Pub quiz,identify the piston!

mikeyboy

Well-known member
UKGSer Subscriber
Joined
Jul 14, 2010
Messages
8,662
Reaction score
453
Location
Overland and classic,vale of belvoir,Melton Mowbra
Hi all ,bought these 1000cc pistons off eBay for £2:D
The seller was unsure of the bike they came out of,can't say I can recall ever seeing flat top ones:confused:
Anyone know what model they might be for:p
Thought I might bore out a set of 800 barrels for them:)
 

Attachments

  • IMG_1622.jpg
    IMG_1622.jpg
    238.7 KB · Views: 407
  • IMG_1623.jpg
    IMG_1623.jpg
    232.8 KB · Views: 409
  • IMG_1624.jpg
    IMG_1624.jpg
    233.5 KB · Views: 410
  • IMG_1625.jpg
    IMG_1625.jpg
    229 KB · Views: 409
Look like the so called squish band pistons fitted to some of the late 70's bikes with cast iron liners - it looks like there is a fair bit of metal above the top ring groove.
Boring out liners isn't always a success, it needs a torque plate and the barells hot, and someone who has done a few and knows what he is doing, and even then there isnt a lot of meat to play with.
There are more than one type of cast in liner, I have seen sections of barells which had a proper Alfin insert and others with just a flanged tube, and they would need a a different approach too.
I had a R75/7 bored out to 900 and it was right at the limit - you could see where the fins were by rings of different wear on the honing, there just wasnt enough meat left and the barell was expanding like a concertina.
 
Look like the so called squish band pistons fitted to some of the late 70's bikes with cast iron liners - it looks like there is a fair bit of metal above the top ring groove.
Boring out liners isn't always a success, it needs a torque plate and the barells hot, and someone who has done a few and knows what he is doing, and even then there isnt a lot of meat to play with.
There are more than one type of cast in liner, I have seen sections of barells which had a proper Alfin insert and others with just a flanged tube, and they would need a a different approach too.
I had a R75/7 bored out to 900 and it was right at the limit - you could see where the fins were by rings of different wear on the honing, there just wasnt enough meat left and the barell was expanding like a concertina.

Hmmm,
Might take some measurements,
See what sort of piston protrusion I will have,:)
 


Back
Top Bottom