Here is a good example of a "good" cylinder "just needs a hone" bought off evilbay for a "good price" jackass painted it and sprayed the studs and gasket surfaces.


This pic is pretty much just a reference for me for the future so if I gotta bore another I can look at the pics and see how I had the cylinder setup, for this cylinder I had the intake and exhaust facing the clamps and used the tall side or #1 side of the parallel bars, meaningless to you guys but will save me 10-15 min in setup time on the next one.

Thsi cylinder is for a friend of my sons, it needed a major over haul my buddy Don did the work and brought the cylinder over for a bore, we had a hard time trying to finsd center of this bore, we messed around for an hour then when the cutter just touching most the way around the top and middle we would turn it on and let the cutter run all the way to the bottom of the bore.

With the center of the exhaust port being 12:00 the only place the cutter made contact with the bore was almost at the bottom at about 10:00

After another few thousands skim cut

And another cut, the arrows are pointing to where it is actually making contact with the cylinder.

At the top it starts making contact at about 12:00 to 4:00 then at the bottom its making contact 9:00 to 10:00 only

Talk about a totally screwed up bore.

Here is another view.

Notice about 3:00 below the transfer its touching a little.

Next to the last cut and their is still these areas of the bore not touched by the cutter, we almost didn't have enough material to work with to make a 1st over bore piston work, this was on the intake side of the cylinder to boot, I would like to see the slide on the carb I bet it had most the chrome worn off from all the dirt it ingested lol


FYI all these pics were taken with the boring bar running once you start cutting you don't stop until you reach the bottom.

With a ridged hone like my Sunnen AN-112 you can put a lite hone on the cylinder and see it is not really round but it wont show up like in this pics taking a skim cut in a boring bar, you guys using a ball hone will think you got a perfect bore in your machine because it will follow over all the shit you see in this pics and scratch it up to look good, this is why I don't own or use a ball flex hone...

Hope you left the "Salesman" proper feedback. Its jackasses like him that are ruining Ebay. He could have easily just stated it need bored.

That would be up to the friend of my kid he didnt seem to mind its condition, I agree with you, I think the problem is people don't have a clue as to what they are looking at and really think it is good.

I bet your 420 bore is about the same with all them strange measurments you were getting.

Good stuff Hoser, shows what the poor little piston has to go thru at high revs if everything is not trued up and parallel.

Here is some pics of my new hone stones these are design for 2 strokes.

After a lite hone the arrows point to areas of the bore that are low spots you can see others in the next set of pics.

Scuffing below the exhaust but only on the exhaust side of the cylinder, perhaps their was a exhaust leak and it was sucking dirt?

Hi hoser long time no post form me, What machine are you useing to bore that cylinder?? Also did you torque the clamps down.

Hi glad to see your still around where you been?

Here is some info on my boring bar http://pilotodyssey.com/PO/viewtopic.php?t=892

Torque the clamps down?

Been very bussy with work, When i last posted i had just moved into a new shop so i had to put the pilot on hold. i have been collecting all parts for the Rebuild.

I have now just got aound to start the dummy build.

Ok i don't know if you know but i specialise in 2 stroke cylinder manly Re-sleeving cylinders and we do around 30 bores a week so i do have a bit of Experience with Cylinder Reboring and honeing.

The machine that you have go i have seen a very similar one in the uk about 20m years ago that one was no good on two stroke as it chatterd on the ports.

How do you centre the cylinder to the cutter ???

Re the torque, you can clamp the cylinder down and distort the cylinder out of shape also in my experience the cutter likes to cut at least 0.005 or it just rubs the bore rather than cutting it.

Here are some photos of my kit

3 SPS boring bars
1 Sunen Honing machine
1 Delepena Honing Machine

I have have 3 portable hone heads

Hi
Yup its a OLD machine probably 30 years old, it does really well on 2 strokes but we only remove about .001 at a time (increase bore size .002 per pass)
I haven't done many bores with this setup yet but my buddy has, over the years he has done hundreds using the same machine (this one and another one just like it) he said the only time he had chatter was when boring a CR500 cylinder, I say it does really well because I have had 2 bores done on this machine on 2 different engines , one was my Pilot and the other was my ATC250R, and worn out 2-3 pistons on each bore, at the end of each season during the tear down and inspection and inspecting the bore you can see a even wear pattern looking at the cross hatches on the cylinder walls, the ring seal has always been really good with minimal blow by, having had a new cylinder from Honda on the Pilot I had something to compare to I didn't see any noticeable difference between their finish product and what I seen on mine, this boring bar has quite a history in this area it has done hundreds of bores for the weekend rider to the racer over the years, for years the local Honda , Yamaha, Suzuki shop sent customers to my buddy to have their cylinder bored so the former owner had good feed back from the work he done being able to inspect the cylinder before it needed its next bore.

I doubt you could tighten the clamps this machine uses tight enough to distort the cylinder they are hand tight I doubt the clamping force meets or exceeds that of the clamping force the cylinder nuts applies to the base of the cylinder.

I have thought about making up some torque plates for the Pilot and Odyssey cylinders so I can simulate torque whilst boring and honing but after seeing the wear patterns on cylinders bored in the past with this boring bar figure it is not worth my time, other old timers I have talked to agreed that the majority of the uneven wear patterns you find on the upper part of the cylinder come from distortion caused by over torquing the head.


This pic shows the centering device used to center the bore on the machine, with the cutter removed you stick the end of it into the end of the boring bar shaft, you push it down it has 3 fingers that push out against the cylinder wall to center the bore over the boring bar, once centered you can double check it by just bringing out the cutter until it touches the cylinder bore then turning the machine over with the hand wheel to see where and how much the cutter it touching the cylinder wall, not as high tech as centering the bore off the 4 studs of the base of the cylinder it relies on what the factory left...










Nice looking equipment you have their you have any pics of them in action?

Any pictures of the fixture you use to deck the top and bottom of a cylinder?