Puch MV50 engine gasket/oil leak/poor running/plug carbon.

I posted a while ago but trying to narrow this down. It seems oil is seeping where the crank cases meet when engine is started. The moped is very low mileage(980) from new and was stored (fluids drained) for years. Bike starts and rides although does not rev clean (constipated). I know these bikes are simple but I'm a bit reluctant to start pulling the engine apart. I guess if the central gasket is gone that would be the option. Probably get shop to do it. Any advice appreciated.

John (UK).

PuchM2gasket.jpg
PuchM2crankcase..jpg

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

John Beever /

Well.....oil has stopped leaking as I wiped it away a few times....maybe it's possible to overfill and it gets past gasket under pressure ?

Still not sure how to get it running well. I have cleaned carb/excellent spark but the plug quickly goes black and engine will not rev clean and so bike is tops 20mph.

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

Sounds like it might be too rich .

Before you switch out jets or mess with carb settings , insure that the exhaust is clear .

Oven cleaner does a pretty quick job in the exhaust .

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

John Beever /

Thanks PD,

I took the exhaust baffles out......all clear.

Going to be a process of elimination,I guess.

It needs a starting procedure.....1). 2 or 3 good fuel trickles.

2). Choke on full. 3) Kick and turn off choke as soon as it starts.

It then idles fine but will not give smooth power....only about 50%.

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

Service the ignition system I would put in a new condenser and points and make sure that the cam lobe that opens the ignition points is not pitted with rust..

I can assure you that the lubricant is needed chances are the points cam follower has warn down due to this fact.

So get your timing set nice and pretty so that's all good.

I suspect your exhaust port is plugged with carbon I suggest removing the entire exhaust system I think you will notice that the header pipe will be lined with a thick layer of carbon and I would be surprised if you could even get your little finger in the exhaust port the rough casting loves to hang onto carbon and oil. (edited)

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

Jeremy Homser /

Where on the seam was it leaking. If it was leaking close to the cylinder then you could be losing crankcase pressure through the seam gasket. That would definitely make the bike run like crap. One the top of the case the first few inches of the case gasket seal the Carter then the rest just seals the oil in the transmission.

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

John Beever /

It seemed to be leaking a few inches back from cylinder (where letters are stamped on in photo) but it seems to have stopped for the moment.

What's the carter.....excuse my ignorance.

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

The Carter is what the French call the engine cases.

And most of your gasket oil leak subside due to the fact that it was stored with no oil soaking the gaskets.

Gaskets are mostly paper so they are now soaking up some oil to make it seal be careful though there will be others to tell you to spray it with choke carburettor cleaner or brake cleaner to check for leaks this will only dry and damage the gaskets more. and dry week seals further so don't do it. if you checking for leaks with the engine running use water are propane gas on a house.

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

John Beever /

Thanks for that,Neil.

That all makes sense now.....dried gasket then absorbed oil....hopefully now ok.

Still can't figure this poor running. Have cleaned carb twice/exhaust and baffles all clear/good spark......but plug sooting up/won't rev freely.

Timing maybe ?

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

Bad Cadillac™ /

Looks like fro the pics you've taken things off or apart.

Have you taken off the carb cleaned and replaced the 40 year old parts that wear out?

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

John Beever /

Yes...I've removed/dismantled/cleaned carb....all looks good. Checked air filter.

Maybe I've missed some perished rubber/gasket somewhere.

John.

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

Remove the entire exhaust system and post a picture of the exhaust port with the spark plug out so we can get a little light in there to see how plugged up it is also posted a picture of the inside of the exhaust header Shine a flashlight from the other end so we can see what's going on thank you.

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

> Neil Rayborn Wrote:

> -------------------------------------------------------

> The Carter is what the French call the engine cases.

>

> And most of your gasket oil leak subside due to the fact that it was

> stored with no oil soaking the gaskets.

>

> Gaskets are mostly paper so they are now soaking up some oil to make it

> seal be careful though there will be others to tell you to spray it with

> choke carburettor cleaner or brake cleaner to check for leaks this will

> only dry and damage the gaskets more. and dry week seals further so

> don't do it. if you checking for leaks with the engine running use water

> are propane gas on a house.

Why would anyone tell him to spray anything in this instance ?

I think that maybe you've never used brake cleaner . If you had , you'd know it evaporates too quickly to dry out a paper gasket .

I wouldn't use carb/choke cleaner on anything . That stuff eats rubber , doesn't clean well and stays too long .

Propane is a proven good method , if it can be pin pointed .

Water makes a mess .

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

Spray some brake cleaner on your plastic laptop and get back to me when you try to close the lid.

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

> Neil Rayborn Wrote:

> -------------------------------------------------------

> Spray some brake cleaner on your plastic laptop and get back to me when

> you try to close the lid.

Gee , my laptop doesn't have an oil leak , at the moment , not to mention that it's made of completely different material than motor seals . We're talking about motors constructed of aluminum and a couple paper gaskets with a few chemical resistant seals . (edited)

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

> P D Wrote:

> -------------------------------------------------------

> > Neil Rayborn Wrote:

>

> > -------------------------------------------------------

>

> > Spray some brake cleaner on your plastic laptop and get back to me

> when

>

> > you try to close the lid.

>

> Gee , my laptop doesn't have an oil leak , at the moment , not to

> mention that it's made of completely different material than motor seals

> . We're talking about motors constructed of aluminum and a couple paper

> gaskets with a few chemical resistant seals .

But you were just saying how brake cleaner won't hurt anything it just evaporates.

Sorry sorry but I don't feel like wasting my time explaining the properties and chemistry of what's going on you can research that yourself or better yet to spray some on your laptop's plastic, it does wonders when you spray close to the hinges.

Re: Puch MV50 engine gasket/oil leak/poor running/plug carbon.

> Neil Rayborn Wrote:

> -------------------------------------------------------

> > P D Wrote:

>

> > -------------------------------------------------------

>

> > > Neil Rayborn Wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > Spray some brake cleaner on your plastic laptop and get back to me

>

> > when

>

> >

>

> > > you try to close the lid.

>

> >

>

> > Gee , my laptop doesn't have an oil leak , at the moment , not to

>

> > mention that it's made of completely different material than motor

> seals

>

> > . We're talking about motors constructed of aluminum and a couple

> paper

>

> > gaskets with a few chemical resistant seals .

>

> But you were just saying how brake cleaner won't hurt anything it just

> evaporates.

>

> Sorry sorry but I don't feel like wasting my time explaining the

> properties and chemistry of what's going on you can research that

> yourself or better yet to spray some on your laptop's plastic, it does

> wonders when you spray close to the hinges.

I never said brake cleaner works on EVERYTHING . And , as for wasting time , why are you on this site , wasting time ? LOL

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