Six Days oversize piston advice/recommendations

[sccasey]

Rebuilding my "new" '72 Penton Six Days and checked the ring gap -- it's at the limit (.015) so was thinking it make sense to go up a size.  But the piston, which is marked Mahle on the wristpin boss and ELKO on the dome, is also marked 55.75 (twice) -- see picture.  Is it possible to get a 60.00 mm piston for this cylinder? Looks like there's still some (?!?) meat left on the liner, but a quick scan of previous posts here indicates I may be at the bore limit.  Which may explain why Al B has 125 pistons in smaller sizes only.  Also sounds like his 60.00 mm piston for the 152 engines is not a direct/easy fit for the Six Days, based on other posts here.  I have a PM into member Crazy Jake, who indicated he has pistons in the size I need in a previous thread.  Thanks in advance for any guidance on best next steps.  Plan for bike is to be a rider, maybe a vintage enduro or two, but mostly just light trail riding.

Steve C.

[Larry Perkins]

Jake is probably the only one without going to Europe with 60mm pistons.  Start hunting a cylinder or a liner because it is almost over for that one.  Sorry!

Larry P

[Daniel P. McEntee]

You mentioned ring gap, but not piston skirt clearance. The ring may be worn but piston and bore still viable. I would check that out very carefully especially since you just want the bike for casual riding use. If everything is usable, just locate a ring and move on. While you are enjoying the bike, be on the lookout for a cylinder liner and standard piston for future use.. Just my 2-cents worth.
   HAPPY NEW YEAR!
  Dan McEntee

[sccasey]

Thanks for the quick responses Larry and Dan -- sounds like 60mm is not an option.  Will measure the piston clearance and continue the search for 56.00 mm piston...

[Kip Kern]

.080 over is 56mm, max bore, go for it, Wiseco makes them on Ebay all the time.

[454MRW]

Here's on without a pin. Mike
http://m.ebay.com/itm/WISECO-NOS-PENTON-125-PISTON-KIT-2mm-OS-SR-167P8-/350709228540?hash=item51a7e623fc%3Ag%3AgpoAAOxyW1NREVnj&_trkparms=pageci%253Adcb76833-cc3c-11e6-9ff8-74dbd1e0600d%257Cparentrq%253A4095546d1590a605c0f87accffcf2ac6%257Ciid%253A1

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico

[sccasey]

Thanks Mike.  What's the consensus here on one ring vs. two?  

quote:Originally posted by 454MRW

Here's on without a pin. Mike


Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico

[firstturn]

If you ever need to buy a sleeve I think I have one left.  Go with what Kip and Mike said.

Ron Carbaugh

[sccasey]

Dan -- good idea, checked piston clearance last night, was just a little beyond spec.

So just now found and bought a Wiseco 168P8 (forged piston .080) on eBay.

Ron -- will PM you about sleeve.

Thanks everyone!  Looking forward to reliving my youth this spring.

Steve

[454MRW]

As you may have come to the conclusion, the 2 ring piston will probably help with slightly better bottom end response. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978-1979 MX-6 175 & 250 KTM's
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico

[Richard Colahan]

Keep that bike properly tuned...the right fuel/oil mix...and most of all a good, non-leaking air filter...and that .080 over bore job may be the last piston it will ever need...certainly good for well over a 1000 + miles.

Richard Colahan
1969 V1225
Upper Black Eddy PA