Ooooh, looks like it'll be piston rings then...

Dukedesmo · 27-09-2018, 08:18 AM

Don't want to put a downer on anyone's business but I have an ongoing bore wear problem with my Monster.

The short of it is I had the cylinders bored & plated to 944cc by Langcourt, who I had previously used to replate my 916 cylinders which have been fine; plenty of compression and uses no oil between services.

Afterwards it always used a lot of oil and within a year/3,000 miles the bores were worn so much that they needed plating again. I sent them back to Langcourt who re-did them at a discounted price and everything was re-assembled meticulously but oil usage continued despite engine running well and having plenty of compression.

Over the last few years the oil usage has increased and now it is very smoky, using way too much oil and I know it is bore wear causing the problem. Compression, whilst still good is also reduced and so I'm going to get them plated again over the winter.

Now I don't know exactly what the cause is but the engine was assembled both times with new rings (new pistons 1st time), correctly gapped and run with quality oil so unless there's a ring material compatibility problem? (I did look into this as there was some doubt on JE rings being OK with Nikasil? and so fitted a different brand the second time) I can only assume the bores are not hard-wearing enough?

I am not the only person to have had this problem, I know of two others that had the same issue at around the same time.

As I said at the top of this post, I don't want to damage anyone's business reputation and I have had cylinders plated by Langcourt that are still going strong 10 yrs down the line and so I've held back from saying too much about the problems but I also want to tell it like it is because I'm facing a 3rd replate in 12,000 miles which to blunt is a pain in the arse.

I'm now looking to get mine redone by Poeton of Gloucester of whom I have heard good things.

27-09-2018, 08:18 AM	#16
Dukedesmo Registered User Join Date: Sep 2010 Location: Leics Bike: M900 Posts: 2,842	Don't want to put a downer on anyone's business but I have an ongoing bore wear problem with my Monster. The short of it is I had the cylinders bored & plated to 944cc by Langcourt, who I had previously used to replate my 916 cylinders which have been fine; plenty of compression and uses no oil between services. Afterwards it always used a lot of oil and within a year/3,000 miles the bores were worn so much that they needed plating again. I sent them back to Langcourt who re-did them at a discounted price and everything was re-assembled meticulously but oil usage continued despite engine running well and having plenty of compression. Over the last few years the oil usage has increased and now it is very smoky, using way too much oil and I know it is bore wear causing the problem. Compression, whilst still good is also reduced and so I'm going to get them plated again over the winter. Now I don't know exactly what the cause is but the engine was assembled both times with new rings (new pistons 1st time), correctly gapped and run with quality oil so unless there's a ring material compatibility problem? (I did look into this as there was some doubt on JE rings being OK with Nikasil? and so fitted a different brand the second time) I can only assume the bores are not hard-wearing enough? I am not the only person to have had this problem, I know of two others that had the same issue at around the same time. As I said at the top of this post, I don't want to damage anyone's business reputation and I have had cylinders plated by Langcourt that are still going strong 10 yrs down the line and so I've held back from saying too much about the problems but I also want to tell it like it is because I'm facing a 3rd replate in 12,000 miles which to blunt is a pain in the arse. I'm now looking to get mine redone by Poeton of Gloucester of whom I have heard good things. __________________ M900, 916, LeMans II.