Overtightened cam chain tensioner...now what?

[Kaisersoze]

Installed an APE manual cam chain tensioner and had a choice to make. Do I leave the tensioner looser, hoping its not too loose and instantly destroys my engine, or do I put it to the max distance my auto tensioner goes to and start from there.

Took the second option and engine worked fine, however it was definitely too tight and after running it that way for 2 - 3 days I took it down another 1/4 to 1/2 inch. After running it for a couple weeks I still feel like its too tight I will let it out a fraction more. Any idea what kind of damage I could have done, if any? Bike runs fine but I've seen so many "DO NOT OVERTIGHTEN" warnings on the instructions for installation that I fear it is as bad as letting the chain jump and tooth.

Any thoughts guys/gals?

 

[FinalImpact]

IF you set the tension while at TDC on the #1 firing stroke there should be minimal forces from the other cams lobes trying to rotate the cams backwards or forwards. The point being; what you see is what you get tension wise as the valve springs are not trying to rotate the camshafts loading the chain and faking you out.

It can have some play as its not going fly off even if ran a little loose. Starting it with NO tensioner, ya - that could be a problem.

To Tight leads to excessive wear and this can break a chain. I'd guess the guides would wear very fast when too tight, followed by chain stretch, and cam bearing journal wear.

 

[Kaisersoze]

So check the oil filter for plastic bits next oil change basically? :BLAA:

 

[SovietRobot]

Worst case scenario, you shred the delrin sliders to pieces and stretch your cam chain until it snaps and your engine explodes.
Or if it's just "slightly" tight, the life of the sliders and chain will be shortened somewhat.

I recently installed the APE tensioner and the one thing I hate is how it's impossible to get it just right without taking the valve cover off and measuring chain slack.

You'll know it's too tight when 1. the bike shutters when you rev it and it takes extra throttle to engage the clutch and 2. when the lights dim while you rev it.

I measured the distance that my stock tensioner was at(based on the color of the metal) and set the manual one at that. I plan on buying a new chain, sliders and OEM tensioner though.

 

[iSteve]

You'll know it's too tight when 1. the bike shutters when you rev it and it takes extra throttle to engage the clutch and 2. when the lights dim while you rev it.

I don't understand how these symptoms can be caused by a tight timing chain. Usually over tight chain will result in a failed guide, worn sprockets or a broken chain not clutch and electrical problems.

 

[ChevyFazer]

+1 because that makes 0 sense.... Sounds like he has other issues on his bike

 

[FinalImpact]

No other issues, He's saying the extra drag from the over tight condition will drop RPMs as this is parasitic drain on the crankshaft & camshaft. Tell tales signs of lowered RPMs are the dim lights and/or slow accell and rough decell of the engine. Its allot of parasitic drag on the engine which ultimately takes the life from the chain and everything it contacts.

Chains are not piano strings. They're much more forgiving of being slightly loose than slightly tight. If left tight, they stretch until they find that happy spot.

If you overtighten them the rollers do not easily roll over the pins while going around the gears, this make lots of heat thinning out the oil and the rollers seize on the pins snapping the chain.

 

[Kaisersoze]

Well I knew I had it way too tight the first time because I could hear the whine of the chain against the guides as I would accelerate and I would stall very easily if I did not increase the throttle more a slightly bit more than normal when taking off. Plus, I could feel the "decreased horsepower" they warned about when it was too tight. I think it is only very slightly over tightened now because I have none of the issues I had before but I didnt let the tensioner out enough to hear a slight rattle in the chain because, honestly, I am too afraid of jumping a tooth. So when I started to let the tensioner out I did it by hand till I felt vibes on the bolt minus the actual audible sound of slight chain rattle. It runs absolutely fine, but I figured I'd ask anyways.

+1 to the above statement about how hard this thing is to install to exacting measurements.

 

[iSteve]

A cam chain tight enough to cause enough drag that the FZ6 engine struggles to make enough HP to take off normally is hard to imagine. I guess he could be exaggerating this a little to make a point. But still the light dimming, my light doesn't dim even when I shut the engine off.

This could all possibly happen with a smaller low HP motorcycle but I think the FZ engine would tear up a chain and sprockets if it were that tight.

 

[ChevyFazer]

What makes 0 sense to me is mainly saying that the lights going dim when you rev it is a sign of it being too tight

 

[Kaisersoze]

I dont know about the light thing, didnt experience that myself. But I can say it was like riding with the e-brake on in a car. No way you are gonna feel it when going at speed but it would grab the bike in slow maneuvers.

 

[FinalImpact]

A cam chain tight enough to cause enough drag that the FZ6 engine struggles to make enough HP to take off normally is hard to imagine. I guess he could be exaggerating this a little to make a point. But still the light dimming, my light doesn't dim even when I shut the engine off.

This could all possibly happen with a smaller low HP motorcycle but I think the FZ engine would tear up a chain and sprockets if it were that tight.

Not so much. Friction eats power. Lets say the engines only making 6hp off idle and you now have an 8% loss being eaten by friction. A person who notices details is going to feel the change and notice all peculiar effects it has. Low idles, stalling, hesitation, stumbling, odd noises, increased throttle position to obtain same feel as before . . . etc

Off hand, his still sounds too tight.

Ever notice how the transmission whines when the drive chain is too tight? How its very happy with slack in it. Its wants lube and proper alignment and chains will live a long time. Granted some of the explanations used are distracting but I'm chiming in so an engine doesn't get waisted.

 

[FinalImpact]

What makes 0 sense to me is mainly saying that the lights going dim when you rev it is a sign of it being too tight

agreed - but its likely when he lets off, the idle drops lower than it normally would.

 

[iSteve]

You're probably right someone may be able to tell that the timing chain is to tight. But it would have to be crazy tight you would really have to have no idea what you're doing when adjusting it.

But it's not quite the same as a drive chain. The drive chain is large heavy and has to turn a large tire pushing a lot of weight. Even a tight cam chain would use a tiny fraction of a HP to turn it compared to a tight drive chain. But then again I just can't imagine someone over tightening a cam chain that much. Of course in 35 years of owning bikes I have never had one with a manual tension adjuster.

 

[SovietRobot]

No other issues, He's saying the extra drag from the over tight condition will drop RPMs as this is parasitic drain on the crankshaft & camshaft. Tell tales signs of lowered RPMs are the dim lights and/or slow accell and rough decell of the engine. Its allot of parasitic drag on the engine which ultimately takes the life from the chain and everything it contacts.

Chains are not piano strings. They're much more forgiving of being slightly loose than slightly tight. If left tight, they stretch until they find that happy spot.

If you overtighten them the rollers do not easily roll over the pins while going around the gears, this make lots of heat thinning out the oil and the rollers seize on the pins snapping the chain.

Yes this is what I was trying to say. Thank you.

For what it's worth I loosened the tensioner and those problems went away, which explains parasitic drag.

 

[FinalImpact]

And what ever came of this one???