Pleased with mods........ (Thanks Jag)

Well,Well,Well,

Once again, you did it Jag..... I put extention on expansion, and its now got the best torque of anything I've done with motorbiking. Only thing I dislike, is its just a bit louder, but overall, a very good gain............Anywhere!~ One thing you need to know, is around here, there are very few flats, just HILLS!~ Not good pic, but you can see.....................

It extended expansion about 3" . That 200yrds long hill that bike would only top at 15mph, can now be topped at 20.1mph. Uno, considering the power to weight ratio.............One would never think a little 66cc china engine would do this?! BUT, it is!~ GRACEFULLY.

I went about 7 miles, and right when I got off bike, I felt baffle, and it had a very cool temp.
 

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Baffle extension

Before:










After:
 

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With your pipe being wrapped its hard to tell exactly what you did to it. If you'll look at my Torque Pipe page on my site it is the E section that I was proposing you "splice in" to the baffle cone.
Well, as long as you're getting the results you wanted I guess we can't complain. People don't understand that its the strong compact return wave from the baffle that diminishes the potential of really good mid range power because that positive wave cancels out the negative wave from the diffuser cone at mid range rpm. Only at top rpm does the baffle cone have any benefit. Pipes sold for these bikes were not made for it, they were made for screaming pocketbike racers.
 
ahhhh, I see. I would say that that would even be better than.

I'm really still seeing positives from cutting mid way in the belly of the expansion. You post the baffle is about a couple of inches back from belly. Well, at this point I guess I can just cut it all I want, but do believe I need to stop before I really mess things up. Where I did cut, It still helped quite a bit. More torque................... Still glad I did.
 
Some street bikes have a diffuser, belly, and a silencer replacing the baffle cone so that they get maximum low rpm power.
So obviously you diminished the baffle cone effect which enhanced your low end power, so just stick with it because it worked.
What you did reminds me of the expansion chamber on my old Husqvarna 125cc which gave good mid range power:
'77huskyPipe.jpg
 
Stinger

Jag, wonder if it would help torque even more to make this stinger a bit longer than this? Fabian, was telling me that it really helped his. How long, if any, would you try? Or, do you think it would be better without?
 

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More exhaust restriction improves torque. On mine I cut a rectangular piece of aluminum (from cheap cookware), rolled it to fit inside the stinger (before the silencer), and glued it in place with JBWeld. I think on a 66cc you can go as small as 12mm inner diameter.
 
So, in hearing that, I believe that I'll put this silencer I have from SBP's on for good. I just wasn't using it because I thought it would inhibit power more?
 
Jag, wonder if it would help torque even more to make this stinger a bit longer than this? Fabian, was telling me that it really helped his. How long, if any, would you try? Or, do you think it would be better without?

:eek:

I don't use an expansion chamber on my bike, just a stock standard exhaust system.
 
The three inch silicon exhaust deflector (attached to the end of the muffler tip) was used primarily to reduce noise, but this has now been changed to a 2 foot length of high temperature silicon tubing to further reduce noise (which it does terrifically) and can be seen in the third photo from the bottom.

Just do a search for:

"Twin Spark Plug Cylinder Head for 80cc Happy Time Engine"
 
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