To deglaze or not to deglaze

[old_chopper]

There's a lot of things the manual doesn't tell you that you will hear on this site as well as from other seasoned mechanics. When you consider the expense of gaskets, seals, labor, etc, the price of a set of rings is minimal. That's why I would hone the cylinders and put fresh rings in.
Your engine was smoking when you tore it down, are you CERTAIN it wasn't pulling oil past the rings causing this? The end gap measurement is one thing to check on a piston ring. The edge finish is another. Many rings have a tapered face that forces the rings against the cylinder wall when pressure is applied by the fuels combustion. I am not sure if these do but if so how do you check that? How about the temper of the rings, are they applying adequate force outward toward the cylinder walls? You probably see what I'm getting at. In the end it's up to you whether you replace them or not. Good luck and good riding!

 

[razooki]

If you've removed the rings from the pistons and are not 100% sure which pistons they came off you will definitely need to hone.

The comments about the honing marks wearing the rings when running the motor fresh is absolutely bang on - that's one of the reasons they're there. If your rings are in spec - and comfortably within spec - you can reuse them after honing (as long as you don't over do things). They'll wear a bit but stay within spec if there's enough leeway to begin with (they don't wear much).

From my experience I've rebuilt using old rings and without honing (too lazy to look for the hone ) a good few times. On two occasions I had a smokey engine (not just puffers but real smog makers), the rest were fine. When I've honed with old (good) rings I've never had a problem.

Having said that, although I'm still a tight g*t, I'm not as poor as I once was and would always fit new rings now.

I know which rings belong to which cylinder as I removed them one piston at a time and inspected then put them back. I'll give this honing thing a try since the rings were well within spec - I just hope I don't screw it up more. As for the rings lasting me another 30K I doubt I'll have the bike that long. I've never held on to a bike for more than 2 years but who knows maybe this one will be different.

 

[Dogma]

Last year when Pearson repaired my head (spark plug hole), he also rigid honed my cylinders. I reused the same rings after removing, cleaning, and inspecting them. Same power as before, and it didn't start smoking. I've put a couple thousand on it since. IIRC, she's got about 34k on her now.

(Pearson used the rigid hone instead of the ball hone because the ball hone will follow any shape defects in the cylinder, rather than smoothing out the high spots.)

 

[bwringer]

You still haven't revealed how many miles are on the engine...

If it's 80,000 miles, that's one thing. If it's 30,000, that's likely another.


FWIW, the 850 engines are very easy on their bores compared to their larger brothers. I've seen an 850 engine with 80,000 miles where the OEM crosshatch pattern was still easily visible in the bores.

Rings are another $100 on top of the time and money for the head gasket and such. A few years back when $100 loomed larger, I would have slapped it back together and taken the slight chance of a problem. Nowadays, I do a quick flex-hone and install new rings -- it's worth it to eliminate the chance of needing to fart around with it again.

 

[razooki]

The odometer says 34000km but I'm not sure it's the original one. The PO replaced #4 piston (had receipt to prove it) but I did not ask him if he had done anything to the other 3. He had not even broken in the engine when I got it. when I ran it I got some blue smoke so not knowing exactly what he did i decided to take it apart and inspect it.

 

[razooki]

OK so I'm going to attempt to deglaze the cylinders with the 3-stone tool that I bought at harbor Freight (2"-7" range). Could somebody give me some pointers/tips on the procedure. I will be using a cordless 19.2V Sears drill that has two speed settings - which one do I use? As far as I can tell I make sure the stones and cylinders are clean of any debris, oil the stones and the cylinders, insert the tool and move it up and down about 5 or 6 times. I noticed the tool has a spring adjuster - how do I adjust it?

Thanks all

 

[Nessism]

OK so I'm going to attempt to deglaze the cylinders with the 3-stone tool that I bought at harbor Freight (2"-7" range). Could somebody give me some pointers/tips on the procedure. I will be using a cordless 19.2V Sears drill that has two speed settings - which one do I use? As far as I can tell I make sure the stones and cylinders are clean of any debris, oil the stones and the cylinders, insert the tool and move it up and down about 5 or 6 times. I noticed the tool has a spring adjuster - how do I adjust it?

Thanks all

You have the wrong kind of honing tool. You need the kind with the dingo balls, not the kind with the three skinny spring loaded stones. The ball hones will do a much better job of hitting all surfaces of the cylinder, those straight hones will skip over the low areas on the cylinder unless you remove a bunch of metal.

 

[Dave_17954]

If I had my engine down that far I'd defiantely use a ball hone to deglaze and put new rings in. Doesnt make sense to me to take an engine down that far and not do anything. It makes sense that you'd want to make your engine seal up tighter with less chance of smoking by just doing it. Them gasket sets can get expensive if you'd have to pull it apart later on if it continued to smoke after you got it back together but it was a good move to replace the valve guide seals and do a hand lap on them. Did you do a leak test on the valves after after your lap job?

 

[piester]

definetly deglaze it.