Do I have to hone my 02' CR250?

[Rich Rohrich]

Hi Rich,
Can I use this hone on a 1996 CR250 cylinder also?

Yes.

 

[NWetRider]

on a related note...
I rebuilt my cr250 last year. I saw blow by through the exhoust opening so i pulled it apart. The ring gap measures fine so I am gussing the problem is because I never honed the bore. If I get it honed should I replace the rings or reuse them?

 

[bleeds]

I was told the same thing by my local shop. They said ALWAYS hone, even if just a little. It removes embedded junk, and bring a clean metal surface to aid in the ring seating correctly. Also, he said it give the crosshatching to aid in the oil lubing the cylinder..but hey thats what he said..
Bleeds

 

[trev]

I was just talking to millenium technologies about the same topic and they told me NOT to use a ball hone that it would damage the area around the ports ? I don't know if this is true or not but they told me to use a de glazing brush which to me looks like a ball hone but with little strips of fine sandpaper on it instead of the balls.

 

[dklink2000]

As a general rule of thumb, do you get a hone the same diameter as your cylinder, or one a little bigger?

 

[Rich Rohrich]

As a general rule of thumb, do you get a hone the same diameter as your cylinder, or one a little bigger?

As close to the bore size as possible unless it's an old electrofusion Kawasaki cylinder (then just get it replated with something that isn't total JUNK :) )

 

[holeshot]

No it's not true. The cylinder needs to be deglazed to get the new rings to seal properly.

I found this when replacing the rings on my 125 - they just won't seat properly when put into a glazed bore (It probably had less torque than with the old rings).

There's a hill in our area that I call "mother nature's dyno" -not too difficult, but a challenge for the power of a 125. Stock, it climbed the hill with ease, but with new rings on a glazed cylinder, it just didn't have the ooomp to make it up (and still doesn't). The bike ran fine and wasn't noticably slower on level ground, but it just didn't have the pull required to climb a big, sandy hill (I hope it wasn't just the rider ;) )

Next ring replacement gets a deglazed cylinder first. :nod:

 

[blackjack]

I was just talking to millenium technologies about the same topic and they told me NOT to use a ball hone that it would damage the area around the ports ? I don't know if this is true or not but they told me to use a de glazing brush which to me looks like a ball hone but with little strips of fine sandpaper on it instead of the balls.

The ball hone will work fine, dont worry about it damaging the ports, the honing balls will just smooth the edges slightly, which is ok anyway.

Use some 2-stroke oil on the balls when honing and hone the cylinder from the head side and then the case side using an up/down motion of 1 stroke per second. You are trying to achieve a nice cross-hatch pattern when the honing lines will cross at a 40-45 degree angle.

Wash the bore thoroughly when done to remove any grit.

 

[dklink2000]

Does the hone have to be aluminum oxide?

Sorry for all the questions, I'm not trying to hijack the thread, I'm just planning on doing two rebuilds over the winter and am sick of paying the shop to do all of my machine work.

 

[Rich Rohrich]

Does the hone have to be aluminum oxide?

Aluminum oxide is correct for deglazing. :cool:

 

[Mike_socal]

On average, how long should one hone the cylinder to remove the glaze?

 

[QKENUF4U]

presonal experience at the shop i worked at that i did ALOT of rebuilds for.
the ball hone was a bit bigger than the bore
lots of lube in the cylinder (we had a honing tank so we had the nozzle dumping lube at all times)
match the up/down stroke to the speed on the drill to get the 45-60 degree hatch marks (faster the drill goes faster your arms go)
only takes 15-30 seconds to do a very nice job
then wash wash wash scrub scrub scrub , i usually sprayed it down with SIMPLE GREEN before washing to help remove the oils/shavings etc.

 

[cdncr125]

So i would want the 2 1/8" (54mm) for my 02 CR 125 54mm bore. or do i need to go one bigger?

 

[CR3999]

I usually just run the hone back and forth about four times, that cleans up the jug just fine. Been using a ball hone for manys years with no probs. Use slow RPMs on the drill (150rpm) and run it pretty fast through the hole to get the 45 degree hatch pattern. To slow and it will not be enough, to fast and you have to much. Just work it a few times and I am sure you will figure it out.

 

[Mike_socal]

So what is a deglazing hone going to do for a cylinder that a scrotch brite pad won't do? Does a hone work better in deglazing the valleys of the hatch marks?

 

[RM_guy]

I always use a scotchbrite first and if it looks like the cross hatching is worn, then I hone it.

 

[motometal]

Question for Rich, what if the engine you are working on is going to be re-assembled with the same rings? For example, I just sent in a Suzuki cylinder that is off of a near-new bike, I'm reassembling with the same piston/ring. Should it be honed? If the ring is already seated to the cylinder, wouldn't re-honing just wear the ring more in this case, or is that not significant?

 

[Rich Rohrich]

Good question. I've always tossed the rings and honed the cylinder, but I guess it's a judgement call. If the cylinder looks clean and there is no evidence of combustion scag or burned oil on the walls, then cleaning the cylinder with a degreaser like Brake-Kleen might be enough.

Before I made that call I would look really hard (grab a 10x loupe or something similar) at the ring face, and the upper and lower ring land sealing surfaces. If the wear isn't really consistent and even , then I would hone it (at least).

Just because it's fairly new doesn't necessarily mean it's any good. ;)

 

[motometal]

point well taken. so to make a long story short, considering that most of the engines Forward Motion works on are due for new piston/rings anyway, I'm guessing your standard policy is to just (at least lightly) hone them all. Maybe I shouldn't be all that concerned about ring wear from the hone anyway. Now that I think about it, whenever I check the ring gap in a two stroke either there's no measureable difference from a new ring, or the wear is very minimal. The pistons wear to the point where I choose to replace them sooner than the rings wear out. That seems backwards from conventional practice.

 

[Rich Rohrich]

Ring end gap delta isn't a particularly reliable indicator of ring condition or it's ability to seal. You can glaze the cylinder walls and the ring gap would never change much, but it wouldn't seal worth a damn either.

All the interesting info is in the ring lands and the upper and lower ring area. That's where the sealing is really being done. ;)

 

[motometal]

please explain more. I think the ring land area is ignored by most folks, including myself. If it's a tight machine fit, than I figured gasses can't get past. Am I understanding correctly that this can wear considerably over the life of a piston?

I've taken apart a few engines where the piston had black/scorch marks below the rings, but the engine still had good compression and ran fine. Ring gap still ok. I'm wondering if this is related.

I would imagine that stresses on the ring lands used to be even worse with non-plated bores, as the bore became tapered or worn irregularly the ring would be constantly moving within the land as the piston moved up and down.

 

[ellandoh]

could not talk my local shop into honing my cylinder, they claim it will ruin the cylinder. i said im paying you to do it, do it, nope guess i have to mail order a dang hone