OEM Chain Tensioner vs Manual?

I know everybody likes the manual tensioner, but is it necessary on a street build?

Personally I thought the J engine automatic tensioner was a great idea. And I know a guy who worked on Police bikes breaking 200k miles and never saw a problem.

The theory is that OEM may possibly backup during extreme deceleration conditions (possibly jumping time). But is that realistic on a street build, or just an all-out race engine?

Very early on my bike jumped time when mostly stock . A manual cam chain tensioner is not nessasary but they do work well.
I run one now on my turbo build and the system is bullet proof
Dave

The earlier KZs used a different style tensioner, which I think is even better than manual. You loosen the lock bolt and spring tension adjusts the chain tension. Once you re-lock the bolt there's no chance of it backing up. But it still requires periodic adjustment. If yours jumped time due to the tensioner, I would imagine it was from lack of periodic adjustment, or the tensioner pre-load spring was no good when you adjusted it last.

It's just with the manual tensioner there's no accurate adjustment. "Finger tight" then a 1/4 turn out is not accurate. If they had an inch/lb spec on the adjuster bolt while rotating the engine, that would work.

But I read about so many folks adjusting by instructions, too loose, and they have to kill the rattle by adjustment running.And with my carb setup, there's no way of adjusting it running.

I have the old style adjuster. The ramp got worn so it would loosen. I installed a bolt at the end to prevent that. I had a aftermarket one but it was too hard to feel when it was tight. I ruined the center roller and guide. I went back to the old manual one.
Steve.

I like and still use the old style manual cam chain tensioner on my KZ1000 motors. Never had a problem with them causing the cam timing to jump. Hell, I used to shut the throttle at 10,500RPM all the time on my KZ1000, and never had a problem with it jumping cam timing.

The best way I found to adjust them was when I did my valve clearance check. With the spark plugs out, I would release the locking bolt, listen for the little click sound if the tensioner arm moved forward, then I would tighten the locking bolt. Then I would turn the motor over with the kick starter, and then grab the cam chain by the top tensioner and see if there was any slack part in the chain. I always run the cam chain through its whole length looking for any slack. If there was a loose spot, I would try to put it by the tensioner, and loosen the locking bolt again, and lock it again. Then I would turn the motor over, and make sure I could not find a loose spot in the cam chain. I don't care what the shop manual tells you how to adjust the cam chain, but thats the way I have done it since back in 1974!!!

Agree! The stock tensioner on my 1977 KZ650 is the old manual type. To adjust it you position the crankshaft at a certain position, loosen the tensioner bolt, and the spring in the tensioner adjusts the tension. You then tighten the tensioner bolt and lock nut, and at that point it is impossible for the tensioner rod to move in any direction. Ed

650ed wrote: Agree! The stock tensioner on my 1977 KZ650 is the old manual type. To adjust it you position the crankshaft at a certain position, loosen the tensioner bolt, and the spring in the tensioner adjusts the tension. You then tighten the tensioner bolt and lock nut, and at that point it is impossible for the tensioner rod to move in any direction. Ed

Yep, that was a great tensioner. The only issue would be a worn or broken spring not giving you the correct tension.

And if you notice there are high and low spots on the chain. So if you screw in an aftermarket tensioner bolt by hand on a high spot, then back off a 1/4 turn, you're not even close.

Has anyone ever heard of a J motor automatic tensioner failing and jumping time? I know it's bullet proof on a stock engine. The only relative difference on mine is 10.5:1 compression, .410 lift and heavier valve springs.

I got an OEM tensioner with the angled sliders, and I don't see how the hell this thing could possibly back up from extra chain force on decel? But I'm always a little paranoid, and will go this route.

I'm gonna drill out the back of the housing where the main slider rides. Tap it and install a bolt and lock nut. Once I have the tensioner installed, I'll turn the bolt in until it just touches the slider, then back it out a 1/4 turn., and lock it down. This way the automatic tensioner functions as as designed by Kawasaki, and the bolt is a failsafe preventing the slider from backing up enough to jump time under any condition.

That's what I did. No problems.
Steve

For the time it takes to mod a stock one I'd just get the APE one.

I charge $50.00 an hour for my time doing simple repairs so the time it takes to remove the stock one disassemble it
Set it up in the drill press so the holes straight, drill it, tap it, clean it, install bolt and reinstall on the bike then adjust it correctly.
I'm thinking around a $150.00 bucks would be fair for me to do a customer bike.
I could install an APE one for $50.00 plus parts and be done in under an hour.

I don't trust the APE ones anymore. Too easy to overtighten.
Steve

SWest wrote: I don't trust the APE ones anymore. Too easy to overtighten.
Steve

Then your not doing it right.
I've got them in two motor's now and will be putting one in the connie motor in a few weeks.