My 2009 with 10,000 miles has developed a fairly loud ticking noise, especially at idle and slightly above. I have traced it to the auto decompressor on the exhaust cam. If I turn the engine over slowly using a socket on the end of the crankshaft, there is a point at which the decompressor suddenly moves and makes a "tick". It might be the point at which the exhaust valve is allowed to close. The whole decompressor mechanism is loose and sloppy. The only part that can be replaced on it is the small spring, and I have ordered one, but that doesn't seem likely to be the problem.

I could buy another exhaust cam, but that is $181 on Bike Bandit.

Another option is to remove the decompressor. Has anyone had any experience with this problem. I could live with the noise if it wasn't for the fact that it is getting worse and I'm afraid the decompressor might come apart and do some real damage.

 

It may not be the KACR device, and it may be the cam chain. That "clack" you hear when turning over the engine with a wrench is fairly normal from my experience. It is the KACR, but that doesn't necessarily indicate a failure. The noise you hear when the engine is running may be a loose cam chain due to a faulty OEM tensioner. I'm not standing there with you looking at and listening to your engine, but that's my best guess from here.

 

I also have a 2009 KLX250

Knowing how the compression release works - when the shoes are out it is disengaged, I bent a piece of coat hanger wire (perfect because of size and that it is mild easily bendable steel) and put it in place to disengage the compression release. The reason was it was free, getting the compression release pressed out would cost me or be a pain in general.

Made a squared off U bend, 41mm inside length, perfect fit with the shoes full out, disabling the CR. Then...



I bent the wire out to the outside and clipped the excess off.




At the same time I did the Marcelino cam timing modification. In fact that is why I disabled the compression release. It would not be properly timed for the repositioned cams and repositioning it would be a pain to do and have to be redone if I set the cams back to the original setting. Just easier to securely wire it in a disabled position.

The 250 turns over and starts fine without the release. I have the richer pilot jet recommended and so far my engine starts with full choke when cold, being able to be ridden off almost immediately, warming very quickly and when fully warmed up it starts no throttle almost instantly then too. I believe Kawasaki left it on there because all the KLX300s and 90s versions of the 250 had kick start only and may have needed the compression release.

I also did some research and found the Honda CRF250L doesn't use a compression release in their engine and I think I also found the WR250 doesn't either, so it makes sense that the KLX really doesn't need it. Fact is there are KLX650 riders who have removed the compression releases from their KLX650s, but I won't go that far. The 650 doesn't spin over quite as easily as the KLX250.

EDIT: Just saw TNC was here, replying at the same time... I would say verify the clacking is coming from the upper left corner of the head and not from the right side cam drive. If you disable the comp. release you should check valves as well and if the noise is still there, do the cam chain tensioner. Contact me if you need a tensioner - I make them.

 

I know it is the KACR because I can see it click when I turn the engine over by hand with the valve cover off.

 

KLX 678,

Your mod looks like the way to go. Can it be done with the cam still in place?

 

Don't they all do that when the engine isn't running and you turn the motor over by hand/wrench?

 

^^ Mine does...the shoe on the ACR rides on the valve shim and when it rotates past it(the shim bucket) snaps close to the cam profile-that's what is making that noise. I would take a closer look at the tensioner.

 

Why, yes, they do. It holds the valve slightly open then clicks as it closes. Sorry to say to the OP, it is no proof of any issue with the release. Fact is it proves it works. The only time I've ever had noise from a compression release is if the idle drops low enough that it starts to kick in.

Still, I'd disable it again in an instant on the 250 just because it is one less moving part to break. The 650s actually occasionally have one break, but I don't believe it is common occurrence though. From reading the Marcelino thread it is clear the timing of the CR isn't particularly perfect and is totally wrong with the mod. The other 250s don't seem to see it as a necessity, others backed that up having taken the springs off (still leaves moving parts), and per my experience at this point, the CR isn't needed for that small an engine with an electric start.

 

I believe it would be rather awkward to try to do so and if you clip the wire end the bit of wire could end up in the engine somewhere. I'd only do it with the cam out and I'd do the Marcelino cam mod at the same time if the bike is the stock 250. Check the valve clearance to see if it should be reshimmed (work the middle spec or bigger, valves will usually lose clearance on shim over/under bucket valve actuation, valves seat/wear deeper into head). Remove the tensioner, pull the cam and do the lock out. Do the mod if you like.

The simple key is to read the post, then notice in the pictures, once the cams are bolted into the different hole set. Having started with the engine at TDC compression, the cams are placed in with the marks 2-1/2 teeth above parallel with the head surface. the intake is 2-1/2 counterclockwise and the exhaust is 2-1/2 clockwise looking at the two inner lines. That is the visual key that the cam settings are correct. Actually pretty simple once understood.

As noted earlier, that clicking you notice is proof of normal compression release action. Take a serious look at the tensioner. I have quite a record of failed Kaw ratchet style cam chain tensioners based on how many I've sold - not just for the KLX250 either. I had two fail in less than 14,000 miles on my 650.

Personally if I pulled the OEM tensioner for any reason I would dump it and put in a manual unit, but then having had four total failures in my three most recent bikes and the fact that my SR500 actually has a manual set up from the factory, that just makes sense to me.

Sure, I sell the parts, but I could work 2 hours at Home Depot and make more than I make on a tensioner. More a case of trying to help head off problems, problems I experienced, for others and a bit of enjoyment...

 

That's the only point I was trying to make to the OP. That "clack" from the KACR when you turn the motor over by hand is normal.