charliechaindrive
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I got this old rupp that origanally had a fiberglass body on it that looked like an AMC gremlin, but the body was missing and the frame was cracked. So I cut out the weakened and cracked tubing and streched the frame 6 inches and put a new axle in. So now I can fit into it easier.
I got an old lawn boy two stroke mower from the dump, and from the looks of it someone must have ran it on straight gas
the piston is slightly crusty.
the flywheel side needle bearing was toast, and the bottom piston ring was seized. So I called my father who is a motorcycle mechanic and I showed him the ruined bearing, and he is confident that a bearing out of a harley twin cam engine will be a direct swap. If not, I'll just build a brass bushing. There's a little damage to the crank shaft but I polished most of the ridges off in the lathe and all that is left is the discoloration.
I put the crank into the late and turned the shaft down betweeen centers to bring it to 3/4inch. I believe it was about 7/8ths from the factory, and that was some hard stuff! Even with a new carbide tool in the lathe i couldn't take more than about 15 thousanths at a time. But after i got through the case hardened layer it cut more easily. Then after I trimmed it to length I clamped it into the mill and carved my keyway into it.
My clutch slides on smooth, but I don't have any way to put a center bolt in precise enough in my opionon, so I'm just going to put some set screw divvots into the pto to hold the clutch onto the shaft. I slid everything back together for a quick photo
I also built an intake manifold to put an old Dellorto dirt bike carb onto the hs50 tecumseh thats on the rupp right now, and with a little machining it fit right onto the lawn boy. The carb bore is 25millimeters, and the ID of my manifold matches up on the edges of the square port onthe lawn boy crank case. I think the dellorto might be a bit too much carb for the lawn boy, so I dug this old HL 22 tillotson out of my box of carburetors. I found this carb in an old chainsaw in a junk yard, so it was absolutely filthy inside and out. Lots off dirt and sand inside, and also old gooey 2 stroke oil.
I like this Model of tillotson because the high speed jet is operated by that long handle thing coming out from under the throat, so I'll be able to adjust the mixture ratio easily when I'm riding. I'm planning on putting the lawn boy into the rupp, and modifying an old yamaha 125 expansion chamber pipe to fit the lawn boy port. I know it's not exactly tuned for the lawn boy, but it'll look cool and sound better than an open port or header.
Thats all I've gotten done so far, I'm gathering stuff to convert the rupp to a live axle, so I'll have to build a brake drum. I am planning on using the rear brake off of one of the old dirt bikes I've got in the barn, I'll just machine a flat surface across the outside and bolt it to the frame rail.
C
I got an old lawn boy two stroke mower from the dump, and from the looks of it someone must have ran it on straight gas
the piston is slightly crusty.
the flywheel side needle bearing was toast, and the bottom piston ring was seized. So I called my father who is a motorcycle mechanic and I showed him the ruined bearing, and he is confident that a bearing out of a harley twin cam engine will be a direct swap. If not, I'll just build a brass bushing. There's a little damage to the crank shaft but I polished most of the ridges off in the lathe and all that is left is the discoloration.
I put the crank into the late and turned the shaft down betweeen centers to bring it to 3/4inch. I believe it was about 7/8ths from the factory, and that was some hard stuff! Even with a new carbide tool in the lathe i couldn't take more than about 15 thousanths at a time. But after i got through the case hardened layer it cut more easily. Then after I trimmed it to length I clamped it into the mill and carved my keyway into it.
My clutch slides on smooth, but I don't have any way to put a center bolt in precise enough in my opionon, so I'm just going to put some set screw divvots into the pto to hold the clutch onto the shaft. I slid everything back together for a quick photo
I also built an intake manifold to put an old Dellorto dirt bike carb onto the hs50 tecumseh thats on the rupp right now, and with a little machining it fit right onto the lawn boy. The carb bore is 25millimeters, and the ID of my manifold matches up on the edges of the square port onthe lawn boy crank case. I think the dellorto might be a bit too much carb for the lawn boy, so I dug this old HL 22 tillotson out of my box of carburetors. I found this carb in an old chainsaw in a junk yard, so it was absolutely filthy inside and out. Lots off dirt and sand inside, and also old gooey 2 stroke oil.
I like this Model of tillotson because the high speed jet is operated by that long handle thing coming out from under the throat, so I'll be able to adjust the mixture ratio easily when I'm riding. I'm planning on putting the lawn boy into the rupp, and modifying an old yamaha 125 expansion chamber pipe to fit the lawn boy port. I know it's not exactly tuned for the lawn boy, but it'll look cool and sound better than an open port or header.
Thats all I've gotten done so far, I'm gathering stuff to convert the rupp to a live axle, so I'll have to build a brake drum. I am planning on using the rear brake off of one of the old dirt bikes I've got in the barn, I'll just machine a flat surface across the outside and bolt it to the frame rail.
C
