SOHC.co.uk Forums > CB350/400

Oil control rings too big for bore

<< < (3/3)

AshimotoK0:

--- Quote from: K2-K6 on August 07, 2020, 11:29:50 AM ---
--- Quote from: Laverda Dave on August 06, 2020, 11:30:04 PM ---
Has anyone put a caliper across the ring land diameter to see if there's any machining discrepancy there that could cause the problem? The rings don't generally sit hard up against the internal diameter once installed,  so essentially floating on the piston and centralized by the bore.

--- End quote ---

On mine it was definitely the ring not the piston land ... when I inserted the ring into the bore there as a slight overlap.
--- End quote ---

Laverda Dave:
Thanks for the info Nigel. The second article is very interesting, one of the contributors has a photo of a MAP piston in a Morgo barrel. I have a Morgo barrel to but having to use modified Hepolite pistons due to the squish band built up in the head by Dave Degans (Mr Dresda Triton) when he built the engine 20 years ago. I would gave fitted forged pistons if I could have found any with the crown height I needed, unfortunately I could only find Hepolite that had the dimensions I was after.
Intresting to come across the name Mahale pistons, I put one of these in my 500 Jawa speedway bike in the early 80`s and running a 16:1 CR. It went well around Wimbledon 👍.

Winterfield:
Dave, I'd be interested in knowing what the difference is between the two sets of rings, if you manage to measure them. I tried to figure it out with my non-existent machining skills, but couldn't measure accurately enough to see exactly what was wrong.

I ended up just using the old rings - not ideal, but I just want to get this engine running while I rebuild a second engine I have (this time properly... I hope).

Navigation

[0] Message Index

[*] Previous page