Sport moped exhaust on 66cc (Build thread)

[Vikingimike01]

Cool. However, I can not weld yet. Will be my first time trying on scrap metal soon though.

That looks complicated to make. I think I'll stick to getting the moped exhaust, because that's probably alredy tuned.

 

[Street Ryderz]

no I didn't widen ports, just smooth out the passages. long offset intake helped boost the low end and plenty room for filter.
here is Jaguar's torque pipe if you can weld. www.dragonfly75.com/motorbike/torquepipe.html
I have a Voodoo pipe and it's good for me bcs of the long header and I don't rev out past 5000.
View attachment 85715

There are serious flaws in this design and his figures are wrong!It says that this pipe is meant for moddified engines with the exhaust raised 1.5mm for 150 degrees of duration and 7k LOL and that's BS.First raising the exhaust 1.5mm from stock would be 165.28 degrees of duration not 150,Next is the fact that the length and dia of header is wrong the dia is too small and length to long!Last is the 7k BS a stock engine and pipe will turn 7k easily and beyond,think about it with the stock gear on a 26" wheel 7k is 30mph and 40 is easily attainable with a well tuned stocker that's 9.5k and some of us have gone 50 with a stocker witch is over 11k with stock port timming.

 

[Vikingimike01]

This is why I'll buy a scooter tuned pipe!
That just makes people confused then.

 

[JerboaJohn]

Ryderz, you may well be right as some ppl say he based his stuff on engines 5-6 years ago, but some principles still hold. I read a lot on 2 Stroke Tuner's handbook, yeah 16" is way too long. mine is 12" and thats close to the figures for port size on my engine.

peeps were saying that scooter pipe is at least as good as a MZ65 but isn't it top-endy?

 

[Vikingimike01]

Well. What RPM's do these engines reach? 8k? I can just ask the guy at the scooter shop, what RPM is the pipe for, and then weld on an extra centimeter or two of stinger pipe.

 

[Street Ryderz]

Ryderz, you may well be right as some ppl say he based his stuff on engines 5-6 years ago, but some principles still hold. I read a lot on 2 Stroke Tuner's handbook, yeah 16" is way too long. mine is 12" and thats close to the figures for port size on my engine.

peeps were saying that scooter pipe is at least as good as a MZ65 but isn't it top-endy?

Jag's info was based on engines from 10-8 years ago and most of it on a 48cc,my point is that even then alot of his port timming figures are not correct,when measured from the deck to the top of the port those linear depth figures can be input to Lambretta's port timming calc witch he says he uses btw and they don't match up!The 2 stroke tuners hand book is great for formula's and the theroy's used then but it's old too and their are some good advancement's made since those day's!Both a good read and Jennings work's are price less imo,Jag's has it's merit's aswell just not all gospel LOL you know what I mean!here's a link to the calc it's a great tool for those whom want to experiment.http://lambretta-images.com/archive/porttiming.php

 

[Street Ryderz]

Yes the scooter pipes are much better suited to our needs than a dirt bike pipe! Are they peaky NO not really much different than a dirt bike pipe when it comes too peak rpm,The difference is that a scooter pipe was designed for single speed use and are generally 2 staged witch spreads the power band out over a wider rpm range,then they have shallower baffle angles so that they don't fall of as hard and will rev a bit past it's peak.It's starting to catch on as I have been saying this for years now and Dave Rust at Arrow is now using this type of pipe on his race setup's and selling them to the public but his price is very high! The same pipe can be found on ebay for $80 or less and the brand name pipes are 150-200 bucks,My next pipe will be the Yasuni c-16 it's a little pricey but it's performance is proven.

 

[Vikingimike01]

I visited the moped/scooter shop today. The pipe I will probably get looks very similar! The middle (The widest) part may be a bit longer, and at the end, when it comes back together, is a bit shorter. Also, the header is shorter.

It is 86 USD. If I get it, should/can I remove the muffler part from the end?

 

[Frogslayer]

I don't know where you guys buy your engines at but I've only held the throttle open for a few seconds on mine but there is no way i would turn this thing 7k with stock ports and stock balancing. I'd probably vibrate right off the seat lol. It will take off from a stop without pedaling and cruise nicely down the street though.

 

[Vikingimike01]

I got my engine from ebay- it came with upgraded hardware, widened ports, and nice polished intake.