We stripped an M8 today in search of a noise.
The bike had original cylinders bored to 117 and CP pistons.
We discovered the cylinder spigot had broken and rendered the piston U/S.
I am curious to know what can cause this!!
Original head bolts were reused. The base gasket was on arse about
And the head bolts were seriously tight when being removed.
Any thoughts would be welcomed.
Was this a 107 cylinder originally? This issue was talked about with 107 cylinders, but not 114 cylinders, prolly because the 114 liner is thicker?
This (https://www.youtube.com/watch?v=gOoDmViH4WQ) mentions the cracking.
This exact thing happened to me when I had cylinders bored for a 124 build using CP pistons from a source I won't name. The pistons, I later discovered, were the wrong pin height and resulted in piston-piston contact being made at the bottom of their travel and the cylinders also cracked. Take a look at the bottoms of the piston skirts - any contact?
Are you saying a base gasket was not installed correctly?
Those cylinder sleeves are pretty thin in that area where stress risers like to live around the base.
I would recommend re-sleeved or aftermarket cylinders for the next build.
Quote from: rigidthumper on September 21, 2019, 04:24:34 AM
Was this a 107 cylinder originally? This issue was talked about with 107 cylinders, but not 114 cylinders, prolly because the 114 liner is thicker?
This (https://www.youtube.com/watch?v=gOoDmViH4WQ) mentions the cracking.
Good stuff, thanks for the link. I have talked with TR a few times - good guy that knows his stuff. I may be going that route with relined cylinders this winter.
Those T-Man cylinder/piston kits are pricey at $1695, but look pretty good.
Quote from: rigidthumper on September 21, 2019, 04:24:34 AM
Was this a 107 cylinder originally? This issue was talked about with 107 cylinders, but not 114 cylinders, prolly because the 114 liner is thicker?
This (https://www.youtube.com/watch?v=gOoDmViH4WQ) mentions the cracking.
Yes, originally 107.
Those T-Man cylinder/piston kits are pricey at $1695, but look pretty good.
Yes they do look the business , but would s@s 124 cylinders be all we need for a mild street build. I can get the s@s kit for about $1500.00 aust where the Tman would cost me well over $2200.00 aust plus all the freight :emoGroan: Max
Yes the exchange rate is killing us privileged Aussie males. 68 cents to the dollar.
At this point, the 4.25 bore kits from S&S and others are in wide use. Do you guys have access to Western Power Sports (http://catalogs.wps-inc.com/2019/vtwin/303/#zoom=z)?
Quote from: rigidthumper on September 22, 2019, 05:51:55 AM
At this point, the 4.25 bore kits from S&S and others are in wide use. Do you guys have access to Western Power Sports (http://catalogs.wps-inc.com/2019/vtwin/303/#zoom=z)?
As a trading business, I am sure we can access western power sports.
We continually struggle with high freight costs and extra taxes.
But thanks for the heads up!
This bike belongs to fastidious owner. He runs and extra oil cooler and Mobil 1 Veetwin.
We have checked this over and over.
Could over torqueing these cylinders cause distortion.
Is it the case that these cylinder are unsafe to bore out?
The liner in the 107 is thinner than the liner in the 114, and I believe that's the reason this happened.
Quote from: Sunny Jim on September 23, 2019, 03:40:23 PM
This bike belongs to fastidious owner. He runs and extra oil cooler and Mobil 1 Veetwin.
We have checked this over and over.
Could over torqueing these cylinders cause distortion.
Is it the case that these cylinder are unsafe to bore out?
I think if you assemble half the case with crank and rods pistons and cyls and view what goes on at bottom dead center in rotation, you will see why they crack if too thin with the side loads. Not a pretty sight to see piston skirts come out of the cyls.
Ron