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Old 05-18-2013, 10:09 AM   #1
ciukes OP
ciukes
 
Joined: Apr 2011
Location: London, UK
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KTM 640 LC4 - Loud clicking noise when idle

Hi guys,

Can you help me to identify source of loud clicking noise I can hear when idle?
It goes away if I rev a bit and comes back when engine is back to idle.
It comes from exhaust valves area. Can it be automatic decompression ?

http://www.youtube.com/watch?v=yqmnOkkR4iE

Any idea? Is this something to worry about?

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ciukes screwed with this post 06-04-2013 at 02:27 PM
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Old 05-18-2013, 11:24 AM   #2
Idle
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Is there any metal on the oil screen or the magnet?

It sounds like the valve clearances are too large. If that's the case, the cam follower bearings (CFB's = rocker arm bearings) are suspect.

If you find either intake or exhaust clearances way too big, the valve cover needs to come off to check the CFB's.

When you pull the inspection caps, find TDC and wiggle the rockers up and down. Note how much if any movement there is, then kick the engine over 6-8 times or use the starter to turn it over.

Then find TDC again and do the wiggle test again. If it's different, even a tiny bit tighter or looser than before, the bearings are likely toast.
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Old 05-18-2013, 11:33 AM   #3
Seikkailu_R
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Too slow idle and automatic decompressor working?
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Old 05-18-2013, 12:02 PM   #4
Droptarotter
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It sounds like it is idling high enough to stop the auto decompressor noise.

Better check your valves and go from there!

If valves too loose.......you might have a rocker bearing going.

Idle nailed it!

Cheers
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Old 05-18-2013, 03:17 PM   #5
ciukes OP
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Thanks you all for the advice!

Quote:
Originally Posted by Idle View Post
Is there any metal on the oil screen or the magnet?
Yes, I found some small bits of metal on the magnet.

Quote:
Originally Posted by Idle View Post
It sounds like the valve clearances are too large. If that's the case, the cam follower bearings (CFB's = rocker arm bearings) are suspect.
I adjusted valves to the expected values.

Quote:
Originally Posted by Idle View Post
Then find TDC again and do the wiggle test again. If it's different, even a tiny bit tighter or looser than before, the bearings are likely toast.
Damn... looks like this is the case.
I know I should fix it ASAP but... how many more miles I can put on the bike before the engine will give up?

Considering I can do the fix, is it the part #12 on the diagram we're talking about (rocker bearing) ?
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ciukes screwed with this post 05-18-2013 at 03:40 PM
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Old 05-18-2013, 06:10 PM   #6
laramie LC4
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Quote:
Originally Posted by ciukes View Post
Damn... looks like this is the case.
I know I should fix it ASAP but... how many more miles I can put on the bike before the engine will give up?
depends, how much you like your bike?

get it fixed, don't ride it until you do.

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Old 05-18-2013, 10:22 PM   #7
bmwktmbill
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Don't try to ride it, you can do very expensive damage.
You will have to rebuild the waterpump at the same time most likely if it hasn't been done so prepare yourself for that too....

Think about what will happen if the bearing fails completely, think about metal in your oil and about your roller bearing crank.

Just saying.

You are paying, this is, the price of KTM 640 ownership.
bill
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Old 05-19-2013, 05:14 AM   #8
ciukes OP
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The story continues...

I removed the cylinder head top. Disassembled the rockers for inspection and found nothing alarming to my eye.
Rollers are tight, surface is even. Visual inspection proves they're not oval.
What do you guys think? Have I done all the checks to make sure rockers are in tip-top shape?

All things together before disassembly


Exhaust valves rocker


Intake valves rocker
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ciukes screwed with this post 05-19-2013 at 06:24 AM
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Old 05-20-2013, 12:42 AM   #9
bmwktmbill
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Ciukes,
I don't know a way to be absolutely sure they are good except to completely disasemble the rollers. If they feel tight they are still good.

I just replace mine every 15-20k miles and redo the water pump because I know they will fail.

Gunnerbuck has a very good thread on rebuilding them in the index.

I couldn't find his video but here's some of his wisdom.

http://www.advrider.com/forums/showthread.php?t=659238

We didn't see a picture of the metal on the magnet...were there broken pieces or just fuzz.

If it's chunks, I'd keep looking.

What year is your machine?

bill
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The faster it goes the faster it breaks.
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Old 05-20-2013, 03:00 AM   #10
ciukes OP
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Quote:
Originally Posted by bmwktmbill View Post
Ciukes,
I don't know a way to be absolutely sure they are good except to completely disasemble the rollers. If they feel tight they are still good.
They're tight and roll smooth. Beside, if the problem were rollers then clicking sound would be permanent regardless the revs, right? In my case clicking goes away as soon as I rev up a bit.

Quote:
Originally Posted by bmwktmbill View Post
I just replace mine every 15-20k miles and redo the water pump because I know they will fail.
I done the waterpump, because the propeller was shattered. Not sure if that's related to the "clicking problem"


Quote:
Originally Posted by bmwktmbill View Post
We didn't see a picture of the metal on the magnet...were there broken pieces or just fuzz.
If it's chunks, I'd keep looking.
I lost the photo:/ but what I found it was definitively fuzz forming a nice hedgehog on the magnet.

Quote:
Originally Posted by bmwktmbill View Post
What year is your machine?
It's 2001 with 6700 miles on the clock.
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Old 05-20-2013, 03:01 AM   #11
ciukes OP
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While cylinder head top is removed I went for crankshaft inspection. Focused on automatic decompression hoping to find something unusual that causes "The Damn Loud Clicking Noise"(tm) ;)

I know auto decompression should be a bit loose to work but can't justify if what I see is correct. I'd like to save myself the trouble of removing camshaft and messing with timing, so before I go too far can you guys have a look and tell me what do you think? Auto decompression moves in all directions but always springs back to initial position ( see 0:06 to 0:10 ).

http://www.youtube.com/watch?v=78KQ4uSbGv8
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ciukes screwed with this post 05-20-2013 at 03:56 AM
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Old 05-20-2013, 11:31 PM   #12
bmwktmbill
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Ciukes,
Fuzz on the mag is normal.

Has the transmission bearing been changed?

Got rocks in your skidplate?

b
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'02 KTM 640 Adventure-lowered
"On the road there are no special cases."
Cormack McCarthy-The Crossing

The faster it goes the faster it breaks.
And high performance=high maintenance.
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Old 05-21-2013, 01:37 AM   #13
ciukes OP
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Quote:
Originally Posted by bmwktmbill View Post
Has the transmission bearing been changed?
I don't think any sort of maintenance was done to the transmission. The gears change smoothly, I don't feel any problems. It has only 6,700 miles surely the gearbox can last longer than that. Am I wrong?


Quote:
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Got rocks in your skidplate?
Nope
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Old 05-21-2013, 07:57 AM   #14
rz35027
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Where are the parts from the water pump? You don't want to leave them in the coolant tract....
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Old 05-21-2013, 08:15 AM   #15
tundradirtbiker
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Put a straight edge across the swivel foot adjuster for your valves. They tend to cup with age. If you measure a perfect .005 the center space is greater making more noise.

Good advice on the bearings, my thumper chewed one and it was a mess. 400 hours max and I replace the complete rocker(s).
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