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Keeping Spree Elite Aero 50cc and Gyro Alive!
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PostPosted: Thu Jul 17, 2008 7:17 am 
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Goped
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i am just wondering if there is someone who makes custom exhausts for Honda sprees or if there is a way to make on like instructions on how to make one? thanks in advance.


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PostPosted: Thu Jul 17, 2008 9:12 am 
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i always wondered if you could bend a dio exhaust because the look the same.


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PostPosted: Thu Jul 17, 2008 9:42 am 
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Can it be done for $5 with no tools? The answer is no. I've fabricared a couple that work quite well based on the calculator found in the tech section and on the Jennings book. Start to finish it's about a day and a halfs work plus the expense of the metal and welding supplies. Am I going into production and sell them for $100? Not a chance. I could make more money selling fries for Jack. A good pipe can about double your HP and is the best bang for the buck by far. The Spree can be hot rodded but you need to do your homework and either fabricate parts or find someone who can. The Spree has the same 49cc displacment that much faster bikes have. It was just built as a lower powered engine. Since it was designed in it's entirety as a lower HP engine to get the most out of it you pretty much have to touch every piece, Intake, porting, exhaust, head, drive ratio and a few more.

Sorry for the rambling, I do go on sometimes :wink: .
keithw

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Honda Pal (Speed-o-scooter) JDM Spree with varator trans.
Honda Spree, 1985.
Another Honda Pal

Let's give it a try, how hard could it be?


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PostPosted: Thu Jul 17, 2008 9:48 am 
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no problem i learned.


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PostPosted: Thu Jul 17, 2008 2:31 pm 
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lol sweet do you think i could make one in my metals class at school?


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PostPosted: Thu Jul 17, 2008 3:20 pm 
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you could try


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PostPosted: Thu Jul 17, 2008 4:13 pm 
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lacrosseboy wrote:
lol sweet do you think i could make one in my metals class at school?


Yes.

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PostPosted: Thu Jul 17, 2008 4:28 pm 
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nosiey guy why dont you make spree exhausts any more??


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PostPosted: Thu Jul 17, 2008 4:53 pm 
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lacrosseboy wrote:
lol sweet do you think i could make one in my metals class at school?


That's where I made my first one. It's really fairly basic sheet metal work. Layout, cutting, rolling cones, welding, good skills to learn. Your instructor will be impressed if you do your homework and build a decent one. You will be impressed the first time you get into the sweet spot on the pipe and it sets you back on the seat and stretches your arms. The Jennings book goes into all the details.

keithw

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Honda Pal (Speed-o-scooter) JDM Spree with varator trans.
Honda Spree, 1985.
Another Honda Pal

Let's give it a try, how hard could it be?


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PostPosted: Thu Jul 17, 2008 4:55 pm 
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do you have like the page number in tech help i cant seem to find it:?:


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PostPosted: Thu Jul 17, 2008 5:25 pm 
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Check the advanced technical section. Look for Jennings book and the tuned pipe calculator. The calculator came up with a little bit different pipe than the Jennings calculations but both worked well. When you make it the first thing folks will say is that it is too skinny because it doesn't look like the commercial ones they have seen. Don't pay any attention to them, they work great. I did find that adding about an inch to the center section made it work better. Also read up on inverted stingers and silencers, you will need them.

keithw

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Honda Pal (Speed-o-scooter) JDM Spree with varator trans.
Honda Spree, 1985.
Another Honda Pal

Let's give it a try, how hard could it be?


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PostPosted: Fri Jul 18, 2008 8:33 am 
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keithw wrote:
When you make it the first thing folks will say is that it is too skinny because it doesn't look like the commercial ones they have seen. Don't pay any attention to them, they work great.
keithw


Heh... that's what I found too when I played with those calculators. Big pipes are like padded bras... all show. :twisted: I also note that fatter pipes are called for on shorter exhaust port timings...

The stock Spree exhaust port is 9x25mm, or 225mm^2, which is really small. If you expand this out the pipe starts to fatten up. From the Kriedler calculator, 225mm^2 is barely enough for a 35cc engine. When I run numbers for a 50cc engine on the Kriedler page, I get a 25mm downtube, a lot larger than the 19mm stock tube.

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PostPosted: Fri Jul 18, 2008 1:08 pm 
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is there a way to like take one off like a pit bike or something like that and fabricate it to fit on a spree or will it be all wrong and stuff if you can do that what would be best to do it with like that kind? also how many hours does it normally take? like kathew said it only took him a day and a half but is that like working all day or just a couple of hours?


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PostPosted: Fri Jul 18, 2008 1:22 pm 
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keithw sorry lol about that spelled his name wrong:o


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PostPosted: Fri Jul 18, 2008 3:58 pm 
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That's fine, just don't call me late for dinner. I would think that a good sheet metal guy could knock one out in less than a day. Welding thin sheet metal takes a bit of a touch. If it's your first one be prepared to take your time and spend a few days off and on doing it. Adapting a common aftermarket one could work reasonable well. Run the calculations and see how close you can get. The tuned rpm on an 8000 rpm pipe will vary by about 500 rpm per inch of length. It doesn't take very much long or short to cause the power band to be all wrong. The basic dimentions are a 4" to 6" head pipe. Then a 8 degree diverging cone to 1.75" - 2.0" diameter. Straight center section to adjust tuned length. Then a 16 degree converging tail cone. Then about 4" long 1/2" diameter stinger. The normal drill is to make the cones and center section straight. To fit to the bike you cut them on a bias, turn the piece and reweld.

For best performance the measurements, ratios, and proportions are very touchy. The only real way to tell if an aftermarket one for a different bike tacked on would work is to try it and see. Based on the dimentions of the pipe and the calculations you can make a reasonable guess, but, that is really what it is, a guess.

With all the unknows of adapting another pipe I just found it easier to build from scratch.

Trying to not be unfriendly about it, the tuned pipe stuff is in the Advanced Technical Section for a reason. Designing and building them isn't beyond most folks here, but, you do need to study up and develope the skills to do it.

keithw

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Honda Pal (Speed-o-scooter) JDM Spree with varator trans.
Honda Spree, 1985.
Another Honda Pal

Let's give it a try, how hard could it be?


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