Cylinder Hone for twostroke

[DGW]

The Asrto is getting a new ring for the season. I'm looking for a hone with long stones. Any I have found are all 3" stones. I think that could be a problem passing over the ports. Any info out there ?

[anotherguy]

Are you talking about sizing the bore or prepping for new rings?

If you're just prepping the surface for rings a ball hone will do the trick.

Sizing the bore is a different story. It's not the length of the stones it's surface area that does it right. You'll need a double stone/guide set-up for sizing to keep the stones from hanging in the ports. These things make doing big bore smokers a pleasant job. Small and medium bores are downright fun with this deal.

Here's a photo on a Sunnen AN-600 head.

[DGW]

I have two years racing on a new bore and piston. I pulled the top end to check everything, so best to put in new rings. I can still see the hone marks on the bore. I was thinking it best to give it a clean up with new rings. If a ball hone will do the job thats terrific.

[anotherguy]

What kind of rings? Tell me and I'll let ya know what grit.

[darmst6829]

Originally Posted by DGW

I have two years racing on a new bore and piston. I pulled the top end to check everything, so best to put in new rings. I can still see the hone marks on the bore. I was thinking it best to give it a clean up with new rings. If a ball hone will do the job thats terrific.

Leave the bore alone and just stick new rings into it. The motorcycle will run better then trying to make it better by honing the cylinder. In my humble opinion and years of experience.

Dave

[anotherguy]

nah...........

[DGW]

The cylinder do's look really good. I'm running a two ring Wisco piston.

[anotherguy]

Is the top ring a chrome faced ring? If so 320 grit. If it's a moly (bright gray in color) faced ring 240 grit.

They are moving towards a much finer finish than older ringsets. When I don't know I always defer to the manufacturer and every ring manufacturer recommends preparing the bore surface for a new ringset.


Cleaning after the preparation is important. Wash in hot soapy water,dry with compressed air. Then using a lint free towel with WD-40 wipe from the bottom to the top changing the wiping surface until it comes out clean,i.e. no gray honing remnants.

There's no reason to try something that isn't recommended and risk the cylinder in a nice Astro.

[supershaft]

Originally Posted by darmst6829

leave the bore alone and just stick new rings into it. The motorcycle will run better then trying to make it better by honing the cylinder. In my humble opinion and years of experience.

Dave

+1

[anotherguy]

Originally Posted by darmst6829

leave the bore alone and just stick new rings into it. The motorcycle will run better then trying to make it better by honing the cylinder. In my humble opinion and years of experience.
incredible luck

dave

ftfy

[supershaft]

What do you call incredible luck when most everyone has it?

[CharlieT]

Get one of these:



Called a brush hone or flap hone.

Disagree with the gentleman above who stated do nothing. Smokers will develope a glazing on the cylinder walls. Even though you can still see the hone marks, new rings will seat much better and maintain compression longer if you deglaze the cylinder walls first. You only need to run the brush hone thru it for maybe 15-30secs to do this. You will not dimensionally alter the cylinder or damage the existing hone marks, nor will it damage the port edges. All it will do is deglaze the cylinder.

If you have small dainty hands, you can acheive the same thing with some soapy water and a scotchbrite pad. Just do a google search on deglazing a 2-stroke cylinder and you'll find plenty of info and alternatives.

[anotherguy]

It's what you cannot see that is bad. The peaks of the finish wear as well as valleys between the peaks fill with wear debris. A renewal of the finish is required for the rings to seat properly.

Two-strokes are hardy beasts by and large however the pictured bike is a Bultaco Astro,a vintage race bike. If you want to win,hell if you want to finish the bike must be all it can be.

[supershaft]

IMO renewing the surface is mostly just going to get you that much closer to needing a bore job that much quicker. I have seen too many rings seat perfectly on untouched used bores. One thing is for sure, if by some odd chance the ring(s) doesn't seat after just replacing them, it only takes a few minutes to go back and do it differently. You might very well need a piston and/or bore job versus a hone job.

[anotherguy]

The Flex-hone is not for material removal. It's for surface preparation as is the brush posted earlier.

When the Flex-Hone is used properly measuring any bore enlargement requires tools I'm certain you don't possess. When used improperly it will take hours and hours to remove any appreciable material.

Even using the 2 stone set up pictured above I can remove half-tenths when sizing a bore. And can measure them too.

To the OP and others. My apologies for the explanations. But when charlatans offer bad advice I feel compelled to keep it from being considered good advice. Just because it makes noise doesn't mean it's right.