Any reason half a sportser exhaust, the one for the frong cylinder wouldnt work? I can see it wouldnt work in the stock position but otherwise what am i missing?
like this.....
http://www.youtube.com/watch?v=n8tRwrA8zqc
Ok so searching for my answer while awaiting some one more knowledgeable offering insight i think i have found my answer. Seems most sportster exhaust is 1-3/4", and the blast should be 1-5/8".
1)Going with a larger exhaust , you should loose bottom end? and gain on the top end?
2) when speaking of exhaust are we speaking O.D. or I.D.?
Not really sure of what you are trying to accomplish...do you want to run a sporty exhaust on a Buell twin? what or how are you going to deal with the rear cylinder?
On my tuber 97 S1. i debated about running some Stainless Super trapp waist high flat tracker style pipes on it, and they DO fit but the ones i have are for my cafe racer project. But i dont see how you could fit a sporty exhaust on a XB framed bike, unless,,,,,,are you running a chopper?
pipes for Buell XBs are not too bad stock, they work pretty well, designed for flow and performance, not a lot of rom for improvement except for appearances like the polished stainless Keda or something (mufflers a different topic)
But to answer one of your questions,,,,, size DOES matter, bikes have optimum pipe sizes based on size of the motor and velocity of the gases which is largely translated to RPM (but not always) so a low revving bike like a XB will favor a smaller ID pipe and it helps with torque.
Theres a lot of technical theory involved with combustion chamber scavenging, Bernoulis theory, then theres, lengths, expansion chambers, stepping up and down for port velocitys and such, not room or time to get into here,
But for a simple comparison,, on old Iron Head sportys, everybody ran 1 and 3/4" drag pipes which makes a lot of noise and were popular (Cycle shacks) but a good way to go slower. On vintage Triumphs, say a 1967 650cc Bonnie, people also would tend to put on 1 and 3/4" drag or TT pipes, and again, go slower. they only thing they are good for is racing and 5,000 to 7500 RPM which in reality,, no one rides them on the street at the RPM or at least very long. the stock pipes were 1 and 5/8ths and some even 1 and a half inches, These all made more useable power on the streets,,
In 1970 Triumph, Norton and BSA started using a cross over pipe between the 2 cylinders. the reason for it was that it actually made the exhaust quieter as the exhaust pulses cancelled each other out to some degree and helped importers meet new noise and emissions standards in the US. However, the cross over pipe actually BOOSTS power as well. street rod and hot rod car guys often pick up 5 to 10 hp and torque down low where it really matters with a cross over withon inches of the header collectors.
thats why you see cross overs on stock Sporty exhausts,, cuts down on noise and boosts power.
You might find Buzz Buzzellis Harley Sportster Performance handbook useful, the latest one is abit dated at this point, but still a very good book, Ive had each of his books over the years and updated when the newer volumes came out. You can buy them off Amazon, or sometimes used copies on Feebay.
thanks for the theory lesson, its good to know why.
I guess my idea got lost in translation, but i was thinking since the Blast is half a v-twin , then a sportster style drag pipe for just the front cylinder would bolt up to the blast, but not under the bike in the stock blast position. I dont mind the looks of the pipe in the position in the video, actually like it, but i figured there must be a reason why if more folks werent using them.
How much power are we talking about loosing?
Sportser pipes will work, but it's like putting XB12 header on an XB9, you lose low-end power while gaining top-end pull. The biggest reason for not doing it on a Blast is that we have a 6500rpm rev limiter instead of the XB9's 7500rpm. What good is top-end pull if you're limited to such a low rpm?
1-3/8" ID is stock on the Blast. I kept that until I got really wild with mods. It let me pull to the rev limiter just fine. I actually dyno'd 31hp at the wheel with only carb mods and a drilled stock muffler.
1-1/2" ID is best for a stock Blast, with a good-flowing muffler/can.
1-3/4" pipes lose quite a bit down low on a stock Blast.
My next pipe on my highly-modified Blast is only going to be 1-5/8" because my stepped header (1.5"-2" in 4 steps) feels too cammy ("comes on" like a crotch rocket in upper rev's). It hauls ass when I stay in the upper revs (lifted front wheel on 3-4 shift at ~80mph), but I want more linear power.
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