Something is wrong.

Ok so I posted a bunch of stuff on here before trying to figure out whats going on with my ped (78 Sachs Sparta). I just read a thread about the cluth and I think that might be the issue. I don't know what the the best way to explain the problem is but lets say I start from idle, when I go it sounds and feels good. The engine sounds steady as it gets going and then it starts actting funny, like instead of maintaining a steady noise and speed and it starts kinda cutting out and and will slow down and then jump forward. Does this sound like the clutch is slipping? Also, when I pedal it to start it obviously is slipping as when I hold down the start lever and pedal the flywheel doesn't always spin and it seems to be getting worse. I think the cause of this might be the fact that I removed the decompression valve screw on the head and replaced it with a bolt. So when starting it has to try and start at full compression which I think is what made the clutch start to wear. I know this is obnoxiously long but it's driving me crazy! Does it sound like a clutch problem? Is there any fixes that don't involve totally rebuilding the clutch? Sorry for the long post.



Re: Something is wrong.

Craig, I'm not sure if those symptoms describe a slipping clutch or not, but I would suspect some kind of carburetion/fuel flow problem first.

But, I wanted to tell you that you actually have two clutches, a starter clutch (which engages when you pedal fast enough) and your main clutch (which engages when the engine is turning fast enough.) So, even if starting without a decompressor has worn out your starter clutch, that wouldn't affect the main clutch at all.

Do this right away.

Take you flywheel off and check the four metal plates, sounds like one has come loose and is striking your armatures. They may look okay but they are greatly magnetized, pry up on them in couple place, if you detect any movement or any scratches on them just let us know for further help.

Spoke too soon (maybe)

My advice may not be accurate, I guess if you have a start lever (and it's not for the decompressor), then it could be possible that your bike only has one clutch(?) My bike works the way I described, but I guess not _all_ mopeds necessarily work that way.

Re: Do this right away.

Thanks guys, I'm gonna look at it tommorow.

sachs are weird

Sachs 505 and 504 motors only have one clutch. It serves double duty- both starting and driving. The two problems they have is that the plates will wear out, and need to be replaced, or the gear shaped holder that they all ride on slips on the main shaft. The only way to keep the clutch together is to make sure that the nut on the end is really tight, and not pinching any of the washers at the end of the clutch stack.

If you can't get the nut to stay tight, you can either take the crank to a machine shop to have a keyway cut in it, or do it the home-brew method by drilling a hole on the joint between the clutch carrier, and the shaft. use something like a nail or set screw to keep the holder from rotating on the shaft. That's what I did when I couldn't get mine to stay together. It worked too well, I damaged parts when I had to take it back apart.

Sachs will make a weird noise that sounds and feels like a shift when it finally gets up to speed. It's the weights fully expanding and putting pressure on the clutch.

If it's actually dying when you are at speed, check your kill switch wire to make sure it's not grounding on anything.

The horn on mine used to make it backfire whe I was at full throttle. Depends on what flywheel and coil you have.

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