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Discussion Starter · #1 · (Edited)
Ok so i'm no stranger to working on engines but i'm having an issue with my zx6r. I pulled the cams for a shim change and a new cam chain tensoner. I reassembled everything and tried to do the standard hand rotation prior to buttoning it all up. Well the darn thing won't spin; I can get it to spin just a bit counterclockwise enough to see that the cams will start to rotate( at least the intake cam). Almost as if it's just taking up the slack in the chain. If I try to rotate clockwise nothing. To me it seems as if the chain is hung up in between the exh sprocket and the crank gear or maybe the exh cam some how? Everything worked fine prior to the work except for a little valve trane noise, and I have checked and taken it back apart many times but just can't figure it out-WHAT AM I MISSING?!?!?!?! Thanks in advance for any help.

Doug
 

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Ok so i'm no stranger to working on engines but i'm having an issue with my zx6r. I pulled the cams for a shim change and a new cam chain tensoner. I reassembled everything and tried to do the standard hand rotation prior to buttoning it all up. Well the darn thing won't spin; I can get it to spin just a bit counterclockwise enough to see that the cams will start to rotate( at least the intake cam). Almost as if it's just taking up the slack in the chain. If I try to rotate clockwise nothing. To me it seems as if the chain is hung up in between the exh sprocket and the crank gear or maybe the exh cam some how? Everything worked fine prior to the work except for a little valve trane noise, and I have checked and taken it back apart many times but just can't figure it out-WHAT AM I MISSING?!?!?!?! Thanks in advance for any help.

Doug
Have you put the cam bearings on properly? Hopefully you did not lose any bolts in the cam chain guides
 

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Discussion Starter · #3 ·
The cam rests in the head on aluminum journals and then is sanwiched by the top peice with the other journal half. They have been checked and the clearances are fine. All nuts, bolts and hardware have been accounted for.
 

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When you say...atleast the intake cam tries to move when I rotate it counterclockwise

that tells me that something between the intake cam and the crank - via past the exhuast cam-is the problem
*option 1-unlikely but...Do you have the cams in wrong and have valves pushing on the piston tops. 180 degrees off perhaps? but that generally wont have them hit, just not run
*option 2-the cam chain is bound up on the crank sprocket (although unlikely because it is damn near impossible to get the cams in then)
*option 3-you removed the sprockets from the cams? or did you just slide the cams out....either way, the cams are in the correct side? exhuast in the exhuast spot, intake in the intake spot
*option 4- you are sure the dowel pins and the small alignment pin (solid steel roller thing) are all accounted for- nothing fell down into a combustion chamber through the spark plug hole?

I have never had this problem, so I am out of ideas for the moment...I certainly would exercise caution and restraint on how hard you try to turn it over in this condition

You could remove the cams again, and hold the chain up and see if then you can turn the engine over freely (would eliminate the possibility of the something in the combustion chamber idea, or the chain being bound on the crank sprocket)

You could loosen the cam caps and try turning over the engine, that would eliminate the possibility of having it on backwards (although I think already mechanically impossible on that head due to design) or something being wrong with clearances there

You're sure the valve shims are completely seated under the buckets-you did re-check clearances after adjusting....an unseated shim would really open the valve allot with the cam installed and may or may not hit the piston.

Keep us informed.
 

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^ what he said about the exhaust and intake cam on the wrong side.
I've heard about it a few times on forums. they look almost alike but there is a way to tell.
 

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Discussion Starter · #7 ·
yep, made sure the intak/exhaust cams are in the proper location, checked for all pins/dowels, checked the buckets/shims to be sure a shim didn't wander(that was one thing i was thinking), the sprockets are pressed on the cams and i didn't remove them-I would almost bet they moved but they are marked with white paint and the bike ran prior.

I have had the cams in and out multiple times going back over everything again, and again. I have pulled them and held the chain while rotating the the crank and it spins fine. I'm ready to fireball this thing!

I'm getting ready to go back out and try again. The cam lobes on a cylinder at TDC should be poinying outward-correct?

I didn't bother marking the cams or their location when I took them out because I knew they had markings/indexing on them for install. Any chance the cams are marked wrong from the factory-exh/int? I know it's highly unlikely but I'm graspping!

Thanks to everyone helping to fig this out with me.
 

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Discussion Starter · #9 ·
looking at the location of the cams and knowing that they spin clockwise i would say that #1 is in the intake stroke and #4 is in the compression phase. Doesn't it appear that the cam gears are on 180 degrees off, shouldn't #1 and #4 be flopped with the index marks on the gears at this point?
 

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going stictly by the pics you provided, if this is how you are orienting the cams with #1 cylinder at TDC(far left as you sit on the bike) then you are in deed 180 degrees off.

The cam lobes at the bottom of your picture should be pointing away from each other.

4 stroke, has two TDC, one is on the compression stroke, one is on the exhuast stroke. There is a total of 360 degrees of rotation for 1 firing sequence.

show me a pic of your pic up rotor as it relates to your installation in the manner you are trying.
 

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oh and highly unlikely your sprockets moved at all on the cams. So I would simply rule that out already, for the purpose of what you have described-you simply were doing valve adjustments and removed the cams for this...no reason to think you could have possibly applied enough force to move the sprockets.

clockwise as you look at it from the right side of the bike (as you sit on it) yes.
 

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Discussion Starter · #12 ·
I'll get one but it's on the 1/4 line at the engine case gasket surface. This is why I'm starting to think the cam sprockets had been pressed on 180 off and whoever worked on it prior to me just installed them 180 off to compensate for it instead of taking them off and redoing it.

Mechanicly it shouldn't matter if I installed them 180 off but ignition timing would be the factor-right? I mean it shouldn't bind or hit anywhere because of being 180 off.
 

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Discussion Starter · #13 ·
oh and highly unlikely your sprockets moved at all on the cams. So I would simply rule that out already, for the purpose of what you have described-you simply were doing valve adjustments and removed the cams for this...no reason to think you could have possibly applied enough force to move the sprockets.

clockwise as you look at it from the right side of the bike (as you sit on it) yes.
yes on the engine direction but what if the sprockets were off for another reason by someone else and re-installed 180 off? I didn't take note when taken apart as I knew there were index marks for installation
 

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I dont know if you have ever had to remove or reinstall pressed on cam sprockets, but it just isn't something you do.

180 off, should not make a mechanical hit, correct it would make it not run because of ignition timing.

And you said it ran before, so unless you removed the sprockets-it didnt happen
 

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I'll get one but it's on the 1/4 line at the engine case gasket surface. This is why I'm starting to think the cam sprockets had been pressed on 180 off and whoever worked on it prior to me just installed them 180 off to compensate for it instead of taking them off and redoing it.

Mechanicly it shouldn't matter if I installed them 180 off but ignition timing would be the factor-right? I mean it shouldn't bind or hit anywhere because of being 180 off.
Not to keep questioning your abilities but;

The #1/4 mark is lined up with the case halves seem....In the rear of the engine correct? closest the clutch.
 

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Discussion Starter · #16 ·
no prob on questioning but yes to the rear by the clutch

I'm not the original owner so who knows what has been done to this engine. It has 26,000 miles on it so.......
 

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Just trying to eliminate the silly mistakes, and get the big picture.

Well if by some chance the sprockets have been changed (they do wear, so it is possible)...Then don't care how the sprockets orient, care how the #1 cam lobes orient and install the camshafts.
based on your pic then the in_ ex_ marks will be upside down and the ex_ mark will be upside down but flush with the head on the intake cam, and the IN_ mark will be upside down and flush with the head on the ex cam.

In your top view picture, you can clearly see the EX stamping on the camshaft, so if the cams were unmoved between those 2 pics, then yes you probably are correct that the cams sprockets at some point were put on 180 degrees off. (which really isnt a big deal)

Unfortunately, this doesn't seem to be the problem with your turning the engine over when it is is installed though. But certainly worth some thought. ( I would not remove the sprockets and try to put them back on 180 degrees acroos from where they are now, as the risk-reward is too high on the risk end-for a do it yourselfer, or anyone without extensive experience with cam timing)
 

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Do you have the service manual? I believe they are supposed to be 30 pins apart, but upside down (as I suggest you try) I think it would only be 28.
those flat lines under the IN & EX would now be a little high of the head surface but they should run parrallel to it.

You understand how the EX is underlined and the line is the line up with the head surface.....upside down it would be on top of the EX so it would no longer line up flush.

I know this may be hard to understand-its hard to explain...sorry
 

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Discussion Starter · #19 ·
I hear you and understand completely. I think I have it and will update later tonight. need to take some time off to entertain the wife-LOL

thanks again!
 

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Discussion Starter · #20 ·
all the pics of the different items is how everything sits with the chain on


#1cyl intake lobes, exh is pointed in just like these

#4 intake lobe on left and the exh is facing the same(outward)
 
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