7/8" flex pipe for 4 strokes

[CrazyDan]

I found a cheap source for 7/8" galvanized flex pipe for exhaust sold by the foot.

https://www.ebay.com/itm/FLEX-TUBING-7-8-in-x-1ft-Galvanized-Standard-THICKNESS-A-028-Exhaust/111999638791?_trkparms=aid=111001&algo=REC.SEED&ao=1&asc=20160727114228&meid=5e0d6d01db204f62899d0657fe8f77d6&pid=100290&rk=2&rkt=4&sd=222813585500&itm=111999638791&_trksid=p2060778.c100290.m3507&redirect=mobile . I'm about to buy a 2' section and chop my muffler off for lulz. Gonna need to get a better air filter and jet up probably...I love this hobby with endless upgrades.
Edit: this might be next

https://www.amazon.com/Cylinder-Mot...eASIN=B078J339FH#immersive-view_1517272757343 .

 

[Frankenstein]

I found a cheap source for 7/8" galvanized flex pipe for exhaust sold by the foot.

https://www.ebay.com/itm/FLEX-TUBING-7-8-in-x-1ft-Galvanized-Standard-THICKNESS-A-028-Exhaust/111999638791?_trkparms=aid=111001&algo=REC.SEED&ao=1&asc=20160727114228&meid=5e0d6d01db204f62899d0657fe8f77d6&pid=100290&rk=2&rkt=4&sd=222813585500&itm=111999638791&_trksid=p2060778.c100290.m3507&redirect=mobile . I'm about to buy a 2' section and chop my muffler off for lulz. Gonna need to get a better air filter and jet up probably...I love this hobby with endless upgrades.

Lebanon pa, not far from here, and just happens to be the same exact individual I bought mine from. In fact my most recent pipe I made up is using a piece from the length I bought.

 

[CrazyDan]

Lebanon pa, not far from here, and just happens to be the same exact individual I bought mine from. In fact my most recent pipe I made up is using a piece from the length I bought.

Are you running open pipe or do you have a muffler on the end?

 

[CrazyDan]

I also figured this would be good for the length at around a 50% overlap

https://m.ebay.com/itm/1-x-15FT-Bla...221672&hash=item56967b6a5b:g:U5UAAOSwEzxYZeVf , and I'll have extra left over because I'm not gonna wrap the straight part of my header that extends out 5" from my exhaust port, that imma use for my TEG to generate electricity in the future.

 

[Frankenstein]

Also funny enough I wrapped mine in red, turns out over heating it with a blowtorch makes it almost white, really like a very pale straw color. Certainly what ever color I had picked would up ended up looking much like that black one does. The tube is not incredibly resistant to letting exhaust excape along the furling, but it seems that once it turns into tar along the lining wrap it doesn't keep coming through. The wrap I had stayed silver looking on the flex tube but definitely picked up black crap from the roads and engine.

They have stainless steel zip ties and they are a pain to tighten but work well. As a side note I noticed the plain nylon ones don't melt on the wrap either. 4t runs even cooler than a 2 so I'd bet it would be ok. I used hose clamps as well on it to make it easy starting the wrapping of the muffler and left it there lol.

Soak in water first and if you have a bend in the pipe wrap it bent not straight, once you wrap it putting a tight bend can be really hard.

 

[FurryOnTheInside]

I never thought to soak it in water first. I made the mistake of touching the wrap with bare hands too, a mistake I didn't make twice lol.
I had to wrap over a big change in diameter at the front of my muffler so the cable ties were absolutely essential to prevent the wrap slipping off, but I also had some little loose bits and I was able to glue those down (and also prevent any slip) with a bit of leftover JB Weld which nearly matches the charcoal grey of the "black" wrap.
The stainless steel ties are a pain to cut the excess off after tightening (because I already had the exhaust mounted when I added a couple more for the support brackets) and then curl the sharp ends in so I can't cut myself if I pick up the bike too carelessly.
I would save the steel ties for the header only and use the nylon on the muffler, next time.

 

[CrazyDan]

Just got my pipe installed, I am very pleased with both the sound and performance. Ran circles around my buddy on his 79cc predator build. I can keep a much higher rpm on hills I previously bogged on.

 

[Frankenstein]

Just got my pipe installed, I am very pleased with both the sound and performance. Ran circles around my buddy on his 79cc predator build. I can keep a much higher rpm on hills I previously bogged on.

But 4 strokes need backpressure!!

 

[CrazyDan]

But 4 strokes need backpressure!!

"Backpressure caused by the exhaust system (consisting of the exhaust manifold, catalytic converter, mufflerand connecting pipes) of an automotive four-stroke engine has a negative effect on engine efficiency resulting in a decrease of power output that must be compensated by increasing fuel consumption."
Source: https://en.m.wikipedia.org/wiki/Back_pressure
Back pressure is a lie.

 

[CrazyDan]

Also just set off a car alarm driving by, so funny .