Author Topic: Blue smoke from exhaust, Oil leaking from #2 flange  (Read 1144 times)

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Offline AintNoEasyWay

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Blue smoke from exhaust, Oil leaking from #2 flange
« on: July 29, 2014, 05:18:32 am »
Started up my bike after work last night  & have a new issue(s). Blue-ish smoke coming out of the exhaust & an oil leak coming from the front of the engine. You can see the leak slightly in the photo below. The leak comes from around the #2 exhaust flange & drips down onto my frame before forming a puddle below the engine.

I've only had the bike in running condition for a few weeks & haven't ridden it more than a few miles back & forth around town. I changed the oil as part of the typical 3k maintenance stuff, but my oil is already down to pretty low on the dip stick.

How should I move forward? I don't have a way to do a compression test, but will see if I can rent a tester this evening. Forum member enwri recommended I check the spark plug & possibly look inside the exhaust port. My spark plug from #4 is below (#1 is the same, didn't pull #2 or #3).

I shut off the bike & won't run it again until I know for sure what's going on, lest I create some bigger engine issue I'm not aware of. Thanks, guys.

If I need new valve seals or rings, I can go there. But this is my first bike, so I'm sure I have a lot to learn.

Online calj737

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #1 on: July 29, 2014, 06:02:20 am »
If you're losing that much oil, it is bound to be due to a leak. If you're getting oil through the exhaust, and using that much oil, I'd venture a guess as it's valve seals. Typically, if the oil smoke is constant, it's rings, if the smoke is present at start up and after stopping, it's seals. But this is not a guarantee.

The "leak" on the head, could be gasket, could be a crack in the head at/near the exhaust (pictures shows some type of horizontal crack or casting mark on left side ((looking)) from the port to the flange). Do you out have any means of doing a compression test and a leak down test? Compression will check your rings, and leak down will check both. The latter will identify which side (top end or bottom end) is leaking.

Lastly, did you adjust the valves as part of huge 3k service? If not, then do so. If you did, are they correct? This is important so the compression and leak down tests are conducted on a good state engine.
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Offline AintNoEasyWay

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #2 on: July 29, 2014, 06:12:00 am »
I am wondering if I can rent a compression tester for the evening. I've never heard of a leak down test. Could you give me some detail on how I'd do this? If I can check both rings & seals using this, it seems preferable.

I did a valve adjustment as one of the last tune up procedures. Only one valve needed adjustment; the gauges fit properly for the remaining valves.

Smoke does seem to be constant for the most part. Any rev of the engine gives me a good amount of smoke.

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #3 on: July 29, 2014, 06:37:00 am »
Leak down is sort of opposite of compression. You fill each cylinder with forced air, them measure the volume of "leak". This will indicate whether it's leaking through valves (you'll hear hissing through top end) or through rings

If smoke is constant, likely rings.
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Offline flybox1

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #4 on: July 29, 2014, 08:31:07 am »
is this a new bike to you?  How long have you had it?
was it sitting for a long period of time before you got it?
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Offline AintNoEasyWay

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #5 on: July 29, 2014, 08:41:49 am »
is this a new bike to you?  How long have you had it?
was it sitting for a long period of time before you got it?

Hey flybox, I've had it since last year. But it wasn't running when I bought it. Had to rebuild the carbs, clean out the tank, change out coils & ignition (put in PAMCO), rebuild master cylinder & front brake, among other things.

Yes, it had been sitting in a garage for about 3 years according to the PO.

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #6 on: July 29, 2014, 08:45:58 am »
May mend some mile on to re-settle the rings. Could be some congestion in the chambers allowing some oil past. Make sure you keep the oil topped off and run it some. The head leak will have to be fixed, but smoking may subside.
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Offline flybox1

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #7 on: July 29, 2014, 08:58:01 am »
May mend some mile on to re-settle the rings. Could be some congestion in the chambers allowing some oil past. Make sure you keep the oil topped off and run it some. The head leak will have to be fixed, but smoking may subside.
agreed. run it and deal with the oil leaks until the chambers clean out.
if it still smokes after 100 miles or so, then you'll have to decide what direction to go with the cyls/pistons/rings....
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Offline AintNoEasyWay

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #8 on: July 29, 2014, 09:02:50 am »
Would you guys recommend I still try a compression or leak down test today if I can get my hands on the right tools?

I should emphasize that I've ridden around town for about a week, no more than 30 miles, with no leak & without any irregular smoke from the exhaust.
« Last Edit: July 29, 2014, 09:09:28 am by AintNoEasyWay »

Online calj737

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #9 on: July 29, 2014, 10:08:12 am »
There is always benefit to doing these tests. If nothing else, they are a baseline for engine health.

If, after riding for 100-200 miles, you still have the same problems, retest and notice the delta.

One tip for the compression test: WOT during test, and perform the test "dry". Then, add a touch of oil directly to cylinder and re-run the test. If the compression jumps, that's a good indication of ring wear. But, as stated earlier, this may improve with some mileage. May not... But at least you'll have empirical evidence to refer to instead of "some smoke"...
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Offline enwri

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #10 on: July 30, 2014, 01:07:36 am »
I'll go with Calj and Flybox, just didn't want to be the one to suggest to keep going and see what happens. Gave mine many thousands of k's to fix itself.( very different situation than yours though.)  But I was just living in hope of not having to take the engine out.
Std. rings and guide seals eventually fixed it.

Calj and Flybox, What do you guys think about the frame kit thing? I don't have a clue how much it would cost to get and fit, but it's got to be worth something to not have to wrangle that 85kg lump out and in again. Especially if it's not something you might usually do.
« Last Edit: July 30, 2014, 01:10:57 am by enwri »
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Online calj737

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #11 on: July 30, 2014, 04:29:02 am »
I don't own a 750. But, if I did, a frame kit would always be the first purchase after the bike, regardless of the condition of it. I'd even install one in a perfectly running bike, as long as it wasn't some spectacularly rare Sandcast model. Because, in truth, I'd sell that on and spend the cash  :)

Definitely frame kit. EasyWay - you can reach member 754 for a no-weld kit to install. He's sold dozens of these and haven't heard of a single complaint or regret from anyone about installing one.

You can rent a compression tester in some areas. But it must be a motorcycle type, not a car type for accurate results.
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Offline AintNoEasyWay

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #12 on: July 30, 2014, 05:30:33 am »
Great. Thanks, guys. Another forum member came by yesterday evening & rode my bike around. We got smoke at start up, but after riding around a while, smoke was non-existent. The oil is still an issue throughout the ride though. After his short ride, a small puddle of oil had formed in a nook on the engine just under the carbs. Looking back on the engine, I could also see oil on some of the fins. I took a second ride after, getting the bike up to about 60mph & had oil splattered on my right side cover!

The other member figured it could just be the gasket that needs replacing. But whether it's gasket or not, I'm thinking I should go ahead & get new rings & valve steam seals once I have the engine out. What other things should I look to replace? I will be doing this on a budget...

I first heard about frame kits yesterday thanks to enwri, but I'm not sure what they do exactly. Make the engine easy to remove? Just assuming from the way you guys are talking about it. But it's probably not something I can do financially at this point. Will have to find some alternatives for getting the engine out & back in.

Online calj737

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #13 on: July 30, 2014, 05:39:54 am »
Oil leak - clean the engine exterior. Then, sprinkle some baby powder along the suspected areas of leakage. Run the engine, and look for wet spots. Simple and foolproof. Also cheap.

Frame kit - they are cheap. Basically, it cuts a section of two horizontal frame tubes, under the tank, and the vertical brace, making it removable with a spliced section that is screwed into itself. You can search "frame kit" on the forum to see examples.

Rings/Seals - if the smoke is abating while riding, I'd not spend the money. If oil is only present at start-up, it's likely seals. But, this may improve with some riding, so don't rush to do this. Fix the leak, sure, it's dangerous and an engine hazard. But the rest you can probably live through for some time.

With the frame kit installed, you can service the head with the engine in the bike. That is not possible without it. If you have to remove the head to replace a gasket, then you must re-torque the head after letting it stand for 24 hours or running it in. Either way, but it must be done.

Here's a thread you should read before undertaking your leak repairs: http://forums.sohc4.net/index.php?topic=107040.0
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Offline enwri

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #14 on: July 30, 2014, 05:52:47 am »
That's good that the smoking isn't too bad, when you stop at the lights and your cloud wafts past you, that's the time to worry about it. oil leak will keep your boots shiny, The frame kit thing? It's the reason everyone generally recommends you rebuild the engine in one go, rather than bit by bit.
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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #15 on: July 30, 2014, 06:01:23 am »
That's good that the smoking isn't too bad, when you stop at the lights and your cloud wafts past you, that's the time to worry about it. oil leak will keep your boots shiny, The frame kit thing? It's the reason everyone generally recommends you rebuild the engine in one go, rather than bit by bit.

Somewhat true, but not completely. As states, head bolts must be re-torqued. If you wait until after heat cycling the engine, then the engine must come out again to do so. With a frame kit, it can stay put. They make everything easier on 750s.

A for the oil, shiny boots means oil on road, which leads to rear tire slippage. You can polish boots, but hard to polish the asphalt with your bum.
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Offline AintNoEasyWay

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #16 on: July 30, 2014, 06:28:37 am »
Here's a thread you should read before undertaking your leak repairs: http://forums.sohc4.net/index.php?topic=107040.0

This is exactly what I need to start learning more. Thanks!

Offline AintNoEasyWay

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #17 on: August 02, 2014, 05:36:45 am »
Here's a look at the leak from my exhaust. It also seems like the leak from the engine case is getting worse because now it's leaking at the sides from some of the fins. As far as I can tell, the leak from the engine stops once I'm riding, but I pulled back in the garage & found this residue on my exhaust. Figured I should take a pic & show you guys. I changed my oil yesterday before riding.

I haven't found a motorcycle specific compressor that I can borrow, so I still haven't run any tests. But I've just begun plan to rebuild what I can of the engine despite my budget. Would be great if some of you could point further in the right direction. After reading some threads, here's what I've come up with:

APE studs from z1 enterprises, 77.31
Cometic head gasket from z1, 48.23
Cometic base gasket from z1, 12.52
Rings, (need to check my engine number) but 4into1.com has them for $40 a set
Valve stem seals, not sure the best kind to get?
Cam chain tensioner, roller, & guide set from Dynoman, 99.95
Tsubaki cam chain from z1, 32.51
Cylinder head rubber seals from z1, 3.38 each

Cylinder hone, not sure about prices from local shops or if this would be necessary?

This is assuming the valves are in okay condition & only need to be lapped. Does this seem like a thorough enough list for a top end rebuild?
« Last Edit: August 02, 2014, 05:40:15 am by AintNoEasyWay »

Offline Don R

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Re: Blue smoke from exhaust, Oil leaking from #2 flange
« Reply #18 on: August 02, 2014, 07:53:01 am »
 There are rubber seals under the cam holders, called pucks or nickle washers, they are prone to leaking, They seal the smaller head bolts access holes. There's a good chance they are the source of the external oil. Engine removal is needed to replace them too but I would not want to remove an engine without doing the pucks too.
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