The Lawnboy project

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by trackfodder, Jun 28, 2017.

  1. trackfodder

    trackfodder Member

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    Things are moving slowly. I machined a magnesium carburator spigot and mounted one of those aftermarket China Girl carbs with the red cone shaped aircleaner on it. Then I discovered it will have to be mounted at the top of the frame under the Cranbrook little top bars due to excessive length. No biggie, but disappointing except that the exhaust port on the engine mount plate is high enough I can easily mount a 180 degree exhaust pipe with oodles of room over the sprocket I have (4) 6" X 1/4" pipe nipples bent 90 degrees to weld to the frame and bolt to engine plate. I have masking tape on the frame and a 90 degree cross on the crankshaft hole that line up with marks on the frame tapes to locate the position for welding with the plate clamped 2-1/2" from centerline of the frame without having the engine in place. If carb trouble or plug trouble occurs, it means an engine pull but that is only 4 bolts, so, OK I guess.
     
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  2. Dan

    Dan Staff
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    Sounds cool, Track. Any pics?
     
  3. curtisfox

    curtisfox Active Member

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    YA! pictures, sounds good to me. Glad you are getting somewhere, lot of trial and are doing a home build ...............Curt
     
  4. trackfodder

    trackfodder Member

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    Major mount change-- My 6" nipples didn't pan out like I hoped, so now have milled crescents in ends of 1" 16 ga. square tubing that will weld to the 1-1/2 and 1-1/4" frame tubes in 4 places with 3-1/2 X 3/8" bolts welded through them extending through 4 corners of engine plate with nut and lockwasher behind and acorn nuts outside. Will cut tubes so that I can close the end where the bolt goes through. It's kinda fun to plan that stuff while trying to go to sleep at night. Whatever works.
     
  5. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    I still can't wrap my head around what you're describing.

    Pictures?
     
  6. trackfodder

    trackfodder Member

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    The lawnboy srips down to a flange mount which is mounting on a 7 X 8" 10 ga. plate with a shaft hole in the middle and mounting holes on each corner. An exhaust port is fitted with a forward pointing tube. The cooling fins have been machined from the flywheel. I am fitting 4 square tubings from the frame to positions where the bolts register with the corner holes. They will be welded to the tubings and the shanks will back up the plate with nuts and lock washers and acorn nuts will secure the plate, A bit early for pix but will follow soon
     
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  7. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    Motor mount pics, please.
     
  8. trackfodder

    trackfodder Member

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    OK you guys, I did some cutting and fitting today . I must be getting funny in the head, I made a mistake and drilled the bolt holes 90 deg. off and had to re-drill In the fitting I found I had engine where I wanted struts so had to grind away some Lawnboy and it looks like crap. I promised myself I will slick it up later (ha) Tomorrow I will weld the ends on the struts I folded over and the bolts to the struts. After that I need to grind paint away for welding, tack the struts in place and get Mike Sawyer to TIG them and make them lovely. Anyhow here are the pix as promised. The lines are to position the plate in the frame and give a hint of where the struts will point. If the struts are vertical in the frame, the engine will be exactly perpendicular at the shaft to the frame.
     

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  9. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    Wow! You got some skills here.

    Is your flat motor plate to be mounted vertical?

    Are you going to bolt it to a big rear wheel sprocket?

    Are you running as jackshaft for more gearing?

    Is the engine's exhaust port flange going to be bolted onto the motor plate?

    Is there a reason why you didn't clearance the motor plate and have the LawnBoy's muffler bolt directly to the engine?

    How are you bolting the motor plate to the engine's exhaust flange?

    It seems like a likely place for an exhaust leak.

    Friend, I'm not telling you what to do.

    Just asking.
     
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  10. trackfodder

    trackfodder Member

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    OK you guys, I did some cutting and fitting today . I must be getting funny in the head, I made a mistake and drilled the bolt holes 90 deg. off and had to re-drill In the fitting I found I had engine where I wanted struts so had to grind away some Lawnboy and it looks like crap. I promised myself I will slick it up later (ha) Tomorrow I will weld the ends on the struts I folded over and the bolts to the struts. After that I need to grind paint away for welding, tack the struts in place and get Mike Sawyer to TIG them and make them lovely. Anyhow here are the pix as promised. The lines are to position the plate in the frame and give a hint of where the struts will point. If the struts are vertical in the frame, the engine will be exactly perpendicular at the shaft to the frame.
     
  11. trackfodder

    trackfodder Member

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    I plan on a large gasket to mount the engine to the plate. Since there are 2 bolts at the exhaust port, I don't anticipate leaks. Not sure about final drive, but if the Comet VST lines up well, may go that way or if not a centrifugal clutch to a jackshaft and chain to rear wheel. If Comet is used, I had already fitted a #40 sprocket to it, but have a whole family of # 40 racing bike sprockets. I used to mount one on a lathe spindle to register the spindle in various positions for drilling holes in big PVC tubes where I worked, I could set the spindle in any number of positions for however many rows of holes were needed around the tube by selecting the right sprocket. The Lawnboy muffler was crapped out. The motor plate will be vertical to the ground. this makes the engine horizontal. Today I weld the bolts to the struts and weld the folded flaps over the ends of them. Once I get the shortest upper rear strut welded in place, will mount plate to it and insert the remaining 3 to position them to weld. As mentioned, will only torch-tack them in place and get my friend Mike to TIG them for pretty.
     

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