NGC-machining solution needed

[SIR REAL ED]

That was a lot of work to get those two small brackets.  I assume the old frame was never to be used again.  Fabricating from a new piece of steel is not hard if you pattern it with a piece of paper or cereal box board.  In this case you may still need a couple more at the top side and making them right will go along way in making this project work.  Looks good so far.

One of my wild hair ideas for the upper rear engine mount, and the cylinder head engine mount is 45mm ID shaft collars with a tab welded to them.

It sounds crazy stupid I know, but if the frame sitting in front of us both, I could walk you though my thinking.

Hacksaws and handfiles can be very limiting.....

[SIR REAL ED]

I think that a creative solution would be to use a back spot facing cutter from the opposite side

If you can get a long enough one the 2 holes will hold everything square

https://www.drill-service.co.uk/products/countersinks-counterbores/back-spot-facing-cutters/

The trouble doing by hand is controlling the cut sufficiently that you don't get a dig. Multi tooth cutters will make that easier

Well said.  In another lifetime we used to install dowel pins and spot face with hand drills to provide datums for optical measurements.  Slow speed, steady feed, and cutting oil can allow you to do a lot of stuff.

[SIR REAL ED]

Small setbacks just means “ back to the drawing board”
I’d be doing the frame bracket.

You are correct.  Super easy to accurately fixture so even a blind welder (but one who is more highly skilled than i) could weld it.

Just need to remove some paint and it is good to go.

[SIR REAL ED]

I really appreciate all the help and advice you guys are providing.  I'm going to start a build thread that will
be mostly pictures.  Any thoughts all y'all have throw em out them.

Well intentioned dopw slaps are also appreciated.  Tough love we called it back in the day.

[John A]

I debated going that route.  Since my machine tools are primarily hand tools, I thought this was the easier route.  The cross tube diameter of the DR frame and the MZ frame were very close.  So that eliminate a huge amount of hacksaw, jigsaw, round filing, and die grinder work.  The bend in the brackets would have been very problematic for me.  I don't have the equipment for bending anything that can't be clamped in a vise and hammered.  The DR mounts are about 3mm thick.

The handwork isn't practical at times, but it is recreation, and therapeutic.  The DR mounts were dimensionally correct, except for being about 2mm too long when measured from hole edge to frame edge.  Very quick work with a die grinder.

Finally there is something poetic about reusing the DR mounts.

I agree with you 100% on making patterns.  Cardboard, sheet metal, UHMW, thin plywood, whatever is at hand is sometimes just fine.

It is like using stacks of Post-It notes as an Ultrathick feeler gage, or using drill bits, bolts, wood dowels, ar pencils as measuring tools.  It might make the real machinists cringe, but hey, if they did not have machine tools, they wouldn't be real machinists!!   

It’ll look factory doing it with the donor brackets

[Shiny Hat]

It looks like you are aligning the new tabs/ears/brackets to the existing ones. I would suggest you mount them to the new engine, fit the engine in the frame to get proper clearance for the case and sprocket alignment. Tack weld, remove engine then final weld.

[SIR REAL ED]

It looks like you are aligning the new tabs/ears/brackets to the existing ones. I would suggest you mount them to the new engine, fit the engine in the frame to get proper clearance for the case and sprocket alignment. Tack weld, remove engine then final weld.

Good advice! 

Based on dozens of measurements, I am confident in elevation and front to back location, and most importantly, countershaft parallel to swingarm pivot. 

I am building in 0.20" movement to either side to be controlled by spacers to allow for future tire or swing arm changes.

[Shiny Hat]

Good advice! 

Based on dozens of measurements, I am confident in elevation and front to back location, and most importantly, countershaft parallel to swingarm pivot. 

I am building in 0.20" movement to either side to be controlled by spacers to allow for future tire or swing arm changes.

You got this, I just mentioned in case the new motor dimensions caused contact against the frame (weldment).