cylinder o-rings

[oldktmdude]

G'day FJer's,  since I rebuilt my engine it's been using a lot of oil. There are no oil leaks so it's being burnt. It blows smoke on hard acceleration and also on backing-off the throttle. On cold start-up it blows smoke if you blip the throttle but not if I just let it idle. I've fitted new valve stem seals sourced from Randy since the rebuild, thinking that the cheap quality seals supplied with the gasket kit were the cause. The new seals made no measurable difference to the oil consumption. When I removed the head, there was oil sitting on top of all four pistons, (about 1mm deep) so if I had a problem fitting the oil-rings it's very unlikely that I had stuffed-up all four sets. When I fitted the new o-rings to the base of the cylinder sleeves, some of them wouldn't sit properly in the groove. Could this cause the oil consumption by not sealing between the sleeve and the block and allowing oil to be sucked up into the combustion chamber? I realize that the head gasket should seal this area and stop the oil entering the cylinder.
  My other theory is, that my cylinder bores maybe out of round. The block came from another engine, low milage,  I checked the bore diameters but didn't check if they were round. Either way it looks like a major tear-down again. Regards, Pete.       

[Dan Filetti]

It does sound to me, like another tear down.  How much is it using?  'a lot' is subjective. 

Side point but I had an Audi dealer tell me with a straight face, that my 3 year old Audi 90, with 35,000 miles, that burned a quart every 1,200 miles, was 'perfectly normal'!!  Only when pressed did they reveal that they did not see it as anything worth worrying about until you were burning a quart in less than 1000 miles.

I sold that pig, and bought, (and have owned since then) Honda's.  My Pilot has 130,000 miles on it and looses no measurable amount of oil between changes every 5,000 miles.  THAT in superior engineering -plain and simple.  German engineering... -bah!

Dan

[weymouth399]

Hank at HSR doesn't even use the o-rings under the cylinder just a oem gasket. So there is probably another reason for that much oil.

None of the stock cylinders are round from yamaha, sorry to be the guy that tells you that. Thats why the legends guys take brand new engines an bore them. But that is not your problem.

My bike smokes at cold start (most of the time) that is vavle seals, I have good comp. But it doesn't smoke while running.

Did you break the engine in correctly? (not trying to be a wise ass)

Have you done a comp test or a leak down? (kinda important)

It is abnormal for it to be on all four cylinders. It does sound like it's in the head area, or the rings aren't gapped right.

Hope this helps Bob W

[andyb]

Okay, let's start with a couple of things.

-Leakdown test results?
-Compression test results?
-Oil consumption rate?
-New pistons, or used?
-New rings or used?
-What prep did you do to the cylinders?
-How much is blowing out the crankcase breather?

Because it's not one cylinder, we're going to have to assume that it's happening all across, obviously.  Because the valve seals are fresh, but more tellingly that it's smoking not only on decel, I think we can likely take the head out of the equation.

It sounds like a very large amount of oil if there is that much flying around in there.  To start, I'd say absolutely ensure the head isn't the problem.  Pop the carbs off, shine a flashlight down the intake tract, and see if there's oil in the runners, particularly down near the valve stems.  Should oughta be dryish up there and mostly clean.

Past that, I'm seriously wondering if there's an assembly problem someplace.  Guessing the head is going to be coming off, and probably the block's going to come off as well.  So if you can answer the initial questions above, I think that'll save you some time getting pointed in the right direction.

[Travis398]

  My other theory is, that my cylinder bores maybe out of round. The block came from another engine

[oldktmdude]

Leak-down and comp tests were fine. There's a small amount of fumes coming from the breather but not excessive. It's using about 1 litre per 1000km or 1 quart per 600 miles. The new block was cleaned and honed before assembly. The pistons that came with the new block were in good condition, so I fitted them into the same cylinder that they came from. Rings are OEM standard size. I originally put it back together with the original head but noticed it was using oil. I suspected worn valve guides so I bought another head (low milage,came off the same the block I fitted), lapped the valves, fitted new seals and installed it. No change in oil consumption.
  The engine was using very little oil before I rebuilt it , so looks like I stuffed-up something. I've rebuilt several engines over the past thirty years, so it's not like my first attempt at doing this sort of thing. Thanks for your replies. Regards, Pete.   

[Mark Olson]

Well , how bout .

over jetted and washed the rings out.

air filter problem.

drain oil and replace with non-detergent and go run the hell out of it.

[oldktmdude]

Well , how bout .

over jetted and washed the rings out.

air filter problem.

drain oil and replace with non-detergent and go run the hell out of it.

Mark, it still runs the standard jetting which appears to be a bit on the rich side but not overly so. I'm running pod filters and a 4 into 1 system and haven't been running in dusty conditions, so no issue with restricted air flow or dirty air. It seemed to blow smoke as soon as I started it after the rebuild, at first I thought it was only the assembly lubricant burning but has continued to blow smoke ever since. As far as running the hell out of it, I've flogged the shit out of it quite a few times after the run-in was finished. I haven't tried a non-detergent oil yet, might give that a try before I pull it down.  Nothing ventured, nothing gained. Thanks for your input. Regards, Pete.   

[Pat Conlon]

    Mark, it still runs the standard jetting which appears to be a bit on the rich side but not overly so. I'm running pod filters and a 4 into 1 system and haven't been running in dusty conditions...............

Pete, when you say "standard jetting" what do you mean? Are you running oem jetting with pods and a pipe?

If so, I would not worry about being on the rich side, rather....

[oldktmdude]

Pat, I'm fairly sure it still runs OEM jetting, but I could be wrong. It was fitted with the original air filter when I bought the bike and even with that set-up it appeared to be a bit on the rich side. Fitting the pods hasn't changed the appearance of the spark plugs to any noticeable degree. Apart from burning a shit load of oil, it runs great. Once I get on top of the oil consumption problem it maybe a bit easier to diagnose any jetting problem, if one exists.   Regards, Pete.

[Bozo]

Well , how bout .

over jetted and washed the rings out.

air filter problem.

drain oil and replace with non-detergent and go run the hell out of it.

Mark, it still runs the standard jetting which appears to be a bit on the rich side but not overly so. I'm running pod filters and a 4 into 1 system and haven't been running in dusty conditions, so no issue with restricted air flow or dirty air. It seemed to blow smoke as soon as I started it after the rebuild, at first I thought it was only the assembly lubricant burning but has continued to blow smoke ever since. As far as running the hell out of it, I've flogged the shit out of it quite a few times after the run-in was finished. I haven't tried a non-detergent oil yet, might give that a try before I pull it down.  Nothing ventured, nothing gained. Thanks for your input. Regards, Pete.   

Hi, I'm new to this forum but considering I had a similar problem on my 1978 Z1R I rebuilt many years ago I thought I'd add my two cents worth. To put it mildly my oil scrapper piston rings were put in upside down (the third ring from the top, it can only go one way). Hope this helps - PS I also own a 1990 Fj1200.

[bcguide]

   Just thought I'd contribute some of my limited smarts

If it smokes on deceleration oil is getting in to the cylinders from the vave guides

smoking on acleration is probably the rings

I had some smoking once when I added (alzimers) the it as STP to the oil, it thickened the oil and on start up the rings were not able to
wipe it off the cyl walls

Soooo maybe try a lighter oil and see if it helps

Scott

[imikie]

G'day FJer's,  since I rebuilt my engine it's been using a lot of oil. There are no oil leaks so it's being burnt. It blows smoke on hard acceleration and also on backing-off the throttle. On cold start-up it blows smoke if you blip the throttle but not if I just let it idle. I've fitted new valve stem seals sourced from Randy since the rebuild, thinking that the cheap quality seals supplied with the gasket kit were the cause. The new seals made no measurable difference to the oil consumption. When I removed the head, there was oil sitting on top of all four pistons, (about 1mm deep) so if I had a problem fitting the oil-rings it's very unlikely that I had stuffed-up all four sets. When I fitted the new o-rings to the base of the cylinder sleeves, some of them wouldn't sit properly in the groove. Could this cause the oil consumption by not sealing between the sleeve and the block and allowing oil to be sucked up into the combustion chamber? I realize that the head gasket should seal this area and stop the oil entering the cylinder.
  My other theory is, that my cylinder bores maybe out of round. The block came from another engine, low milage,  I checked the bore diameters but didn't check if they were round. Either way it looks like a major tear-down again. Regards, Pete.       

make sure your oil level is not overfull and breather tube is not blocked or kinked

[Bozo]

My mistake about the rings, its the second ring that is the scrapper ring, it took me a while to work out why I was getting oil in the cylinders, I agree smoke on de -acceleration is most likely valve guides (loose) or the seals, out of round/ warn/ glazed bore would would smoke under acceleration. Unless the head gasket is a copper one without a copper wire I don't believe the cylinder outer would leak into the bore But don't dismiss the scrapper ring because it works one way only, if its upside down, it will allow oil into the bore.
It might not be the correct answer (without seeing the bike) but it is an option, no harm in having a look.
Oldktmdude, have you fixed the problem since this debate started?

[oldktmdude]

   G'day and all the best for the New Year FJers. Thanks for your recent replies to my oil burning problem.  Valve stem seals have been replaced twice. Firstly with seals supplied in the after-market gasket kit . I kept those in for a few rides but suspected they weren't sealing properly so I ordered and fitted seals from Randy@rpm. These are a great looking seal and I am very confident that they are sealing. I checked valve-stem to valve-guide clearances and all were fine. The rings were fitted with the indexed (lettered) surface facing up, bores were honed but not checked for roundness. I agree that it's very unlikely that the oil is being sucked past the o-rings and getting through the head gasket, I guess I was trying to cover all possibilities.
   I haven't pulled it down yet as I have been spending my spare time and cash fitting a complete Fzr1000 front end and Fzr1000 rear wheel to it. After the few short rides I've had on it so far, I am so pleased with it, that I have almost forgotten about the oil situation, so thanks for reminding me. I'll keep you posted on any progress. Regards, Pete.