cam chain tension

fjbiker84 · July 19, 2016, 05:08:20 PM

The previous owner of my FJ installed a manual cam chain tensioner which I've heard is a good thing but my question is: how do I determine how much tension should be on the chain? I know there should be no slack, but i'm sure it could be tightened too much. Should the tensioner be "finger" tight?

racerrad8 · July 19, 2016, 07:15:54 PM

This is not a question I can answer.

I personally remove all manual chain adjusters that come through my door when engine work is required. The automatic adjustment of the Yamaha tensioner is what I have always had trust in.

If not the top of your chain will be really shiny like this

That is a new chain next to it in the back ground. This engine had the manual tensioner that was so loose when it came in the cams had jumped teeth. But it was pretty tight at the beginning before it wore all of the rubber off of the chain guides. The top of the chain being polished like that as is from rubbing on the metal under that rubber that was on the chain guides.

In my opinion, I would install a new Yamaha tensioner and then you never have to worry about adjusting it again.

Randy - RPM

fjbiker84 · July 19, 2016, 08:11:21 PM

Thanks for the info, Randy. That would seem to be an example of a manual adjuster that was tightened way to far. I'm going to check this out this weekend. I have the original tensioner in a box of parts that came with the bike when I bought it. My cam chain isn't worn on the top like the one you show (the picture I posted was taken about 3000 miles ago) but it hasn't been adjusted since putting the engine back together 10 years and 17,500 miles ago. The fellow I bought the bike from was the one who performed all the adjustments and he's a fairly knowledgeable mechanic. The bike runs flawlessly and I have no reason to believe anything is wrong now. I'm just not sure where to go from here. Put the original adjuster back on? I sent an email to the guy I bought the bike from asking him what his "procedure" was when adjusting the chain all those years ago.

Tuneforkfreak · July 20, 2016, 06:52:42 AM

How many factory adjusters has there ever been reported as actually failing? Was this a common problem with the unit that spurred the CNC mill to come out and create a better idea? The MCCT was a common thing to put on the DRZ 400's as it was said they "could" fail. I do have one on my DRZ and to adjust it, I simply run it in finger tight until it touches the guide, I then start the bike and slowly adjust it in until the chain slap noise disappears and no more than that, then set the nut while holding the adjuster in its adjusted position. Setting the nut is key as you easily over tighten the chain if you don't pay attention. Its not to bad to do on a dirt bike, On the FJ I'd say its a bit harder to accomplish due to the location of the adjuster.

fjbiker84 · July 20, 2016, 08:30:29 AM

Got an email response from the guy I bought the FJ from. He basically said the same thing. Adjust the slack out of the chain but nothing more. He said to then turn the engine slowly by hand and look for slack to develop in the chain. If no slack after one complete spin of the engine then it's set. I took the automatic adjuster out and felt the spring pressure it applies - pretty strong spring.

ribbert · July 20, 2016, 09:51:26 AM

Quote from: racerrad8 on July 19, 2016, 07:15:54 PM
This is not a question I can answer........
Randy - RPM

Manual adjusters have to be set at a particular point of engine rotation, say 10 o'clock (just an example) unlike other settings that use TDC as a reference point. This affects both chain tension and valve timing.
If fitting a manual adjuster, you need a means of measuring tension, you need to know where in the engines rotation you need to measure it and what that tension should be. Why bother!

The bottom line is as Randy says, get rid of it and install and OEM tensioner. To the best of my knowledge they give no trouble. Manual adjusters are boy racer stuff.

Noel

ribbert · July 20, 2016, 10:07:55 AM

Quote from: fjbiker84 on July 19, 2016, 08:11:21 PM
......I sent an email to the guy I bought the bike from asking him what his "procedure" was when adjusting the chain all those years ago.

Why would you assume his method was correct just because he was the PO? Take you advice from someone known to have experience with these matters, like Randy@RPM.
Change it out for the original.

Noel

fjbiker84 · July 20, 2016, 10:21:39 AM

All good advice. I think I'll just get a new automatic adjuster since the hard rubber tip at the end of the pushrod on the old one seems to be worn a little - plus it's obviously very old.

a.graham52 · July 20, 2016, 10:53:16 AM

Back when I was riding my z400, manual adjusters were the thing because supposidly the autos would wear the chains too fast. I had an auto in mine and I had to do a chain since I owned it. But I bought it used and abused

fjbiker84 · July 20, 2016, 12:53:57 PM

Just ordered a new adjuster from RPM. Randy, the center bolt sold separately is the bolt on the old OEM adjuster that I have, right? Are there instructions that come with it on steps to install?

racerrad8 · July 20, 2016, 03:22:09 PM

The early tensioner bolts are very short and difficult to get back in because the spring is trying to pop out while compressing. If you are doing it in the bike I recommend a new Tensioner Center Bolt.

Also, you should get a new tensioner gasket as well.

As far as instructions, there is not much to install it. Compress the plunger all the way, install the tensioner into the block with the locking paw down. Once installed in the block, install the springs & center bolt and tighten. Installation complete.

Randy - RPM

Pat Conlon · July 20, 2016, 03:47:56 PM

Name that album: "We have miles and miles of Files, pretty Files, of your forefather's fruit...."

http://www.fjowners.com/index.php?topic=5620.0

racerrad8 · July 20, 2016, 04:15:30 PM

Quote from: Pat Conlon on July 20, 2016, 03:47:56 PM
Name that album: "We have miles and miles of Files, pretty Files, of your forefather's fruit...."

http://www.fjowners.com/index.php?topic=5620.0

Moody Blues...On The Threshold Of A Dream

Randy - RPM

fjbiker84 · July 20, 2016, 08:12:04 PM

Thanks, Randy, for taking the time to call me and go over everything. Is this great customer service or what!

fjbiker84 · July 21, 2016, 05:36:41 PM

Randy, the old Clymer service manual I got with my FJ says to install the tensioner with the one-way cam up. You said to install it down with the RPM adjuster. Is the OEM adjuster just different or maybe the manual made a mistake? The picture is sideways - sorry - if I turn it 90 degrees it cuts off part of the page.

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cam chain tension