ZX6R J2 Engine Problem

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

Hi everyone, I hope you can give me a little help on this as I'm a bit stuck on this one. I am experiencing really bad vibration from the engine on my bike - a ZX6R J2 Y reg 16500 miles. I recently had the chain and sprockets changed and the bike has flown through it's MOT without any issues. All the usual stuff such as wheel alignment and chain tension has been checked and suspension and head bearings are spot on.

What I'm experiencing is very large amounts of engine vibration through all rev ranges. It's like riding a hammer drill for want of a better description. I know that the bike isn't normally like this but I'm at a loss as to what it could be. It is definately engine related. There doesn't appear to be any sign of misfire although I wont rule it out. As for the carbs - well I guess a balance of them wouldn't go a miss but not sure that either of these would be the answer. I'm hoping that maybe the forum can shed some light on the problem. By the way I'm not ruling out the dreaded CCT either.

I'd be grateful for any assistance you can give me. Many thanks. Martin

mad4it028 · World Chat Champion Joined: 04 Jul 2006 Karma :

maybe an engine mount bolt come loose?????
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Barry_M2 · World Chat Champion Joined: 09 Sep 2004 Karma :

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

I had thought about a mount bolt but all seem okay. Barry_MC21 in answer to your question - YES you can tell it is there at all rev ranges although less pronouced at tickover. Worst at 3.5 to 4.5k revs and when bike is well upto temp.

I can liken it to the effect of an offset cam rotating like they use in games controllers for vibration effects.

DaveH · World Chat Champion Joined: 03 Feb 2006 Karma :

Have you taken up the gap between the engine and the frame by adjusting the castelated nuts?
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DaveH · World Chat Champion Joined: 03 Feb 2006 Karma :

or does clutch in, or out make a difference?
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oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

I haven't seen any gap on the mounts but I'll check this again anyway.

The vibration is present in neutral although I did wonder if it might be clutch or even gear related. Mind you, no clutch slippage and have not had gear change problems as such but have noticed a bit more of a clunk between 2 and 3 - seems to be common for my bike though. Certainly isn't anything drive related - sprockets have been replaced and correctly torqued up. Chain has been correctly adjusted and checked for stretch regularly with it being new.

Thanks to all for the suggestions so far - I will check all these out just in case.

DaveH · World Chat Champion Joined: 03 Feb 2006 Karma :

Here is the diagram from the manual, if it is any help.
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oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

Thanks for your help so far folks.

Right I have done some more investigation tonite.

Had the tank off and all the plugs out. All look okay and are correctly gapped. One of them was a little dirty from weather at a guess but seemed to be okay. Cleaned them all up and put them back in. Air filter could do with changing so will do that with a new set of plugs as it hasn't had some in 12 months. Put it all back together and started her up. Vibration still apparent and a noise that sounds like a blowing exhaust. Checked over all the pipes - nothing. All look fine and are getting very warm. Put my hand near the exhaust and revved slightly. as the exhaust blew I could feel a slight uneveness in the gases coming out. Now I am planning on getting the carbs balanced when I do the plugs and filter so I wonder if this colub be the reason. There doesn't seem to be any other excessive engine noise and it is starting on the button each time. Am I on the right lines?

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

Almost forgot - checked all engine bolts and all are torqued up correctly so i can rule that one out

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

In all honesty I have noticed something but on past experience put it down to general performance. But it has got progressively worse yes CHR15

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

Yes pretty good with a spanner. Not too worried about attempting sttuff as I'm quite practically minded. Mind you I think the quickest way is to borrow my friends set of gauges and do the job correctly. At least I'll know then. Failing new plugs and filter - after they are replaced and it is still doing it I'll be at a loss again I have to admit so fingers crossed.

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

I'm back again on this one. I really need to get to the bottom of this as it is really getting to be one of those kind of mysteries that you just can't solve.

Since my last post I have been over it regarding engine mounts and exhaust system. All is in good working order. Regarding the carbs - well I haven't done the balancing as I discovered that changing the plugs made a big difference so I guess the unevenness was due to them. I also replaced the air filter while I was about it. All this has not really made much difference.

I am beginning to think this is down to something like the clutch. Although the gear changes are okay they do seem a bit clunky. I know kwaks can be but I'm starting to think this could be a part of the reason. I am wondering if the clutch is failing - maybe warped plates or something and as a result it is spinning badly hence the vibration. The only other thing I can think of is valve clearances. Would either of these be the root of the problem? I'm no mechanic but I'm a capable fella with a spanner being an engineer so Quite happy to do the work myself and have a good toolkit to do the work with but I do need some pointers on this.

Whatever is causing this problem is literally shaking the bike around. I can also hear that nasty ticking now so I will have the CCT out and check it isn't stuck up or something and let you know the outcome.

Martin

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

Point taken on the clutch CHR15. It is certainly not the main chain. If you sit on the bike and rev it in neutral the problem is there still. Like I described it is like sitting on a hammer drill maybe even a neumatic drill frankly. Hence the reason why I'm beginning to think it is more serious. I rode it to work and back today to see if the plugs and filter would have made any difference. By the time I got home this evening I couldn't think of anything more pleasing that getting off it ASAP. It has never ever been like this since I bought it 12 months ago. You can even hear it, sounds rough and throaty. Okay it does have a scorpion exhaust on it but even so it does sound a lot louder. Having said that - the exhaust output is quite even now - no evidence of unevenness - nice and constant.

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

Thanks for your offer CHR15 sadly I can't get any time off work at the moment otherwise I would definately take you up on that.

One thing has occurred to me though. I can describe the way it is running at idle. It is sort of like a chugging sound rather than an even droney engine noise. It has always done this a bit due to the exhaust but now it is very apparent.

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

Right been and had a play again. Foot powder is a wonderful tool lol. Nothing from the exhaust system - no leaks.

However - did do a feel test of all pipes at startup. Pipe on cylinder farthest right gets warm quite quickly. The others take a little more time but do get warm. Leads me to think that although the plugs are new, they are not working very evenly. So....

1) Plugs aren't correct - Well they were the right ones for the bike and I did check the gap before putting them in.

2) Coil pack fault - possible!?!?

3) ECU fault - EEEEEKKKK expensive but unlikely.

Plan of attack, get an enclosed fuel bottle and hose rigged up and check each plug and coil pack for spark.

Second - and just in case check tightness of exhaust pipe bolts with torque wrench.

Grayzo · Borekit Bruiser Joined: 14 Feb 2008 Karma :

Hi martin,
I am not a mechanic, but am talking from experience, my brother had an exup 1000 and it developed very similar problems, my brother being very technical and also being an engineer pulled the motor and stripped it, and found the fault, which was a manufacturing fault, the fault being a crack around the circumferance of the crank, which was causing an imbalance and therefore the vibration, I hope that this is not the case for you in the finacintial sense, but if it is the fault I hope that I have helped you to solve the problem, good luck with it, ( I know it is a pain to check if I am Correct or not but it is the only thing that I can put it down to being the fault ) hope I have been of some help, good luck.Allan.
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oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

Been over the ignition with a fine tooth comb tonite. All functioning correctly so I can eliminate that from the list. All coil packs are in spec. the IC Igniter is okay. All wires from it meter good and just to be on the safe side had the plugs out and rechecked their gap. All good and the new plugs looked good and clean and have clearly been sparking correctly.

While I was about it I checked all the vacuum hoses for obstructions and made sure there was a suitable suck from them. All seem good and are in place.

Something my dad mentioned to me - Timing. I guess that could be an issue and I'll check it over tomorrow. However these electronic systems only tend to fail if the pulse is intermittent. Plug condition would suggest that not to be the case.

I guess I'm left with the fuel system. If it is a carb problem then I guess it's back to the balancing - maybe even a good clean and service would not go a miss.

One thing I did note. There does seem to be a lot of noise when I rev it gently from the top. A bit like a tim of marbles. Slightly worrying as it would suggest valve clearances or similar. I hope not because I know that is a time consuming job but doable by myself as there are plenty of good guides about how to do it around.

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

SUCCESS!!! Well kind off.

Was going to have the carbs off tonite but thought I would check the dreaded CCT before I did. Glad I did so because that has made one hell of a difference. Gear changes are smoother - noise I mentioned gone and vibration reduced somewhat. i say somewhat as there is still a bit there. What puzzles me is how the CCT got like it did. All I have done is have it out, cleaned it, reoiled it, set it up as per service manual says and - all works fine. I will certainly keep an eye on it.

I still think I need to look at the carbs as well though. It is still a little uneven but certainly better to ride and has more go than it did. I have included a video of the bike running now. I think it sounds a bit chuggy still but maybe all of you can tell me what you think if it gets here. If not I'll post it somewhere and put a link to it.

Special thanks to you CHR15 for all your advice. Looks like I'm on top of this now. Gonna have to wait till pay day so i can get some carb balance meters. Was gonna get some anyways so not to worried about the spend. All adds to the toolkit at the end of the day.

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

Thought it was too good to be true. Got to work (21 miles) this morning only to find that the CCT had moved and the noise was back. GRRRRR!!!!!

So question now is does the CCT need to be replaced or is there something more serious going on inside the engine? I know one thing for certain, this takes the bike off the road for a fortnight. Double GRRRRRR!!!!!! Crying or Very sad

Barry_M2 · World Chat Champion Joined: 09 Sep 2004 Karma :

Yes, replace it. If its being pushed back then the teeth on it will be worn.

If you dont, you run the risk of it backing right off and allowing the cam chain to go slack and jump the cam sprockets. Then the pistons will demolish the valves (and themselves) which in turn will ruin the head and then thing start getting really expensive... Shocked

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oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

I'm back again with this one. Tonight I sync'ed the carbs after purchasing a set of meters. They weren't bad at all, 2 & 3 were very slightly out but not by much. Anyways no improvement so I am now out of ideas and resigned to the fact that barring taking off and redoing the exhaust I have to take it to someone who has more expertise than I do. To recap here is what I have done to try and cure the problem.

New plugs, all properly gapped. Plug coils checked and all in specified operating parameters
Wiring loom to coils checked back to the igniter unit and all okay
Cam chain tensioner checked and reset - did suspect it but it is okay after all
Timing checked and in spec. Valve clearances checked and in spec.
Carbs cleaned and serviced and checked over fully. Vacuum hoses checked and inspected - no problems
Coolant system drained and refilled, filter checked and cleaned
Air filter replaced

Apart from taking off the exhaust and fully checking it over I'm at a loss as to what it can be now. It still sounds rough and very chuggy for want of a better description. Putting my hand on the air box I can feel the rough running as though something is out of sync.

oggy1610 · Two Stroke Sniffer Joined: 22 Apr 2007 Karma :

Well false alarm on the cct front thankfully - a case of me not realising that it will move to tension the chain properly after being reset.

Well I am going to do the shims at the weekend. I figure from my measurements and having rechecked the specs that it may well be that the exhaust ones are out of spec. They did feel a bit tight and in some cases equal to the inlet ones which would not be good. I've ordered one of those kits that you can get. Perhaps an expensive way but I'm taking no further chances. Besides I'm sure I can ebay what I don't use from it and recoup some of the costs. The only thing I haven't got is some of that plastigauge stuff - gonna try and get some in my locality. While I'm about it and before I do the valves I'm gonna do a compression test. I don't think there's a problem there but never harms to check these things out does it.

I'll let you all know how I get on. Thanks again for all your help CHR15

Scouse · World Chat Champion Joined: 12 Feb 2004 Karma :

Irezumi aka Reuben · Carrot Top Joined: 28 Sep 2004 Karma :

Only just seen this thread. I'd go back and look at the frame mounts. Does your exhaust line up perfectly or does it require a bit of forcing to get all the holes lined up?

If it's the latter then your Engine bolts may well be torqued up fine but your engine isnt quite sitting in your frame perfectly. If it is this then just slacken off the bolts then re-tighten them.

If it isnt this then it will most likely be something seriously wrong with your engine internally.