Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Michael Dreamboat /

My moped was running at about 28 mph. I could have sworn I had an extra 2 or 3 at least before I put this new front sava on a few weeks ago, but that's neither here nor there in relation to the latest upgrades I guess.

Anyways it was going about 28 recently, with stock everything. I made a thread asking for the best way a newb should start to get a little more out of their stock moped.

After reading a lot of great advice from experienced members I decided on a tecno circuit pipe, hi flow metal air filter, and a bigger jet (I got 3 new jets, starting at 2 sizes bigger than stock and going up).

I had a pretty experienced member from the boards help me get all this stuff going today, as well as helping with some general tuneup (new clutch cable, adjusting the chain etc.).

After tuning and getting everything on, here are the pros.

1. Sounds a million times better.

2. Runs a lot smoother.

3. Slight increase on the low end, but still not great, sucked donkey balls before the new exhaust and filter however, so it is technically an improvement.

Now the cons.

1. I gpsd myself at like 29 mph. I heard all these people talk about how much speed they gained with as little as adding a new air filter, nevermind the supergains I heard from people who got the new filter, pipe, and jet.

It did feel slightly faster at first, but I think because it runs so smooth now, that it may have just made it seem faster.

Any ideas why there is no speed gain with these upgrades?

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Aaron Bowen /

What size carb are you running?

What size jet did you go up to?

I just did these same mods to a friends bike 1.5 HP Sears Free Spirit

he was doing 27mph gps before the mods and now doing 35mph gps

check timing if running a bing make sure you have NO AIR LEAKS it's a big

problem with those carbs and check points too report back and let us know

Aaron

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Michael Dreamboat /

Stock carb, 14mm.

Stock jet was 64, we tried out 68, 70, and ended up going with a 72, as that ended up feeling the best.

We sprayed carb looking for air leaks, and there was a very slight one towards where you connect it back on, we put a new seal in there and the leak was gone.

We checked points, and they seemed fine.

At a loss as why there was no speed increase whatsoever, and won't be able to work on the moped more with this guy for a few weeks.

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Aaron Bowen /

Is it a two speed?

we are running a 68 jet and the needle clip is on the second setting

did you adjust the needle?

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Michael Dreamboat /

Not a 2 speed.

Needle clip was on the 2nd spot from top. Dropped it to the very bottom (4th). No noticeable speed difference from either setting.

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Changing needle position wont change your top speed, it changes the mixture through the mid-throttle range.

Maybe you got a restricted techno circuit? And the techno is a mid-range pipe so that is where you will feel the most power (rather than low-end). Also, do what Aaron suggested.

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

64 to 72 for a pipe and filter seems a bit high. Peds tend to run slower when rich. Also I dont know much about that pipe, but check this:

http://www.mopedarmy.com/wiki/Unrestricting_Tecno_Circuit_Exhaust

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

tires do that sometimes, too.

Gazelles especially.

here nor there.

How is it up hills now??

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Overpriced Parts /

What intake size? What gearing?

Run a 14mm intake remove restrictor if you got one

Add power add gearing

I bet you only have 14-16 x45

Run at least 17x45 gears

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Michael Dreamboat /

Jesus, I hope it's not restricted. According to the wiki the only way to tell is to actually cut off your muffler. I'm a stone cold newb and have never welded anything in my life, nor would I even know how to rent welding equipment. There has to be a way to know if it's restricted without cutting the thing in half. Here is the wiki article which claims that most tecno pipes are restricted. This doesn't seem right, all the responses in the tecno circuit thread, and no one in there had a restricted one. Here's the wiki article.

http://www.mopedarmy.com/wiki/Unrestricting_Tecno_Circuit_Exhaust

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

I bet you could take a thicker copper wire and try to push it through the exhaust. If it hits something right after the baffle, its restricted. Personally, mine was NOT restricted, but I didnt care because I left the baffle off anyway (race bike, noise doesnt really matter).

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Christian Giron /

quite honestly man I don't think the pipe is the problem.

I just did a search for 'circuit restricted' across all dates and all forums. there wasn't much on it really, but I didn't come across one person saying their pipe was indeed restricted except for one thread that led to nowhere. A lot of the threads are asking the same question about restriction and dead end without anyone really having conclusive evidence besides that wiki page.

I also found that the wiki article may have been from a european site and also that it really shouldn't restrict you THAT much, more so just rob a little top end (not 29mph rob..)

Even if the information I have gathered is absolutely incorrect, I haven't seen a single thread about those pipes not giving much performance gains.

I could be absolutely wrong though and I don't want you to completely ignore the restriction if its there, but I just wanted to shed some more light and maybe point you in the right direction.

Hope this helps.

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Ken Roff Wrote:

-------------------------------------------------------

> What intake size? What gearing?

> Run a 14mm intake remove restrictor if you got

> one

> Add power add gearing

> I bet you only have 14-16 x45

> Run at least 17x45 gears

If you are right at the rev limiter on any bike no matter how much power you are making when you run out of Revs you cannot go any faster. I make enough Power to run 52 MPH but I am geared 28 front and 22 rear. When I put on a 25 front and 31 rear I cannot get over 32 MPH!! Try more gearing

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Christian Giron /

^^ hes on a maxi not a tomos

Re: Made the first upgrades to my 77 Maxi Sport, new exhaust, jet, filter, but hardly any speed increase

Overpriced Parts /

Ya a tomos are geared silly like a 1hp za50

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