athena ajh

Funny thing, either treats sent me the wrong piston when I ordered just the piston and cylinder or somethings up.

Pics:

Clone, ajh, clone piston.

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Re: athena ajh

Pics:

Athena piston, clone piston, Athena piston,

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Re: athena ajh

More than the overall height of the piston, what matters is from the center of the wrist pin to the edge of the top of the piston. Set them side by side and compare? (edited)

Re: athena ajh

Pics:

Clone bdc, Athena bdc.

Both with the Athena piston, the clone piston won't fit in the Athena cylinder, it doesn't drop through.

Looks like a treats piston could fix it.

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Re: athena ajh

Piston side by side.

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Re: athena ajh

Where are the ring gaps on the athena piston?

Re: athena ajh

Same place as the clones, up top in the intake.

Re: athena ajh

So the athena with an athena piston doesn't even clear the exhaust port??

Re: athena ajh

Nope, overhangs by a bit. Any reason I couldn't cut a hole in the skirt of a piston port piston and run it? Single ring and looks to be close to lining up right.

Re: athena ajh

The crown is 24.5mm away from the center of the wrist pin on both clone and Athena pistons.

Re: athena ajh

Bingo-bango.

Spaced with a single thin gasket. K-star piston.

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Re: athena ajh

Whats the compresion like now? Aren't you going to have to counter sink the head?

Re: athena ajh

He's not running it right now, only mocking it up. But yes, you would want to run a countersunk head or deck the top of the cylinder. (edited)

Re: athena ajh

Can you do a port map of the athena? Or maybe just get the distances from the top of the cylinder to the top of the exhaust and transfer ports?

Re: athena ajh

This was in the wiki. I don't know who did it or how accurate it is.

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That port map looks right. I measured the edge of the exhaust to tdc and it was 26mm, which makes sense. On a 43mm stroke, if 20mm of it is exhaust port and your trying to use it all, but its 26mm to the cylinder deck, you'll have 3mm of space left over.

Re: athena ajh

So how much would we have to deck/counter sink? Someone make these heads!

Re: athena ajh

i'll make any head you want me to! just send me an email!

it looks like with the piston that comes with the kit, you need to sink 3.5 mm or so, if you run the TCCD/treat kit piston you are looking at about 1.5 mm.

i can also cut out some 3.4 mm spacers if anyone is interested, hit me up via email, lots of parts i aint got time to make everything!

Re: athena ajh

@graham how do you ussually cut spacers, i bet everyone wants em for the puch mk65 too.

right now i've got some 1/8 jigged on the vice ontop of parallels , gonna m7 the four studs and a center , then im gonna hole saw the center.

what ya think, tons of different ways to machine somthing

Re: athena ajh

yeah i make mine with a CNC plasma cutter from aluminum sheet, then i anneal them with a heat treating furnace so ya dont need gaskets. I finish them by drilling and deburring the holes and thats about it.

i made some Batavus ones so you can put an M56 cylinder on your M48 engine bike. It would just be the same thing.

The MK65 thing, well, i guess they aren't going to be getting any more of those? so there isn't much money in making things for it, plus they tend to vary a lot so you cant do a 1-size-fits-all. i've probably installed 4 or 5 of them since 2005 or so, they all require different amounts of layers peeled off the provided aluminum shim gasket thing.

Re: athena ajh

Mars has an awesome jig setup, he does all my head work for me, but laser cut base spacers sounds awesome. Sabat is making me one now, so if this one works I'll be straight, but if not I'll definitely contact you Graham.

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i run that clone kit. i absolutely love it. e50 go 60 with no case boring? yes please. gilas can suck it.

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Mwahahaha. (Evil laugh)

Sprockets are purchased! Thanks Roff!

Tick, what gearing are you running?

Re: athena ajh

Better yet tick, post your gearing and setup in this thread:

https://www.mopedarmy.com/forums/read.php?7,3076297

Re: athena ajh

hey sabat, do you make a lot of spacers for people or is this a one-off thing? i'll make them if enough people are interested but i try really hard to make things nobody else makes because i dont like steppin' on toes and the moped market usually ain't big enough for two people making the same obscure part.... ya'dig?

Re: athena ajh

This is a one time thing for me, like I bought a square foot piece of 16ga milled steel and hacksawed it into a workable smaller size piece. Make these. The 1977 cheapo piston port kit needs a spacer too.

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Probably Fred /

If 1977 knows now that their kits have wrong timing/spacing then they need to have them made correctly

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Every one of em does, the 50cc racey kit needs like 4mm of spacing so the piston doesn't hit the head, the cheapo 70cc needs like 2mm so the piston doesn't hit the head and we all know about the 3.4mm and insane-o timing on the reed kit.

Graham, you should contact 77 and do a run of spacers and heads for them so their shit actually works.

Re: athena ajh

Probably Fred /

No just have them cast them correctly or don't buy them.

Even if they include a free spacer you/we will still have to mess with head issues

Re: athena ajh

The 50cc racey kit wasn't bad and from preliminary/air leaky tests, the cheapo 70cc kit is straight, even though it needs case welding to seal.

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