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Ring Life in a 650
#603439 06/07/15 4:15 pm
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I got a bit confused about bore and ring wear in some threads I have been contributing to. How many miles should a set of rings last (changing them without a rebore)? How many miles should the bores themselves last?
Dave

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Re: Ring Life in a 650
dave jones #603445 06/07/15 5:01 pm
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I have to preface my answer with a disclaimer. I have never owned one (T120) long enough to see first hand.

That said the question is too subjective for a definitive answer. Just think about all of the factors involved here. Assembly procedure, hone condition, ring type, piston material, ring gap, piston clearance, engine balance, oil brand, and viscosity, areas the bike was ridden, maintenance issues, The list is too long to continue.

Comparing an average among all brands of bikes I have worked on, and known conditions for each of them I would have to say you can get 75 - 85k miles from a cared for engine, and rings. On the other hand you can destroy them in less than 10 miles.

It's a tough question to answer so I'm just going w/ some of the longest lasting engines I have been around.

Honestly nothing can replace putting eyes on the bore, and inspecting the condition. If compression is within 10% of spec., there is no need to open the head. If compression is low, a leakdown test, and the head needs to come off anyway.
As long as you can still see cross hatching, and the cylinder passes the leakdown... no need to pull it apart.

If it is already a high mileage engine, (50-60k engine) and there is no cross hatching... As long as the head is off, go for the gold, and hatch the bores, replace the rings, and do the head work.

I had an '85 Goldwing GL, that rolled in w/ 135k miles. I kept it as a daily driver when my daughter was born, rode it for another 27k miles, and sold it in excellent shape after 2 years.

It all depends on how they were treated, and maintained.

Re: Ring Life in a 650
dave jones #604106 06/11/15 3:52 pm
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Air filtration probably makes a difference.


Ed
1970 Bonneville
Re: Ring Life in a 650
dave jones #604113 06/11/15 4:57 pm
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I'll put my head above the trench and state the maximum bore life you will see is 40K, and 20K for a set of rings. I have also noticed that after 10k miles ring gaps typical show a noticeable increase.
These numbers are based on A10s and Commandos, both long stroke motors and A65s (short stroke) running traditional mineral oils with no full flow filtration, but fitted with air filters.

I am running a T150V on synthetic oil which has done 15000 since I re-ringed it and continues to burn no oil (well > 1500 mpp). We shall see my numbers can be exceeded!

Re: Ring Life in a 650
dave jones #604121 06/11/15 6:54 pm
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You didn't see the sign?

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Re: Ring Life in a 650
dave jones #604122 06/11/15 7:01 pm
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I was told by a engine guy that any engine should do 5 miles after cold befor you even think of giving it a squirt and 10 miles if your going to get up it
more cleaning after boring/honing with a nail brush and a good non abrasive hand cleaner
run your fingernail up and down the bore to feel for any protruding nicks -even a good hone can leave them
sand out with 800/1000 grit and reclean.

slide your piston down the bore with no rings /little oil and feel for any scratchy feeling
find it and fix it
I don't rering I read and have been told of the lip even though honed, can cause the top ring to break
because the lip ends up with a radius and your new ring is square edged,
on running in ocassionaly back off the throttle -it causes a vacume that pulls oil up around your oil rings

when oiling the rings put the piston on it's side so the rings protrude on the top side-heaps of your engine oil in your ring grooves , oil skirts

get the best guy/shop to rebore and hone square/flat -check for rod straightness


Re: Ring Life in a 650
dave jones #604132 06/11/15 8:29 pm
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Bore taper is guaranteed to break your rings. If you've got a lot of miles on your bike,say, more than 12-15K, a couple of trips to the red line could be all it takes to break them.

So check your bores for taper. It's unlikely a ball hone will address this.

Cheers,
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Black Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: Ring Life in a 650
dave jones #604139 06/11/15 10:04 pm
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Check your piston ring land clearance to ring clearance, bore taper causes your rings
to go in out every time your piston travels

get a new set of oversize harris pistons from montys -pistons/rings gudgeons for cheap

Re: Ring Life in a 650
HawaiianTiger #604140 06/11/15 10:19 pm
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Check your piston ring land clearance to ring clearance, bore taper causes your rings
to go in out every time your piston travels

get a new set of oversize harris pistons from montys -pistons/rings gudgeons for cheap

Re: Ring Life in a 650
dave jones #604177 06/12/15 4:29 am
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I have put 29644 on my 650 since it had new rings (well the previous owner said he put new rings in). I actually went through the engine quite soon after I got the bike and noticed then that there was a bit of oil in the left cylinder but the bike had made no smoke. Now the right cylinder is still fine but the left is a little more oily I would say but still no smoke. The plug is not wet with oil. I get some emulsified oil from the breather when the bike is parked. I suppose that the left hand rings never seated quite right. The bike still goes ok by my standards but I may put some new rings next winter. I am a reasonable mechanic but I don't like doing work on it unless it is essential. Should I change them?

Dave

Last edited by dave jones; 06/12/15 4:35 am.
Re: Ring Life in a 650
dave jones #604211 06/12/15 11:51 am
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Do a Compression Test ! davey jones locker .

25.000 and rings awol , and it still did 14.5 @ 90 .
one ring intackt , 1 half missing . 1 in 16 and 1 in 22 pieces .

Though likely the ex rice burner pilot at that stage
with notacable unsymathetic throttle operation did em in .

monoblocks arnt C.V. carburators .

Use prior was sympathetic to the land speed record , as was maintanance .

Re: Ring Life in a 650
dave jones #604230 06/12/15 1:39 pm
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I think that the bores can last 100,000 miles and the rings 50,000. I have a 71 T120 that I rebuilt in 1983 with +.030 pistons. I used the original air boxes with K&N elements. I put about 50,000 miles on it. I had the head and cylinder off once during that time because I left the bike out in the rain under a tarp and the rings stuck in the grooves. I took it apart freed the rings and kept riding it until a tooth broke off the layshaft high gear quite a few years later. It was still running great. I started taking the engine apart and began the re build. The valve guides were very worn, the rings had a huge gap. There was almost no bore wear though and the pistons were fine I had a spare engine, STD bore so I installed that in the bike. That engine began to smoke after a few years and one of the pistons failed while I was reving the crap out of it racing a Harley. I put the original barrels and .030 pistons, with new rings on the spare engine with the head rebuilt with new guides and have taken that set of barrels and pistons to 60,000 miles now. I think that the rings chrome type can still work well at 50,000 miles but the gap might really be excessive. The barrels seem to wear very little. The valve guides wear a lot I had iron ones in my 1983 rebuild. The valve seat hardly wear at all. Now I am using aluminum bronze guides that I made in my lathe. I changed the oil every 1000 miles. Different mineral type oils were used during that time. Usually Penzoil or Castrol. In the 80s and 90s I used car type oils. Now I use 20-50 synthetic motorcycle oil Red Line or Amsoil and change about every 2000 miles.

Right now I have to fix the gearbox oil seal before I can ride that bike again.
Nigel

Re: Ring Life in a 650
dave jones #604359 06/13/15 3:11 am
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Originally Posted by dave jones
I have put 29644 on my 650 since it had new rings (well the previous owner said he put new rings in). I actually went through the engine quite soon after I got the bike and noticed then that there was a bit of oil in the left cylinder but the bike had made no smoke. Now the right cylinder is still fine but the left is a little more oily I would say but still no smoke. The plug is not wet with oil. I get some emulsified oil from the breather when the bike is parked. I suppose that the left hand rings never seated quite right. The bike still goes ok by my standards but I may put some new rings next winter. I am a reasonable mechanic but I don't like doing work on it unless it is essential. Should I change them?

Dave


sounds like your oil ring Is sealing-no smoke
if you want it to run you can get away with all cheap repairs
iff you want it at it's best then get it right

Re: Ring Life in a 650
dave jones #604364 06/13/15 3:58 am
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Thanks for those answers. I certainly am hoping that the bores will be ok. Have been warned off chrome rings in the past because they are hard to settle in. What is the procedure for these?

Dave


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