Author Topic: Piston ring pin relocation  (Read 2449 times)

0 Members and 1 Guest are viewing this topic.

Offline big mac

  • C-Grade
  • **
  • Posts: 87
    • View Profile
Piston ring pin relocation
« on: May 01, 2013, 05:48:36 pm »
I have a DT yamaha piston that I am going to use in a cooper 250 motor, I need to move the ring location pins does any body know how to do this & what material the pins are made from. Any info would be a great help.
Thanks Rory

Offline Tomas

  • A-Grade
  • ****
  • Posts: 321
    • View Profile
Re: Piston ring pin relocation
« Reply #1 on: May 01, 2013, 06:50:54 pm »
when i was about fourteen i had to replaced one of those pins that was missing on a piston i got for my JAWA 50. got a piece of brazing rod, taped it in the pin hole, filed off the rest of it , rings on, piston on, cyliner and head on and off for a ride. worked well.

Offline cemotobull

  • B-Grade
  • ***
  • Posts: 249
    • View Profile
Re: Piston ring pin relocation
« Reply #2 on: May 01, 2013, 07:37:12 pm »
Can you just turn the piston around and cut/alter the piston skirt or does another port get in the way?

Offline JohnnyO

  • Legend
  • *****
  • Posts: 4658
  • Qld
    • View Profile
Re: Piston ring pin relocation
« Reply #3 on: May 01, 2013, 07:47:40 pm »
I've done it years ago by drilling a small hole where the locator has to go then breaking the other end off the drill bit and grinding it to length then pressing it into the piston..

Offline TT5 Matt

  • Legend
  • *****
  • Posts: 1538
    • View Profile
Re: Piston ring pin relocation
« Reply #4 on: May 01, 2013, 08:15:35 pm »
get a single ring dt1 mx piston and no mods required,as to turning the piston 180 degrees don't do it as the piston pin hole is slightly offset.coopers use dt1 head gaskets as well

Offline cemotobull

  • B-Grade
  • ***
  • Posts: 249
    • View Profile
Re: Piston ring pin relocation
« Reply #5 on: May 01, 2013, 08:32:48 pm »
The 180 degrees works for bully's as the pin is central. Unsure of the yammys

Offline big mac

  • C-Grade
  • **
  • Posts: 87
    • View Profile
Re: Piston ring pin relocation
« Reply #6 on: May 02, 2013, 10:59:14 pm »
Thanks for all the advice might look for a dt1mx piston 70.5mm in dia.

Offline BETRIC

  • A-Grade
  • ****
  • Posts: 312
    • View Profile
Re: Piston ring pin relocation
« Reply #7 on: May 03, 2013, 07:14:12 am »
Big Mac I use a DT1 piston in both my Cooper MX and Enduro bikes, I had Greg Ball engineering (in SYDNEY) do the mods to the pistons, DT1 pistons need 4mm cut form the bottom of the skirt for clearance of the crank.
DT1MX pistons were standard fitment in Cooper MX bikes, ISLO made there own copy of the DT1 piston for use in the Enduro model, Big Mac if you need any info on Coopers send me a PM or email me with phone number and I will set you in the right direction. ;)   
« Last Edit: May 03, 2013, 07:28:29 am by BETRIC »
DELTEK, 72 MINI TRAIL, 73/4 XR75, 77/78 XR75, DG MONOSHOCK FRAME XR75, REDLINE FRAME XR75, PK RACING MONOSHOCK FRAME XR75, JWRP XR FRAME, SL70K1, 81 CR80RB, TY80A/B, YZ80A/B/D, GT50/80A, GTMX80A, 73 GTMX, GT1, COOPER MX, COOPER ENDURO,MX360A,MX250B,YZ125X MX100, 72 XL250, TC100,TL125, TY250C,IT250J

Offline big mac

  • C-Grade
  • **
  • Posts: 87
    • View Profile
Re: Piston ring pin relocation
« Reply #8 on: May 04, 2013, 11:36:35 am »
Thanks Betric I am about to rebuild the motor so any advice would be great. The model I have is an enduro so I am not quite sure if I will do it as an mx or vinduro rider, how hard is it to get lights & other enduro gear.
Thanks Rory.

Offline BETRIC

  • A-Grade
  • ****
  • Posts: 312
    • View Profile
Re: Piston ring pin relocation
« Reply #9 on: May 05, 2013, 05:06:12 pm »
Big Mac the standard Cooper lighting and switch gear is hard to find, the standard Cooper tail assembly is the same as used on Rupp minibikes and are avalible.
« Last Edit: May 05, 2013, 05:27:18 pm by BETRIC »
DELTEK, 72 MINI TRAIL, 73/4 XR75, 77/78 XR75, DG MONOSHOCK FRAME XR75, REDLINE FRAME XR75, PK RACING MONOSHOCK FRAME XR75, JWRP XR FRAME, SL70K1, 81 CR80RB, TY80A/B, YZ80A/B/D, GT50/80A, GTMX80A, 73 GTMX, GT1, COOPER MX, COOPER ENDURO,MX360A,MX250B,YZ125X MX100, 72 XL250, TC100,TL125, TY250C,IT250J