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True dual exhaust vs stock I need some help

Discussion in 'Motorcycle Tech Talk' started by wildman1122, Dec 12, 2008.

  1. wildman1122

    wildman1122 New Member

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    ok heres the rub I have stock 1990 ultra 80 inch motor n was thinking of putting true dual exhaust but I have been getting mixed opinions . Some say stock motor with true duals will not run great n others say it will . Any input I am being told stock y exhaust has more power n torque than true dual unless u have built motor that needs more volume . Oh I have changed the slip-on mufflers to Samson Silver Bullets with Baffels . Thx For Your Input !
    wildman1122, Dec 12, 2008
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  3. AFNurse

    AFNurse Moderator Staff Member

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    So, I am not as familiar with the 80 compared to the 88....but here is how I understand it.... Stock meets EPA. True Duals will work, will give you a bit of gain depending on how you adjust things. For the MOST gain, a 2 to 1 will give you the best performance. If you want to sacrifice some of the power gains of 2 to 1 for the LOOKS of True Duals, go for it! to get the most of either true duals OR 2 to 1, make sure you have stage 1 air filter (free flow) and then make sure the jets and carb are adjusted for the free flow. may take a bit of work (in my case would take the shop!), but can be done. Lots of good info here so I am SURE that someone else will chime in with more specific info. (by the way, I want to go to true duals, just need to save up the money...get close, then something else eats the $$.....)
    AFNurse, Dec 12, 2008
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  4. kenfuzed

    kenfuzed Administrator Staff Member

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    There's always a give and take when it comes to exhaust systems. AFNURSE is correct in saying that a 2into1 system is your best bet if you are looking for the best performance. Stock head pipes have the advantage of the ideal pipe diameter of 1-3/4 for good flow.

    I personally like true duals myself but they do have their draw backs. Duals are not always that good at scavenging exhaust gases. What this means in terms of actual performance and rideability is a rougher idle and loss of low end torque.

    I've known quite a few who have converted to true duals on 80" Evo bikes. Many of those who have successfully tuned them used a set of well baffled mufflers and AR cones installed between the pipe flanges and the heads. Tuning is the key here in keeping your low end torque from suffering. If you can afford it I would recommend upgrading to a single fire ignition as well.
    Last edited: Dec 12, 2008
    kenfuzed, Dec 12, 2008
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  5. wildman1122

    wildman1122 New Member

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    thx for the info guys

    So let me make sure I have this right 1st make sure I have the money for new ignition n have baffles inserts ready to go too . Oh one last question I and going to take off my y pipe n this friend is gonna cut y out n weld shut the hole in the back cylinder pipe n give me new piece of pipe for the front similar to fulsack conversion kit . Thx
    wildman1122, Dec 13, 2008
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  6. AFNurse

    AFNurse Moderator Staff Member

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    I can not discuss the ignition or baffles....I have heard talk of people dropping a plug into the Y of the back cylinder to change that into a "true dual"......from what I have heard, it sorta works at best......best bet is to get a true dual set of headers as they have already done the measurements to balance the length of pipe for cylinders or something.....
    AFNurse, Dec 13, 2008
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  7. kenfuzed

    kenfuzed Administrator Staff Member

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    The fulsack method of plugging the 'Y' can work if done right, but I haven't seen any performance testing on this.
    kenfuzed, Dec 13, 2008
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  8. 1WildPig

    1WildPig New Member

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    I went from running a set of Samson staggered duals back to my factory head pipe with some Wild Pigs mufflers due to the Samson pipes getting too loud (mufflers made to pipes) after about 8 years of running...but I missed the true dual sound...so, just to see how it would work on my '97 RoadKing, I found an extra "junk" Y pipe at a friends shop and cut the pipe that Y's into the right side where it would be hid by the heat shield and between the clamps, welded a freeze plug inside and drilled a 3/8 hole in the center and then welded the pipe back together and installed...you can leave it completely blocked off but knowing that the crossover helps with low end torque, I decided to just reduce the amount instead of block it completely....anyway, it sounds about 90% like a true dual system and seems to run as well as or better than before. There use to be someone on ebay selling a kit that did the same thing using plugs, screws and clamps without the welding and was around $100 ! ... I'd rather have it welded....
    Last edited: Feb 5, 2009
    1WildPig, Feb 5, 2009
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  9. chucktx

    chucktx Moderator Staff Member

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    real oldschool there........:) we did that same thing in the 70's....but back then the pipe off the rear head was 2 piece instead of one. didnt have to cut it..........:) great info....thanks
    chucktx, Feb 5, 2009
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  10. wildman1122

    wildman1122 New Member

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    Thx for all the info guys . There is a guy on Ebay if you send him your y pipe he cuts the y out and welds the top piece looks pretty good and the he sends you a brand new bottom pipe for the front cyclinder . I contaced some of the guys he has done it for and they all say it is working great and the cost difference is well worth it . So I am going to try it I am looking for another y pipe so if I do not like the out come I can put my old one back on . Again thx guys
    wildman1122, Feb 7, 2009
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