Cam Chain adjustment...

[ViperRon]

My 2 cents

A tip I got some years back may help a little with the slip issue on the original tensioner assembly. After tightening the lock screw a few times it can cut groves in the flat spot that the lock down comes in contact with. After this surface has several spots in it it has a tendency to first of all hang in a previous location not fully taking slack out of chain and second tightening down on a damaged hump not getting a full grip on the shaft. All this is intensified by someone not using a torque wrench and too much torque. Not having a tight chain it tends to have more vibration on an already weak piece of metal and can loosen up much easier.

The cure is take out the shaft and use a fine flat file to create a smooth surface in the flat spot for the lock down to tighten against. Also make sure and remove any ruff spots from the sides caused by the file so the shaft does not stick. The end of the screw should be checked also as some can have a bur that will tend to cut in and in rotation actually move the tensioner plunger out of adjustment. Remember if you remove too much metal then you create a weak spot which can cause the mechanism to flex and or bend and that can cause adjustment problems also.

I feel the best fix is the auto tensioner once you have a damaged original tensioner.

[James England]

A tip I got some years back may help a little with the slip issue on the original tensioner assembly. After tightening the lock screw a few times it can cut groves in the flat spot that the lock down comes in contact with. After this surface has several spots in it it has a tendency to first of all hang in a previous location not fully taking slack out of chain and second tightening down on a damaged hump not getting a full grip on the shaft. All this is intensified by someone not using a torque wrench and too much torque. Not having a tight chain it tends to have more vibration on an already weak piece of metal and can loosen up much easier.

The cure is take out the shaft and use a fine flat file to create a smooth surface in the flat spot for the lock down to tighten against. Also make sure and remove any ruff spots from the sides caused by the file so the shaft does not stick. The end of the screw should be checked also as some can have a bur that will tend to cut in and in rotation actually move the tensioner plunger out of adjustment. Remember if you remove too much metal then you create a weak spot which can cause the mechanism to flex and or bend and that can cause adjustment problems also.

I feel the best fix is the auto tensioner once you have a damaged original tensioner.

Yes, mine was like that re the humps etc. As you've said though, filing it flat can take quite a lot of metal off and the flat area is already a fairly pronounced reducftion in the plunger rod diameter.

Personally, I don't see the point in keeping the OEM tensioner if it's reached the stage of needing to be filed. It's a weedy looking thing all round, I reckon, and not exactly confidnce inspiring.

The auto CCT on mine really is a great modification and it's had some hard use.

[Bonz]

So, here's a twist to this that was pointed out to me by a fellow forum member...

With the Auto CCT, could it keep constant pressure on the cam chain vs the manual CCT (that the bike was designed with) to the point that there is less room in the grand scheme between links for oil to circulate, since it is under constant tension vs. going through a "wear cycle" and overall having some bit of play to allow for more thorough oiling of the cam chain?

Hmmmm.......

I'm still using the manual tensioner, loving the heck out of it and my bike is running like a top. Just over 19,400 miles now, heading toward 20,000 soon.

[motoman]

Good try, but that twist isn't gonna work either. Automotive world timing chains need to be tight....and are unless needing replacement. 3Phase IS correct in his analagy Howard. To step that up to one better, the auto tensioner will pickup any and all additional slack when engine is heavily loaded with the right hand. Doing it while running at an idle will NOT load all the slack to the front side and even though may be quieter and smoother idleing, the cam timing is still gonna move around a bit. May not be enough to notice..................until you install an auto-tensioner. Iregardless Howard, ignorance is no longer bliss.......your scoots valve-train is now on borrowed time. How lucky do you feel...............

[DGXSER]

So, here's a twist to this that was pointed out to me by a fellow forum member...

With the Auto CCT, could it keep constant pressure on the cam chain vs the manual CCT (that the bike was designed with) to the point that there is less room in the grand scheme between links for oil to circulate, since it is under constant tension vs. going through a "wear cycle" and overall having some bit of play to allow for more thorough oiling of the cam chain?

Hmmmm.......

I'm still using the manual tensioner, loving the heck out of it and my bike is running like a top. Just over 19,400 miles now, heading toward 20,000 soon.

Interesting point. Now IMO, the answer in short is that is inaccurate.

The reason I believe that is this, the point at which the oil is being introduced to the chain is in the top end of the engine, or the bottom end of the engine. In either location, the chain is being pulled equally tight by the spinning crank shaft, and the cams which have tension due to valve springs being compressed. No matter how much slack is or is not present on the upward/back side, the tension on the chain from the exhaust cam to the cranshaft will not be effected. The chain is only being pulled tight by the tensioner when it is running up the engine between the crank and the cams. That is the only place the CCT actually sets the tension or the tightness of the links. That is not where it is getting oiled, so again, no that would not be true.

[TADracer]

Guess the next time YOU need to adjust or check your valve shim/lash, you could perform the adjustment idling adjustment first. Then pull the cam cover, and check how much actual slack you could pull up between the cams. Then perform the STATIC adjustment, and recheck the slack to see if you get more or less, and then you/we'll know if it's better or equivical, or not as good!

T.C.

I actually did something like that years ago when I switched to the manual tensioner I still use. I set the tension by the factory method with the OEM tensioner I was taking off because the plunger kept slipping back on deceleration. Between the cam sprockets the chain had 3/16"-1/4" of up/down play. That is the benchmark I still use to adjust my chain. Since I use a totally manual tensioner it requires popping the top off to see the chain and sprockets but you should be doing that every now and then to check valve clearances. After over 20,000 miles on this method there is just no wear on the sliders or sprockets and the chain stretch is negligible.

So I cannot say anything positive or negative on an auto CCT because I have no experience there but, the OEM tensioner seems to be a real weak spot IMHO.

[motoman]

The cure is take out the shaft and use a fine flat file to create a smooth surface in the flat spot for the lock down to tighten against. Also make sure and remove any ruff spots from the sides caused by the file so the shaft does not stick. The end of the screw should be checked also as some can have a bur that will tend to cut in and in rotation actually move the tensioner plunger out of adjustment. Remember if you remove too much metal then you create a weak spot which can cause the mechanism to flex and or bend and that can cause adjustment problems also.

Makes you feel good about it, but doesn't work........BTDT many years ago. Issue being many by design. The housing is weak and flexes under the side-load from bolt, and fractures in many cases. The set-bolt is the poorest excuse for an actual set-screw I've seen. Those are just two of the many design issues with the stock tensioner.

[James England]

Yamaha ditched this weedy OEM CCT on all subsequent engines. That speaks volumes. I mean, if it were any good, you'd have two of them on a V-Max, or one of them on any of the auto CCT donor models.

I did a post-mortem on my OEM CCT. The flat bit of the plunger was full of dents and had quite obviously slipped position in the past because I could see a compressed line between two indentations from the lock-bolt. Plus, the danged things always end up leaking from the rubber plug, the subject of many threads here. The auto CCTs have a copper sealing washer and no plugged-off hole.

I would not advise removing metal from an already thinner area of that plunger. I bet if one were to X-ray an OEM plunger (would X-rays work?), it would be full of stressed areas just waiting to break.

[motoman]

I would not advise removing metal from an already thinner area of that plunger. I bet if one were to X-ray an OEM plunger (would X-rays work?), it would be full of stressed areas just waiting to break.

Not likely........by design it slips, and with enough re-setting.........one begins to think timing chain replacement is in store...........lol.

[ViperRon]

In a chain drive situation unless you put excessive force which the autotensioners are not capable of creating tight is better both for function and wear. I always adapted the statements on bolts of righty tighty lefty loosey. Chain should be righty tighty not left loosey. I still have the old tensioner assembly but I check it often and I have replaced it before because of wear. The next time I will get a auto unit. For people who do not have experience or just not mechanically inclined its a nessisity because if you leave it loose once and it can be all over with for the head and pistons.

[Bonz]

You guys are a wealth of knowledge, thanks for all the input and continued discussion.

Motoman, always nice to have you looking out for my scoot and keeping it's best interest in mind!

[motoman]

Motoman, always nice to have you looking out for my scoot and keeping it's best interest in mind!

Nice catch hbonser.........exactly my point. Next door neighbor of mine some thirty yrs. ago in Durango had the identical scoot. We regularly swapped XS's and rode together. Hadn't seen one that pristine as a 'rider' or been on one since ......till yours made its debute......

[Bonz]

Yeah, that bike had been a well-kept secret in my buddies shed for 10+ years or more.

Maybe I oughta make a museum piece out of it? I know it can clean up better than it already is.

That SG is the smoothest in-line 4 I've owned or ridden, can't believe how well Yamaha made those bikes.

[motoman]

Yeah, that bike had been a well-kept secret in my buddies shed for 10+ years or more.

Maybe I oughta make a museum piece out of it? I know it can clean up better than it already is.

You could............but it would'nt be happy.......neither would you.......or I..........

[Bonz]

Glad you enjoy living vicariously through my bike! I kinda like that Venturer you have, from what I recall it's in pretty good shape. Not too many of them around. You have it running well?