KLX 250 - Noisy tappets, or about-to-snap cam chain?

[Mr Hammers]

Got a KLX250 recently, and it's got quite noisy over the last couple of days. Once it's hot, there's a sharp metallicy tap all the time, which sounds to me that it's tappets or cam chain. Not sure which, tbh.

Also, it's impossible to rev over around 7 - 9k revs (I'm guessing as there's no rev counter), even on full throttle it seems to be limited and won't rev beyond that. I'm having problems with the carb at the moment as well, (but I'm sure there's enough fuel getting through on full gas) so I'm not sure if that's related, or if it's just the tappets or cam that won't let it rev freely.

Before I take the cover off, can anyone advise what it's most likely to be? I don't want to shell out on a new cam chain if I can avoid it, but if it is likely to be that, I'd rather get a new one before I take the cover off.

Lastly, until I get a manual for it, I'm not sure whether I can just adjust the tappets (easy and cheap) or if I have to bugger about with shims. Anyone know which system it uses..?

It's a 1994 KLX250E, btw.

Cheers!
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A Guide To Powerbands

[Gazdaman]

I had a KLR250, and it always sounded tappy.

They do have a tiny oil capacity, so make sure the oil level is ok. It's very easy to run them pretty much dry.

I think my old noise was cam chain. Could do the old screwdriver stethoscope trick. Listen to the handle end, and prod the tip end around the engine and listen for the noise.

Gaz

[Mr Hammers]

Tried the screwdriver trick already, but while I can hear a difference, depending on where I put it, I still don't know enough to be able to tell what it is I'm actually hearing..

Oil level is ok, if slightly under the mark.

Would yours rev all the way from 1k to 'screaming', btw? Or would it feel as though it was limited at around 7-9k, and feel a bit sluggish when riding? (No experience of mid capacity single 4 strokes, so I'm not sure what I should be expecting..)
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A Guide To Powerbands

[Gazdaman]

It does sound like you're reaching the 'redline'. I don't think mine was limited as such, it just runs out of power to rev any further.

They don't rev very high, being a single cylinder 4 stroke. And mine wasn't particularly quick either. I think it topped out at about 90mph.

How long have you had it? Could just be that you're not really used to the bike and the noises it makes.

Definitely worth whipping the cam chain tensioner out and checking it's ok. And checking its set up ok.
And maybe worth checking the valve clearances, I think they're just locknut adjustments.

Gaz

[Mr Hammers]

[Gazdaman]

It doesn't sound right! Mine would only cruise comfortably at about 65mph, but it was capable of going at least a bit faster.

I'd give it a compression test if you've got a tester (or can borrow one). Saves buying any new gaskets.
Low compression could account for your problems, let's hope not though.

Gaz

[Mr Hammers]

I do have a tester, but it's for the bigger plugs and not this tiny one. I've been trying to find an adapter for it, but no joy yet. But still, I'm hoping it's not that too
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A Guide To Powerbands

[Gazdaman]

Can't remember how the ignition works, if it's points, they could be knackered, which is messing up the timing.

Gaz

[Raffles]

[Robby]

Check the valve clearances first, then see. Checking them is free, camchains are surprisingly expensive. Also it's quite often the tension that is knackered, rather than the chain. Think of it this way:
The camchain is taking less load than the drive chain, is a triple row job, and is always perfectly lubricated. Considering that a drive chain can last 20k with maintenance, a camchain can last an awful lot longer.

Tensioners can be a bit shit though, jamming up and failing to extend to take up stretch in the chain being a fairly common failure.

[Gazdaman]

I agree with Robby, I would say either the noise isn't cam chain, or it's unrelated.

Since it sounds like you have a performance problem, I would be focussing on things that would affect the performance, like valve clearances, compression and timing.

Gaz

[Mr Hammers]

Pretty sure it doesn't have points, as it has a leccy box unit on it.

Will check the valve clearances at the weekend, hopefully it's just that (looks like it's a shim job then, if Raffles's was shims ) or it's just the cam chain tensioner that needs looking at.

Although saying that, just rode back to work and it seems to have gone quieter..maybe the auto adjust has kicked in..? It's still pretty sluggish though.

I'll keep looking to see if I can find an adapter for the compression tester in the meantime too.

Anyway, cheers all, much appreciated
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A Guide To Powerbands

[Grazoid]

Okay first step is to check valve clearances... if the ignition side has closed up you will get crap starting and it will run like a slug.

Next is cam chain tension. You can check this when checking the tappets. You should not be able to raise the chain off the sprocket teeth.

Next step is the tensioner. Make sure you are at the timing mark and whip the tensioner off. Check for wear and if it is working correctly ten either replace with a new one or re-tension and re-fit.

Then check your air filter.

Also does the noise go away if you pull the clutch in ? If so then check your clutch plates for wear.

[Grazoid]

Also how many teeth on your front and rear sprockets.... ?

[Mr Hammers]

[Raffles]

[Mr Hammers]

[ben_wheely]

I have this problem with my wr250 at the moment too.

I don't have a loss of performance though, just a unusual noise coming from the engine block (more from the exhaust side).

Its probally due for the valve clearences to be checked, just hope its nothing expensive.

To the OP let us know how you get on
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Rides: '05 Yammy WR290-F