bottom end vs top end

[joe novak]

I have a 5A bottom end with the aluminum rod.  Which year bottom end is this?  Which pistons will fit on the rod end (I guess I am asking do all Sachs pistons have the same diameter wrist pin, also)?  Can these pistons be used in either the cast iron cyclinder or the aluminum cylinders?  Did all the cast iron cylinders use pistons with rectangulare rings.   Did all the aluminum cylinders use pistons with one rectangular lower ring, and one L shaped top ring?  How can I build a 152 Sachs?   This engine would be for a trail or play Penton, not for competition.   Joe

[Lew Mayer]

I can answer a couple. Al Buehner sells 152 pistons. You need a cast iron cylinder to do it.

Lew Mayer

[Paul Danik]

Joe,
   The aluminum rods were standard in the early engines, 68 and possibly into 69, I don't know when they went to the steel rods.

   The Sachs pistons will fit that rod.

    From what I know both the cast iron and aluminum cylinders used pistons with a dykes top ring and rectangular lower ring.

   Building a 152 can involve several different situations, depending on what piston you use.  The early 152 engines used a piston from a Yamaha twin, these pistons had a larger wrist pin and the pin was located higher in the piston, requiring the base of the cylinder to need machined to lower the cylinder.  Once you know what to look for, the thinner cylinder base, you can tell a 152 engine from a standard engine by eye, if it has the Yamaha piston in it.  Using the Yamaha piston with the larger wrist pin requires the use of the aluminum rod as the wrist pin bushing needs to be reamed out.  The steel rods have a needle bearing and will not accept the larger wrist pin.

   Penton eventually had pistons made up that had the same size wrist pins as the Sachs pistons and located the pin so that machining the bottom of the cylinder was not needed.

   The cylinder will need bored to accept the 152 piston, I am pretty sure that you need to use the 125 cylinder and not a 100 cylinder as the 125 liner is thicker.

   The head will also need machined to accept the 152 piston. Most of the 152 engines I have seen use the high compression head and not the stock head.

   I did have at one time an aluminum cylinder that was 152cc, I don't recall much about it and I never used it, but I do agree with Lew, the cast iron cylinder seems to be the cylinder of choice.

I hope this helps, maybe Doug, Dane, Kip, Ron or someone else can add to what I have said or if needed correct it.

Good luck.
Paul

[Lew Mayer]

I can answer a couple. Al Buehner sells 152 pistons. You need a cast iron cylinder to do it.

Lew Mayer

[Paul Danik]

Joe,
   The aluminum rods were standard in the early engines, 68 and possibly into 69, I don't know when they went to the steel rods.

   The Sachs pistons will fit that rod.

    From what I know both the cast iron and aluminum cylinders used pistons with a dykes top ring and rectangular lower ring.

   Building a 152 can involve several different situations, depending on what piston you use.  The early 152 engines used a piston from a Yamaha twin, these pistons had a larger wrist pin and the pin was located higher in the piston, requiring the base of the cylinder to need machined to lower the cylinder.  Once you know what to look for, the thinner cylinder base, you can tell a 152 engine from a standard engine by eye, if it has the Yamaha piston in it.  Using the Yamaha piston with the larger wrist pin requires the use of the aluminum rod as the wrist pin bushing needs to be reamed out.  The steel rods have a needle bearing and will not accept the larger wrist pin.

   Penton eventually had pistons made up that had the same size wrist pins as the Sachs pistons and located the pin so that machining the bottom of the cylinder was not needed.

   The cylinder will need bored to accept the 152 piston, I am pretty sure that you need to use the 125 cylinder and not a 100 cylinder as the 125 liner is thicker.

   The head will also need machined to accept the 152 piston. Most of the 152 engines I have seen use the high compression head and not the stock head.

   I did have at one time an aluminum cylinder that was 152cc, I don't recall much about it and I never used it, but I do agree with Lew, the cast iron cylinder seems to be the cylinder of choice.

I hope this helps, maybe Doug, Dane, Kip, Ron or someone else can add to what I have said or if needed correct it.

Good luck.
Paul

[firstturn]

Joe,
  I think that Paul covered most questions.  The only thing i will add is that I feel that you should get everything (152 cylinder, piston, rings and wrist pin) in front of you and then be sure everything fits.  The reason I say this is I always find old engines and bikes have surprises that I am not expecting.  I know this sounds like common since, but so be it.
  I am traveling right now so I cannot pull out the 152 set ups I have setting on the shelf.  I know when I am in doubt I check with Doug Wilford.

Ron Carbaugh