Cross Hatching in Cylinder

[Starwave]

Wrecked a pair of piston rings recently after seizing a Rapido 225. The scoot fired up again and ran well enough to get me home the 60 odd miles.
I've bought some new rings for it that fit fine in the barrel with a gap of about 0.4mm but there appears to be very little in the way of cross hatching hone marks on the walls of the cylinder. A little odd (maybe?) as it had been rebored and honed only about 500 miles previously. But maybe the cross hatching had not be done or was very light............
There are no major scuffs or scores and I would like to hone it (if that is the right term), but only to introduce the cross hatching and not to enlarge the clearance between cylinder and piston.
Is this feasible?
And does anyone know if those 3 legged flexi honing tools that cost about 20 sheets are ok to use at home? Or will it end in me needing a new barrel and a new face?
I only really want to go down the route of doing it myself to minimise down time.

Cheers

[Soulpunk]

know of 4 new rapidos with oval bore (200+225s).
bore should be always checked unfortunately on rapidos befoere assembling.
in case of oval bore > honing / rebore.


get the bore of the cylinder professionally checked and honed.
and forget the honing by a 20.- ebay/walmart honing -set.
its not that easy and simple. you need proper tools for that.

[dirtyhandslopez]

Damn, I thought this discussion might have been a bit longer. I have a proper hone with the felt wipers, the lot.
First problem is the abrasive legs keep getting cracked because of ports and damned if i can get a cross hatch out of the thing.
Chamfering the port should help the breakage I realize that, but the cross hatch prob. comes up.
I have seen it done(on Harley cylinders), up and down movements, but what is the official word on it.? Done wet or dry?
Or is everyone doing it on a Sunnen hone type machine?

[Terry Artell]

Hi

This isn't to answer your question, just wondering is it the race version you run or the classic.

What piston?

Finaly what do you think of the kit and what performance were you getting?

Any ideas why it seized?

Thanks

[starreem]

I've used these ball hones successfully to refresh the cylinder cross-hatching:

http://www.enginehones.com/technical.html

Surely there is a supplier on your side of the pond

[dirtyhandslopez]

I already have the ball hones. That's not what machine shops generally use though. I have only ever seen them use a Sunne type hone machine, or the adjustable hone with wipers that goes in a drill, with the operation usually carried out in a honing tank. I would imagine it's just another one of those things that has to be learnt by feel.

[starreem]

Hey DLo For amateur hacks like me, it's difficult to mess up totally with the ball hones. Seems too easy to taper the bore with the three-legged thing when lacking the proper shop and skills.

[dirtyhandslopez]

I was told by my machineist to actually not use the ball hones as they don't leave a proper surface for rings to seat in, it was either to rough a surface or to smooth, I can't remember which. I do know I used the ones I have a couple of times and the rings wouldn't seat.
Anyone else care to comment or know anything?

[Starwave]

Cheers for your responses. Gunna get the cylinder done at an olde scoote shoppe after all that.
The cylinder should be nice and circular as I've had it bored out since new so any ovality should have been machined out or discovered.
Regarding the kit itself Terry, it's the 225 race. Performance isn't blistering but pretty good. Uses quite a lot of juice mind. Nice and torquey, hardly noticed me mate on the back for a short journey. The pistons I've used are both Asso 2 ring jobbies. If I had a serviceable 200 barrel I'd personally probably get that tuned to your spec rather than buy a kit though. Currently fitting an LTH reed valve for (hopefully) more torque and fewer visits to the petrol station.
Could be one, some or all of the following reasons it seized: Was still running in new rings and rebore (just about), running a bit weak, holding it at one throttle setting for a long time on a dual carriageway when very tired and hung over, bits of cak from a new stainless tank getting through. It was destined to die.

[Special X]

Rapido 225 cylinders break rings as std because of the sharp port edges. I would usually chamfer the edges and polish them with a felt polishing pad. However, if you use a ball hone it has the plus of doing a superb job of chamfering the ports.