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CaptainKnobby

TDC on camshaft dots?

29 posts in this topic

Put a new piston an rings in ny 2011 YZ450 and I'm at this point.

I have the camshafts in and the timing chain on.

Does the dots look like they are in the right spots?

The Intake cam looks spot on. The Exhaust one looks bout right but dont know if it could be 1 tooth low.

The lobes on cam (tapered ends) point toward each other as in the manual. However the exhaust lobes seem just a tad lower than the intake ones.

If I was to go one tooth back on the exhaust cam to raise the lobes on the the EX cam, the cam dot on the EX cam would be way to low.

The timing marks are aligned down at the cover.

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This is my WR head. I know it's not a YZ, but you can see the lobes are way different. I know mine are right. You can atleast see compare, it may help.

ImageUploadedByThumper Talk1454892808.102973.jpg

ImageUploadedByThumper Talk1454892829.887428.jpg

It is interesting how your cames are on a different side then mine.

Edited by RMK800

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Are you sure you have your cams in right? Here is a photo on Google ImageUploadedByThumper Talk1454893305.860200.jpg

ImageUploadedByThumper Talk1454893390.453661.jpg

Edited by RMK800

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Are you sure you have your cams in right? Here is a photo on Google attachicon.gifImageUploadedByThumper Talk1454893305.860200.jpg

attachicon.gifImageUploadedByThumper Talk1454893390.453661.jpg

This is my WR head. I know it's not a YZ, but you can see the lobes are way different. I know mine are right. You can atleast see compare, it may help.

attachicon.gifImageUploadedByThumper Talk1454892808.102973.jpg

attachicon.gifImageUploadedByThumper Talk1454892829.887428.jpg

It is interesting how your cames are on a different side then mine.

Even the lobes in the manual show them to point toward one another.

I will take a pic of it so you can see.

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Even the lobes in the manual show them to point toward one another.

I will take a pic of it so you can see.

Obviously go off the manual. Edited by RMK800

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You will know for sure when you put the cam chain tensioner in and let the screw go. Mine went off when I let the screw go, I had to pull the cam and move it.

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You will know for sure when you put the cam chain tensioner in and let the screw go. Mine went off when I let the screw go, I had to pull the cam and move it.

With the cam caps on and the Cam Chain Tensioner in completely, The cam dots are aligned up just like the 4th picture above.

The pic where I have the light over top of the head.

 

The Intake dots look like in the manual but the exhaust dot is just a tad below the surface of the head.

 

But if you wiggle the flywheel bolt at the cover or just turn it a tad to the left, you can get the dot on the Exhaust cam to come up level to the surface of the head but the Intake dot will fall just a tad below the head surface about the same distance as the Exhaust cam dot was when you had the Intake cam dot level with the head, if that makes since.

 

I know when you turn the FW bolt at the cover to the left just a tad to where both dots are level with the surface of the head, the mark on the FW is 3mm's off to the left of the mark on the cover.

 

What if it is off just say a tooth on the Exhaust cam. Would it be safe to start it up just enough to tell if its on right?

 

Where I have it now is the best I can get it.  I fooled with it for about 2 hours or so and that's the closest I can get the Exhaust cam Dot to come the closest of being level with the surface of the head. 

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I ran into the same thing with my YZ250F. Not sure why it is that way but it runs fine. I put in a new timing chain so I know it wasn't that and I didn't see any abnormal wear on any of the teeth that would cause it.

A couple things though....my manual says the lobes should be pointing outward (10 & 2). The 450 manual might be different but I'm not sure why. Make sure you're in the "setting timing" section or whatever it's called. do whatever the manual says.

Physically check to make sure your piston is TDC using a drinking straw or long piece of wire down the spark plug hole then turn the flywheel until the straw stops going up out of the hole. If it starts to go down as you're cranking you've passed TDC.

Once you think you've got it right put the timing chain tensioner back on then turn the flywheel a few times then check to make sure it all lines back up.

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Just watched a YouTube video about setting timing on a 450. Looks like you've got everything right.

Like I said before when I put my cams back in, one of my dots were slightly off but it doesn't seem to be a problem. I fooled around trying to move it forward or backward a tooth but it was obviously off then.

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Just watched a YouTube video about setting timing on a 450. Looks like you've got everything right.

Like I said before when I put my cams back in, one of my dots were slightly off but it doesn't seem to be a problem. I fooled around trying to move it forward or backward a tooth but it was obviously off then.

Thats what I meant.....Like you said. I fooled around with the exhaust cam for anout 2 hrs trying to get it deaf level with the head surface.

And like you said by trying to get it spot on you could definitely tell is was off .......in either direction (above or below) the surface.

Anyways .....as soon as I get my Low Friction band for my Shock and a few other pieces for it and get it rebuilt, I will put the shock on and see if it will start.

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I ran into the same thing with my YZ250F. Not sure why it is that way but it runs fine. I put in a new timing chain so I know it wasn't that and I didn't see any abnormal wear on any of the teeth that would cause it.

A couple things though....my manual says the lobes should be pointing outward (10 & 2). The 450 manual might be different but I'm not sure why. Make sure you're in the "setting timing" section or whatever it's called. do whatever the manual says.

Physically check to make sure your piston is TDC using a drinking straw or long piece of wire down the spark plug hole then turn the flywheel until the straw stops going up out of the hole. If it starts to go down as you're cranking you've passed TDC.

Once you think you've got it right put the timing chain tensioner back on then turn the flywheel a few times then check to make sure it all lines back up.

I done all you said above and all was good. It doesnt have anything in the manual about timing that I can see.

However in this pic in the manual where it shows the two dots level with the surface. I couldnt get the exhaust cam like the picture. Closest I could get it was just a tad.....a tad below the surface.

Now you could wiggle the FW an get it level bit the Intake dot would drop just a tad.

It has to be right cause I dont think you can get both of em exactly level with the surface.

Edited by CaptainKnobby

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I done all you said above and all was good. It doesnt have anything in the manual about timing that I can see.

However in this pic in the manual where it shows the two dots level with the surface. I couldnt get the exhaust cam like the picture. Closest I could get it was just a tad.....a tad below the surface.

Now you could wiggle the FW an get it level bit the Intake dot would drop just a tad.

It has to be right cause I dont think you can get both of em exactly level with the surface.

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Put a new piston an rings in ny 2011 YZ450 and I'm at this point.

I have the camshafts in and the timing chain on.

Does the dots look like they are in the right spots?

The Intake cam looks spot on. The Exhaust one looks bout right but dont know if it could be 1 tooth low.

The lobes on cam (tapered ends) point toward each other as in the manual. However the exhaust lobes seem just a tad lower than the intake ones.

If I was to go one tooth back on the exhaust cam to raise the lobes on the the EX cam, the cam dot on the EX cam would be way to low.

The timing marks are aligned down at the cover.

Your cams are aligned correctly. The dots are not an exact science just a rough guide, as close as you can get them to flush with the head is correct.

After the chain is tensioned just get the exhaust as close as possible to be flush. Slight disalinement may be an old cam chain to. Did you replace that as well?

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Yeah ....since I was in there I went ahead an installed a new cam chain. I figured the cams had to be aligned. Fiddled with it for another hour last night an when I moved the exhaust cam one tooth....you could tell it was wrong . Where it is at now is right.

I have it all back together now.

Got my parts for the rear shock today. Going to rebuild it wednesday night and it will be done.

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Had the exact same issue on my 03 250f. Made me crazy that I couldn't get the dots to line up perfect. Finally buttoned it up and it ran great.

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Here is the cylinder. Doesnt look bad at all with 90hrs on it. I kinda was guessing it would have a tad of glaze on it.

I checked the piston to ring gap and all measured to spec. Piston was good, same for wrist pin.

I dont think nothing would have been done for at least another 50 hours.

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Something must be a little out of kilter. Went to fire it ip todau an all you done was kicked it an kicked it. About every other kick it sounded like it wanted to back fire but just barely would.

I thought were the tank had been off there was no gas, so I opened the throttle WO and kicked it a few times an then let off throttle an kicked it an it back fired.

Im thinking the cams may be off, especially the exhaust one since I couldn't get that one dot on it "EXACTLY" flush or level with the head..

Could it be out of time some how?

I can't understand what it could be. I did exactly what the manual stated. It has to be something with those dots......got to be.

How else could it have gotten out of time?

Is there a fool proof way to get those dots lined up EXACTLY on the money?

Or a way to check now to see if the dots are right?

Only thing I know to do now is.......... Line the marks up down on the cover and then pull the valve cover back off and see if the dots are level with the head.

Is this correct?

Edited by CaptainKnobby

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