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Post by mechanical1990 on Feb 24, 2011 2:37:37 GMT -5
I was looking at some parts to compile a list of what I wish to buy for my scoot, then stumbled upon a variator with this in the desciption
"THIS VARIATOR IS DESIGNED TO ENHANCE THE PERFORMANCE OF AN UNRESTRICTED SCOOTER , ALL KYMCO 50cc 2 STROKES WILL NEED THE EXHAUST CHANGING FOR AN UNRESTRICTED VERION. THE RESTRICTION IS DEEP INSIDE THE SILENCER AND CANNOT BE SIMPLY CUT OR HAMMERED OUT."
Never heard of this before, but I am still new to 2 strokes! Any info would help.
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Post by lshigham on Feb 24, 2011 4:13:44 GMT -5
Have you got a pic of the exhaust? That way we can give you some idea about the type of restrictor. If it's anything like the Piaggio's the restrictor is about 6" down, the only way to get it out is to cut the exhaust open.
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Post by mechanical1990 on Feb 24, 2011 5:44:30 GMT -5
My exhaust is just the stock Kymco one. I just never heard of restriction being in the exhaust system, seemed a bit odd.
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Post by lshigham on Feb 24, 2011 6:23:46 GMT -5
It's certainly not uncommon with the 2T's.
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Post by buiditright on Feb 24, 2011 10:49:40 GMT -5
In a 2 stroke it is common for them to put a restriction in the exhaust. when I changed my stock exhaust to my Tecnigas I gained almost 10 mph and that was certified through police radar. Wheather I am just lucky or not I believe that it makes a difference.
Bill
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Post by mechanical1990 on Feb 24, 2011 14:04:40 GMT -5
Any suggestions for a cheap replacement without the restriction? I don't have $150 to shell out on the ones I have seen.
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Post by lshigham on Feb 24, 2011 15:20:35 GMT -5
$150 is a cheap as it gets for a two stroke exhaust. My exhaust cost $400.
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Post by mechanical1990 on Feb 24, 2011 15:26:18 GMT -5
Well, I guess it will have to wait then...  |
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Post by lshigham on Feb 24, 2011 15:44:57 GMT -5
Well, I guess it will have to wait then... Unless you feel like taking a saw to your exhaust, fraid so. |
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Post by kixome on Feb 24, 2011 15:51:46 GMT -5
it would be cheapest to cut the exhaust and take the restriction out then have it welded back together. If you know it is 6" in then you know about where to cut.
A muffler shop would charge no more than $30 if they are honest. Usually a simple weld would cost about $10 here at maxi muffler.
This is especially true since they don't have to take it off of, or lift a car. Before cutting make straight line marks at 4 places around the pipe,and straight across the area to cut. This way it can be lined up correctly.
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Post by buiditright on Feb 24, 2011 19:01:30 GMT -5
I tried that with my United MOtors XSpeed 50R but it did not change anything. But when I got the tecnigas it got me all kinds of speed and torque. It was unreal the power and speed that I obtained.
I could not believe how awesome it was..
Bill
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Post by digitalinsite on Feb 25, 2011 6:47:44 GMT -5
i've considered cutting my stock sf50 exhaust open but i doubt its worth it as it barely has any type of expansion chamber or enough length to get high rpm powerband. I think a new exhaust is basically the way to go.
just a question for you guys running technigas exhausts. To get good performance out of the exhaust do you need to swap your CDI for an unrestricted racing one - or is the factory CDI with the wire clipped OK?
also, what roller/slider weights are you guys running after putting the technigas exhaust on?
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Post by buiditright on Feb 25, 2011 7:37:34 GMT -5
Mark,
No just clip the wire that is the redtriction thats all I did. I do have a Bando coil though..
BIll
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Post by Panaramaguy on Feb 25, 2011 12:03:47 GMT -5
I find the stock CDI is fine even with a lot of modifications.On 2 strokes the timing advance is set at full advance all the time so there is little need to change the advance curve.
As to the rollers.....the Tecnigas Next usually comes with a 5.5 gram roller set when you buy their exhaust. I assume they believe that is a good fit for the power band of their pipe.
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Post by mechanical1990 on Feb 25, 2011 15:34:40 GMT -5
When a performance exhaust is put on, is there any other tweaking that needs to be done at that time? (other than rollers mentioned above)
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Post by buiditright on Feb 25, 2011 15:48:12 GMT -5
Mark the tecnigas I got came with 6gr rollers. It was not good enough and I had no low end. I like sliders so I went with 3-6gr and 3-4.5 gr sliders. I have better low end and kick ass mid and top end. It is really a srtange thing cause when that pipe kicks in it is bad. It likes takes off to about 48 and that is it for now. I am trying to locate a good manifold and a good carb. Right now I have a 14mm and I want a 17mm but it takes money and right now I just have to wait.
Bill
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Post by Panaramaguy on Feb 25, 2011 16:33:36 GMT -5
When you put the Next on you'll notice you have a "dead" spot from a standing start to about 3-5mph. You can just live with it (it isn't that bad) or install stronger clutch springs that will engage the clutch at a higher rev point. The Next has a power band that is higher than stock and needs the extra rev's to get into the range where it produces power.
Problem is.....the Hyosung clutch has an unusual spring size and there are no aftermarket springs available for it. To solve this problem you need to get an aftermarket clutch that will take aftermarket springs. I use a Motoforce, but I would assume there may be other manufacturers out there. If you use the Malossi green spring (that will fit the new clutch) it will raise the rev engagement point from about 2500 (stock springs ) to about 3500 rpm. No more stumbling from a standing start.
The aftermarket clutch may also have an activation spreed adjustment. Set it high and you'll get a snappier engagement, or set it low for a smoother pull.
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Post by digitalinsite on Feb 25, 2011 18:02:13 GMT -5
thanks guys. i'll stick with the stock destricted CDI then.
Reckon the Bando coil made much of a difference bill? Gives stronger spark right?
I've got 6 gram sliders being shipped right now and plan to chuck them in with my stock exhaust for now. Sounds like I might need lighter ones again when I get the performance exhaust.
has anyone here experimented with fuel additives to give it some extra hp?
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Post by jimh on Feb 25, 2011 18:29:40 GMT -5
I've messed around with some additives; no notable increase in performance though stabil or seafoam help keep the jets clean and the fuel, viable.
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Post by digitalinsite on Feb 25, 2011 20:10:42 GMT -5
cool - whats seafoam? is that a carby cleaner?
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Post by buiditright on Feb 25, 2011 20:19:07 GMT -5
Mark
the bando coil does give a hotter spark therefore helping to start better. I run non ethonol 93 octane in my scoot. I have tried the high octane additives but really showed no signs of any better performance. Seafoam is an additive that a lot of the guys use and like. I use Sta-Bil marine stabilizer. I sometimes use aviation fuel but not worth the money.
Bill
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Post by jerryd on Mar 4, 2011 21:55:34 GMT -5
Mark, No just clip the wire that is the redtriction thats all I did. I do have a Bando coil though.. BIll hello, which wire needs to be cut on the cdi? thanks |
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Post by klapool on Mar 6, 2011 13:55:38 GMT -5
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Post by kixome on Mar 6, 2011 15:20:08 GMT -5
why not make a new thread? |
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Post by klapool on Mar 6, 2011 15:45:54 GMT -5
I guess I should have, I just saw the conversation about 2 stroke motors and exhaust and felt I could get a better answer here. I am sorry, I wont do this again!
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Post by mechanical1990 on Mar 6, 2011 15:53:21 GMT -5
if you start your own, you will get more specific answers, posting it in another thread could get you some confused answers...
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Post by klapool on Mar 6, 2011 15:54:14 GMT -5
I'll do that right now, Sorry!
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Post by jimboduncan on Apr 16, 2011 22:23:02 GMT -5
The trick to a Kymco 2 stroke exhaust restriction is simple: The hole coming out of the exhaust pipe is too small. I would cut off the 1.5 inch nipple coming out of the exhaust pipe off. Then simply ream the hole out a little. You can use a 1/2" drill bit to give yourself a little power without having to rejet. You can go up to a 17/32 or large bit but you will have to rejet at this point. It will give you all the results of an aftermarket pipe and cost you nothing. This is the only restriction in a Kymco pipe. My reference is to my zx50 exhaust but I assume it is similar to other Kymco pipes. The result was an overwhelming increase in power!
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Post by jimboduncan on Apr 16, 2011 23:17:46 GMT -5
Just to be clear: a 1/2" drill bit will not make any noticeable difference because it is very close to the actual size of the hole. Start with this to clean out the hole. You have to drill out 4 inches deep into the exhaust pipe because after that it opens up inside the exhaust on both sides to a much larger opening. You can see this with a flashlight. Boring it out to 17/32 is a 12% increase in exhaust flow and 9/16 is a 26% increase and you will have to jet accordingly. I base this on pi x radius squared. Don't be a knucklehead and drill holes anywhere else on the muffler because that is just stupid and I don't need to explain any further
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Post by gitsum on Apr 17, 2011 1:15:42 GMT -5
$150 is a cheap as it gets for a two stroke exhaust. My exhaust cost $400. Jiangwayne has two different exhausts here: www.jiangwayne.com/scooter/p_tags.php?t=3&p=1I bought the $69 one for my Sym DD50 which says it also compatible with your Kymco. Top speed for me is about 44-45 mph with the stock carb and the stock 49 cc piston and cylinder. It's reasonably quiet too, about the same noise level as the stock restricted pipe. They have an expansion pipe for $99, but I believe the noise level is quite a bit louder. www.scrappydogscooters.com has a CDI for $14.95. |
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