Sachs Head Questions -

[KJDonovan]

I need a little help with some Sachs heads.  I thought I knew the difference between a 100 head and a 125 head, but after reading this post http://pentonusa.org/forum/topic.asp?TOPIC_ID=12243&SearchTerms=berkshire,head I am confused.

I have a couple of heads, both with the same casting number 0613106096.  On one the domed area measures 36MM across, on the other 40MM across.   I thought these were both 125 heads, but in reading the thread above it says this casting number is for 100's not 125's.  I am also confused that the domed area is a different size on 2 heads with the same PN.  I would also add the one that measures 36MM across came off what I thought was a 125.  So what does that make the one that measures 40mm across for?

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

[gooddirt]

For NON Iron barrel motors its aprox 33mm across for 100 cc.  I have 125(non Iron barrel) heads with larger opening than 36mm some are milled heads and some are opened up for larger pistons 55.55 to 56mm  to have the correct Squash bend/ squish band clearance.

[Paul Danik]

Kevin,

    I would need to pull a head off to check for sure, but possibly the 40mm is for a 152cc engine.

   I have a standard bore 152cc piston and it measures 60mm, what is the inside measurement of the cylinder to head contact area on the 40mm head?

  There seems to be about a 10mm squish area around the outside of domed area of the 125cc head I am looking at, that would add 20mm to your 40mm dome measurement, and that would equal 60mm, same as the 152cc piston.

Hope this helps.
Paul

[KJDonovan]

Paul,

The inside on the head with the 40mm dome is 54mm. Not sure if that helps or not.

Thanks,

KD

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

[gooddirt]

I give up[|)] .... if its a 1972 125 and not a iron barrel its not a 152.[B)]

[Paul Danik]

If it is 54mm I would say that it is a 125.

Larry,

   I have seen several alloy 152cc top ends. The last one I had was set up for a reed valve and a fellow POGGER bought it for a project he was going to build. This link will take you to the discussion about the alloy 152cc topend.

http://www.pentonusa.org/forum/topic.asp?TOPIC_ID=5522&SearchTerms=152

Take care,
Paul

[gooddirt]

 Paul thanks for the topic link might have to build one up;) I Know of a 5B military that was finger ported for Preton Petty but it was never used.

My base line was based on what bikes Penton had made . And the other post KJD was looking at.  

Anyway ... above pic's is a  40mm 125 head from a early 1972 CMF  with a 71  06  Vin # . I have two of these 40mm heads the other is off a Vin#  71 07.The other head is a 152 Penton Wassell which is 34mm across dome . The bike has title and on the pink slip calls it a 152cc.

[gooddirt]

 disregard the purple marks.

[gooddirt]

   

 gs pro monark

  second head for 56mm piston

[KJDonovan]

Thanks guys, this clears up my confusion.  It appears the head I have with the 40MM dome is for a 125.  The size of the dome in conjunction with the casting number is what had me confused.  Below is a photo of the head.



Thanks,

Kevin

[pklinck]

Kevin,

The other thing you can do is buy from Al B.  100cc and 125cc sachs head gaskets to help with the identification size.  Sounds like though you have figured it out as per previous msgs.  Good Luck.

peter klinck