Ugh...long bike maintenance day

[Honclfibr]

So today was the day I was going to fix my ZX6. I had all the fairing parts, and started up at 9. First problem was that, as I should have known, the upper fairing bracket was bent. I managed to bend it back enough to get the fairing on, but I really do need to find the part soon, it doesn't fit quite right still. Regardless, had the bike back together around noon and spun it around the parking lot. Seemed fine, so I took it on the road, and noticed that at about 6k in first the bike started bucking and hesitating with more throttle roll-on. Second gear was a mess, I couldn't even hit 3k. Basically, it looks like whenever I hit around 25-30 mph the throttle causes hesitation. If I roll steady on the throttle through the hesitation they smooth out a bit around 9k in first, but they're still there.

So I brought it back, yanked the fuel tank, and opened up the airbox. Some oil in there, I guess that shouldn't be a surprise since the bike was upside down. Cleaned out the oil, pulled the spark plugs and found oil in the two leftmost plugs and on the wires also. Cleaned the plugs, put them back in, checked the ram air intakes, bike back together. No dice, still hesitation.

By this point, I'm pretty much out of daylight so I called it a day. Next chance I get, I'm going to check the crankcase ventilation hose, maybe there's a kink or something in it. Failing that, any other suggestions for what might be causing this? Could my carbs be gummed up somehow from when the bike was upside down? Any other issues I should look into? I'll spend another half a day poking around, then the bike goes to a mechanic.

Oh well, at least the new tires came for the EX. Once I get them spooned on I'll be a bit more patient about getting the ZX running...

[Rye]

Fill me in on what happened again? Did you endo it on a front wheel lockup to avoid crash?

[Honclfibr]

Yep, that was it exactly. Right over.

[stoinkythepig]

Prolly got some crud in the pilots jets. Might need to pull the carbs but try draining the float bowls first.

[Honclfibr]

Originally posted by stoinkythepig
Prolly got some crud in the pilots jets. Might need to pull the carbs but try draining the float bowls first.

Thanks Dave, I'll look into that. I considered the carbs initially, but then I dismissed them as I couldn't see how flipping the bike could clog my carbs. One thing though, the bike will rev up perfectly in neutral once warmed up with no hesitation, would this be the case with the pilot jet clogged?

I'm really hoping it turns out to be something minor, the bike was idling upside down for a good thirty seconds before I was able to get to the kill switch and turn it off. I'm hoping I didn't do any major damage.

[stoinkythepig]

Originally posted by Honclfibr
One thing though, the bike will rev up perfectly in neutral once warmed up with no hesitation, would this be the case with the pilot jet clogged?

Thinking this would be another symptom of the same problem.

My thoughts:

It won't make any power under load which means it's probably not getting enough fuel. Without the fuel and under load, it can't create enough vacuum to lift the slides and get into the main jets. The bigger the load, the worse the problem (which is why you can't get past 3000 RPM in second gear and why it revs OK in neutral). Being upside down and running would force all the crud in the bottom of the float bowls into the pilots. Yuck.

I could be very wrong too but draining the float bowls into a clear container will at least let you know if there is/was crud in there to clog the pilots and is very easy to do.

[Honclfibr]

The part about the crud getting into the pilots makes sense now that you explain it, I never thought of that. I don't know enough about carburetor operation to comment on the part about the vacuum slides, so I'll accept it at face value.

I will check the float bowls, and probably end up pulling the carburetors regardless. It looks like a tricky job on the ZX but I've gotta learn to do it. Once I get them off, should be no problem, I rebuilt the carbs on the EX and they ran just great.

I tell ya, I really enjoy riding the ZX6. But every time I need to do work on it, I miss my EX500. Modern inline fours are really a maintenance headache compared to ancient little v-twins...

[stoinkythepig]

compared to ancient little v-twins...

huh? EX is a parallel twin, man.

Easy to work on though. Half a Concours engine.

[Honclfibr]

Originally posted by stoinkythepig
huh? EX is a parallel twin, man.

Easy to work on though. Half a Concours engine.

Ugh, duh, what was I saying, I knew this. If I was told right, They cut the old Ninja 1000 engine in half to make the EX500...I guess they used the same 1000 in the Concours?

[Rye]

Was the bike completely vertical and upside down when it landed or did it endo and fall to it's side. The cheapest and easiest thing to do is to trash the plugs and get new ones, and clean the carbs thoroughly with carb cleaner.

[Honclfibr]

Rye,

http://www.nestreetriders.com/forum/...&threadid=5113

That's what happened. But the short answer is that the bike was totally vertical, both wheels straight up, for about 30 seconds idling while I got myself up off the tarmac and recovered my bearings. I cleaned the plugs and they look ok now, but I'll take your suggestion and replace them when I clean the carbs, as I'll have the bike stripped anyway and a set of plugs won't break the bank.

[Rye]

Oil could have shot straight up the crankcase breather hose and into the airbox. Kawasaki uses a halfass flow preventative on their breather hose that is actuated by a moving ball inside a catch cylinder. Less than optimal. Your 6r may have the same setup. You may be running a modified 2 stroke right now if a substantial amount of oil got into the airbox. 30 seconds is quite a long time. Oil would have shot right through the cam chain "tunnel" and into the head. If you've got emmissions crap still on the bike it could have also sucked oil through the reed valves on top of the cylinder head cover. If you think about it, the head was basically the sump and there was no way of oil pumping back to the bottom end. Valve actuation just circulated it more violently. I think the motor is still choking on a little oil in the combustion chamber and possibly sifting it's way into the carbs via the float vents. I would say to check the plumbing running off the valve cover. Whatever you unplug, inspect, clean and reinstall.

[Honclfibr]

Thanks for the advice Ryan. You seem to know quite a bit about Kawi's. My bike is actually a ZX6E, now known as the ZZR-600. It's a little less aggressive than the 6R.

There was definitely oil in the airbox, about 5-10cc's; I wasn't sure how it got their, you're saying it can be sucked out through the crankcase. That's interesting, one of the potential losses of power listed in my manual is lack of positive crankcase ventilation. You mentinoed some sort of flow preventative, is it possible there's some oil still choking my crankcase breather tube and preventing it from breathing some how?

As for the other things you've listed, I'm trying to follow as best I can. Oil in my head would be a really bad thing, right? Because the piston would try to compress the oil, and when it reached BDC it would try to compress the oil and...blow a head gasket? I should probably mention that the first time I started up the bike after it sat, afterwards I noticed about 1-2cc's of oil dripping down the engine into a little pool. When I took the airbox off and found oil there, I assumed it was from that. Thinking about it, I hope I didn't blow a head gasket, that would be bad shit.

I will inspect as much of the crankcase breather tube as I can when I have the bike apart. You also mentioned hoses that connect to the valve cover...what hoses would these be? Intakes from the carburetors? I'm just a small time home mechanic and so I'm still learning about engines, so I apologize if I sound dumb. I appreciate the pointers though, I'll definitely check all that stuff out while I have the tank off and the airbox off to look at the carburetors. Now all I need to do is find the time to do all this, I'm going away for this weekend so I'm gonna try to get to it one evening if it ever stops raining. I'll post any progress I make back in this thread.

Originally posted by Rye
Oil could have shot straight up the crankcase breather hose and into the airbox. Kawasaki uses a halfass flow preventative on their breather hose that is actuated by a moving ball inside a catch cylinder. Less than optimal. Your 6r may have the same setup. You may be running a modified 2 stroke right now if a substantial amount of oil got into the airbox. 30 seconds is quite a long time. Oil would have shot right through the cam chain "tunnel" and into the head. If you've got emmissions crap still on the bike it could have also sucked oil through the reed valves on top of the cylinder head cover. If you think about it, the head was basically the sump and there was no way of oil pumping back to the bottom end. Valve actuation just circulated it more violently. I think the motor is still choking on a little oil in the combustion chamber and possibly sifting it's way into the carbs via the float vents. I would say to check the plumbing running off the valve cover. Whatever you unplug, inspect, clean and reinstall.

[Rye]

Think of it this way. Oil is a liquid, and much more viscous when it's 200 degrees (like water almost) It can find it's way past alot of "preventative measures" (reed valves, breather hoses) when given the chance- especially under pressure. The plumbing coming off the valve cover is emmissions junk. You'll notice tubes running to the airbox that make no sense. I haven't cracked open a ZZR but, the same basic kawi I4 setup is likely. I don't think you've got a gasket issue. But it makes sense that oil's getting into that combustion chamber. A thorough cleaning of air filter, airbox, carbs (mostly float bowls), and plumbing is in order. I would say it will clear itself after running a bit, but don't start it until you've gone through everything connected to the motor.