Nestrick

Mi. Trail Riders
Member
Aug 6, 2003
215
0
A couple of years ago I purchased a new 06 KTM 300 XC-W to replace my aging 02 CRF-450R ... it has been an excellent bike in every respect ... rides well, is comfortable, plenty of power and will chug through almost anything you can throw at it. However, soon after I put a few hours on the meter, the clutch began making a terrible "squawking" noise on engagement after the bike had reached normal operating temperatures. I have searched a multitude of dirt bike sites looking for reasons and/or solutions to this "squawking" problem ... all to no avail.

Interestingly, a buddy of mine recently obtained a virtually new 04 KTM 525 MXC from his brother who rode the bike twice and then let it set in the garage for several years. After cleaning up the bike, changing the oil, new plug, new fuel and new tires he began riding the bike in the mountains of Colorado and Moab. Aside from having MXC gearing, the bike rode nicely ... except, when fully warmed up, the clutch would also make a terrible "squawking" noise. Since my buddy was riding it in the mountains, fanning the clutch mandatory at times because of the tall MXC lower gears ... both the poor "engagement feeling" and the constant "squawking" of the clutch were driving him crazy. Although he was aware my clutch also made these noises, it took the problem coming to roost in his barnyard to get him working on it in earnest. Being a trained mechanical engineer and long time dirt biker, he was eminently qualified for the endeavor.

Recently he called to tell me that he had run across a post on KTM Talk that suggested the "squawking" noise was caused by insufficient oil getting into the plate stack at operating temperatures and at dynamic rpms. Seems that some KTM clutch pressure caps and inner basket designs do not allow sufficient oil to enter the central cavity of the clutch unit when it is spinning ... which at least appears to make sense with regard to the fact that both my 300 and my buddy's 525 clutches operate noiselessly after setting overnight and only begin to "squawk" after warming up ... oil easily seeps into the plate stack when the clutch is static for an extended period of time.

It is fair to state that my buddy tried several other "cures" before investigating the one I am about to describe ... e.g.; changing oils, disassembling the clutch and cleaning the plates, checking the plates for size and shape imperfections ... none of them provided a permanent cure. Note that disassembly of the clutch and cleaning the plates does help for a short period, but the squawking returns after only a few tens of engagements.

Fundamentally, the "cure" for "squawking" amounts to boring several extra holes in the pressure cap assembly thereby allowing more oil to enter the central cavity of the clutch while it is spinning so centrifugal force can push it out through the plate stack which thereby keeps the plates from sticking together and moving as a group rather than sliding over each other independently. It is this "group movement" within the stack that causes the poor engagement feel and the "squawking" noise.

The following are several pictures showing how he accomplished said task on his 04 KTM 525 MXC.
 

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Nestrick

Mi. Trail Riders
Member
Aug 6, 2003
215
0
The upper picture shows the 525 clutch cover removed and the pressure cap exposed. There are no oil inlet holes on this unit and it sets tightly against the inner drums of the clutch surface ... oil really has a hard time penetrating the central cavity of the basket, even under static conditions.

The lower picture shows the pressure cap removed, the plate stack removed and you are peering into the inner cavity of the clutch basket ... each of the six cavities has only a single hole to permit oil a passageway out to the stack under centrifugal force.

The solution to this problem was accomplished via boring two, concentric sets of holes in the pressure cap as shown the following two images.
 

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Nestrick

Mi. Trail Riders
Member
Aug 6, 2003
215
0
The upper photo shows the inside view of the pressure cap ... my buddy opted to drill a 3/16" hole in each of the cast squares between the spring towers, and a slightly larger hole [~5/16"] just outside the square casting. The pressure cap is aluminum so drilling is quite easy ... the unit was clamped in a vice vertically and each hole was drilled horizontally ... these were all done by eye, measurements are not that critical.

The lower photo shows the finished part with 12 new inlet holes for oil to penetrate the inner clutch cavity.

After careful cleaning and reassembly, the modifications have proven to be completely successful. The clutch no longer has a "vague" engagement feeling and the squawking noise is gone! The bike can be started from a dead stop in 4th gear, with considerable fanning of the clutch at full operating temperatures and not a bit of noise can be heard.

On the basis of this result I opted to apply the same operation to my 06 KTM 300 XC-W today ... here's a few shots and a bit of explanation regarding what happened ... interestingly, the clutches on these two bikes are rather different!
 

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Nestrick

Mi. Trail Riders
Member
Aug 6, 2003
215
0
The lower photo is the obligatory shot indicating that all you need to do to begin the work on a two stroke is lay the bike over on it's side and take off the clutch case cover ... don't have to take off the kick starter or the break pedal as you do on the 525 model.

The center photo shows how everything looks when you get started ... plenty of room ... only have to remove the brake spring from the case cover ... something best done after you get it loose ... and by the way, don't forget to hook it back up before you bolt the cover back on when you're done ... it's a real pain to get it off or on when the cover is attached.

The upper photos shows the pressure cap ... very different design than the previous 525 ... note that there are no oil inlets on the cap and also the close tolerances for the plate stack relative to the case diameter.
 

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Nestrick

Mi. Trail Riders
Member
Aug 6, 2003
215
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The upper photo shows the inner clutch cavity on my 300 ... I didn't remove the plate stack as my buddy did on his 525 in the shots above. Note that there are now five holes in each of the six cavities ... two on the bottom which presumably are to admit oil and three on the periphery to allow it to flow out and subsequently through the plate stack.

The lower photo shows the pressure cap ... looking at it from the inside ... interestingly, the spring towers have been cut to remove about 1/3 of the wall with the cutout facing the inside of the hub.

At this point in the "operation" I can tell you that I was considerably skeptical that my buddy's modifications were going to resolve my "squawk" ... although my clutch housing did lack any inlet holes on the pressure cap, it did have considerably more inlets and outlets on the inner basket.

Oh well ... I had come this far ... I might as well give it a try!
 

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Nestrick

Mi. Trail Riders
Member
Aug 6, 2003
215
0
The upper photo shows how I managed to drill 12 concentric holes of 3/16" diameter around the outer portion of the pressure cap ... drilled using the same technique described above for the 525 model.

The lower photo shows the outer surface of the pressure cap with my new oil inlet holes nicely arranged around the outer periphery. From this point on, I cleaned the parts and put everything back together ... didn't take the clutch plates out and clean them ... left them just the way they were when I started.

Conclusion:

To my amazement ... I fired up the 300 in the driveway and took off in low gear down the road ... the clutch being cold didn't make much of a "squawk" but it was still there and the engagement had it's normal "vague" feeling. I simply rode the bike for about 5 miles around town in stop in go traffic with several long, high speed legs to boot. When the bike was at full operating temperature I began testing the modification.

AMAZING ... I can't make it "squawk" no matter what I do! Even starting from a dead stop in 4th gear with tremendous fanning of the clutch and lot's of rev's the bike simply takes off without any noise whatsoever! Before the modification, even trying to do this in 2nd gear would have made a "squawk" that would make most riders cringe and wonder what was wrong with my bike.

I rode it twice more today ... allowing it to cool between runs ... same result ... engages much more smoothly, no SQUAWKING ... to say the least, I am extremely happy.

This modification has been in operation for a somewhat longer time on my buddy's 525 and it continues to function noiselessly.

For those of you who might be interested, both of these bikes are meticulously maintained, ridden hard and given 20W-50 Amsoil Motorcycle Oil on a regular basis.

Hope this information is of interest to others who might be suffering these same clutch "problems" ...

terry nestrick
 
U

Unregistered_Nikos

Interesting thread. Regarding the KTM 300 mod, I wonder if it would be worth filing the existing hub oil intake holes at an angle, so as to make them more efficient at letting oil in..
 

Danman

LIFETIME SPONSOR
Nov 7, 2000
2,211
3
My 06 450 has the "squak". I just deal with it. It does it when its crazy hot and cold. I might try this before I sell it. If I don't I will pass the info along to the new owner.
 


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