Al's exaust pipe By tvnacman (Read 680 times)

[tvnacman]

Al I know you got a custom exaust pipe . What diameter was the stock one and what is the diameter of the custom one . Did a local guy do this for you or was it done by mail . The scooter that I'm doing a drum to disk conversion to is 16" wheels . It has the valve cover with 2 bolts (I think GY6B) . I changed the air filter to aftermarket cone type it sounds great . I want to follow with a large diameter exaust . I have been thinking about putting fuel injection in it . Since i got the vespa with fuel injection its day and night . Don't get me wrong the 24mm keihin is the way to go if your using a carb . I remember pop always said the power is in the intake/carb . Do you think I can keep the heat to a minimum with a larger diameter exaust .

If what I have is a GY6B what part of the engine is different , head or jug and where do i get the odd ball parts ?

John

[alleyoop]

The pipes are usually 1" and mine is 1 /14 had it made out of really nice thick piping not the thin stuff that you buy.
If you have the GY6B the head is a little taller it also has bigger valves i believe the chain is also a little longer. Some guys have that motor and parts can be gotten but a little harder to find. But that motor has a little more power than your 157QMJ motor, so on the case it probably says 1P57QMJ.
Alleyoop

[tvnacman]

I would have to double check but that looks correct . What about temp with larger diameter exaust ? any thoughts!!!!

John

[imnts2]

I wish it were so simple that "power was in the intake and exhaust".

I would agree that years ago if often was the weak part of the engine. Old flat head fords needed a new overhead valve system simply awfully. The standard GY 6 engine needs a big valve or 4 valve head long before it needs a "performance" exhaust or air cleaner.

Noise is not power. Backyard engineering is often just that. Labeling does not make it so. Accurate measurement of speed and power is not state of the art anymore, but it does require a bit more than a china meter or even a phone app gps. It is not at all difficult to measure out an 1/8 mile and set up a simple, but accurate stop watch timing course.

But I do love the sound of some exhausts.

cheers
Imnts2

[tvnacman]

I'm not expecting any real proformance gain , we are talking 8hp . However a cooler engine lasts longer . If you restrict air flow you hold heat longer . Thermal dynamics if you let the hot gases flow out faster it will reduce heat transfer from the hot gases to the engine .
John

[sprocket]

If you get the exhaust running too well you will loose vacuum and the engine won't perform worth a damn..the GY6 needs a balance between intake vacuum and exhaust back pressure...

[tvnacman]

old wet fart , key word muffler not straight pipes . then there would be no back pressure , so it would only be wet and old , not a fart at all . I was looking at a proformance muffler .

.scooterworks.com/NCY-Exhaust-Carp-Mouth-Stainless-GY6-P6651C498.aspx" rel="nofollow" target="_blank">.scooterworks.com/NCY-Exhaust-Carp-Mouth-Stainless-GY6-P6651C498.aspx

or
.scooterworks.com/Performance-Exhaust-150-cc-Stainless-Steel-GY6-P12675C498.aspx" rel="nofollow" target="_blank">.scooterworks.com/Performance-Exhaust-150-cc-Stainless-Steel-GY6-P12675C498.aspx

I wanted to get something with adjustable baffle .

John

[sprocket]

Nice.. I know some people running the NCYs but EXPENSIVE!!!

[tvnacman]

Post a link sprocket , I got the drum to disk conversion done . I'm looking to play .
John

[alleyoop]

You want a nice muffler that will OUTLAST your scoot and they are adjustable you add or discs to the end of the muffler this is the one I have.
Alleyoop
You can check out some of the others and scroll down and they usually have a Video so you can hear how they sound.
.supertrapp.com/product_sections/cat.asp?CatID=34" rel="nofollow" target="_blank">.supertrapp.com/product_sections/cat.asp?CatID=34

[sprocket]

Those supertrapps are great and not too bad in cost...use a stainless exhaust header... but I still think you need a reducer to work with the 1" pipe...

[terrdnf]

TRAPPS are great silencers. i ran them on my desert racers and my GPZ 550 back in the 80's liked the tuneablitly of being able to add or remove discs and for teardown to clean them