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ok I heard the pros / cons about loud shiny pipes but wondering if anyone has tried to mod the stock baffle buy cutting off the reduction end where it goes from one inch to 5/8 im sure it would open up the pipe but while retaing the spark arrestor and I would imagine still keeping enough back pressure . any thought would be appreciated thx
 

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When I put my 45* degree copper street elbow on, the resistance gave me more torque and increased my HP by about 10 horses. :p
 

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If I remember correctly, Lizrdbrth posted that no improvements could be made to the exhaust system to increase hp with a stock engine. That included modding the stock exhaust or using an aftermarket exhaust. The stock exhaust was as good as it gets with a stock engine in his opinion. I've always been disappointed when I've "upgraded" to a different exhaust on a bike. Lots more noise and little to nothing performance gain, and that's with using recommended carb jets and settings. Your time is better spent riding it and your money better spent on mods that will have a benefit. Just my opinion. (based on experience)
 

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Figure about 5% gain in HP max if you go whole hog, intake, jets, exhaust, on this low tech 2 valve motor.
So doing the math, 13 HP on a good day X 1.05 = 13.65 HP (a modest gain that you likely wouldn't notice)

I have messed with this on a number of bikes over the years, 5-10% on a 100HP sport bike can be felt. The reduced weight of replacing steel with titanium or carbon fiber even more. The HP gain doesn't necessary reduce torque, there are in fact usually gains. But there torque curve is often less linear. Strong spots and flat spots is the typical outcome. For track use where you can just keep the engine in the sweet spot it is worth it. For riding around town it sucks, (but sounds cool)
 

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We have played with open non restrictive exhaust systems on our dirt stock cars and it was alot of work for the gain. The TW is set for having some back pressure on the exhaust and the carb is tune to suit, but as soon as the back pressure is reduced or removed everything changes. There are many thread in past posts where mods were made and carbs were tweeked but there is always something lost where there are other gains. To give up low end torque for noise and bit more peak horsepower does not go well with a bike build for trails and climbing, so unless its a cafe racer or street drag (ha ha) its not worth the effort. The main reason for opening up an exhaust is to help evacuate the spent fuel/exhaust gases to allow more fresh mixture into the cylinders, but this can then cause excessive heat and backfiring as process now pulls some unburnt fuel into the pipe which will ignite on deceleration. We fought this endlessly on the race car till we tried the "H" pipe method where we welded a tube between the pipes and opened a passage to each side. This created a vacuum as the opposing side vented and back fire / bogg was gone. Now having a single cylinder on the TW it cant be done and installing a larger header to non restricted exhaust is very hard to tune, so that is one area of my TW I have left untouched.... still runs like the day I bought it and I was one of the lucky ones that has never needed to tweek my carb. Starts easy, runs smooth off choke once warmed up, enough torque at low rpm to still pull the front wheel off the ground when climbing hills, and goes all day on a tank of fuel.

As for LT's bike, I thinks he is running high octane / av gas mixture with that added 45 deg elbow causing downward thrust which creates upward lift of the rear of his machine, which then lightens the weight to horsepower ratio and allows those hugh smoke shows he does on the street in front of his house!
 

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ok I heard the pros / cons about loud shiny pipes but wondering if anyone has tried to mod the stock baffle buy cutting off the reduction end where it goes from one inch to 5/8 im sure it would open up the pipe but while retaing the spark arrestor and I would imagine still keeping enough back pressure . any thought would be appreciated thx
One of my riding buddies cut off about 3/4 inch from tip of his stock TW exhaust with no discernable changes in performance that we could detect.
 

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As seen in my avatar I removed the guts on both bikes and sweated copper pipe fittings (under $20 each). I added a removable spark arrester (spring lock) to keep the flames under control. The sound is perfect. I ran both my bikes with these at the same time for a couple years and never compared one against the other. The reason they are not on now is because of the California Drought. Plugs looked fine.
 

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I swear the 45* street elbow gave me more resistance that I can feel with more torque, but nothing more, except I like the sound better also. :D It just gave it a little more Growl....
 

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I've had a DG-O series pipe on my bike for about 3 months now. Performance gains = absolutely none. It's loud as f#@&. Once I jetted the carb I did notice improved mid-range throttle response, but that was about it. Didn't feel any noticeable loss of low-end torque. She tops out at an indicated 70mph with stock 14/50 gearing and me at 220 lb. which is pretty damn good IMO. So in the end, I did make some minor gains...mostly from the jetting. The pipe certainly looks better than the stocker, but that's honestly the only improvement (and a subjective one at that.) I did however gain some valuable knowledge by going through the jetting process.

Bottom line, aftermarket exhaust for the TDub really isn't worth the $200-$300 unless you're reeeeaaaaalllllyyy into shiny:cool:
 

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I swear the 45* street elbow gave me more resistance that I can feel with more torque, but nothing more, except I like the sound better also. :D It just gave it a little more Growl....
Did you point the end of the elbow up or down? I understand that down equals 10 more HP. Up equals 11, but results in carbon monoxide poisoning. Your thoughts?
 

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And if you need more back pressure try this. Might keep you warm on cold rides too. View attachment 32693
Aim it up and both buttcheeks stay warm at least. :D

Did you point the end of the elbow up or down? I understand that down equals 10 more HP. Up equals 11, but results in carbon monoxide poisoning. Your thoughts?
I mounted my 45* at a 45* so it is aimed to the ground right behind the bike and not to either side. Quieter that way and still causes lift off, so the bike goes faster easier. :D
 
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