which engine is this ?
Tag says 47cc
angled cylinder fins
Mostly likey a 505/1A 25mph engine
thanks I was only getting about 17mph on flat road and no power up hills so I took it apart and ordered all new seals bc it started leaking when i changed tranny fluid to atf. i took the head up and the exhaust hole in the head was almost clogged so i cleaned it out now there's a bigger hole. what else should i do while i still have the motor off?
Check out Fred’s Guide in the wiki on this site. It’s a good starting point for restoring mopeds
17 is rubbish. Have you cleaned your jet?
I cleaned everything. I'm just waiting for the new seal and gaskets to come and oil screw. and I also broke the bottom piston ring trying to put the head back on without greasing the cylinder and piston smdh... I'm learning.. so I also ordered new piston rings that are 38mm x 2mm. those are correct right?
You should open a repair thread for something that complex
I checked and both of the rings I had were the same size and radio somewhere that they should be 38mm x 2mm I just wanted to make sure.
They should be 38 x 2mm, it loks like they needed to be replaced anyways by the amount of soot on the Piston under the Rings.
> Chöschi21 C.K. Wrote:
> They should be 38 x 2mm, it loks like they needed to be replaced anyways
> by the amount of soot on the Piston under the Rings.
yeah and they had some slack dont know if it should of been that way but when I tried to move one ot literally just shattered under almost 0 tension. I got a pack of two coming. I want to install them carefully so you have a way to do it easily? I dont wanna break a new set they aren't too cheap.
> Stephen Simmons Wrote:
> I think it's more of your gearing and carb than the actual engine it
> self. If you look where I circled it clearly says 20mph and that's about
> all your going to get until you upgrade some things. Sure 17mph isn't
> 20mph but it's not far off.
yeah that's why I posted that pic bc of what ot said. but I was getting up my hill easily before and then it started bogging down and not moving at all without heavy pedaling up the same hill so I took everything apart to just rebuild the whole motor. why not right? I just want to bring this thing back to life better than ever. like brand new.
I'd also check to make sure the exhaust isn't clogged.
Oohhh it says 20mph? Dang. Guess that means its a 505/1B. Pretty sure the wiki has the differences listed on how a "B" is different than an "A".
I checked yet I still can't figure it out. it says 40km on the cylinder and the piston has 2 rings. the carb has 12 on it?
Myron's has some good info too:
Thats a Columbia Commuter, thats what I have ,heres what I did to get it a little faster before I started buying parts.
Open up the carb and there should be a little silver plate, thats a restrictor, take that out!
The mechanism sticking out of the jug is a decomp, plug that up with a bolt, make sure it seats at the very bottom.
In the exhaust, cut about 2 inches off for a higher RPM, use some aluminum or copper as a spacer to seal up where the header and pipe meet.
There are sprockets on treats you can buy, A-Plus or something like that, just have to grind it a little for it to fit.
Boom 22 mphs.
it's a sachs - ------
have you tried: throwing the whole thing in the garbage and buying a banjo?
Yea, that’s a carb.
0_o what do I do with it??? lmao
That's a 12mm carb. drill that out to 14mm
where and how do I drill it?
that's a 10mm carb, it's a B
The engine plates didn't always have the letter designations stamped but you can tell by the following
If it says 49cc, it's a D
If it's 47cc got a square jug (and 12mm carb, 26mm header exhaust) it's the C (rare)
if 47cc and angled jug, but still 14.5mm intake, 12mm carb and 26mm header, it's an A (by far most common)
and 47cc angled jug and tiny intake, header and 10mm carb - B. you've got a B.
lots of detail written up here: https://mopedarmy.com/wiki/Sachs_Motor_Differences
and lots about how to make them faster here: https://mopedarmy.com/wiki/Sachs_505/1a_performance though the B's are quite restricted. You need a new cylinder, intake, carburetor and exhaust to get anything useful out of it
They also restricted them sometimes by crazy huge timing advance so retarding timing might recover some speed.
The B at 17mph is about right on, especially since it'll have lost some power to maybe lost compression over the years, chain, brakes and bearings not spinning smoothly etc etc
One last important thing, you didn't break that ring because it wasn't greased- you broke it because the ring's gap wasn't lined up with the pin. there's a little locating pin in each ring groove that has to line up with the gap in the ring. if that's not lined up and you tryn shove it in the cylinder, it snaps rings. if you're familiar with 4 strokes, they don't have that pin, but all 2 strokes do because you have to keep the rings aligned so they can't accidentally catch on the ports.
what does the little plate look like? my carb is a 85/12/101 A which is a 505.1a carb
well shiver me timbers, I thought that looked like a lil ole 10'er, I guess you do have an A!
also - lil plate I just mean the little engine plate in yer 1st picture, with the "505/1" stamped on it.
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