'07 Vector Cam Chain Question

[4strokeluvr111]

Oh before I forget. Max - have you driven a new Doo 1200 Renegade? I put some quality miles on one yesterday and while the motor is nice, the front end was twitchy and the rear skid comfort was just OK. Now I know that working on the setup will help, but the one thing that would be hard to change is the bar ergo's. Too narrow for me. Flipper had a weird shape to it. Brake handle was way too short.

For some other time I'll talk about a Poo Switchback on the AXYS chassis......but I will say I love it even more than I did before! Too bad Poo doesn't offer a 4S engine!

 

[theCATman]

UPDATE: There hasn't been squat for snow all winter here, so I haven't been in any hurry to do my verification on which tensioner it is. I did borrow it to a friend & we rode 100 miles a few weeks ago. Anyhow, I got an inspection mirror & there it was, ORANGE!... S.O.B. Blue dot on cylinder case didn't mean nothing.

So, for piece of mind, I bought the updated tensioner & swapped them today. Not a bad job, but time consuming. It took me roughly 6 hours, but I took my time, tripple checked everything. I zip tied the chain as Grizztracks said to do, but I'll be Damned if the exhaust still managed to jump a tooth. So, I carefully moved the chain off the sprocket, and rotated it back in line.

Put the new tensioner in & ran the engine thru 2 full rotations zip tying as I went to make damn sure it stayed.

I will say my old tensioner had noise, but not alarming. At idle to about 1,800 rpm there was a distinct quiet, yet audible "flutter" coming from it. I had to be right down near it to hear it.

I listened to a video someone had posted here of an obvious bad one & I'd equate the sound to a baseball card in bicycle spokes. A loud, rapid "flutter". My old tensioner had the exact same sound, yet faint. If you didn't know what to listen for, ya woulda never known.

Now, the new tensioner... dead quiet. Do I feel mine was bad? No I dont. I'm thinking all the old ones have that faint flutter as a normal sound. Ones that have failed, I'm guessing the spring get fatigued, and either totally breaks, or gets weak enough that it only holds maybe 1/2 the tension, hence hearing a loud flutter as the guide & chain are allowed to bounce. That being said, that's what I feel is being heard. Not the tensioner itself, but rather the guide & chain bouncing/vibrating.

 

[grizztracks]

I also believe it's the chain that makes the noise and not the tensioner. I've taken many of the old tensioners apart looking for a failure but have never seen anything indicating it was bad. I don't believe it's the springs in the tensioner which rotate the adjuster out to take up any slack because once the plunger extends you can't push it back without using a tool to reverse rotation. I've never taken a new tensioner apart for comparison but I believe that once the guides, chain and gears break in more slack is developed and the old tensioner can't extend far enough to compensate for it.

 

[theCATman]

Maybe that's it?? Maybe new tensioner plunger is a bit longer?

Sent from my SCH-R970 using Tapatalk

 

[theCATman]

Quick edit.

I replaced it (tensioner) for two reasons. One, for piece of mind. The failure rate is in the 0.5-1% range it seems, which is statistically very low, but if it happens to you, it's suddenly 100%

And two, this will become the machine my kid steps into in a couple more seasons, & I'd hate like Hell for her to be the one riding would it decide to fail. She would be devastated thinking it was her fault. Just the type of soft hearted person she is.