Cam Chain Tensioner Adjustment-Video

Thanks XSLeo, I just went out and finally made these adjustments. My valves were jammed shut lol. What is the purpose of having those gaps in the valves anyway? What does the gap do?
 
Parts expand with heat. The gaps are there to compensate for this. Without them, the valves would start not closing all the way once things heated up and parts expanded. You would lose compression. You shouldn't need videos to do any of these adjustments, just a simple understanding of how your motor operates.

This is a 360° parallel twin. Both pistons move up and down together but they are not on the same stroke (doing the same thing). When both are at TDC (the "T" slash mark), one cylinder is on TDC of the compression stroke and can have it's valves adjusted. The other cylinder is on TDC of the exhaust stroke. Both valves are tight (exhaust just closing, intake just beginning to open) and cannot be set.
 
@5twins
It would be nice to have a video if you've never seen it done. I do agree that its super simple once you have done it once and know you have done it right.

So I have a question, so when your turing the alternator counter clockwise and you have your valves on one side TDC. Are both exhaust and compression on one side in a place where you are able to adjust them both at same time? Do you then pass the alternator around one more time to get the other side TDC?

I noticed that One side was super tight and One side was super loose. So is it safe to say if you can get a gap on one side that is the side to adjust then you crank around again and get the other side once its loose as well? Or have I misunderstood the process?
 
Yes, I think you've got it. Both intake and exhaust valves on one cylinder, the one that's at TDC on the compression stroke, should have some play in them and are at the proper point for setting. Both valves on the other cylinder should be tight. Now, this is assuming the valves were set somewhat close to spec to begin with. On a new-to-you motor, they could be way off, some being very loose, some very tight. That's why you want to run through the routine that Leo outlined and watch the valves open and close as you turn the motor over by hand. That way you can determine exactly when the cylinder is at TDC on the compression stroke and ready for valve adjusting. I start with the left cylinder because it's easier to watch the valve action as I turn the motor over by hand. Once those valves are set, another complete (360°) rotation brings the other cylinder up to TDC on the compression stroke and it can have it's valves set. Yes, you want to use a wrench on the alternator nut or you'll run past the "T" mark. A ratchet is no good for this.
 
So your saying that as I'm cycling through to watch the valves bob up and down I should see the gap open up in the valves as they hit TDC on each side? I'll have to take a look at that in the broad daylight. Mine were pretty tight until I followed Leos advice and some other written info. Even now I don't know if I would be able to see a gap as the feeler gauge for the exhaust valve was almost paper thin .006m for exhaust and .015 for the other. I have to check what I set it at against my manual when I get home to make sure I'm accurate.
 
You won't be able to see the gap, it's too small. You will be able to reach in and wiggle the rocker up and down, feeling the play. Both valves on that side should have play. Reach in on the other cylinder and both valves should be tight with no play.
 
Once you run through the turning the engine, watching the valves and feeling for the wiggle, you will get the idea.
Once you get the idea you will see it's not hard at all.
 
Its not bad at all but I should add for anyone who hasn't done this before, I originally watched a video on Youtube and the guy on that video had mentioned that his clearances were I think .015 for the front and .006 in the back. I was reading over the Haynes manual this morning and the manual mentioned that depending on the year and model you have the clearances are different. So make sure you adjust correctly based on the bike you have.
 
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Yamaha tried several different specs over the years. The early years, the 70-73 256 engines had cam that is different than the later 74 up and a bigger gap was used. On the 74 up, I think they tried the different specs trying to quiet the valve noise. Most find a .003 intake, .006 exhaust to work well. A gap a touch on the wide side is better than one on the tight side. To tight and intakes leak and exhaust burn. Loose they just get noisy.
Leo
 
I thought I would get up today, hit the manual and adjust my valves again just to see if I can get as close to perfect as I could. I checked the manual and they only have xs650 A, B and C models. Turns out I have an H Special 2. Do you think I should go .003 intake, .006 exhaust and I will be good to go?
 
Yes, it's accepted practice to use .003" for the intakes and .006" for the exhausts on just about all the 650s (except the early models as Leo noted) and that actually is the spec given for your H model. Note, these settings are in INCHES, not MM. Metric equivalents are .06mm for the intake, .15mm for the exhaust. Make sure you're using the right kind of feeler gauges (inch or metric) with the right measurements. Most of the time around here, we refer to our valve clearances in inches.
 
There is no way to view the video unless the guy who posts it takes 2 minutes to view his settings and fix the video. Youtube rolled out some new options a month or so back and it screwed a few peoples videos up. From what I have read if you didn't take a few minutes to read through the options and clicked out to quickly you would accidentally privatize your videos.
 
Maybe there's more involved than just 2 minutes.
I'd like to thank Littlebill31 for having put these up in the first place.
It's a drag not to be able to see them now, but maybe it's a real pain in the butt to change it, or he'd have done it by now.
 
I'm not trying to dog anyone. No disrespect to Littlebill31. Just would like to see the videos. I'm blaming Youtube. I expect better usability from Google.
 

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