Granite peak geometry issues

Discussion in 'Pre-Motorized Bicycle Information.' started by zestyzebra, Aug 18, 2016.

  1. zestyzebra

    zestyzebra New Member

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    I have seen people use the 26 inch roadmaster granite peak before but its hard for me to tell what they did. The frame angle by the crankshaft is a bit more acute than the engine wants (48cc flying horse). IE the engine mounts are made for a bike with a less sharp frame and a more horizontal down tube and bottom tube. The engine mounts and universal mount are not quite flat with the tubes. I have not yet turned around the slant head to make room for the spark plug. I have yet to add an offset intake manifold.

    I was wondering how people deal with the mounts not laying flat on the tube and the general lack of space. Part of the mount to the seat tube is removable and I was considering replacing it with short polymer or something like that or grinding down the back of this piece so it makes the frame a bit less cramped.
     
  2. crassius

    crassius Active Member

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    those take some work - I often bend the flat plate for better fit or replace it with a rounded spacer plate - don't recall off hand if that one also needs longer studs when using rounded plate

    I do a lot of builds where half the work is making good mounts.
     
  3. SpeedingTurtle

    SpeedingTurtle New Member

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    I recently abandoned my Granite peak project (not to discourage you, but to allow you a general idea of what I know). The carb got in the way so I decided on a different bike. With the piece you stated before to make room for the carb, what I did to make the engine stay was slant the carb and tighten down the universal mount bolts very tightly and left the exhaust bolts a little loose on one side to make up for the tight fit. I may not have answered the direct question, but once you get the piece for the carb ( intake manifold? ) it should only be a matter of 'how tight' you screw the nuts in. :-||
     
  4. LandSpeedRecord

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    About 10 minutes with the dremel and my kits direct mount to the frame with 8mm studs front and rear. It's an extremely strong mount set up and I have done about 20 of them now. The basic set up I do Is a dual pull brake lever, Lock the front derailleur in the middle ring, remove the rear shifter and install it on the left upside down, clutch and throttle as normal. I can send you some detailed pics if it will help, the bike works great and has become my top seller. You only need to machine away about 1mm of the cases at the front of where they are touching fading to about .5mm at the back. Then the front of a normal China girl will rest perfectly directly in the frame, I have the process down to excellent tolerances and I bet you could almost ride it before you put the mount straps on it fits so perfect. The carburetor will be tight with the stock manifold but it fits. P.M. me if you need help.
     
    #4 LandSpeedRecord, Aug 20, 2016
    Last edited: Aug 21, 2016
  5. LandSpeedRecord

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    I could only find one pic that showed the front mount but this gives you the idea of how to make it fit in the frame.
    [​IMG]
     

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