Sachs 505/1D Decomp Valve

So the 505 I have has a regular old decor valve, which probably leaks, but it doesn't run yet so I don't know.

I do know that it doesn't seat. When I screw it in, it gets to a certain point and just spins. I assume it is stripped, at least lower down in the threads

Any ideas for what to do with it?

I'm thinking about using some JB weld in there, but I'm lothe to go with so permanent of a solution.

Thanks!Edited 1 time(s). Last edit at 01/07/19 04:23PM by awakebyjava.

Re: Sachs 505/1D Decomp Valve

I know that I can plug the port, but I"m not sure if that is as advisable on the D as on the A. Same problem too, as the threads are the problem.

Re: Sachs 505/1D Decomp Valve

Just plug it. Sachs dont need the decomp

Re: Sachs 505/1D Decomp Valve

Yep, that's an option, but like I said, still have the stripped threads problem.

Re: Sachs 505/1D Decomp Valve

if it's actuall stripped threads the whole way down you could probably just fill it with JB weld or something and be OK, but clean out all the oil well with like brake parts cleaner degreaser and make sure the putty doesn't go into the cylinder while it's all liquidy. some of it might burn out too. Or better just drill and retap it, and plug it with a bigger bolt.

But i'd be surprised if it actually is the threads in the cylinder which are gone. get a little bolt in there and see if it holds first, might be that there are threads that are still good that you'd reach with an actual bolt, or maybe it'd just work out otherwise.

Also be sure you chose a bolt that bottoms out against the actual bottom - it's explained better here:

https://www.mopedarmy.com/wiki/Sachs_505/1a_performance#Leaky_Decomp

Re: Sachs 505/1D Decomp Valve

take out clean n post picts. why r sachs cylinders so pricey?

Re: Sachs 505/1D Decomp Valve

the D cylinders are pricey because it's an easy bolt-on upgrade that won't shred the clutch. And cuz sachs are fairly common but the D's are much less so, and people don't kit em as often, again presumably from fear of the clutch, so the cylinders stay in use. low supply, high demand. I couldn't give away an A cylinder (I have 2, want one? free?)

you can definitely plug it and I would be willing to bet it's seal. the decomp valve set only has like 3 threads down on the bottom, theres very likely still good threads above it that'll grip your plug bolt just fine. and no theres no issue plugging the decomp on a D vs an A

Re: Sachs 505/1D Decomp Valve

Thanks, that’s a very useful answer, along with pat splat’s. I’ll grab a bolt and see what I can do.

Re: Sachs 505/1D Decomp Valve

On the one g3 we built, we turned down a socket cap bolt to sit nice and flush inside the hole.

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