MOPED ARMY

People use larger carbs made by Dellorto, thats the most common. Exhaust can be de restrcited a bit, but I dont think theres much of a point UNLESS you also run a larger carb.

If you are very mechanically inclined, porting costs virtually nothing but drill/dremel bits and time, and yields fantastic results.

With a 2 stroke, the best bolt on is expansion exhausts, but for a Moby, expect some custom work and a near $200 price tag for that, not to mention probably having to figure a way to get one out of Europe.

Theres every performance part you can imagine in Europe, but nothing incredibly cheap or easy to get.

If not just for performance though, the Dellorto is recommended as it is considered more reliable, more tunable, and easier to work with than a stock Gurtner. I use one, I like it.

porting a 15mm carb and an exhaust pipe if u really want to, also the speeds u posted are typical fast moby speeds, and u should be proud u have a quicker moby.

I have a dremel tool and consider myself somewhat proficient with it. Can porting be done just by holding the dremel free-hand (no drill press attachment or other aids)? Also, what kind of bit do you need to open up the ports?

Thanks for the info!

If you take the end of your exhaust off and look down into it, you will see one large hole and 2 small holes way down inside. I believe the small ones are the main source of restriction, so those should be drilled larger. I will do a few simple math equations tonight and figure out what size you want those to be.

The large hole is what the tube inserts into. Some have cut this tube shorter, essentially bypassing those 2 holes. That will work as well but will probably be louder than by drilling the 2 holes larger.

BTW, this is all theory, I havent actually done this, but I think it is a sound idea. But, these should de-restrict the muffler and still keep it sounding good.

Again, I wouldnt do too much to the exhaust unless I was running a larger carb. On 2 strokes you can easily have too little back pressure and get worse performance.

TREATED

"The large hole is what the tube inserts into. Some have cut this tube shorter, essentially bypassing those 2 holes. That will work as well but will probably be louder than by drilling the 2 holes larger."

i cut the tube shorter...and my moby is cutting out now. but my moby is stock...hopefully a carb upgrade will fix it...or i'm just going to weld that pipe back on somehow :(

Stfu. I never heard one person ever mention anything about drilling those 2 holes larger. I took a long look at my exhaust, figured where the gas flows, and figured out where the restrictions were.

I only heard of one person cutting the tube shorter, so the fact that I mention it is not parrot speech it is simply another logical way to de restrict it.

Look Bret get off my back. I dont know what your problem is but all I am doing is helping people. Go take a look at the inside of a Moby muffler and you will see everything I say makes perfect sense.

hahaha ohh boy. are you sure its a 70 cc?

sorry

i heard he was taking it to the salt flats.

Yes Im sure.

i'm gonna say this for the last time:

NOTHING YOU DO TO A STOCK MOBY EXHAUST AFFECTS PERFORMANCE AT ALL!!!

quote me if u want

unless u stuff it with shit and clog it up, then it will slow u down. u can run no exhaust and will see no gain or fall in performance.

believe me i have tried, all the stupid sudgested tricks to stock moby pipes, non do shit.

the only derestricting u can do is to take the airbox off the stock gurtner. also boring out a gurtner is not possable due to the intricite design and the way the difusser works, u also can't get jets for gurtners so boring it out is not worth it, since uy'd have to drill jets too.

its not worth your time, just buy a bigger carb!!!!

No, you can't get a Gurtner jet but there is a way of adapting an adjustable one from a Tecumseh lawnmower carb to fit, a friend of mine did it with the one on his 50M since it came without the jet. I need to look up some details, I wrote it down and passed it on to someone once. The main hangup with these carbs is the venturi size, there isn't a whole lot that you can remove and still have it work with air leaks getting past the throttle slide, maybe 2-4mm or so.

Not sure what you're telling me. I've read that on the site. Got it today and after 5 mins with a dremel it fit right on. Negligible work, worth it cause I think it's easier to deal with the shorty then the long curly intake. But now should I match up the intake port to the intake manifold, or can I get by without it? Thanks,

-Steve