Does the circuit have any internal baffles/washers anyone knows about? Adverse to chopping mine apart right away to find out (but I will if i have to, dag nabit!)
Does the circuit have any internal baffles/washers anyone knows about? Adverse to chopping mine apart right away to find out (but I will if i have to, dag nabit!)
uh, what?
no? the muffler on those is just a glass-pack i'm pretty sure.
on some of these exhausts sometimes there's washers welded in as restrictors where the header meets the chamber or where the chamber meets the stinger, like the leo vinci's, and i think the promo circuit. wondering if it's the case with the tecno
tecno circuits dont have restrictors.
if you think the pipe isnt doing too well, remember that its a low/midrange pipe and you are using it for torque, not top end.
still tuning, but it seems okay so far. I bet some math'd show that stinger a bit longish, pro'ly why it does what it does on the low end. Very conservative motor, E50 50cc hi comp head 15/15 Dello SHA and the pipe. Still breaking in fresh rings so I don't want to flog it at present, but it definitely feels like it'll slap some hills around past 3/4 throttle.
yeah, that should be a really good torque combo, you'd probably do 45 on 18/36, docking the stinger is probably a bad idea.
as long as I can pull away from multiple stop signs up these long long loooong grades around here I don't care how fast it'll go on the top. 14/45 so far, I'll see once the rings seat and the comp comes up. daily driver.
But golly, that pipe is LOUD!
on my magnomos, the techno circuit gave me +3 mph over a biturbo, and better low and mid range. the circuit may not be a top end pipe, but it's faster than the biturbo
Here's an article showing the techno circuit guts for a ciao. The site is in Dutch so you will have to cut and past the text into a translation program. Even then it’s a challenge.
wow, babelfish mangles dutch, we know that now.
okay, so it makes sense why this is a good low end pipe, with the turbulence created by the kinked headers and the slight restriction/turbulence in the stinger there's enough back pressure at low r's. I think i'll not fidget with it, swap with an estoril maybe if I want things peakier.
Yes, mangle might be an understatement. I think those guys use a lot of Dutch slang too.
yeah i slapped the circuit on a korado engine with a 15 bing (ugh bing)
15x40 gearing pulled me off the line like no other (im a big dude too) It came close to motobecane off the line, but not quite
i've been on the vespa-ciao.nl forums for over a year now, most of those guys know pretty good english too. if you want something explained, you could always try emailing one of them.
that site is full of sooo many goodies. one of my favorites.
The tecno circuit HAS got a restrictor.
It's in the stinger, right b4 the muffler.
Here's a lil how-to on taking it out. Runs much better without.
http://www.mopedarmy.com/wiki/Unrestricting_Tecno_Circuit_Exhaust
I took a closer look inside my estoril chamber while I have it cut up, there is no restrictor like this, but I think I found the reason why they seem to cut out past the peak of their power curve. They welded in a much larger degree cone inside the one you see on the outside of the chamber!
Taking this out should give me a more reasonably angled baffle cone and broader power curve, extending it on the top end, while lowering the peak just by extending the tuned length just a bit.
This is the baffle-cone end we are talking about, right before where the stinger is attached.
Roald,
After drilling out the ritvits on the tenco circuit stinger, what do you use to replace them? More rivits? Bolts? I've got two circuit exhaust, I'd love to try this out!
Philip
Rivets. Or bolts, if you can figure out how to get those in :P
And yeah, that cone trick is old but irritating. They did almost the same on a Honda MT exhaust, but instead of insreting a narrower cone, they just put a plate with a 1/2 inch hole in the center of the belly :|
You mean a wider cone right? I guess depends which dimensions you are talking about. according to Gordon Jennings a wider (more degrees, steeper) gives a slightly stronger wave, so higher peak power, but cuts out after the peak, and no more than 20 degrees should be used (a flat plate!?! thats like 180 degrees!?!), and vice versa; weaker wave, lower peak power, but power curve extends past it, and no less than 12 degrees.
I am glad I found this thanks!
Confirmed: no such stinger baffle in the Puch version. I'll chop this thing up post 65cc spare motor build and see if there's an additional cone or baffle in the chamber. Want to fadiddle it for a moby anyway if the chamber is inside the numbers.
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