For discussion

[mack]

Much has been made about sprocket pointers and cam dot alignment. What am I missing. Remember with the camera angle there is some paralax on the video, but if you look straight down the teeth line up perfectly.
http://youtu.be/VBXLykGJiPs

[TADracer]

I always line them up when I have my stock sprockets on, just because. But I have had them 180 out and makes no difference whatsoever. so I am in agreement with you.

[dbeardslee]

While I agree that it doesn't seem to make any difference, why would you install them 180 degrees off to begin with? Seems like it would only introduce confusion if you ever had the cams out and subsequently reinstalled them - particularly if it was someone doing the work that didn't know they were 180 degrees off. I prefer my dots in the correct place.

[mack]

Well

Frankly I doubt anyone does it on purpose, it happens from time to time when trying to get the sprocket on the chain. Then when it's noticed, people go through the whole process a second time to put them in the right position thinking that if they don't, the cam dot timing will be off one tooth. That's really the issue here. No matter the orientation of the pointer, if your off one tooth, it's how you installed the sprocket in the chain, it has nothing to do with the sprocket pointer.

[crazy steve]

Mack, I'm not sure this is something you can 'eyeball'. I really think someone would have to precision fixture/measure this to put this to rest once and for all. Here's my reasoning....

The 'working diameter' of the cam sprocket is roughly 3.1875". This gives you a circumference of a bit over 10". Divide that by 720 (the number of 'camshaft degrees') and you get one camshaft degree equals .013". That's a pretty small amount to 'eyeball' but yet camshaft designers will move opening/closing events that amount to 'fine tune' performance on a routine basis.

Will being off by some fraction of a degree or even a few degrees make a huge difference in how the motor runs? Of course not. And given manufacturering tolerances, chain stretch, and general wear, it still might be tough to get a definitive answer.

[mack]

Certainly

I would bow to your knowledge Steve. It just seems to me that as you mentioned, chain stretch,sprocket wear and human error are a far more incidious culpret to being off a tooth than having the pointer out 180 degrees.

[IanDMacDonald]

I thought the same thing Mack! Installed them upside down. Went back-in and reversed them. I guess it makes me feel better that they are how the Yamaha manual shows them, for what it's worth.

[skids]

I just want the dots to line up exactly at the arrows. I have never seen it perfect when messing with three new cam chains on three different xs11s.

[crazy steve]

Put the sprockets in backwards but with the cam dots pretty much lined up, you may be off a few degrees or so on the cam timing. Miss it by one tooth on the cam sprocket, you're off by 20 degrees. THAT much you'll notice....

[TADracer]

This is interesting. Not sure when but I was planning on pulling the cover in a few weeks to check some clearances. If and when I do then I will put my degree wheel and dial indicator on and check it out.

[TopCatGr58]

Hey Mike,

Thanks in advance for that, but also please note whether yours are installed "correctly" with the arrows on the cam gears lined up with the dots or 180 out, and if you noticed any seat of the pants difference IF they were 180 out??

T.C.

[TADracer]

Yes, they are installed correctly. I am thinking I will spin them around and check it out to see exactly what degrees it is at the crank.

[mack]

Billyroc

didn't you just go back in to change yours? Did it make any difference?