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.
(https://lh3.googleusercontent.com/A73KBWRkPaSArftp9lOChR2dIuVwKZNCTEmNGk95XRlIOg0NPP2w8f1L2HW2-AotNO8N5XJHmymdj6K2BjFUPcRP7_3ZXGqjLIr2_yA4euUw81lpyR4T9aJPo7bxlBj5B8i-oG0)
(https://lh3.googleusercontent.com/orSAHvooUqTJrgWjvEpjh4wdH54FuIFfYa0VtfstzkbXP-heA6eqmmnzfb8odCxGx2vqH-vHsfSzvcJJICUCfz1TYDn-b6WD-CnO2KgD1yN5Ax3eGQSTJ9qatmIqYwq39LLJlME)
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
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
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...
.080 over is 56mm, max bore, go for it, Wiseco makes them on Ebay all the time.
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
Thanks Mike. What's the consensus here on one ring vs. two?
Quotequote: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
If you ever need to buy a sleeve I think I have one left. Go with what Kip and Mike said.
Ron Carbaugh
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
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
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