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Discussion Starter · #1 ·
Hi there, fairly new to the motorcycle scene... My 2001 Kawasaki KLR650 decompressor on the exhaust camshaft let go/weld broke.... When it let go, it put a hole in the valve cover, which I welded up... I guess I am looking for
1. Information about what the decompressor does.
2. Where can I get a replacement exhaust camshaft
3. Curious, do I even need to replace the exhaust camshaft since it was running well even after the decompressor let go...
Any info on this would be greatly appreciate.
Thank you in advance
Frank
 

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At cranking rpm, the Kawasaki Automatic Compression Release (KACR, or whatever it's called) cracks an exhaust valve to, well, release compression. At engine-running rpm, centrifugal force disables the exhaust valve raising mechanism.

Some have reported successful engine operation without a KACR; might be another story were KLRs kick-start only.
 

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How many km on the engine? Tell us more about the condition of the exhaust camshaft Bearings.

Most KACR failures start with damaged RH bearing because of the engine being run with too little oil volume to reach that last bearing. (750-500ml still in sump after loosing or burning 1.75 - 2.0 L of total 2.5L)
The camshaft then starts to wobble around in the loose fitting bore, until a flyweight snags either the rear lip of the cover or the front lip of the cylinder head.

But I have read of a couple that did fail, probably because of a loose assembly rivet. And I have personally seen a loose rivet, which we had welded, before it could fail.

The KACR allows smaller starter motor & reduction gears to be used and reduces the torque loading on the one-way sprag clutch fitted between starter ring gear & the flywheel rotor. These components are quite durable with designed compression relief. (Specs of 77 - 124 psi with fully active KACR and proper valve tappet clearances.)
Because of the substantially higher engine compression (135 - 185 psi) achieved with an in-active or removed KACR, these components are more highly stressed.

Use of some automotive engine oils can initiate slippage of the starter sprag clutch even with an active KACR, which makes an awful sound as it slips, then grips.
 

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Discussion Starter · #4 ·
Not sure how much mileage, I think my son said about 21,000 km.... What should I be looking for in terms of lack of oil causing the issue. I look at the exhaust cam and it looks like the weld holding the decompressor let go.... This decompressor was welded (tacked) on to the end of the camshaft.
I do have some technical (hands on) car experience but no bike experience at all. So I am also looking for some diagrams to help me put it all back together. My son had some guy take the timing chain and stator cover off. Left me all the parts in a box (camshafts, bolts, washers, timing chain, gaskets etc.....) so slowly trying to piece back it all together. It is like trying to put a puzzle I never seen before all back together.
With help from the internet I am getting there. I put most it back together as a dry run, need to find a home for 3 washers still. These washer I think go in behind the starter motor gears, not really sure. Also looking on some info on how to align/match up the counter weight gear. I notice a small dot on the gear and shaft, guessing they must line up. As you can see, I got my work cut out for me. Any guidance is much appreciated.
Thank you
 

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A link to a Good Parts Retailer is in-valuable. Kawasaki's line-drawings are VERY Accurate in detail.

An OEM Service Manual SET (KL600 base manual & KL650 1996 to 2007 supplement) or a Clymer manual should be mandatory.

Here is the starter reduction gear shimming, 2001 Kawasaki KLR650 (KL650-A15) Starter Motor | Babbitts Kawasaki Partshouse
 

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Discussion Starter · #6 ·
A link to a Good Parts Retailer is in-valuable. Kawasaki's line-drawings are VERY Accurate in detail.

An OEM Service Manual SET (KL600 base manual & KL650 1996 to 2007) or a Clymer manual should be mandatory.

Here is the starter reduction gear shimming, 2001 Kawasaki KLR650 (KL650-A15) Starter Motor | Babbitts Kawasaki Partshouse
Thanks for that....

One more thing, since the counter balance chain and gears were taken off, how do line them up. Now that I am thinking about it, this is where I think those washers belong. Oh if I can ask, torque specs available somewhere...
I know I am asking more than offering but its a first time challenge for me. My son (he seems to know it all-not) is learning a lesson in patience.
Thank you
 

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Discussion Starter · #8 ·
Thanks for the info.. I will continue to learn and explore. Thank goodness for the internet. Still trying to figure out the position of the counter balance gears and chain. Patience is becoming a big part of this project.
 

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Discussion Starter · #10 ·
Thank you for that..... I will give it a dry go a little later on..... Working all day, coming home and doing some house work, leaves one a little tired :(
Thank you
 

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Discussion Starter · #11 ·
Not sure if I got it 100% (see picture).... And how can I confirm TDC without camshaft chain attached.
 

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The woodruff KEY in your crankshaft appears to be about 1 tooth too far to the right of Straight Between the Cylinder STUDs. I think that I remember seeing a Casting Line on the engine case, indicating TDC.
 

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Discussion Starter · #13 ·
So do you mean, I should rotate the crankshaft counter clockwise by one tooth...then reposition the chain accordingly. I will need to double check my TDC then.
 

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And how can I confirm TDC without camshaft chain attached.
Without confirmed witness and reference marks, TDC can be achieved with something like a dowel or rigid piece of wire stuck down the spark plug hole. As the crankshaft is rotated, TDC resides at the uppermost excursion of the "stick."

TWO TDC crankshaft positions exist with each four-stroke cycle; the one you want occurs when ALL the valves are fully closed.
 

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Discussion Starter · #15 ·
So without the camshafts installed, all I have to do is place the dowel down into the sparkplug hole, rotate the crankshaft counter clockwise until the dowel reaches top of its travel.... Without the camshafts in place, the valves would automatically be closed. Does this sound about right to achieve TDC.
 

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One can rotate the crankshaft fore & aft to feel the dowel pin. stick, wire, etc is at TDC.
Without the camshafts installed, keep the timing chain slack pulled UP.

Can you not see the bulges of the cylinder BOLT bosses in the case? Just simply CENTER the woodruff key.
 

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Discussion Starter · #17 ·
Can you not see the bulges of the cylinder BOLT bosses in the case? Just simply CENTER the woodruff key.
Sorry but I am not sure what you mean by the bulges of the cylinder Bolt bosses
 

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So without the camshafts installed, all I have to do is place the dowel down into the sparkplug hole, rotate the crankshaft counter clockwise until the dowel reaches top of its travel.... Without the camshafts in place, the valves would automatically be closed. Does this sound about right to achieve TDC.
Yes; geometrically, when the stick-in-the-cylinder reaches its zenith, you have achieved crankshaft TDC.

The, "two TDCs per cycle" comment applies when an operational camshaft is involved. Some, sometimes, make adjustments (e.g., valve clearance) at the WRONG TDC. Fully-closed valves provide a clue the correct TDC orientation has been met.
 

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Look between the 2 camchain guides and directly below the upper alignment dowel pin of your pic.
 

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Discussion Starter · #20 · (Edited)
So I doubled and tripled checked the TDC position.... Reinstalled (dry run) the chain and gears again, this is how it currently sits at TDC. Am I good to go, install chain guides etc.... or does something look off.... I did the TDC with the covers back on aligning the key with the T mark on the crank.
If this is good, I am going to dry fit the cams and camshaft chain.
I might even remove the other side and clean out the oil screen. I got a couple of weeks to play around and learn more before the gasket set shows up...Thanks for all the advice/help so far.
front 3.jpg
front 3.jpg
front bottome balancer gear.jpg
 

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