Glaze-breaking a barrel before fitting new rings

[zedsixfiftyb]

I am in the process of rebuilding a 250D from a very sorry state and was wondering what the quickest way of glaze-breaking a barrel is, before installing new rings. I have previously used PB Engineering in Bristol for this purpose but I now live in darkest somerset so over an hour and a half journey each way. A bit of emery cloth perhaps?.

[Chewie01]

I would start by doing a search in YouTube for honing a motorcycle cylinder. It will at least give you an idea what's involved and the tools you'll need.

[geoffb]

A honing tool on a drill might do the job, albeit very cautiously and evenly to get the crosshatching. Flex-hone is a brand that gets good reviews and works with 2-stroke barrels. I have honed 4-strokes before but never 2-strokes so I am just sharing my thoughts and not giving advice. 😉

[steeley]

Hi , myself i would use a strip of emery paper .

[Dave B]

An old piston,ideally one that fitted the bore before a rebore is the perfect size for an improvised hone. You need to make a wooden "con rod" as a handle. Then use coarse valve grinding paste as a glaze busting compound. Use a push-pull and twisting motion to get the crosshatch pattern. Do take the rings off first though!

[stusco]

Mar 6, 2022 11:33:29 GMT 1 Dave B said:

An old piston,ideally one that fitted the bore before a rebore is the perfect size for an improvised hone. You need to make a wooden "con rod" as a handle. Then use coarse valve grinding paste as a glaze busting compound. Use a push-pull and twisting motion to get the crosshatch pattern. Do take the rings off first though!

Sounds like lapping in a steam valve😩

[Dave B]

It is like lapping in a steam valve. I learned from my father, who was part of the generation that had done that sort of thing in his apprenticeship. His first apprenticeship was as a fitter in a Flax mill. Then he ran away to London and became a mechanic in a race team.

[chrisg]

Try this.


www.amazon.co.uk/KS-Tools-150-1190-Cylinder-%C3%9832-89mm/dp/B004YZORKQ/ref=asc_df_B004YZORKQ/?tag=googshopuk-21&linkCode=df0&hvadid=309952971598&hvpos=&hvnetw=g&hvrand=9869435653245934106&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9046455&hvtargid=pla-432043239273&psc=1&th=1&psc=1

I have used one in the past. Use gently, removing minimal material and lubricate well (I used 2t, as it was at hand).

[steve63]

The problem with a lot of the hones is the length of the stones. The short stones are fine on a four stroke but for a two stroke you really need the long stones so they don't catch in the ports. Most of the adverts don't give the length of the stones.

I used a short one in a pretty much scrap cylinder and it just destroyed the stones.

I'm not just saying this to promote my mates company but I was in there a few months ago and hanging up on display cards were some of these hones and the stones were (now this is a guess because I'm at work) about 80mm long so I bought one. 

www.rchull.com/Products/000c00210021/KDPKDPAU219

The company is R&C Components, Reform Street in Hull.

www.rchull.com/

[lcmarky]

I recently re-honed my Montesa Cota barrel with a Draper honing tool in my cordless drill.

Worked perfectly and as said above it does have quite long stones to manage the ports.

I think it's this one & use a light oil on it.

www.ebay.co.uk/itm/390053758436?epid=1312889282&hash=item5ad10405e4:g:PjIAAOSwZrJajsEw