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Valkyrie Riding Member
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Discussion Starter #1 (Edited)
Burning Oil in rear cylinder HELP

I bought this bike last September as a possible bike for my brother or girlfriend.

I've done quite a bit to this bike and it was running perfectly until Friday. I rode up to get an ice cream and it didn't want to stay running. Finally I got it to stay running with some dificulty but oil smoke was pouring out of the LEFT pipe and I see oil under the rear cylinder.

Do I have a bad gasket? What other problems should I look for?

-Brian, F6Rider from Columbus, OH
 

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Discussion Starter #2
Okay, decided to replace rear cylinder's head gasket. Upon removing the head, I see burnt oil on piston itself. Not something I didn't expect, however, I see NO signs of a failure to the gasket. Do I possibly have another issue?

If anyone has experienced this or any similar issues, please reply.

I'm having a LOT of fun with this project though. It's been raining a lot here, and at least I'm working on my #2 bike. :smiley_th
 

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Aside from the hints above, there is the possibility of a broken ring(s). Do you see any significant scratches on the cylinder wall? Also check the automatic valve lash and make sure it isn't frozen from ingesting some recent junk. I disagree with anyone saying using a quart a month is normal. I ride daily (38 miles both ways), my 88 has 64K on it, and I use zero oil between changes. Good oil, good filter, good maintenance, good engine!
 

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Discussion Starter #6
I'd definately have to agree with George!

"I disagree with anyone saying using a quart a month is normal."

I'll be checking these suggestions later today.

Thanks guys!:smiley_th
 

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Discussion Starter #7
Okay, no scratches on cylinder walls...

Valve Lash isn't frozen...

Valve seats are good too...

:confused:

Any other suggestions? :)
 

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yep could be rings too:smiley_th

as far as 1 quart of oil being used..........didn't say it was "norm" but acceptable especially if your running it hard any shop will tell you the same thing keep the engine around 7 to 8 grand for a while, you'll burn oil the Vulcan engine wasn't meant to putt putt around like a Hardly at 4k all the time:drool:


if you try to bring it into the shop and say my bike is eating a quart of oil every month to 3000 miles they will ask you and? That's acceptable.....

but yeah if you putt around never really let the engine open up then you may not burn that much or very little at all....... I on average have added half a quart in the past 3000 miles its around the same for the Triumph as well.
 

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Okay, we're off topic from what F6Rider was asking. But just for the H of it, I don't putt putt anywhere, anytime. I rarely shift 1-2 below 7500, consistently hit the on ramp in third at about 8K and when I'm pissin off an HD guy I'll rev to 9500 3rd and 4th. Still have 64K on my motor and zero/nada/squat oil use between 4000 mile changes. If ANY of my bikes burned a quart/month, I'd at least hone and re-ring if the cylinders miked to within .002 of factory and over bore if it was beyond. But, that's me. And the last time I asked a shop mechanic anything I was riding a f'ing moped and packing lunch to school in a paper bag. Try this on for size, my c5 'Vette has 8 cyclinders and about 80 times the Hp of the VN750, and it also doesn't burn a quart/month...never met a 'Vette owner that did burn oil unless the engine was fubar...so why would a 60Hp twin suck that much oil unless it was hurtin?

Now, back to F6Rider, another question comes to mind...you said it was smokin out the exhaust, found oil on the piston etc...did you notice if there was a large amount of oil in either or both of the air cleaners?? If you did, then it's a clear sign of excess blowby, and that's a ring problem without question whether there is cylinder scarring or not.

Also, even though you didn't see an "obvious" sign of gasket failure, it takes less than .005 inch seal loss in the VN750 to cause oil migration.

The big question is, how many times do you want to pull that motor from the frame, and how much can you spend right now? The problem is that you yanked the mill before taking a CR. That would tell a lot. Because if the CR was low, but the valves are solid (turn the head upside down and pour mineral spirits in the intake and exhaust ports, if it runs out then the valves are fubar) then it has to be the rings. Or the gasket. Or the stem seals. Point is, once the pumper is outta da frame, replace all that is within financial grasp. Or, Rinse. Lather Repeat. Personally, I hate the repeat option.
 

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F6Rider, just reread your posts from earlier. IF there is no significant oil in the air cleaners, and IF the valves are okay, and IF the auto lash is Okay...then I'd still bet on a crisped head gasket. I'll go out on a limb here and bet more than one pair of tools has wrenched on your motor previously. Inattention to head torque readings can be problematic and lead to unexpected joy for no apparent reason. I'd slap a new gasket on, and, against the Kaw service manual advice, I'd use either the spray on Permatex CopperCoat or the Yamaha head sealant on both sides of the gasket an hour before reassembly...not on the cyl or head....because if in a previous life someone did not use anti-freeze in the motor, there could be some minor corrosion that eyeballs can't see on the mating surfaces.

I'll be checking back and wishing you luck.
 

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Discussion Starter #11
CuriousGeorge, your advise seems sound and accurate, I spoke with my father today and told him that I used the "(turn the head upside down and pour mineral spirits in the intake and exhaust ports, if it runs out then the valves are fubar)" test and he said the same thing, "if it didn't run out, then don't touch the valves."

There is not even a HINT of oil in the air filters.

Dad says same thing, "likely just the gasket". So I'm reassembling the bike tomorrow.

Yes, money IS tight and I still need to put new rubber on it. As well as the fact that I'm riding my Valkyrie to Gatlinburg for the week of Memorial Day, I don't wanna spend any excess cash on this project right now.

I plan to follow your advice and purchase some Permatex CopperCoat. I had used some on my boat head gasket and didn't have ANY further problems with that. It was 30 years old and had over a million hours on it; and when i was done, it purred like a lazy old cat. lol

:beerchug: Cheers and thanks...

I'll be updating my progress throughout the reassembly. Gonna take my time and clean it up as I reassemble, so it'll likely take all week. (Damn job)
 

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Ok without getting into a pissing match.....

The oil lubricates the pistons and no matter how well the engine is broken in some oil will be left behind and get burned away.

When an engine fires one byproduct of combustion is water, and this water tends to get into the crankcase. Through an irony of mechanics, the amount of water that builds up in the oil is roughly equivalent to the amount of oil that is burned away. Normally the apparent level of oil stays fairly constant, but if you did a lot of high speed running and got the motor really hot you might see a large drop in the oil level all of a sudden. Part of this drop in oil level is water being boiled away and part is an actual increase in consumption of the oil.

Fundamentally, seeing some oil consumption is a good thing, and apparent oil consumption should increase with higher speed riding. Obviously, seeing a lot of oil consumption can be a bad thing. but anywhere from 1 oz to a quart will burn off.

there will be a number of factors.

1.) How was the bike broke in ( I never follow manufacturer way of break in, I warm up to temp before i take off ALWAYS...... and without keeping the motor at a set RPM level I break it in hard for the first 50 miles, change the oil run it hard to moderate for 500 miles change the oil run Dino oil for the next 3-5k miles then switch over to synthetic)

2.) How many miles are on the engine.

3.) What kind of oil you use.

4.) do you ride like grandpa or like you stole it.

5.) engine design etc. etc. ( Subaru's eat oil like mad due to flat 4 design)

6.) Rings, Valve guide wear, valve seals, PCV, also high compression engines will use more oil than a low compression engine.

What I have noticed is I do alot of highway miles over an hour long at a given rpm range of 7k-8k Vulcan and 9k-11k on the Daytona the bikes will eat more oil during this time than the running around town putt putt, but by no means is anything wrong with the engine, ask a black-hawk Heli mechanic he'll tell you if it dont burn/leak oil then it isn't safe to fly:)

but just to ask and see what "group" your in.

how do you break-in? per manufacturer or run it hard?


without looking at it if it burns oil just on start up then Id say its your valve guides/seals if its all the time then your piston rings are more than likely shot.
 

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Discussion Starter #13
To use a adolescent quote from my kids' cellphone chatter...

OMFG!

Queezy, this is NOT a place for your "quart a month is acceptable" arguement. It is off topic, so drop it please. My issue with burning oil has to do with something going majorly wrong with my engine and NOT what is considered usual burn-by. So please take your arguement elsewhere and only post here if it is intended to assist.

Thanks,
-F6
 

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Discussion Starter #14
Oh, and as a follow-up. This bike burned/leaked NO oil until this MAJOR malfunction/change occurred. Therefore something has failed within the engine suddenly, i.e. Ring crack, gasket failure, etc.
 

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Discussion Starter #16 (Edited)
Okay...
Project reassembled!
Problem being encountered now...

Rear cylinder is back firing. I'm afraid I may have misaligned the gears in the top end. I'm VERY afraid that I've done this because (unless there's another way) I'll have to remove engine from frame again to fix.

Suggestions.
 

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Okay...
Project reassembled!
Problem being encountered now...

Rear cylinder is back firing. I'm afraid I may have misaligned the gears in the top end. I'm VERY afraid that I've done this because (unless there's another way) I'll have to remove engine from frame again to fix.

Suggestions.
yeah you should always rotate the engine clockwise 3 full rotations after everything is aligned and the cam ladder is tightened down tensioners in just to make sure the cams and crank 9 so the didn't skip a tooth.. and are still lined up.......... if you got rid of the useless airbox you could prolly take the valve cover off and get to it:smiley_th good luck...... On some of the triumphs ill put the cams 1 tooth off and by the time I tighten everything down and do the 3 rotations its lined up.
 

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Discussion Starter #18
Thanks for the tip

:smiley_th
:beerchug:
 
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