2,000 mile rebuilt top end -- using oil???

I made a 250 mile round trip over the weekend, and I had to add probably a quart of oil. It was all highway, at 65-70 mph riding two-up.

This is the bike I rebuilt last year, and the top end was redone. Bored, honed, new rings, new valve seals, valves lapped, and after 2000 miles a recent compression test is well within spec (individually and to each other).

It doesn't appear to smoke, but I can tell by the plugs it runs rich. They're not oily, but darker than they should be.

The engine case is tight, no leaks. What am I missing here?

 

was it possiable it was low on oil before the trip?

 

No, I always check it and top up if needed before I ride, and even more so before a day trip.

 

and no sigh of leaking around the bottom of the pans? nothing under it once you parked the bike?

 

ony thing i can think of is the rings are not aligned properly, (the gaps) and allowing just a small amount of oil to pass and go into the exhaust, which is why you may not notice it smoking but will still burn oil...

Thats just what im thinking from working on cars anyway, i could be wrong with bikes, but i know the concept is the same.

 

What oil are you running?

 

Yamalube 10w-40. Yamaha has done away with the 20w stuff. At least that's what the dealer tells me.

And there are no signs of leaking around the pan, 213chrisp. I'd be peeved if the rings were not aligned, as I followed the manual to a "T" to orient them properly.

 

Crankcase vent clear?

 

Should be... I have an external chrome Harley-style crankcase breather filter at the end of a couple-foot-long hose to get it to the back of the bike, and when it's warmed up and running, a light vapor wafts up from the filter... so I would think it has to be clear. I can't see what kind of mist might be coming from the filter at highway speed, over the course of a long ride. Maybe all my oil is going out the breather over time (?). But the breather filter stays pretty dry (not oily), so I don't think that's likely.

When I bought the bike ten years ago, it already had pod filters on, and I've never had the original air box... that's why the breather doesn't connect to the airbox, it just evacuates to ambient air. I would think that's what everyone with pod filters does with their breather. Right?

However, I could also see how that could screw with the "designed" pressure balance within the motor, and could cause more oil to be drawn up through the pistons. I'm interested to hear what you guys think...

 

Just a shot in the dark but what about back by the u-joint cover thingy that connects to the trans?maybe your having something rub against something else and its overheating the oil and burning it somehow? also check the area under the carb on the fins of the motor.Its a long shot but mine somehow is getting oil there

 

I wouldn't be surprised at all to find that changes in vent pressure differential could cause an issue. Any chance of plumbing it back to stock for a test? Like Porsche, it's hard to beat what the Yamaha Engineers developed.

 

headhunter1213 it's a 550, it doesn't have a u-joint cover thingie. (It doesn't have a u-joint.)

MoralDK That would involve reinstalling the stock airbox, probably not feasible.

However, I do believe you're on the right track.

The first thing I would do would be to shorten the breather hose to stock length, or even shorter. It's very possible that by using a long hose, you've effectively "obstructed" the breather, causing the motor to pump oil past the rings.

If you no longer have the stock hose, say so and I'll measure one for you later this evening after I get home.

 

You guys are great! I was talking to a fellow cycle guy yesterday at work, and our conversation led to the very same questions related to the breather setup. I'll definitely shorten the hose back to stock length -- what is it, approximately, bigfitz? -- and see if that makes a difference. I may have the original length hose in my tool cart.

Something else I thought of that could be contributing is the turbulence that highway speeds might be generating through that filter (since it's more exposed where it is now). I moved the breather to the back of the bike because the slight vapor it was giving off was crudding up the motor and the frame over time. I thought it would keep things cleaner moving it out back. So much for American ingenuity!

Actually, bigfitz and MoralDK, I asked my buddy at work to look for a stock airbox at a local swap meet this weekend, so going back to the stock setup (for comparison at least) is not totally out of the question. I can keep an eye out on Ebay as well. Thanks for your experienced help!

 

Anytime. I'll measure an original hose for you when I get home.

I was going to add, most folks running a "mini-pod" on their breather outlet mount it right there at the outlet, on maybe a 2" stub of pipe. But it sounds like you started there, and then "improved" yourself into a corner.

I picked up a perfect stock airbox off eBay for about $10; just be sure you get a 550 Seca airbox not a 550 Maxim (they are slightly different.)

Easy spotting feature is the "suck pipe" http://xjbikes.com/Forums/viewtopic/t=31872.html the Maxim airbox doesn't have it.

 

Jeez... what do people do without this forum? Oh, yeah... part out useable machines to folks like us who know where to get the answers!

 

Sshhh...

The original hose is approximately 9" long; I had to measure one "on the bike."

 

Did you take care to properly set in the rings?

I found this great write up when I had mine apart.
http://www.ntnoa.org/enginebreakin.htm

There is a specific routine that the "old school" guys follow. Since you honed and really started from scratch (probably even rougher than showroom new), you should take some care to seat them properly.

Be too gentle to it and you will make a oil drinking baby!

 

You mentioned it was bored honed and new rings. Were the pistons new or second hand? I had to get new pistons due to worn ring grooves.

 

Thanks. What I might do is see if I can move the breather filter to the left-hand side of the bike. 9" is longer (i think) than what I can fit into a right-side mounting position.

Great write-up. Well, I didn't follow such a regimented break-in procedure, so who knows if it was ultimately good enough. I just tried to follow the manual's recommendation, but I also know that I intentionally ran it a little harder after the first couple hundred miles, and varied the RPMs quite a bit up until probably 800 miles or so.

I think I was able to use the old pistons. They were in good enough shape, and with the bore size increase being marginal, I didn't need to go with oversized pistons.

 

Re: The old pistons: Did you check the ring grooves to be sure they were still in spec, gap/play-wise as relates to the rings? I'm not referring to end gap; I'm talking ring clearances within their respective grooves.

 

I must have... I can't imagine not doing that, because it was one of the steps in the manual I was following. (It was a year ago, and I'm middle-aged -- I can't exactly remember :lol: )

I was able to relocate the breather filter, and ride the bike on Friday. I need at least another day's ride to work before I can gauge whether or not the shorter breather hose made a difference to my oil consumption.

My friend at work suggested doing a leak-down test to see if any one cylinder is the more likely culprit, if indeed it is related to pistons rather than breather.

 

Update on my disappearing-oil problem:
I've watched the oil level for more than a month, and since I shortened the breather hose (which is attached to the external chrome breather filter) there is absolutely no change in the rate of oil disappearance. After every 75 miles of predominantly highway riding, I have to add oil from the lower sight glass line to the upper sight glass line.

I did a plug chop on the highway (70mph), and found that all plugs are too white. I have a new set of up-sized jets from Chacal that I need to put back in. So I presume that's also a sign I'm not burning oil in any of the cylinders (is that a safe presumption?).

(Regarding the jetting, I have a cheap J.C. Whitney muffler on this thing (probably only 1" outlet) and I want to upgrade to a Supertrapp. Should I do this before messing with jets? I read that an over-restricted muffler can cause lean running)

Anyway, I'm about to just forget thinking that the disappearing oil is a fixable issue, and I'll just keep checking it regularly. Maybe that's the nature of a non-stock breather setup (?).

 

There are other things to consider.

Let's start with what kind of oil you're running; type and weight?

I agree that with whitish plugs, it doesn't sound like it's being burned; more likely blown out the breather.

And don't be expecting "brown paper bag" insulators on a 550s plugs; the best way to check "color" is to compare them side by side with a brand new plug. When reading them, read the flame ring and ground "strap" don't worry so much about actual insulator color. They tend to be more "self cleaning" than the 14mm plugs in the bigger bikes.

 

Still using the conventional Yamalube (10W-40) from the dealer. The original viscosity (20W-40) Yamalube is not available from them anymore.

There IS a significant amount of oil vapor that comes from the breather at idle when the engine's fully warmed up, and when I put my finger over the hose, there seems to be a net positive crankcase pressure. But I never see any dripping from the breather filter -- nor anywhere else on the bike for that matter. Never any oil spots on the ground where I park it.

The plugs looked lean all over, including the nose and the ground electrode. Not "dangerously" lean, but I would have liked to see a tad more richness.

 

Screw "Yamalube." Yamaha doesn't make oil; they make plastic bottles with hefty price tags.

Spectro still makes 20W40 dinousaur juice;

Or you can run Castrol 4T 20W50 and be fine.

I'm currently running this: http://www.castrol.com/castrol/sectiong ... Id=7040549 in 20W40 and have been experiencing ZERO oil consumption, and I run 80mph freeways on a daily basis; plus rush-hour traffic, etc.

Here's the thing: The factory recommends "10W" UP TO 59*F, but "20W" starting at 41*F. So unless you're riding in sub 59-degree temps, you shouldn't be running "10W" anything. And as long as it's above 41, you can be on 20W-whatever; above 59 you SHOULD BE.

The bike will be just as happy on 20W50 as it will on 20W40; but the factory DOES recommend 20W40, so that's what I'm running. The Spectro is getting harder to find, so I tried the Castrol ACT>EVO X-Tra 4T semi synthetic and I am VERY impressed. (The link I posted.) Bike is totally happy whether it's the superslab or tight rush-hour city streets. And honestly, ZERO oil consumption, and I'm used to seeing a bit. Clutch and starter clutch are fine. Clutch is even more consistent than it was, actually.

Give it a try, but at the very least switch to 20W40 or 20W50 and see what happens with your oil consumption.

 

Cool!
You better believe I'll be trying it. Thanks bigfitz! I've had this bike for ten years with not a lot of drama, so I get stuck with blinders over the simplest things.

 

I buy it online (the semi-synth) it's hard to find on the shelf anywhere. I've got a local shop that stocks the Spectro.

 

Fitz, you are the winner!!!
I changed the oil to the Castrol 4T 20W-50 over the weekend, before a 75-mile ride, and when I got home the level was NOT DOWN ONE DROP.

I would have never believed that a change from 10W to 20W would prevent the vaporizing of oil out the breather. But now I'm a believer.

I ordered the Act-Evo 20W-40, and should be getting it this Thursday or so. It's going in at the next oil change.

Now for the bad news... the oil filter housing contained a fingernail sized quantity of metal shavings (grain-of-sand consistency). My guess is a tranny bearing, as it's been grumbling a bit. The screwdriver-stethoscope trick takes me to that area. Oh well, no rest for the weary.

Now to convince the Yamaha dealer they owe me some money back for telling me I could use the wrong viscocity oil. :roll: