Sachs tom-foolery and hooliganishness

The edge of the paper nearest to the exhaust port is the squish band of the jug. The squares are 4 per inch, or 1 square = .25 inches.

70cc Sachs Athena port tracing. Gonna research once my motor is a bit back together and get an exact TDC, then I can start considering modifications, if it even needs any.

Anyone tinker with porting a Sachs 70cc?

Re: Sachs tom-foolery and hooliganishness

your port map is worthless without measurements, use a caliper on the actual cylinder to get accurate dimensions, then double check with the port map, and calculate all your timings.

http://www.mopedarmy.com/wiki/Calculating_port_timing

i'm working on a minarelli build that i'll be blogging the whole process very soon

Re: Sachs tom-foolery and hooliganishness

Stock vs modified:

The Athena intakes are atrocious.

I do have to clean both up a bit, and I only matched the ramping to the intake, the port window is stock. Graham, I finished the port map and haven't had a chance to dimension with calipers, but I read your blog to get instructions so the actual dimensions are in the works, brother. Will D wanted to see it posted up and I am doing a ton of crap to this engine so this will be my image-dump thread, and we shall discuss Sachs goodness...

I don't know if I will be changing the port timings at all, but I am trying to make it as good as possible before looking into the port shapes. It's still apart on my bench in pieces...

Re: Sachs tom-foolery and hooliganishness

yeah, you'll want to change those port dimensions, i can tell even without measurements they are pretty crappy.

that kit is known for being a dog.

intake porting looks great, keep up the good work

Re: Sachs tom-foolery and hooliganishness

Did a rough-out of the case-matching on the lower half of the Sachs case. It was about -6 in my garage so I didn't clean up the matching all the way. This little bit of work seems to put the transfers dead-on even with the jug so I'm happy with the shape, I just want to smooth the surface and even them out really good.

I'll have to wait for slightly warmer weather. It was so cold that I had a hard time getting paper to burn when trying to start a fire in my wood-stove for a little refuge from the coldness.

Re: Sachs tom-foolery and hooliganishness

I am so hard for mopeds now, but school isn't letting up and so I can't do shit... Updates will come soon hopefully.

No pics, but I did make spacers and install the bearings on my new crank, smooth out the new transfers on the lower-half, and start on the upper-half case transfer matching.

Re: Sachs tom-foolery and hooliganishness

Some updates, finally...

Finished my custom aluminum intake spacer. Lines up beautifully.

Intake and spacer, one happy family of aluminum.

SHA 16 cabled out, with ramped throttle slide inside, ready to be installed on engine.

Didn't get an exact pic of my final transfer case-matching step but this was darn close to the last step of it, with the case-halves together.

Custom decomp plug, fits inside and seals against the original decomp angle-plate-thingee with a thin exhaust gasket & copper gasket spray lightly sprayed on it.

It is really thumpy, spinning the flywheel over... I'm excited to get it to run.

All for now. Imageshack went pay-only, so I had to switch to Photobucket. Hope everything works for you Sachs fans. (edited)

Re: Sachs tom-foolery and hooliganishness

Pic of the engine, ~75% complete.

Re: Sachs tom-foolery and hooliganishness

Moar

I have high hopes for this

Re: Sachs tom-foolery and hooliganishness

Rich Swingewood /

Sorry for hijacking this thread, I have a General 5 Star 505/1A that needs some oomph. I have a spare engine that is in a bad state and needs a new piston. I was thinking of using a Athena piston on the stoke cylinder, will this work and will it have a positive effect on the port timing? I don't want to change much maybe clean up the parts a bit, maybe a slight change in port timing, any recommendations, my main objections is not have to pedal uphill, btw I have tuned it and don't have to pedal much at all now just at the start of the hill.

I have a stock Moby which is currently getting rebuilt that outperforms the Sachs big time.

Cheers

Rich

Re: Sachs tom-foolery and hooliganishness

d. how is this going?

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