KymcoForum.com
Scooters - Big Bore => Xciting 500 => Topic started by: mr_cooper on June 25, 2012, 05:25:10 AM
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Hi All: I'd like to share my experience in trying to tackle the infamous "elephant trumpet" sound which occurs at take-offs.
If you put up with that awful sound (caused by the clutch's “glazed†shoes slipping while engaging at take offs) well, don’t keep reading.
If, on the other hand, like yours truly, you are totally annoyed by that unbecoming whine, then, you’re on the right topic.
After temporarily addressing the problem a few times by taking the clutch bell apart (for which you need an impact wrench, the nut is 18mm) every 500/600 km or so, to clean it and sand the clutch shoes, I really wanted to solve the matter for good.
I did some extensive online research and considered many options, among which, replacing the stock clutch with aftermarket ones.
I discarded the idea given the cost and after reading that the problem came back notwithstanding the replacing of the part. I finally stumbled upon an Italian forum in which somebody nailed the problem by drilling holes on the clutch bell.
http://lnx.xcitingclub.com/forum/viewtopic.php?f=18&t=5647&p=74367#p74367 (http://lnx.xcitingclub.com/forum/viewtopic.php?f=18&t=5647&p=74367#p74367)
This mod is a true win-win: it dissipates the heat on the clutch bell and disperses the powder coming from the clutch shoes!
Mind you: this is not a DIY project, at least not completely: you need some shop machinery to achieve the desired result, namely a professional drill bench.
The holes have to be drilled at specific distances to prevent the bell from an unbalanced rotation.
It' a series of two rows of 12 holes each, drilled 30 degrees apart and 15 degrees off one series from the other.
It’s really important the holes be drilled within the operating surface of the clutch shoes (this is easily ascertainable by looking at the inside part of the clutch bell).
I took pics of my clutch bell before and after the “cure†and I’m going to resize and upload them pretty soon.
Cheers!
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Will the whining affect the engine if i'll leave it alone?
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The "nasty" sound will not affect the engine performance, so I was assured by the Kymco dealer mechanic.
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I wonder if its the same whining sound from my super 8... which sort of I like. :D
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This is the second batch of the pics.
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Instead of drilling holes, why not just replace the clutch bell with ones with holes?
(http://www.scooterdynasty.com/images/products/detail/naraku_clutch_bell_gy6.jpg)
(http://t0.gstatic.com/images?q=tbn:ANd9GcRFCMrRjgmQZO6X4nvKQtw20M-ENeVJRuY8QKsphvZfMr3fhuqPbwsguCPL)
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One very good reason: in my case, it cost me nothing.
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ah...ok ;)
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Vivo, who makes those? I would not want to tackle that job myself. If you are off by even a small amount, it will be out of balance and then all hell will break loose. You look like you did a very good job though. It should work. I like the look of vivo's bell as it should run much cooler, and is lighter too I would guess? :-*
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Vivo, who makes those? I would not want to tackle that job myself. If you are off by even a small amount, it will be out of balance and then all hell will break loose. You look like you did a very good job though. It should work. I like the look of vivo's bell as it should run much cooler, and is lighter too I would guess? :-*
Those are after market, not mine, ;D Naraku and Ruima brands.
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http://www.g-forcepowersports.com/narabe11.html (http://www.g-forcepowersports.com/narabe11.html)
Note: this link shows a clutch bell for quads.
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never had that growling problem again since i drilled holes on the bell. i don't think balancing will have a big effect on it because the shaft sits on the tranny cover
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http://www.g-forcepowersports.com/narabe11.html (http://www.g-forcepowersports.com/narabe11.html)
Note: this link shows a clutch bell for quads.
Does this cluch fit to xciting? If not where I can find one with the holes?
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DO NOT DO THIS!!!!!!! Those after market bells have a reinforced ring around them to keep it from blowing apart. ONCE AGAIN DO NOT DO THIS TO YOUR STOCK CLUTCH BELL....
If you need proof of what happens to a clutch bell when it blows up look here. If you were riding when this happened you wouldnt walk right again.
CVT EXPLODE THE MOVIE ＜scooterchamp2004＞ (http://www.youtube.com/watch?v=FcZ9ixUyV9U#)
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Any ideas what they have done to bell in this video?
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Seriously? This video looks to me as if they staged the whole thing on purpose, just to get their kicks out of blowing the CVT off!
I think that the mod I did with a qualified Mechanical Engineer actually drilling the holes and giving me his blessing, is 100% safe.
Anyway, it was my clutch bell, my experience which I am sharing on a public forum where all sort of teh Xciting mech problems/issues are dealt with. One more thing: given the fact that what I did applies to a 500cc maxi scoot and, therefore, only adults are legally riding it, I take it that it is safe to assume each and everyone is free to do what they want. I am not pushing anybody into doing anything (you wrote in bold and capital letters "don't do this", so maybe they'll listen to you). Once again, my two cents: always get the whole story before jumping into conclusions. Like ahonekal pointed out, I, too, would like to see the condition the bell was in, before the stunt was being pulled.
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I think that the mod I did with a qualified Mechanical Engineer actually drilling the holes and giving me his blessing, is 100% safe.
Yes, but you should have also consulted a Metallurgical Engineer. He's the one who can tell you about the characteristics of metal. Will the drilling of holes weaken the metal? how many drilled holes are considered safe? size of hole? what about the hole locations? etc... The original (no-hole) bell has certified specs of Kymco, tested and evaluated and I don't know if they concur with this drilling. Maybe you can ask them.
Anyway, thank you for this informative post. ;)
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No holes drilled that I can see? It just blew up! ??? :-*
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The fact is that you weakened the structure, and did nothing to reinforce it. I have several racing bells and every one of them is reinforced. Just posting my real world experience of a seeing first hand a home made "lightened" clutch bell blow apart at the drag strip. Has the bell been balanced on any kind of CHRA machine? At very minimal before Id risk my life or people traveling next to your vehicle get it at least on a VSR. An easy way to calculate rotational mass is here if you were interested in real world values of lightening it. Did you get a copy of his auto cad for the spacial points? Ie how many holes per distance.
http://easycalculation.com/physics/classical-physics/moment-of-inertia.php (http://easycalculation.com/physics/classical-physics/moment-of-inertia.php)
I understand your need to feel you did the right thing and your right, but be careful with it is my 2 cents, I have seen the bad outcome but unfortunately didnt have it on film. That video I linked was a representation of what happens when a bell explodes. It isnt just the rider who is injured, remember that. Also further more, if you did have an engineer do this, he assumes liability for the part he modified. Just in case things go south its a good fact to know. That does not mean you are not held responsible for any damages, just he will share the wrath.
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The X500 bell is very very heavy duty, and I doubt the amount of holes he put in it will weaken it enough to blow up? But if it were me, I would go with an after market bell if I thought the honk/squeel noise was that much of a problem. They may be lighter also? And I don't think the cost is that huge for a new one either. Just my 2.5 cents! :-*
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Cannot find any aftermarket bell with holes in it? Can anyone helo me? :o
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Cannot find any aftermarket bell with holes in it? Can anyone helo me? :o
Google...
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Google...
I know, but still cannot find, any hints?
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"Elephant trumpet" ? I'm glad you got yours fixed..
Here's my problem...
My 2012 Xciting 500 makes a noise that I can pinpoint to the variator area. Sometimes it's very noticeable--in particular when it's hot outside (+90) AND WHEN I'm first pulling away under a heavy load. It almost sounds like your poking a sleeping bear / or the rumbles of thunder in the distance. The noise goes away above 4k or so and comes back when leaning into curves. When it's really loud / hot, there's a loss of power. I pull away from a light slower than usual.
When I had about 2k miles on it, I took it to the dealer. They pulled the covers off of the variator and clutch housing for inspection. They took a look at the belt and it looked brand new. Nothing seemed to indicate anything wearing, glazed, or loose.
My dealer is going to change the belt out to see if that fixes the problem. Mine is the only other one of all the Xcitings they've sold over the years that does this. Kymco authorized the belt replacement on the other person's scoot. Acording to the dealership, Kymco had not heard of this problem.
Just an F.Y.I