Sachs B engine - Head gasket leak

[pklinck]

Greetings,
 
I installed a new head gasket on my 1973 B engine penton and within a few hours, (since I had to inspect something else)took the cylinder back off.  I noticed the oil/gas mix was leaking out or seeping out across the head/gasket on the exhaust side.  

I torqued the head bolts down according to the manual about 22 ft. lbs. Does anyone know the problem?

peter klinck

[KJDonovan]

Peter,

Did you re-torque the head bolts after the engine heated up the 1st time you ran it?



Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner (My Ride)
72 Six Day (Wifes Ride)
71 Suzuki TS125
73 Yamaha AT3
72 Montesa Cota 123
88 KTM GS250

[pklinck]

Kevin,

No I did not re-torgue my head bolts after the engine fully heated up.  It is winter here in Vermont and I only started the bike up to listen to the engine for a couple of minutes with the pipe pointed out my walk=out basement door.  ZTell me about it?

peter klinck

[KJDonovan]

Peter,

After a rebuild a good practice to re-torque the head bolts after running the engine up to temperature, things expand then contract and it is possible to end up with leaks.  Probably what happened with yours.

Thanks,

Kevin

Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner (My Ride)
72 Six Day (Wifes Ride)
71 Suzuki TS125
73 Yamaha AT3
72 Montesa Cota 123
88 KTM GS250

[pklinck]

Kevin,

Thanks for the info on re-torquing head bolts.  The other thing is that this is a used cylinder head which I do not know the history of it.  In fact it is the first time using it and therefore, the engine has not been fully heated yet. I could also check to see if the surface is flat??

peter klinck

[Jim Clayton]

Peter,
      Checking that the mating surface of the head is flat would be a good idea...it may neeed to be shaved a little. If so, Ive gotten away in the past (although, admittedly, not on a penton or sachs) with running two head gaskets to keep compression the same.
   - Jim

[pklinck]

Jim,

thanks

peter klinck

[joe novak]

Be sure that one flat washer is on each head bolt.  I am admitting that at one time I did not install the four washers below the head bolts, torqued the bolts, ran the engine (and it ran well), but the head bolts bottomed on the long studs and did not seal the gasket properly.   Also, be sure the studs are not loosening in the cases.  Be sure the head is flat, but I have never heard of such a small two-stroke engine head warping.