De-restricting a 50cc 2 Stroke

[kaintuckdave]

Okay Dawgs, I bought a really reliable scoot so haven't done nearly as much wrenching as many around these parts, but thought this might interest some of you. This is the de-restricting I've done so far on my own and through my dealer. If you want to know what I think of the mods, check the thread; "What a difference a pipe can make!"


Started at home, here's my CVT cover removed to check for a spacer ring between the variator halves: (Glad my ring ended up plastic, check all that angry red lock tite!)





Here's what I busted out of there with a screwdriver:





On many scoots the restricting ring is metal and you have to remove the outer variator half to get it off. I was lucky. Here's what it looks like laying on the floor and looking up at the variator's inside, now de-restricted:





All right, now some time has passed and we go to my dealer to get a SYM approved pipe and jet installed. My dealer is completely cool and lets me 'hang out' while he's working on my scoot.
Ready to start:





Here the air box is removed and the carb is draining:





Carb removed, ready to install new jet:





Installing new jet:





My excellent dealer 'Jake' reinstalls the carb:





Now on to the exhaust. Here's a shot with seat bucket removed, you can see the extra pipes coming off of the main pipe:





Here's the stock exhaust with it's crimped pipe in the foreground and the emissions pipe going to the canister on the muffler. A tube came out of that and went to nowhere under the seat.





New exhaust, notice no extra pipes!





New exhaust at motor:





New exhaust installed:



Well, hope you liked my tour, and hope it helps some dawgs who want to do things themselves get an idea of what's involved. I'll probably do a free flow air filter as well and will post pics! ;D

[90GTVert]

Aug 19, 2008 10:38:46 GMT -5 kaintuckdave said:

Okay Dawgs, I bought a really reliable scoot so haven't done nearly as much wrenching as many around these parts

I bought a pretty reliable scoot, that's no excuse not to work on it! ;D

I thought they always used metal rings for restrictors. I now like SYM much more for using plastic so they can be de-restricted faster and easier.

[kaintuckdave]

Hey, I do all my maintenance stuff, just haven't had to track down problems is all.

[rallyrrr]

Dave. Did you tighten the variator nut after removing the spacer? Others performing this derestriction need to know to do this.

[kaintuckdave]

rallyrrr, I didn't remove the variator nut. The ring was plastic and I popped it out with a screwdriver as stated above.

If anyone needs to remove a metal ring, here's a good how to on a Yamaha C3 scoot:

www.youtube.com/watch?v=Wa5fEnu7kWY

[Karl]

Nice writeup Dave!

I've got a similar exhaust emissions setup on my Strada. I'd like a similar pipe to yours.....something that looks stock but has a little more performance to it.

[rallyrrr]

Dave wasn't the spacer between the outter sheave half and variator spacer/inner sheave guide? When it is removed this leaves a gap and the outter sheave will be lose.

[kaintuckdave]

Rally, all the restriction ring does is keep the variator halves from completely closing, stopping you from having access to the top gear ratio. It has no bearing on tightening the outer half of the variator. Mine's been fine for over 1100 clicks since I removed the ring; tight as a drum.

[rallyrrr]

Ok Dave, I did not realize that the variator halves were designed to actually touch each other. I thought the limiting factor was the maximum travel of the roller weights at their outermost point. Hey, and I learned how to spell outer as well. It's going to be a great day.

[kaintuckdave]

Ha, I learn how to spell all sorts or words thanks to the little red line under em! Have a bone and thanks for the grin.

Oh, and Karl, you might check these links:

scootercityinc.3dcartstores.com/MRP-Minarelli-50cc-Chinese-Japanese-and-European-Performance-Exhaust-for-70cc-kit_p_7-36.html

www.lakenormanatv.com/internet_prices.htm

[scosgt]

Aug 20, 2008 10:31:21 GMT -5 kaintuckdave said:

Ha, I learn how to spell all sorts or words thanks to the little red line under em! Have a bone and thanks for the grin.

Oh, and Karl, you might check these links:

scootercityinc.3dcartstores.com/MRP-Minarelli-50cc-Chinese-Japanese-and-European-Performance-Exhaust-for-70cc-kit_p_7-36.html

www.lakenormanatv.com/internet_prices.htm

That's where I bought my new bike (scooter City). He does not sell any junk.

[lbo]

How much gain did you get from the new pipe? I ask because mine had a similar stock pipe. Besides it weighing 300lbs it had all the restriction tubes and emmissions crap on it too. I got another 10+ MPH just from a tuned pipe.

[kaintuckdave]

I'd say around 7 or 8 mph, but now I can keep it at 35 mph even up hills. It's way stronger at all speeds seems like. Mine also has some air box restrictions which I intend to remove soon. Have a new left brake lever on order (had another side stand incident) so when it gets here, gonna install, remove restrictions, side stand modify and put in an iridium plug all in one go.

[ArsenalRacing.com]

FYI, On the SYM DD5 and other smaller 50cc scooters there is a restriction "Pill" in the intake and should be removed for more power. Did you have the Mech. check this? We find it is easiest to remove with a blind bearing puller.

[kaintuckdave]

Mike, sent you a PM.

[w8tlftr]

When I started my project on my scooter I had no manual,only watched how 2 vids on the same scooter I have, plus after awhile I made friend's with some in the UK who have my same scooter, but I have torn my trans down maybe 25 times since I started my project, 5 of the times were to find this darn washer between the variator , well after takeing all my clutch apart and variator, finally a friend says oh your particular year scooter doesn't have one, well just great? I guess I can now tear it all down blindfolded. But on my Piaggio Typhoon there were restrictors,one where that second pipe off the main exhaust comes off, thats some kinda catalitic converter I guess, and does nothing but take from the power, oh and maybe run cleaner air for all you nature peps. Another was in the intake side of my carb, it was a plate with holes in it, I removed that power stealer as well. Also the stock air filter is designed to allow just enough air for a stock set up, I replaced that with a Malossi filter same filter just more porus<Big differance) I of course upjetted 2 seperate times back when I just replaced the pipe with a Performance one, and again when I upgraded my cylinder kit, going lighter on my variator roller weights when was just a pipe upgrade , then retuning the original roller weights when adding the 70cc upgrade kit to deal with the added power.Something I had a problem with for awhile is back when I installed my new performance pipe, a Tecnigas Next muffler, nobody told me the performance pipe was restricted? I was very upset when I couldn't make my scooter go over 28 mph, again I had a friend say to me did you take the restrictors out of the new muffler? I said what? Well being my pipe came from Europe and most performance pipes are designed to run with a 50cc stock, you have usually two restricors in these pipes, one in the opening where it joined the engine, it is a cone shaped peice spot welded into the opening, I had to buy a dremal tool to knock out those spot welds, the other place is where the silencer joins the pipe, I didn't have one there, but im told looks like a washer also spot welded. But after I figured all this out the hard way, it runs like a entirely differant machine now, alot more power indeed, wants to pop wheelies and has a much better top end not even haveing to change the original gears.

[paemt1]

Sept 9, 2008 10:56:42 GMT -5 ArsenalRacing.com said:

FYI, On the SYM DD5 and other smaller 50cc scooters there is a restriction "Pill" in the intake and should be removed for more power. Did you have the Mech. check this? We find it is easiest to remove with a blind bearing puller.

Can you tell me what blind bearing puller you used. The one I picked up at Harbor Freight was too big. Even the smallest collet (3/8"to 1/2") didn't work and I have been unable to find one small enough to do the job. Any help would be appreciated. ;D

[ryanmiller]

do you have a picture of this part? i have a DD50 and I don't think i have it in my intake, but If i had a picture i'd know what to look for