MOPED ARMY

I think I am just going to grab a 505 engine from somewhere. There is a cast iron Polini Kit that seems like it would work wonders.

Look at the teensy intake!

All well but stk clutches are weak on larger cyls. Maybe you can fabricate a better clutch

fwhew.. for a second there Bret I'd thought youd forsaken the variator

Hmmm, so I just happen to have a 505 and 504 case sitting around, and know how to use a drill and a tap. the hard part would be deciding where to cut the sachs ..... if you replace the clutch with a variator, you would also eliminate the weak-ish sachs clutch. so would you go with a 2 pulley variator, or would you make it a one pulley swinging Belgian bastard?

If you can chuck the engine case up in a drill press, you could probably MAKE anything fit anything else, as long as the cylinder goes into the case far enough.

"130cc sachs":http://www.youtube.com/watch?v=rmpPFvlYrrg

Yes, this kit is used by some guys over here to adapt to an E-50. There's a lot of work in it tho.

The exhaustmounting would be the least of your problems mounting this kit up.

The stroke is the same. Both 42mm (You would need a normal engine, not the "long stroke" 505 engine), but your bolts will probably be far from lining up. That's the first thing you'd need to adapt.

Then you've got con-rod length. If the length of the conrod is not the same, you will need to raise or lower the cylinder to get the proper deckheight. You can do this by making a plate (if the con-rod is too long) which can also fix your bolt spacing and the utterly large transfers. Or you can remove material from the block or the cylinder if the con-rod is too short. A deckheight of +/- 1 or 2mm would be good, as you can then vary the deckheight by using multiple gaskets.

Then you've got the fact that it's watercooled. You'll need a waterpump that's either electric or belt-driven. You can buy the belt-driven waterpumps from www.mopshop.de. Get a radiator from a scooter or small motorcycle and you're good to go in the cooling section.

And yeah, you want to loose the stock clutch. It will never hold that kind of power. It can't even handle a badly tuned 80cc Athena :P I love the variator idea and would love to see how you work that out. I've been thinking about adapting a variator to an E-50, but I won't go into detail about that till I've actually tried it :P

Having said this all, I wish you the best of luck. Very wicked idea and if this works out well, you've got yourself one killer ped.

All this is good stuff. I would actually be starting with a 504, since that's the engine/bike that I just bought. I would almost certainly have to replace the crankshaft with something that accepts a variator, so i was thinking of just using a scooter crank, or a peugeot or motobecane crank.

I actually think the biggest problems are:

1. The Sachs 504 engine mounts, but i suppose there must be a way to reinforce them. I'm only going to be using the front end of the engine anyway, so i could just drop anchors through the case.

2. Modding the frame to accept either a Wariator-spring pulley or a scooter clutch attached to a shaft with a drive sprocket on the inside.

So, take apart a Sachs 504, dump out everything inside it. Take a crank of the appropriate conrod and stroke dimensions, that has either a splined or tapered shaft on the drive side, and use bearings that will match it to the 504 case. Fill in or cut away the case volume to match the crank pucks.

Build up the sides of the case if necessary and match the ports to the kit. Drill and tap new cylinder stud holes. Mount cylinder to engine.

For the variator, chop away the clutch housing portion of the case so there is room for a variator like an Er3 or a Multivar. You could mount the spring pulley and clutch either through the empty space behind where the drive sprocket used to be, or through the 505 pedal shaft hole. I would like the keep the clutch thing off the frame if possible.

The more i think about it, the more I just want to plonker it down into a heavily modified motobecane AV10.

that video of the 130cc sachs being ridden on old European dirt roads had me scared shitless.

woof, you guys aint kidding about this. I think the sachs case has a clutch side bearing lubricated by crankcase oil. minor, after everything else, but could be a problem.

i still think it would be way easier and more productive to just get a 505/2b. they are cheap on ebay.de.

I've done the manual shift bikes. F-that. Variators. Also, the clutches can't take the abuse of 5HP kits and this kit is a 11-15Hp kit, and you can't get proper replacement parts for the two speed clutches..

I can't decide which I am more interested in at this point: a crazy kit or a variated sachs mod. I think I am going to try and get the variated part to work first, hopefully using the stock crank, but I have my doubts on that. I think that I would have to use a 505 case to have enough room to keep the clutch on the engine and off the frame of the bike.

Does anyone have any input on adapting 505 engines into 504 frames? Or can i just get a good picture of the left sides of a 504 and 505 case?

here is a 3/4 view of the top half of a 504 from the front- piston side.

bottom half of a 504 from the front.

I also measured the clutch side of the crank and the shaft measured 11.70 mm The inside of the gear that the clutch disks ride on measured 11.65mm, and it still fit, so I'm not sure how accurate my digital micrometer is. The internal gear reduction is 4 crank revolutions to 1 sprocket revolution.