2nd Build Full Suspension KTM Clone, SBP Shift Kit

Discussion in 'Motorized Mountain Bikes and Road Bikes' started by Wild Bill, May 1, 2013.

  1. Wild Bill

    Wild Bill New Member

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    I am building a second GT LTS but this one will have a KTM 50 clone and a SBP shift kit.
    It also has a KTM 50 tank and pipe/muffler.

    I dont know if the bicycle chain or freewheel will take the horse power and the centrifugal clutch will make shifting different than the manual clutch china girl engines but I think with setting a low rpm clutch lockup and not shifting under hard power along with maybe pedaling one time around for each gear downshifting it may work. I will try the stock clutch setting first, but I may set it lower to tame the power down at each shift.


    If not I will go to single speed if I have to but I really want to get the SBP shifting to work, I do a lot of steep climbing and slow twisty trails.

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    I will make mounting tabs that I will weld to the SBP bracket in the rear and bolt to the billet aluminum mount in the front. The engine wont be here until tomorrow.

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    #1 Wild Bill, May 1, 2013
    Last edited: May 3, 2013
  2. aussiedan

    aussiedan New Member

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    awesome bikes are those pitbike mudguards? that tank looks good is it honda xr/cr?
     
  3. Wild Bill

    Wild Bill New Member

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    Thanks. The fenders are for mountain bikes and the tank is from a KTM 50.
     
  4. Zuko45

    Zuko45 New Member

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    I orded mine yesterday Wild Bill. xct2
     
  5. Zuko45

    Zuko45 New Member

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    I order mine from Daxs yesterday. Its going to be along 2 weeks.xct2
     
  6. Wild Bill

    Wild Bill New Member

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    Right on Zuko!!! Are you gonna put this on the GT LTS you have or is it going on a different bike?
     
  7. 16v4nrbrgr

    16v4nrbrgr Active Member

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    I'm interested to see how it works out handling the power because I bet I'll eventually grow bored of single speed, and like you said its hilly here.

    So far from what I've seen, if the clutch is tuned right and you have the proper final drive rear sprocket, hills shouldn't be a problem even with a 50 mph top speed. Having different gears would be nice though for the sake of rideabiltiy and noise reduction.
     
  8. Wild Bill

    Wild Bill New Member

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    Ya, gearing for high speeds with a single speed and a centrifugal clutch really makes some noise trying to climb or trying to go real slow. Shifting lets you keep a lower rpm and a low speed if you set the clutch lockup at a lower rpm but not loose the higher gearing for speed.....maybe. lol
     
    #8 Wild Bill, May 2, 2013
    Last edited: May 2, 2013
  9. Wild Bill

    Wild Bill New Member

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    It just showed up and first glance holding it roughly in place it looks like no problem I hope. The sprocket is 420 so I will file it down to fit 415.

    OK, back to work I go!

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  10. dmb

    dmb Active Member

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    right now i'm watching the fire's, hope everything turns out ok for you. check out the reed blocks. some times they have slag and are not true, check the reeds too. these motors like to be on the pipe and will just bog at low rpm's. nice frame. talk to headtrama about the motor as he has one set up for racing. dennis
     
  11. Wild Bill

    Wild Bill New Member

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    Thanks DMB, Im about 5 miles from the fire and I have a great view of it all since I live on a little hill. Its traveling kinda from my right to left so Im safe. Its gone all the way from the 101 freeway to near the ocean and the coast hwy.

    And thanks for the info, it all helps.
     
  12. Wild Bill

    Wild Bill New Member

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    Problems in paradise, this thing is wider than a china girl! And the exhaust is in the center of the cylinder and points straight forward into the bottom tube(Which I already knew about the exhaust). But since the cylinder isnt in the very center of the case the offset will workout for spark plug clearence and removal and it sets the exhaust off center of the bottom tube a little, at least enuff I can deal with it.

    It comes close to the pedals but I think where I have the engine mocked up it will work, I wanted the carb float bowl to be more level but this is about as good as it will get, again I think it will work.

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    #12 Wild Bill, May 2, 2013
    Last edited: May 3, 2013
  13. Zuko45

    Zuko45 New Member

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    Same Lts frame as I used last time but different wheels with heavy duty hub and bearing. sents I wont have the clutch handle in the way so Im going to have front brakes this time and grip shift instead of wrachet shift. Ihave a different pipe than yours but i think it will work. Engine looks bigger than I thought after seeing it in your frame, but it will work .thanks Dougxct2
     
  14. Wild Bill

    Wild Bill New Member

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    Well I got some of the important stuff done today. I finished the front and rear motor mounts and got the engine sitting in there better than I thought I could especially the carb, I managed to get it nearly flat as far as the float bowl goes even though it doesnt matter a whole lot.

    I used a billet aluminum mount I found on the net for the front mount and welded tabs to the SBP jackshaft bracket for the rear.

    I got the throttle cable setup right and it was a minor Beeyatch!!! The cable with the throttle handle I am using didnt have enuff free cable legnth to let the slide go down to idle so I had to get a little free length here and there but it works great.

    Then even though I dont have the pipe finished yet I filled the case with ATF, put fuel in the tank and started it. I only ran it a very short time to set the idle and refire it a few times. I fired it every time doing the kick starter by hand, it was easy! Fires first try every time. The fuel tank petcock leaks (Used tank) but it looks like its serviceable so I will replace the o-ring, if not I will get one from the KTM dealer.

    I ordered an 1 1/4" exhaust elbow that I can cut to make the pipe fit within the frame but it wont be here till tues or wed, the auto parts places dont show 1 1/4" in the books and the muffler shops bends crimp down the tubing some so it will be worth the wait I keep telling myself.

    I also ground some off the end of the right side pedal arm for clearance on the right side case.

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    #14 Wild Bill, May 3, 2013
    Last edited: May 3, 2013
  15. 16v4nrbrgr

    16v4nrbrgr Active Member

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    Wow, I'm impressed at how it works with the shift kit plates, looking forward to seeing how it goes.
     
  16. Wild Bill

    Wild Bill New Member

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    I used 1/8" X 1" flat bar laying flush on the right side of the SBP bracket but there are 3/8" thick spacers shifting the motor over to the left to get the engine centered in the frame. I layed the flat bar flat against the right side to make it easier to hold the engine in there while mocking up and tack welding the tabs.

    The first tab was bolted to the bracket using the small bolt hole on the SBP bracket to hold it in place before the tack weld as can be seen in an earlier pic.
     
    #16 Wild Bill, May 4, 2013
    Last edited: May 5, 2013
  17. Wild Bill

    Wild Bill New Member

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    I made exhaust and muffler hangers and bolted up the pipe to hold it in place to make it easy when I cut and tack weld the exhaust tubing so the header clears the bottom tube.

    Then I test rode (pedaling no engine yet) with the pipe in place to make sure my feet and legs clear everything and it rode fine, no clearence problems. So now I wait till my exhaust tubing shows up so I can finish the pipe. I also ordered some 420 chain to run instead of grinding the engine sprocket down (engine sprocket is 420 instead of 415), it should run fine against the 415 SBP sprocket at least enuff for a test to see if the bicycle chain/freewheels will take the horse power. If it does handle the HP I will order a 420 sprocket to run instead of the 415.

    If it doesnt take the HP I will be going to a single speed which should be an easy switch.


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    #17 Wild Bill, May 4, 2013
    Last edited: May 5, 2013
  18. unknownbmxa88

    unknownbmxa88 New Member

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    dang that thing is sick. how much power does that motor put out?
     
  19. Wild Bill

    Wild Bill New Member

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    Thanks, Dax (Dwayne) has the description on his web site as 9HP but I wouldnt be surprised if were closer to 5-6 maybe 7. I may be wrong but 9 seems really high for a Chinese clone, someone running one could chime in and let us know.
     
  20. Wild Bill

    Wild Bill New Member

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    The exhaust tubing came today so I cut up some pieces and welded up the pipe so it clears the bottom tube. It turned out ok but its still about 1/8" from the bottom tube so I will watch and see that it doesnt get too hot.

    Then I started it and ran it with the pipe and muffler on it, it started first try and sounds very good with a crisp high pitched crackle at idle but its a little louder than my other bike ( And it sounds a million times better!).

    All I have left before the first test ride is a final mounting of the engine, put on the left side chain (420 chain) but its not here yet, and a few minor tweeks and check over then its ready for a first ride and see if I think the shifting idea is gonna work before I go any farther. If I dont think it would be fairly reliable (Even if you have to baby it a little) or that I could work out the bugs fairly easy then I will consider going to a single speed. MAN I HOPE THIS WORKS!!!......lol

    If it seems like its gonna work then I will make a chain gaurd for the right side, Im afraid of the right side jackshaft chain breaking and whackin me on the leg. And a chain tensioner for the engine chain and replace the narrower 415 jackshaft sprocket with a 420.

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    #20 Wild Bill, May 6, 2013
    Last edited: May 6, 2013

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