Jump to content

Sign in to follow this  
monty348

Piston / cylinder letter codes

Recommended Posts

Hello all,

What increments in size are indicated by the letters stamped on Beta piston and cylinders? In particular  the 240 TR34 or just Beta in general.

Greg Myers

Paradise Pa

 

Share this post


Link to post
Share on other sites
 

Greg, I'm not sure this is relevant for the earlier Beta's, but here is what the engine service manual for the Beta Evo series lists for the difference in size. In each case they are in increments of 0.01 mm (0.0004").

image.png.e52da91810dbf06d1ed0cf4f6c98f062.png

Share this post


Link to post
Share on other sites
 

Pistons and cylinders for Japanese MC are also classed at one hundreth of a millimetre.

Share this post


Link to post
Share on other sites
 

Its all about limits and fits. Mass produced components have only a finite tolerance acceptable for mass assembly, so depending on quantities say 100 cylinder barrels bored to the specifications may be plus+ or minus- but still acceptable to be married up to a piston again + or - in specification. Thats the beauty of having a new piston and a rebore, the engineer will match everything closely to the specs, more accurately than at the factory. 

These limits and fits are the reasons some engines are noisy mechanically and others are quiet when new.  

Share this post


Link to post
Share on other sites
 

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

×
×
  • Create New...