Seems like a shit ton of work. I know that the challenge is half the fun, but Polini/15 Bing does 50+ out the box, 60+ with some simple porting and a 19 del phbg...
I can't imagine the allure of this kit other than being able to say you got it to work properly, lol. Which would be pretty cool I guess.
In my eyes it a cylinder meant to be ported for race use only pretty much. Its got a huge reed block, big transfers, and a bridged exhaust making it the best candidate for a race 70cc cylinder, as far as I'm concerned. I'm pretty sure this could be a 65+ cylinder done up right.
I can't wait to see what jake does.
yeah this thing is nuts, having the bridged transfer opens up a lot more potential.
with that crazy shimming issue, a shim and a countersunk head would be the way to go for sure. i prefer cutting the cylinder down on a lathe, but i know not everyone has that technology.
it would really be ideal to just find the right damn piston, or a better one, something with one ring.
I know a lot of KTM cobra/junior/senior50 shit is very similar to puch, anyone looked into that? If you really are gonna put the beans to this thing you probably ought to have a real nice piston not some generic pot metal taiwan junk.
just guesstimating off that port map, i would say 12k no prob with the exhaust wide like that. whether it can do that running 18/36 gears i'm not so sure, but we shall see. drew human bean would be the one to talk to, he has the sickest AJH athena that i know of, i think he was getting near 70 on it last i heard.
Charlie BUZZARD Wrote:
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>
> I can't imagine the allure of this kit other than
> being able to say you got it to work properly,
> lol. Which would be pretty cool I guess.
Bingo. I have more fun experimenting and cobbling stuff together than I do just bolting stuff on and blasting. Theres been a lot of interest in this kit from 1977, but no one has documented their ventures with it.
12k at 18x40 is like 70. I think its doable. I'll have tons of pics with this next to an Athena in a few hours so just hold tight!
Intently watching this unfold......
I see lots of potential with this, with the right tools as graham has said.
I have access to a lathe and mill with all the tooling I could ever want. Just have to figure out how to hold the head when turning it and cylinder when I mill it.
Cant wait to see the results !!
Trying to haggle with Mr. Roff right now for a 36t sprocket...
https://mopedarmy.com/forums/read.php?7,3078572 for Athena vs clone
This is the piston that solves the problem. Single ring, just needs a boost window cut. Ring gap is straight, still leaves you with 2.7mm of meat up top. Still need to countersink, but no need to do anything else.
Pics:
1977 w/ treats v2 piston bdc intake side, 1977 w/ treats v2 bdc ex side, 1977 w/ treats at tdc
awesome!
holding the cylinder (if you want to do it) can be accomplished by making a simple mandrel. Mine is a big slug of brass and has the business end turned down to the size of the cylinder (slip fit) and there is a countersunk hole in the middle. Band saw cuts segment the one end into 4 sections, by tightening a countersunk screw into the hole in the middle, it wedges the four fingers out and they hold the cylinder. I have one that is stepped 38 and 40mm for doing puch and batavus cylindeers, and one that is straight 45mm, it sucks you have to make one for each cylinder you want to machine, but they work really well.
you can also fixture it in a mill and use a fly cutter, but you better make sure your mill is dead nuts.
all that said, yeah, getting the right piston is probably a much better idea.
Got my gearing changed to 18x36 but didn't get time to test it out. I'm sure takeoff will be hurt, but I can't wait to see what it does on the top end. Stay tuned for a speed run and video tonight.
Tuned in and waiting patiently.
Me too.
Potential polini killer ?
My clutch needs tuning. :/
Can anyone say KTM?
STILL NOT TRANSFER MATCHED and piston issue still hasn't been fixed. Clutch also needs tuning or I need KTM, BUT here's the video.
Held max speed from :55 to 1:20, then showed a kid my GPS and asked him what the max GPS speed was at 2:00. Turn your sound all the way up.
that is with the porting though?
sounds like you could go down on your gearing, but when you get the piston thing fixed you'll probably have power to pull it.
57 is pretty gnarly either way.
Nope, not ported, case matched or anything. Just bolted on.
woaaaahhhhh
you'd be hard pressed to get 57 out of a slap-on gilakit, thats insane.
wish i had a spare puch motor on the shelf waiting for a kit.
Next step will be ramping the transfers and widening the exhaust. Re-test. Then later on experiment with piston options and countersunk heads.
At first all I could think about is how the hell are you seeing the road without a bright ass headlight....
This is all impressive so far, thanks for the good work.
Try 17x36. I feel like you might go faster or have better take off with the same top speed.
Ok, geared at 17x36 now. Going to ride it to work today and get some miles on it.
Hell ya, I can't wait for the results.
nice. if you make the exhaust port all huge like in that port map, you should kill just about anything.
are you running the reeds that came with the kit or some other setup?
thanks
The stock metal reeds. Some don't trust them, but I think they're fine. My MB5 runs the same metal reeds.
Hey graham drew from the human beans had the small reed athena. He took a bunch off the piston skirt and opened the intake a hair. Not sure if he did anything to the exhaust, but it had good low end and tons of revs with the 8p. Towed broke down bikes at 50.
This one looks like it has a lot more potential. It sucks these chinese kits are way off with the ports and the pistons crowns are stupid. I guess you get what you pay for, but this one might really be worth the headaches.
i raised the exhaust 3mm
also widened 1mm on each side..(i would go wider now)
i took a 25 cent piece and used it as a templet for for the cut out on the piston
mark the piston at TDC
so you know when the piston is at the top of the intake stroke. mark at the top of the intake on the piston.. thats the peak of the arch you want to cut
trying to achieve 360 degree intake duration
it went really fast.. over 65mph
korado cdi
20mm carb
homoet 8p
ktm clutch.
but mostly ran a 3 shoe from the korado.
some really wild case matching
spun over 12500rpm
with that bridged exhaust .. you are going to be able to get wild.. this will be fast (edited)
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