Manual cam chain tensioner

[mad4106]

I was reading on another atv forum with a guy that had a 440 big bore and he sayed a manual cam chain tensioner is a must for a built 400 cause a stock cam chain tensioner can fail and mess us the motor is this true resulting in damage valves or worst is this true and do recommend me getting one before I put my bb kit on?

[jman7290]

The problem with the manual tensioner, is that it is on you to adjust the tension. How do you know when and how much tension to put on the chain? Sure if it makes noise tighten it up, but that may be to late, and like I said how do you know how much to tighten it? My cousin has a built 400 with a x6 cam and he was snapping even the heavy duty cam chains within a few rides. He got a Suzuki Z400 cam chain tensioner because it is a heaver duty tensioner and mounted it right up. The only thing that you have to do is grind out the opening a little bit to make sure that the little piston of the tensioner that puts pressure against the guide to put tension on the cam chain fits through the opening without rubbing against anything. He has been riding since last Fall with no problems so for. I would also get a timing chain for a 450R and put in your bike,, it is heavy duty also.

[400man]

well this is the first ive heard of using a z400 tensioner, so the bolt holes line right up? might have to pick me a cheap used one up and see how good it fits,

[BlasterEaten250]

My stock tensioner failed. The Suzuki tensioners are also known to fail. If you are worried about it I'd recommend a manual one and just read up on how to adjust it right, then you won't have any problems.

[CJM]

The stock ones dont fail very often. Infact every rebuild I have done (3 of them) I checked mine. Whatya know it was fine somehow.

My friend had his fail, were not sure why. he bought another one that was used and it failed. Replaced the cam chain and guides-no more failures.

Im convinced they will only fail if the chains bad.

[BlasterEaten250]

Originally posted by CJM
Im convinced they will only fail if the chains bad. This could be, mine failed before I put the 450 chain in. Mine also had a LOT of hours on it.

[dxcody]

Originally posted by CJM
The stock ones dont fail very often. Infact every rebuild I have done (3 of them) I checked mine. Whatya know it was fine somehow.

My friend had his fail, were not sure why. he bought another one that was used and it failed. Replaced the cam chain and guides-no more failures.

Im convinced they will only fail if the chains bad.

On every 400ex I have never had one go out either. I have rebuilt/helped rebuild 2 of my friends (funny how everyones quad who isn't mine turns out fine, but mine always breaks...? anywho) and 2 of mine... Never had a tensioner go out!

in fact I have a good one still just laying in the garage.

I don't know what causes them to break or whatever but when I had my Z400 everyone told me, do the timing chain tensioner mod (whatever that is) and replace the timing chain... 400ex timing chains usually only stretch if you have your engine apart a lot, or many many hours it seems like to me..

[jman7290]

Yes the bolt holes line right up. Like I said he had at least 3 stock ones break on him in a matter of a few rides each, and has had no problem with the Z400 one for almost a year now. And yes he knows what he is doing, rode and worked on ATV's since they were invented, Tractor Trailer Mechanic by trade, builds Hot Rods from the ground up in his free time, builds modified dirt track cars from scratch that he races, even fabricates cromolly frames for 250R's, 400EX's, and 450R's for $1500 bucks. Some of you may have heard of him, Tommy Marshall of Wild Crowd Racing from Western PA.

[jman7290]

I am not sure where Blastereaten250 got his info from because I just searched the net and the only thing that I found on the Suzuki tensioners is that they have a lot of spring tension and cause the cam chain to wear out on the Z400's fairly quickly. I also found that for $28.00 Alba makes a cam chain extension kit for the Z400 that gives you more riding time before you have to replace the cam chain. It takes less than 10 minutes to install and has been proven for over 8 years now. Like I said its a heavier duty tensioner and works well on built engines. My cousin should get some sort of reconition for this fix on built up 400EX motors!

[atvrider13]

I have personally seen 3 seperate 400exs cam chain tensioners fail causing big damage. I only use manual ones now

[BlasterEaten250]

Originally posted by jman7290
I am not sure where Blastereaten250 got his info from because I just searched the net and the only thing that I found on the Suzuki tensioners is that they have a lot of spring tension and cause the cam chain to wear out on the Z400's fairly quickly. I also found that for $28.00 Alba makes a cam chain extension kit for the Z400 that gives you more riding time before you have to replace the cam chain. It takes less than 10 minutes to install and has been proven for over 8 years now. Like I said its a heavier duty tensioner and works well on built engines. My cousin should get some sort of reconition for this fix on built up 400EX motors! z400 and drz forums. That is a common mod for those engines to upgrade to a manual tensioner.

[jman7290]

Yes it is a common mod that people do to the Z400, but not because the tensioner fails. If you do more research, it is because the OEM tensioner has so much tension it wears out the cam chain prematurely. Also in the reading you will find that it is really hard to adjust the manual tensioner to the correct required position, and the reason that Alba came up with a cheap fix that will keep you riding more so you don't have to replace the cam chain so soon. Anyway it works good on a built 400EX motor, and who cares about Suzuki anyway?!!! I have another cousin that is a die hard Suzuki guy and he gives my other cousin hell for having to put a Suzuki part on a Honda to make it reliable!!! Hopefully this info helps some of you fellow EX guys out, I just feel its a better option than a manual tensioner and an insurance policy.