17mm Pulley Nut

[phin63]

I want to replace the variator bushing, but I was stopped in my tracks by the 17mm pulley nut that holds the variator on the camshaft. I was able to pevent the shaft from turning by holding a screwdriver in between the teeth of the gear and bracing it, but I couldn't get the nut to break even though I was able to get some good force into it. Is it a reverse nut? Should I get a breaker bar and a friend to help? There is a special tool to hold the camshaft still,but I don't have it. Does anyone have any tips or suggestions to remove the nut. Are there any tips or suggestions for the job as a whole?    Paul

[OldGuy]

If you're going to do much of this at all the easy way is an impact wrench. This one is 110 v. and currently on sale at Harbor Freight for $33.99.



http://www.harborfreight.com/cpi/ctaf/displayitem.taf?itemnumber=45252&Submit=Go

Don't know how far Warwick is from you (How far could it be in Road Island? R.I. ain't Texas. ) but, there's a Harbor Freight retail store there.

http://www.harborfreight.com/cpi/ctaf/retail_stores.taf?f=detail&Retail_Store_ID=260

...and no, I do not work for Harbor Freight. I've just found it a great place to buy tools at a reasonable price.

Hey, lookee! I just made Full Member!

[yvg]

Impact wrench is a wrong thing for this nut. It will work and you will get things done, but you will definitely apply excessive force and vibration to all the engine - crank and camshafts, chain, piston and rings - and all this while having lack of lubrication because of the oil pump is not running.

I suggest you to make a simple holder with three or more teeth that you can fix on the bolts that normally hold transmission cover (use minimum of 2 bolts). If you have angle ginger, then here is a hint: 115 mm cutting discs perfectly match diameter of non-moving variator gear that you held with screwdriver.

Yury

[OldGuy]

Been using one for this purpose for years without a problem. With an impact wrench it is relatively easy to hold the variator and just turn the nut. The shaft stays still. It only takes about 3-4 beats to loosen the nut.

[phin63]

Thanx for the replies. I saw a holding tool online that was just a metal bar with a couple of teeth,so I see how the cutting disc would work. I had to go all the way down to Warwick to get the Kymco and it took almost 20minutes to get there. Except for a couple of the islands you can get to anywhere, from anywhere in less than an hour in our state. I'll have to check out Harbor Freight, maybe I can get a discount if I tell them that "Old Guy" sent me.  Paul

[Areomyst]

This is a topic of some debate.

When it comes down to it, if you have a good feel for your impact tools, they will work just fine.  I do scooter work professionally and I use the impact all the time.  Low torque setting, and only let it "ratchet" a few times after the nut is tight.  I've seen people hold the impact gun on the nut... Usually sounds like "Bwadadadadadadadadadavrooooooo!" followed by "Oh sh**!" when they realize they stripped out the threads on the crankshaft.   Guess who got to replace the crank?  Heh.

Holding tools and torque wrenches are the "by the book" method.  When I was in Costa Mesa CA for Piaggio/Vespa training, I didn't see an air tool in the whole shop.  It was pretty amazing really... Many of us though, don't have the luxury of having every puller, holder and specialty tool known to man at our disposal.

~Josh

[phin63]

The variator holding tool would be worth having. Is there one that is made to use on the Agility, or do you use a universal holding tool? If  Kymco had just put a couple slots for  some "maintenance bolts" to hold the variator life would be much easier.   Paul

[phin63]

I found what is supposed to be the correct holding tool for the Agility 4T made by Buzzetti (Holder tool Variomatic Kymco / BU-5582 cost:aprox. $13.50 US). I had to order it from  SIP-Scootershop in Germany. They require a $100 minimum order (to U.S. other countries may differ) which I really don't like,but there were only two sources that I found. The other source also in Germany had none available.  So I also ordered a Polini variator and a Malossi kevlar belt to get the order up to it's minimum. I will report if this is the correct tool, and how well it worked when it arrives. I will also give my impression of the new variator and belt.    Paul

[yajblackburn]

Hey Phin, a fellow Rhode Islander I see!  You must of have went to Java Speed, am I correct?  An impact wrench will work fine, been using them for years. 

[phin63]

I haven't been to Javaspeed in a few months now. I do often ride over to the "east side" on nice days. I've been to many Grateful Dead shows and that tells me that your friend the toad is not from R.I.. I'm really only used to hand tools so I think I'm missing something. A friend helped me (we tried strap wrenches and a few other things) and we couldn't hold the variator face still even with just the force of a hand wrench on the pulley nut. Wouldn't an impact wrench supply a greater force making even harder to hold? The holding tool is on it's way, but my interest in impact wrenches is stirred up and I'm always willing to learn so let the explanations fly.    Paul

[OldGuy]

It's a matter of inertia. An impact wrench works by making use of the concept of "impulse". Ordinarily we view Newton's 2nd Law as Force = mass x acceleration. But acceleration is equal to the change in velocity divided by the change in time, a = dv/dt. If this is substituted into the 2nd law: F = m x dv/dt.

In an impact wrench the wrench socket is given a substantial initial velocity. When the socket contacts the nut, the socket is suddenly brought to rest, thus undergoing a rapid acceleration dv/dt. If the time of the impact is very small, the resulting acceleration will be VERY large and the resulting force will likewise be very large. The point is for this impact to move or break free the nut through this very large "impulse" with very little long-term rotational force being applied. This being the case, it is much easier to keep the part from turning while the nut is loosened.

[yajblackburn]

I've only been to Java Speed a few times.  They are the only Kymco dealer I am aware of in Rhode Island.  The best place I found for Kymco parts is Burlingtonyamaha.com.  They are right near the American Kymco factory in North Carolina, so they can get those hard to find parts and get them rather quickly.  I live in Newport and am great friends with the local motorcycle shop owner, plus the whole trip over the bridge deal is a pain in the ass, not to mention a $2 toll each way.  It's weird how the impact wrench works.  If you took a normal drill and put the socket on it, it would spin and spin and spin.  But the impact wrench pulses as it turns.  Oldguy knows more about this than I do.  All I know is it definetly works.

[phin63]

 I knew was missing something and now I understand what it was. My dad had bought me a Craftsman wrench set in 1977 with metric sockets and it's the set I still use today, maybe it's time to purchase some "modern" technology. Thank you for the explanation it was very helpful.  Paul

[phin63]

The last time I was at Javaspeed they were only repairing scooters and selling coffee. They weren't selling new scooters. Yamaha/Suzuki World of Warwick is the only Kymco dealer in the area that I'm aware of. Between the wind,uphill grade and speed of the traffic I can see the bridges to New Port acting as a trap. I use Rt.24 and I know that it wouldn't be safe (or legal) on the Agility.  Paul

[phin63]

Honda/Suzuki World of Warwick (not Yamaha).