What the compression on a sachs 505 1d

Need to know if I'm getting enough compression . Dunno what 8:1 means in the manual on here

Re: What the compression on a sachs 505 1d

When I sit on it , it bogs and shuts off

Re: What the compression on a sachs 505 1d

matt boda1nz /

When you sit on it????

Re: What the compression on a sachs 505 1d

Moped Lar (OFMC) /

Optimally, it should be 120 or better.

Re: What the compression on a sachs 505 1d

Yea when the rear tire is up and off the ground it revs up just fine but when I lean back it's bogs down and shuts off. I think my compression is around 70 right now . I have an Athena 80cc reed valve kit, 24 mm mikuni and the racing crank from treats on it right now.

Re: What the compression on a sachs 505 1d

Overpriced Parts /

brian faulkner Wrote:

-------------------------------------------------------

> Yea when the rear tire is up and off the ground it

> revs up just fine but when I lean back it's bogs

> down and shuts off. I think my compression is

> around 70 right now . I have an Athena 80cc reed

> valve kit, 24 mm mikuni and the racing crank from

> treats on it right now.

Clutch preload is off and not to mention you're not tuned correctly either

Re: What the compression on a sachs 505 1d

8 x Atmosphere = 118 psi

Might check your decomp valve isn't leaking unless you've damaged the kit in some way. No head gasket to leak on sachs, so it's decomp or rings!

Is it really a D engine or is it a short crank with the 80cc kit? How many base gaskets? Does the tag say 47cc or 49cc (this indicates crank stroke, obviously it's not 50cc anymore).

Re: What the compression on a sachs 505 1d

I replaced decomp with a bolt and gasket and I the racing crank from treats for the sachs

Re: What the compression on a sachs 505 1d

Right.... my bad. You already mentioned that.

Are you sure your compression is ONLY at 70?

Re: What the compression on a sachs 505 1d

Lol it's all good !Yea I'm pretty sure it was at 70. May have read it wrong. It is the first time I've used one of these compression testers so that might be an issue lol. I did have an oil ring around the spark plug when I pull the plug

Re: What the compression on a sachs 505 1d

matt boda1nz /

Google "the right compression tester mopedarmy.com"

Re: What the compression on a sachs 505 1d

I bet your compression is probably fine (and not actually at 70) and like ken mentioned, the end play float on your clutch stack is off. Go read the 505 manual in the portions concerning the clutch. Once that is verified correct or fixed, next up is carb tuning.

Re: What the compression on a sachs 505 1d

Yea I'll check the compression and clutch gap when I get home and hopefully it's something simple that I've just over looked

Re: What the compression on a sachs 505 1d

Sounds good. That clearance is super easy to check with feeler gauges. Pop the cover and basically that's it.

Other than that, yah. Carb tuning. I don't really have much experience with mikuni, except on stock motorcycles and I don't really pay attention to jet sizes so I can't critique or comment on jetting sizes. Maybe someone else can.

Re: What the compression on a sachs 505 1d

Brent Bublitz /

70 is terrible. Absolutely terrible. If it's under 100 you are in trouble.

Re: What the compression on a sachs 505 1d

Oh, the joys of the Sachs clutch. They really are the gift that keeps on giving.

Re: What the compression on a sachs 505 1d

I do have plenty of compression and dunno why I saw 70psi. I am having a problem with the clutch though. If I take a shim out it's not enough to grab if I leave both shims in it bogs out when tire touches the ground

Re: What the compression on a sachs 505 1d

The moped junkyard has the shims available in different thicknesses.

You could try sanding one of them thinner a bit at a time and trying it. Eventually you'll hit on the right thickness.

Re: What the compression on a sachs 505 1d

You need to adjust the small screw on the starter arm. The whims are probably good. Adjust the small bolt on the started arm (behind the clutch cover) to adjust the preload.

Re: What the compression on a sachs 505 1d

Wizards do you know what the gap should be in between the screw and the bell

Re: What the compression on a sachs 505 1d

The manual calls for 1/4 turn out.

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