Cam chain tensioner reoccuring problem!

[Potenza]

First post here. There is a lot of good information regarding this, but I didn't want to open an old thread or steal someone else's, and I really wanted to focus on my specific problem. Thanks in advance for any help.

Here's the situation: I bought my bike April 18th this year. 2005 EX250. It had 5300 miles.

At 5700 miles, I did a valve adjustment. I'm entirely new to bikes, but I'm a car mechanic and followed the instructions on this site, so I think I did it right. Afterwards it ran fine.

Took a motorcycle course a few days later, which involved HOURS of idling in a parking lot on an extremely hot day. Bike ran hot most of the time (though never in the red). Developed a loud "clicking" and started running poorly. The instructor commented that he thought my valves were out of adjustment.

Upon coming home and reading up, I decided to check out the CCT. Sure enough the parts were dry and dirty, and the ball bearings were scored along with the rod and cap which they ride against. I cleaned everything with brakekleen, covered it all with oil and reinstalled it. The bike ran quiet and smooth, like new. I ordered a new tensioner. This was at 6069 miles.

Bike was still running well when I installed the new Kawi CCT at 6270 miles. Added Honda moly grease to the parts. Ran smooth as could be. By 6500 miles it was rattling again. I thought maybe I over-greased it. Took it out, wiped away some of the grease, replaced it. Still made too much noise.

Took it out again, bearings are scored - less than 300 miles on it! Just out of curiosity, I sprayed everything with brakekleen, lubed everything with oil, and replaced it. Ran smooth and quiet. Within 50 miles, it's starting to make noise again. (Though it wasn't my plan to continue running with scored bearings, of course.)

I just want to know what to do now. I figured the old CCT/bearings died from lack of lube and heat stress. But the new one? Did the Honda moly grease hurt it? Oil seems to be the better lube, quieting it both times I tried, even when the bearings were already scored.

Or is it another problem altogether? Seems hard to believe I would have a chain problem at such low mileage. And I've been driving it easy... under 7k RPM for my first 1k miles or so... never over 10k RPM yet. So I'm not abusing the bike. Did that one day of hot idling/low-speed-running damage something permanently?

Or, as I've read, do these Kawi CCT just suck that badly? I don't want to waste another $40 just to do this again. I've been reading about a manual CCT (though I can't see to find where this is sold or who makes it). Is this my solution? (Is it at least worth a try before ripping the engine open to look at the chain?)

I'd appreciate any help or insight. My bike is just sitting in the garage and I can't ride it until I solve this problem.

[Kevin2109]

Just get the MCCT

Is the ticking at idle? Or just above it? You may have thrown a rod bearing, what does your oil look like?

[Potenza]

Originally Posted by Kevin2109

Just get the MCCT

Is the ticking at idle? Or just above it? You may have thrown a rod bearing, what does your oil look like?

Where can I get the manual CCT? People keep mentioning it, but I can only find one for 08-up.

The oil should be good. I changed it at 5400, just after getting the bike. The old oil was fine (he claimed to have used Shell Rotella), and I added the same. But after I put the new tensioner on, I changed oil again just in case the chain was flapping and had caused any debris. There were very minor particles in the bottom of the used oil, but nothing too far from ordinary I'd say. That was at 6300, and I put in Kawi oil. Now it's at 6600.

The ticking/clacking is more noticeable at idle but I'd say it's evident throughout the rev range.

It might be a chain issue, but I don't think it's anything more serious within the engine. Every time I've lubed and reinstalled the CCT, it runs sewing-machine smooth for at least a bit.

[Kevin2109]

Replace the chain soon

and APE makes mcct, thats what im running in the 636

[Motofool]

Welcome to the site, Dustin !!!

All these CCT's look scored.
As you know, they are one-way mechanisms and rarely fail.

All these engines are noisy.
Noise comes from the valve rockers and from the clutch.

Your cam chain may have two problems: it may have jumped a teeth, messing the valve timing up (reduced engine power); or it may have stretched beyond specs (more than 128.9 mm for 20-link length).

One or both cam chain guides may be worn or damaged.

Just some things to consider and inspect.

Check this similar thread:

http://www.ninjette.org/forums/showt...ight=tensioner

[greg737]

Here's what I see as the "bottom line" for the the Cam Chain Tensioner, this is the basic understanding of the Cam Chain Tensioner's function, what it was designed to do and what it can't handle.

What is the Cam Chain Tensioner's job? The Cam Chain Tensioner is there to absorb the relatively slow changes in cam chain tension that occur when you roll on or off the throttle. It can easily handle this relatively gentle type of "lash" effect throughout the design expectation for lifespan between overhauls of the engine.

What isn't the Cam Chain Tensioner's job? The Cam Chain Tensioner isn't capable of dealing with the high-speed lashing effect of a worn (stretched) cam chain. As a worn (stretched) cam chain goes around-and-around at engine speed across the cam gears and the engine's drive gear it lashes excessively as it is subjected to the EX-250 engine's uneven power pulses (the two pistons fire 180 degrees apart and then there's nothing for 540 more degrees of engine rotation) and another possible contributor may be uneven wear of the chain that causes only part of the chain to stretch beyond the specified wear limits which would induce a "loose-tight-loose-tight" lashing effect.

So if you've got a cam chain wear problem no amount of cam chain tensioner maintenance will fix the problem.

[alex.s]

no manual tensioner for the pregens

[Potenza]

greg737, thanks for your reply... I had seen your name on previous, similar threads and you seemed well knowledgeable. Thanks to everyone for your replies as well.

I don't think the chain jumped. Like I said, each time I reset and relube the tensioner it runs like new for a bit. No decrease in power or any other issues.

So it seems like the consensus is that the chain's stretched? Is that even remotely normal for 6600 miles? I don't know how the previous owner treated it, but like I said I've babied it myself.

The final question then would be, where do I go from here... what's the next step? I'm mechanically inclined but otherwise completely new to motorcycles. Not sure I'm ready to rip into the engine. Is it easy to get to the chain? Should I take it to a dealership? The tensioner I can handle, but if it's something more... what's the best plan of action? (For either diagnosis or fixing).

Thanks again guys. Great forum!

[Potenza]

Originally Posted by Motofool

Welcome to the site, Dustin !!!

All these CCT's look scored.
As you know, they are one-way mechanisms and rarely fail.

All these engines are noisy.
Noise comes from the valve rockers and from the clutch.

Your cam chain may have two problems: it may have jumped a teeth, messing the valve timing up (reduced engine power); or it may have stretched beyond specs (more than 128.9 mm for 20-link length).

One or both cam chain guides may be worn or damaged.

Just some things to consider and inspect.

Check this similar thread:

http://www.ninjette.org/forums/showt...ight=tensioner

Thanks! I did in fact check out that thread ahead of time but decided not to take it over. Though the first time through I did not notice the link you posted for the manual CCT. That said, the link doesn't seem to work! Even in this own thread there seems to be a debate over whether a manual CCT is available or not!

So from what I gather with that thread, you have to drop the engine to do any of this? Even inspecting the guides? Starting to feel out of my league.

Starting to feel like I should have gone with the CBR250, in fact... :/

[alex.s]

the cam chain is noisey on kawis unfortunately.

inspecting the chain means pulling the valve cover off, which means moving the radiator and pulling some hoses and a few bolts. you could probably manage that fine. inspecting the chain guides or changing the chain is more difficult and requires splitting the engine. splitting the engine should be done with the engine out. honestly removing the engine is not hard at all though.

screw the cbr250. its slow.

[Motofool]

Originally Posted by Potenza

..........That said, the link doesn't seem to work!....

You are welcome.

The link works for me..... .....here it is again:

http://www.kriegercamchaintensioners.com/

You are just out of your comfort zone; this is easy mechanical work: you will feel confident soon.

Here are the principles:

http://www.dansmc.com/mc_repaircourse.htm

Doesn't Potenza means power in English?

[alex.s]

Originally Posted by Motofool

http://www.kriegercamchaintensioners.com/

oh crap its a pregen manual tensioner!!!

@RacerX

[Potenza]

Originally Posted by alex.s

the cam chain is noisey on kawis unfortunately.

inspecting the chain means pulling the valve cover off, which means moving the radiator and pulling some hoses and a few bolts. you could probably manage that fine. inspecting the chain guides or changing the chain is more difficult and requires splitting the engine. splitting the engine should be done with the engine out. honestly removing the engine is not hard at all though.

I've had the valve cover off to do the valve adjustment, so that I can handle. But probably not worth doing that again... is there really anything to see just by looking at the chain?

If it were simply a bit noisy, but normal, that I could live with. This seems to be a problem that gets too noisy, then continually noisier. I just think something is wrong, and the way it seems to be eating up tensioners - and the fact that cleaning and resetting them quiets it down - seems to verify that.

Maybe I should have a dealership take a ride and listen and see what they can think. I don't know what "normal" is, apart from how it was when I got it.

Or does anyone think it's worth getting the manual CCT and trying that for a bit to see if the problem goes away or comes back? Or is there possible harm in that?

[Potenza]

Originally Posted by Motofool

The link works for me..... .....here it is again:

http://www.kriegercamchaintensioners.com/

Doesn't Potenza means power in English?

Ok that one works, thanks. You should spread that link around... seems no one realizes it exists!

Not sure if I should try that route (the MCCT) before tearing into the engine. Or if it's just a waste of money, if the tensioner isn't the issue. Hmm.

Potenza is a type of tire... not sure about any translation.

[alex.s]

taking the valve cover off, you can remove the cam chain top lash guide thing, from there you can take several measurements throughout the length of the cam chain (turning the engine over by hand from the stator side), if the chain is unevenly stretched like greg is suggesting might be the case, it would account for the odd chain lash you get. if its even, then maybe the tensioner is to blame. the cam chain is never going to shrink, i don't think, so the tensioner getting looser shouldn't happen right? someone said these automatic tensioners are supposed to be "non-return" but it sounds like yours returns until you loosen it and retension it? the manual tensioner will fix that but keep in mind you may need to check and adjust it every now and then

obviously dont turn the engine over if you take off any of the secured bearing cages

[Potenza]

Originally Posted by greg737

What is the Cam Chain Tensioner's job? The Cam Chain Tensioner is there to absorb the relatively slow changes in cam chain tension that occur when you roll on or off the throttle. It can easily handle this relatively gentle type of "lash" effect throughout the design expectation for lifespan between overhauls of the engine.

So if it can "easily handle" this for the lifespan between engine overhauls... what would be the issue with a 6000 mile engine??

What causes a chain to stretch, if that's the issue? With my riding I've been averaging 80mpg. I'm not exactly abusing this thing, to put it mildly.

[davenay67]

A camchain *shouldn't* be stretched or unevenly worn after only 6K miles, but it doesn't mean that it can't happen. If I were you, I would measure the links on the camchain at various places and compare the results you get to see if the chain is either (a) beyond service parameters, or (b) unevenly stretched.

If the chain is fine then you may want to investigate further the potential of a manual CCT, but if the chain is not OK then it may be a case of replacement and moving on from there.

My WAG is that your chain is unevenly stretched and kicking the crap outta the CCT....like I said though, just a WAG.

[Motofool]

Taking it to an experienced shop or Ninjette owner for checking the noise before doing anything is a great idea.

Again, it may be anything but the cam chain.
Rocker arms that get loose or break are another example of increased noise and reduced performance.

Sometimes, we develop a fix idea and attack a "problem" that never existed.

In my experience, inspecting, testing and measuring are always more productive actions than just speculating.

[Potenza]

Thanks for all the good ideas today, guys. I appreciate all the input.

Looks like I'll have to try some things, then I'll update with any finds and solutions, for reference.