2016 Viper Cam Timing

[Darren455]

I'm currently doing a exhaust valve adjustment on my 2016 viper since it had tight exhaust valves and had starting issues. I got the valves shimmed and put the camshafts back in with the timing chain. I followed the Yamaha serivce manual and read the long forum post on this page and I can't get the timing perfect. Cylinder 3 is at TDC, and mark on the flywheel lines up with the mark on the mag cover. There is also 18 pins in-between the exhaust and intake marks. I lined up the intake and exhaust marks on the timing chain sprockets parallel to the head and zip tied it to the timing chain. As soon as I start tightening down the cap screws or install the cam tensioner it would move slightly. I've spent may hours trying to make it perfect like all the other YouTube videos show. This is the closest I've gotten and I was wondering if it would run perfectly fine if it wasn't lined up exactly.

First picture is timing with the marks lined up on the flywheel (TDC)
Video is showing the timing marks on the sprockets lined up to the head, but cylinder 3 isn't quite at TDC.

https://imgur.com/mMila7L

 

[74Nitro]

The mark on the flywheel is not lined up IMO

 

[Darren455]

After a while I managed to get it bang on. But then as soon as I turn over the motor manually all the slack on the chain gets pulled by the exhaust sprocket. The intake doesn't move till all the slack is out of the chain. The chain tensioner is in, but doesn't kick in till after I start turning over the motor.

I've taken the chain tenionser and camshafts out a bunch of times and its getting tiring after many hours of trial and error. There must be something I'm missing. All the YouTube videos make it look easy, which it should be.

 

[74Nitro]

The timing is correct as per the second and third video. The chain has worn and that's why the cams appear slightly retarded when the mark on the flywheel lines up.

 

[grizztracks]

I've timed many of these 3 cylinder engines and your alignment is correct. After these engines get a few miles on them the "II" marks usually don't align when the cams are correctly set. If you were to move the chain one tooth in either direction the "II" marks would move out of the alignment window so as long as those marks are visible when the cams are aligned it's good. Use tie straps to hold the chain on the cams until the tensioner takes up slack then install the valve cover, rotate the engine several times and recheck the timing. Never rotate the engine without tie straps holding the chain in place or without the valve cover installed. The valve cover has a guide that sits on top of the cams and prevents the chain from jumping during valve overlap. Never rotate the engine in the reverse direction. These are interference engines so it's important to get the valve timing correct but it can be off one tooth without interference. I've seen these engines off by a tooth and they still run but struggle to idle.

 

[Darren455]

I've timed many of these 3 cylinder engines and your alignment is correct. After these engines get a few miles on them the "II" marks usually don't align when the cams are correctly set. If you were to move the chain one tooth in either direction the "II" marks would move out of the alignment window so as long as those marks are visible when the cams are aligned it's good. Use tie straps to hold the chain on the cams until the tensioner takes up slack then install the valve cover, rotate the engine several times and recheck the timing. Never rotate the engine without tie straps holding the chain in place or without the valve cover installed. The valve cover has a guide that sits on top of the cams and prevents the chain from jumping during valve overlap. Never rotate the engine in the reverse direction. These are interference engines so it's important to get the valve timing correct but it can be off one tooth without interference. I've seen these engines off by a tooth and they still run but struggle to idle.

Thanks, Finally got it after a couple more tries and talking with on the the guys at the Yamaha dealer.

 

[smitty_j25]

I'm fighting the same thing right now, I've got the 3rd cylinder at TDC, all my marks line up and 18 pins between the lines, but my chain has slack in it

 

[74Nitro]

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[74Nitro]

I'm fighting the same thing right now, I've got the 3rd cylinder at TDC, all my marks line up and 18 pins between the lines, but my chain has slack in it

 

[smitty_j25]

Am I off by a tooth here? First pic is lined up with the TDC marks, second is if I rotate the cam marks to align perfectly

 

[grizztracks]

The problem I see is that the cams are not aligned. If you rotate them CW to align marks that will rotate the mark in the inspection window CW so it will be even further off the mark. With the cams proper aligned the lower "II" mark usually doesn't align perfectly with the case unless everything is new but the mark will remain in the window when timed correctly. One tooth off usually puts the lower mark outside the inspection window.

 

[smitty_j25]

The

The problem I see is that the cams are not aligned. If you rotate them CW to align marks that will rotate the mark in the inspection window CW so it will be even further off the mark. With the cams proper aligned the lower "II" mark usually doesn't align perfectly with the case unless everything is new but the mark will remain in the window when timed correctly. One tooth off usually puts the lower mark outside the inspection window.

In the pic of the inspection window the horizontal marks on the cams are aligned, the first picture (showing the cams slightly off) was taken with the inspection window set exactly at the II mark. I'm trying to figure out if I should adjust 1 tooth before I put everything back together

 

[74Nitro]

Looks like the flywheel mark isn't aligned. Line it up exactly, then show us pics of the cam marks.

 

[smitty_j25]

This is the with the inspection mark perfectly aligned

 

[74Nitro]

This is the with the inspection mark perfectly aligned

You're holding your camera at a bit of an angle, but it appears you have it right. When they don't line up exactly, you always want them to be to the retarded side.