As was mentioned in previous posts, the engine mount bushings in my 1977 Motobecane 50V needed to be replaced. Or, at least removed and properly reinstalled. The manual is emphatic that the factory special tool, #100024 must be used. And looking at the design, I didn't doubt this.
The factory tool was not available, but Mototbecane was nice enough to publish a scale drawing of the tool in the service manual. The manual can be found in the Articles section of www.mopedriders.org. From this diagram, making a few careful measurements, and a guess or two, I designed a tool to do the job. I worked with a friend to machine the needed parts from heat-treated 6061 aluminum billtet.
Here is a copy of the drawing I worked from, taken from the Motobecane shop manual:
Here is what I ended up with. First, a photo of the tool, with all parts loosely assembled, for better viewing:
This is a photo of the component parts, laid out for identification. Starting in the back row, left to right - main tool body, installation stop, push piece. In the front row is the grade 5 drawbolt (additional thread added) and the drawbolt hardware.
Last photo is of the main tool body, with the installation stop installed. This stop sets the correct installed depth for the bushing, at 3/32" (based on measurement only:
So far, I've used the tool to remove & replace the bushings in a spare frame that I have, and it seems to work well. The real test will come later this week, when I attempt an actual repair on my Moby. If it goes well, this is the last step, and the bike is oficially done. This feels good.
Anyway, questions and comments welcome.
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