Dominator barrel, rebore or fit liners?

I have at various times done both. At +60 the top flange is weak and I have had it crack. Not that it was a problem really - it ran like that for a long time. More recently, I have had cylinders lined. No problems encountered with heat transfer. It works. RGM did the last liners for me, previously I used East of Scotland Engineering. Both jobs were absolutely fine. You pays your money and you takes your choice...

Gordon.

Hi Steve, a lot depends on how you intend to use the bike. If you are happy to ride within the U.K. legal speed limits, and don't hold 70 M.P.H. or more, for long periods, a + 60 thou rebore should be O.K. However, if you ride as a Dommy was meant to be ridden, for once, I would agree with Anna.

Don't worry about the heat transfer bit, cylinder liners have been in use, almost from the invention of the internal combustion engine. Just find a firm, with a decent reputation, to do the job.

John.

I have owned, ridden and raced 99 engined Nortons for many years.

Anna is quite correct in saying that going to plus 60 usually leads to a problem. This is certainly whatI have experienced. Either the top spiggot or the bottom of the liner tends to fracture.

On my later engines I just had the top of the spigott ground down and with a good gasket fitted had no further problems.

I always have my cylinder barrels fitted with new liners, as this is always the better cost option, as you can then rebore them out to a larger size at a later date if required. I have an Atlas barrel that was rebored, it looks out to its limitand the liner is showing through the barrel. I had the barrels on my 1961 Manxman relined and kept the spigot. The old spigot had half of the spigotbroken off so a pair of new liners was the only way to go. I always use Tony Hartlen of Hartlen Engineering, who has been reboring and resleeving barrels for a huge amount of years. He also regrinds crankshafts. His company is called the Rebore Shop, and he advertizes in OBM.

I have no experience of liners or 60thou rebores,but would prefer not to do either. Is there any way to deposit metal onto the low spot and get it honed?. Ask an expert.

i have seen peopel try doing this it DOSE NOT WORK dont even think about it a frend did it to a c90 that had gauged the barrel the finished job look ok but it only lasted about a munth then the new section cam away and totaled the engine

as the previus messege said if you are just going to use the bike for a sunday run then go for the 60 over but if you want to use it properly then resleve as then in the future if you do have eny problems it can be reboured

and personaly iv found resleving very simaler in price to a rebour but that is thru the trade

Previously wrote:

After my botched rebore I am now thinking of the best way to proceed. The barrel is now on +.040" and need to go to +.060". This is a flanged barrel (57, 99) and Anna Dixon has made what seems to be a very valid point in that to go to +.060" may weaken the top flange to a point where it may fracture and I should consider fitting liners, back to std.

The flange thickness at + 40 is around .070" so at +60 it will reduce to .060" in thickness but at present the flange is very sound as is the bottom flange.

Has anyone any experience with going to + 60 with this type of barrel or indeed going the liner route? I instinctively worry about fit and poor heat transfer cast iron to cast iron, is this worry unjustified in anyones opinion.

I would be very gratefull for any opinions on this.

Steve Coleman

Hello Steve Now The Pistons I was On about are the Original BHB Piston That was used by Norton them selfs for the 650 ( 8.9.1 )Compression ratio . and light than after market ones .So then if you go down the re-sleeving root . and good standard .it will 40.000 miles before next re-bore , if you still around that is ,and the you have another 40.000mile or so .now this should last you for the next 60years do you see my point here . So good luck and happy riding AJD

If you are going to re-sleeve, I would buy the pistons first and give them to the machinist/engineering outfit to ensure that the finished fit is proper.

Previously wrote:

Thanks Anna. This difinitely seems the way to go, the BHB pistons available through the club are +10 I think, but that is no problem, I guess the company you supplied me with would be able to supply rings for this. do you know if the club piston come with gudgion pins?

Best regards. Steve

Hello Steve The Club Have them in Standard As well as + 10 Parts number 23270 lh &23271rh ok ?

Hi Steve,

I've had my 99 barrels re-sleeved with liners provided by RGM and the job done by people who know classic british bikes and cars.

They asked the pistons being provided so that they could adjust the clearance, and they machined 2 slots at the bottom ofeachliner to give room to theconrods. They knew theyhad to do it.

So, better to deal with someone with expertise & experience!

Altogether, very good job!

Laurent

Bonjour Steve,

The job was done by GONIN Moteurs in Lyon (France), so I guess it's not the nearest place to your home .

But -seriously- if you want them to make the job, I can help you in any manner.

I can ask them more details and figures about what they did.

Yes, the liners got from RGM have a spigot. I don't know whether it is identical to the original one, but they fitted the cylinder, the cylinder head and the cylinder head gasketat first try and without any problem.

I have some photos detailing the barrels with the liners installed. Pls drop me your e-mail details to laurent.husquin@tnt.fr and I'll send that to you.

Another info which may help you: they set a piston-to-bore diameter clearance of 8/100 of a millimeter (with 68 millimeter GPM pistons). It seems to be a minimum. The advantage is a less noisy engine and less wear, butitimplies a careful run-in.

Cheers,