MOPED ARMY

aside from the usual fred's guide stuff?

i just dealt with a leaky decomp (removed and plugged it) and it ran like a raped ape but now the crank seals are pissing oil so i just ordered bearings and seals from treats

not sure if yours sat for a long time or not but a rebuild is only slightly more involved than an e50 and there are more than a few tutorials and vids so if you got the time it may not be a bad idea

Could be a clogged muffler with years of buildup, check that, since it is smokey it might be burning it off.

use the search function for the long form but get:

One (x1) M10x1.5 socket cap screw (i forget the exact length just make sure it doesnt stick out inside the cylinder)

I used JB Weld and a socket cap and let it set overnight. Perfecto.

you can either remove the decomp plug, shorten your starter cable, and be good to go

or of youre in a rush, just zip tie the decomp clip closed and tighten your starter cable at the grip if you can. janky but it'll work

Keep in mind, when you do this compression will look for another path of least resistance so you'll find out pretty quickly if you need seals and gaskets or not.

but def take apart that exhaust while your waiting for the JB Weld to set

ive had decent luck with letting Gunk Gel soak in it for awhile then blast it out at the local diy auto wash. Although sometimes a BBQ followed by a can of high temp paint is the most thorough and clean looking way to go

Cleaned up some of the wiring last night and looked at the pipe and intake. Filthy. Will give a thorough cleaning as per everyone’s advice and will update with results. Not sure if you can see it in the picture but there was chunks of thread coming loose in the decomp port after I removed the valve. Threads on the actual valve are in good condition, but has me wondering if it’s crossthreaded/heli coiled. Should I be concerned, or just send it?

Also with 9,000 miles (wow someone really loved that bike!) you may want to toss in some fresh rings! I bet those things have seen better days.

that square jug is the 50 every time.

Everything above is pretty much what I would've said too, from the 1st post my immediate thoughts were definitely leaky decomp and very likely clogged exhaust.

seems like you're addressing those. my approach would be to clean the hell outta that port with brake cleaner and try to thread in a plug (not the valve - see the 505/1a performance wiki page - section on plugging decomp) maybe using some epoxy sealer to help.

after that other issues maybe leaky crank seals, Other sachsy type issues are they slip timing pretty regularly and generic attention to points etc is key as ever.

Get some brake cleaner and clean the outside of the engine too.

How long is that bolt? It says on the wiki somewhere (I think in the 505/1a page as will said) what length bolt to put in to get a perfect seal. What you have may work but I would spend the $.89 and get a bolt that fits perfectly, it won't leak then.

Update time! I cleaned up the JB weld a little from that picture. Let it set overnight, my 505 now has ALL the compression and no leaks. Runs great again, now waiting on the MLM pipe to replace the clogged stock pipe.

too long is OK, it's when it's too short it can bypass like an open valve

Not true it could be a restricted C cylinder it’s the same lookin as a D

But it’s the same as a A cylinder 1.8 hp