[rd0t]

Hey Guys,

I just picked up a 1985 ATC70, and I'm looking to drop a Piranha 140 motor in it. Which upstyle exhaust options do I have? Will CRF70 exhausts work?

Thanks!

 

[tmas]

I know crf50's fit with a little bending.
tmas

https://planetminis.com/forums/1973-1985-atc70-trx70/103732-exhaust-options.html

Exhaust

 

[rd0t]

I know crf50's fit with a little bending.
tmas

https://planetminis.com/forums/1973-1985-atc70-trx70/103732-exhaust-options.html

Exhaust

How do you go about bending the pipe\? Just heat it up with a torch and bend it down to fit?

 

[tmas]

How do you go about bending the pipe\? Just heat it up with a torch and bend it down to fit?

You might not have to use heat. Check link.
tmas

https://planetminis.com/forums/1973...295-my-crf50-exhaust-conversion-atc-70-a.html

 

[rd0t]

Now will using an aftermarket CRF50 exhaust on restrict the flow of the 140 motor?

 

[SS LS1]

Yes it will, not worth the effort of the 140cc motor with such a restricted exhaust. Biggest mistake people do on a big motor swap is cheap out on an under sized carb setup and home made exhaust system. These alone are almost again the cost of the engine upgrade but are necessary for optimal performance. Also highly recommended a Z40 camshaft and a thin head gasket to increase compression as these cheap mods really wake up the top end of the Honda based 140 and 150cc motors.

Best fitting exhaust system is from Spangler's however it appears to be out of stock right now. Exhaust

Tbolt does have it in stock though >>>> https://tboltusa.com/store/piranha-full-exhaust-system-for-honda-atc70-trx70-p-9663.html


Another (expensive) option is the Two Brothers Exhaust as it looks and fits beautifully.

I have one of each and love them both.....

Two Brothers Exhaust on my orange 150cc trike.... click twice on each photo for a full screen view...

 

[rd0t]

Yes it will, not worth the effort of the 140cc motor with such a restricted exhaust. Biggest mistake people do on a big motor swap is cheap out on an under sized carb setup and home made exhaust system. These alone are almost again the cost of the engine upgrade but are necessary for optimal performance. Also highly recommended a Z40 camshaft and a thin head gasket to increase compression as these cheap mods really wake up the top end of the Honda based 140 and 150cc motors.

Best fitting exhaust system is from Spangler's however it appears to be out of stock right now. Exhaust

Tbolt does have it in stock though >>>> https://tboltusa.com/store/piranha-full-exhaust-system-for-honda-atc70-trx70-p-9663.html


Another (expensive) option is the Two Brothers Exhaust as it looks and fits beautifully.

I have one of each and love them both.....

Two Brothers Exhaust on my orange 150cc trike.... click twice on each photo for a full screen view...

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Nice bike!

So I ended up going with the Pirahna exhaust for the bike. It was kinda weird that it didn’t just bolt right up. I had to press in the head tube a little for one of the header nuts to fit on. Now I’m on to my next dilemma... foot pegs.

 

[SS LS1]

Nice bike!

So I ended up going with the Pirahna exhaust for the bike. It was kinda weird that it didn’t just bolt right up. I had to press in the head tube a little for one of the header nuts to fit on. Now I’m on to my next dilemma... foot pegs.

Thats easy, just hit up Logan at Spangler's and he will set you up with the proper foot pegs, of course you will also need one of their wave style shifters too. >>>>> Footpegs, Footbrake And Shifters

These parts really make a huge difference for adults riding an ATC 70. The footpegs are lower and farther forward so I can fit my size 13 feet on these little things. I also space my pegs about 1" lower to make the ride easier on my hips.

My orange 70 has their shifter, steel footpegs and their foot brake which makes the brakes much stronger for high HP motors. I also have their billet footpegs which I like the best on my Red 70 but they are not offered any longer unfortunately.