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I noticed you didn't mention any noise when it started running rough as crap. First, they have to find out what engine part caused spark plug to get crushed/smashed. The final engine repair cost would depend on those findings. Good luck!

IDT a piston can do that all by itself unless it let go which these bikes do do on rare occasions. Usually much worse damage than what you have.

I have seen a pic of a valve squashed into the piston. That would be timing skipping a tooth but them I would think all the pistons would do the same thing. Maybe they are and just have not hit hard enough to break? Let us know what the verdict is.

Ouch.That doesn't sound good.Seems it could only happen if that piston came free somehow.Maybe the bearing let go and gave it just enough play to hit that plug.Sorry man.It sounds ugly.

I'd say,drain yer oil and see what's in there?

* Last updated by: Grn14 on 7/24/2017 @ 3:26 PM *

Hope they put a bore scope/camera in there to take a look at the piston dome. If that's not damaged a compression test would be my next step.

I think the plug electrode sits in the top of the compression pocket and should not come in contact with a piston unless the wrist pin took a shit and the piston is flopping around in there in which case the valves are a concern also.

Either way I would drop a small LED cam in there and have a look, the cam for your iphone or computer is ~$25-50.