BRed What are the causes of engine smoke and oil consumption?

[fmjnax]

I have done a couple of leakdown tests. Once a few months back when I found the exhaust side valve leak and subsequently replaced the valve seals. Then I did another before I tore it down, but I was leaking air at a fitting (even with pipe dope on the threads) so inconclusive results on that one, unfortunately.

The rings were installed correctly. I did confirm that before I removed them. That much I do know for certain (unless the instructions I received with the ring sleeves were wrong).

Agreed on the wear. 100 miles is even being generous. It's probably even less than that. The only driving the machine has had has been short start/stops (it's a farm machine). Nothing strenuous. A LOT of start up cycles without actually driving anywhere while I've been trying to figure out the issue. Might have been giving WOT 2 or 3 times during that time. But yes, the piston is still in spec.

 

[Doogle]

You've checked everything I would. I'm new to the SXS myself. Just bought less than a year ago. And I leave it in AZ until I return in the winter. So I can't eyeball anything for other ideas. One last thought though. Are there any vent lines that return to the intake system? Fuel overflow, crankcase breather, air filter full of oil. Can you even be sure it is oil burning? I don't know if there are any water sources that could get sucked into the intake system. I don't mean to suggest stupid things, but anything might jog a thought for you. And you sound like you have a good understanding of things.

 

[fmjnax]

Thanks Doogle, I know what you mean and no worries for tossing out anything you can think of. It is much appreciated! This is my first sxs and really my first 4-stroke powersport toy. I'm still learning myself. I do have a fairly decent understanding of engines, etc but this one has been stumping me. I'm just going to re-ring it, throw on a new set of gaskets, and have a shop rebuild the head. If it's still a smoke bomb then I'll let Honda take the whole thing and let them figure it out for me.

I'm not sure if there are vent lines. Pretty sure there is not a PCV, though. No oil at all in the air filter. If I didn't check the dipstick regularly, I'd almost say that I'm not certain it's burning oil. The smoke is very think and lingering, but it's more gray than blue. Not like any oil burning that I'm used to. However, I can almost watch the oil level decrease as it's idling and the coolant level hasn't budged one bit.

 

[TexasJackKin]

Just tossing out a wild guess, could the crankcase be pressurized? I.E. case case vent plugged? Piston drain back holes open? It's a head scratcher for sure......

 

[Jerryg]

One thing I noticed in the picture of the cylinder, if I can see where the piston ring travel is, it's not honed well enough.

 

[bigshoe]

My main question is where did parts come from who made them where did u get them. Just asking I've installed alot of Ching Chong parts 5 sets to be exact they always started smoking pretty fast if its not a wiesco or honda part throw in garbage and start over.

 

[fmjnax]

My main question is where did parts come from who made them where did u get them. Just asking I've installed alot of Ching Chong parts 5 sets to be exact they always started smoking pretty fast if its not a wiesco or honda part throw in garbage and start over.

I've worked on outboard engines long enough to know exactly what you mean! I will only buy from a reputable source or clear OEM parts.

Everything except for the valve seals, cylinder, piston, rings, and gaskets came from Partzilla or OEM new old stock. Not sure where Partzilla source from, but I think they are OEM.

The aforementioned exceptions came from Powersports Nation. Piston is Wiseco. Rings are Hastings. Cylinder is a remanufactured OEM. Not sure on the gaskets. Valve seals likely are not OEM but definitely seems to be better quality than OEM (double sealing rings vs the single on the OEM).

 

[fmjnax]

One thing I noticed in the picture of the cylinder, if I can see where the piston ring travel is, it's not honed well enough.

Agreed. It needs to be rehoned. After washing down the cylinder good, taking measurements, and looking it over with a magnifying glass, it's in good enough shape that I should be able to run the 240 Flex Hone through it to clean it up and give it a new crosshatch. If I notice any flaws, I'll go ahead and have a machine shop hone it.

 

[bigshoe]

I've worked on outboard engines long enough to know exactly what you mean! I will only buy from a reputable source or clear OEM parts.

Everything except for the valve seals, cylinder, piston, rings, and gaskets came from Partzilla or OEM new old stock. Not sure where Partzilla source from, but I think they are OEM.

The aforementioned exceptions came from Powersports Nation. Piston is Wiseco. Rings are Hastings. Cylinder is a remanufactured OEM. Not sure on the gaskets. Valve seals likely are not OEM but definitely seems to be better quality than OEM (double sealing rings vs the single on the OEM).

Your using wiseco piston with hastings rings? I'm confused on this because on all small engines I've done, nothin fits wiseco piston except wiseco rings.

 

[fmjnax]

Your using wiseco piston with hastings rings? I'm confused on this because on all small engines I've done, nothin fits wiseco piston except wiseco rings.

That's what Powersport Nation said they use for the "top-end kit" I purchased. When I talked to the guy yesterday, I wasn't sure if I had a Wiseco piston or a Namura piston. He confirmed it was a Wiseco and I'm pretty sure he said the rings were Hastings. Maybe I misheard him. He already sent out the replacements so I guess I won't be able to confirm until I get them in the mail.

 

[bigshoe]

That's what Powersport Nation said they use for the "top-end kit" I purchased. When I talked to the guy yesterday, I wasn't sure if I had a Wiseco piston or a Namura piston. He confirmed it was a Wiseco and I'm pretty sure he said the rings were Hastings. Maybe I misheard him. He already sent out the replacements so I guess I won't be able to confirm until I get them in the mail.

Ok if its namura chuck it the garbage I've had multiple of them fail and the rings never last if it was me I would order a wiseco piston and ring kit all in one. by the ring landings it looks like namura to me.

 

[fmjnax]

bigshoe, you're not giving me much confidence in what I received from PSN. See, I could have sworn it was a Namura when I first received it. However, when I spoke with the guy on the phone he said that he confirmed it was a Wiseco piston. Even the paperwork that I found in the shop indicated Namura (why would they send Namura swag/stickers with a Wiseco piston?!). I am also pretty sure that the original rings were Wiseco because, again, the paperwork I found in the shop were instructions for Wiseco rings. I have NOT purchased any other piston or ring set in the past 5+ years and we have moved since then so I'm almost 100% certain it's not some old paperwork that somehow made the move and ended up on the bench.

Oof, what a mess. Maybe I will just go ahead and buy a Wiseco piston and matched rings and eliminate that level of uncertainty.

 

[fmjnax]

Update time:

Got the new rings in (it was a sealed Wiseco package but the ring sleeve inside of the package shows Hastings, so who knows). I honed the cylinder and it looked perfect! I filed the rings down exactly to spec after the hone. I disassembled the head, soaked it all in some Berryman's for a few days, and removed all of the carbon. When I reassembled the head, it all looked good (not perfect, though). No light visible and the ports held acetone without leaking. Grabbed a new headgasket as well. Then I bolted the machine back together. I was optimistic on the first few stationary idle cycles and wasn't seeing any smoke. However, on the first light test drive she started smoking again!

Compression is just shy of 90psi (let's call it 88psi). I fixed the fittings on my leakdown tester and hooked it up. Immediate air leak! Nothing coming from the radiator. Nothing coming from the oil dipstick or filler cap. It's coming from the exhaust. Not only can I hear it from the tailpipe, but it's such a large leak that I can FEEL it from the tailpipe. It won't hold any sort of pressure at all. I haven't pulled the intake to see if any is leaking through that side yet.

So looks like I need to have a PROFESSIONAL rebuild my head and use new parts. I had called my local Honda powersports shop and they are 8 weeks out and do not do head work without having the entire machine so that is why I opted to do a super deep cleaning and take my chances. Time to get on the phone and see who I can find to do the job. *sigh*

 

[Jerryg]

Update time:

Got the new rings in (it was a sealed Wiseco package but the ring sleeve inside of the package shows Hastings, so who knows). I honed the cylinder and it looked perfect! I filed the rings down exactly to spec after the hone. I disassembled the head, soaked it all in some Berryman's for a few days, and removed all of the carbon. When I reassembled the head, it all looked good (not perfect, though). No light visible and the ports held acetone without leaking. Grabbed a new headgasket as well. Then I bolted the machine back together. I was optimistic on the first few stationary idle cycles and wasn't seeing any smoke. However, on the first light test drive she started smoking again!

Compression is just shy of 90psi (let's call it 88psi). I fixed the fittings on my leakdown tester and hooked it up. Immediate air leak! Nothing coming from the radiator. Nothing coming from the oil dipstick or filler cap. It's coming from the exhaust. Not only can I hear it from the tailpipe, but it's such a large leak that I can FEEL it from the tailpipe. It won't hold any sort of pressure at all. I haven't pulled the intake to see if any is leaking through that side yet.

So looks like I need to have a PROFESSIONAL rebuild my head and use new parts. I had called my local Honda powersports shop and they are 8 weeks out and do not do head work without having the entire machine so that is why I opted to do a super deep cleaning and take my chances. Time to get on the phone and see who I can find to do the job. *sigh*

Sounds like you need a new cylinder head.

 

[fmjnax]

Sounds like you need a new cylinder head.

At this point, I think that is probably the safest bet. Not really cost effective, but maybe it is in the long run. I got this machine DOA for next to nothing so I'll still be well under its value going that route.

**EDIT**
New head and all associated parts have been ordered. This BETTER do the trick!

 

[Jerryg]

At this point, I think that is probably the safest bet. Not really cost effective, but maybe it is in the long run. I got this machine DOA for next to nothing so I'll still be well under its value going that route.

**EDIT**
New head and all associated parts have been ordered. This BETTER do the trick!

Hopefully the seats don't need cutting. Lap the valves in and see how it looks.

 

[Keebler]

Did you replace the valve seals? If the seals are old or maybe original they might be split or not flexible enough to seal against the valve stem. Valve seals are always advised to be replaced during an engine rebuild. Also, is there any sign of oil in the airbox from the crankcase vent hose?

 

[fmjnax]

Did you replace the valve seals? If the seals are old or maybe original they might be split or not flexible enough to seal against the valve stem. Valve seals are always advised to be replaced during an engine rebuild. Also, is there any sign of oil in the airbox from the crankcase vent hose?

Yes sir, new valve seals used after the deep clean (which is the 3rd new set I have tried). I didn't think to check the airbox but just took a look and it's dry. A little at the bottom of the box, but not more than a cap full.

I've got a semi-local powersports shop building me up a new head. New OEM parts all the way around. Full assembly. Completely taking my "shade-tree mechanic" error factor out of the equation.

 

[ByronM]

I question the leak down bleeding out the exhaust if you checked the valve sealing with acetone, if the valve sealed with acetone I find it hard to see wh6 it would not seal better with air pressure pushing them closed. Are you sure the valve clearance is correct? I am not sure how the compression release affects the leak down test operation. Is it possible that is holding a valve open?

 

[fmjnax]

I question the leak down bleeding out the exhaust if you checked the valve sealing with acetone, if the valve sealed with acetone I find it hard to see wh6 it would not seal better with air pressure pushing them closed. Are you sure the valve clearance is correct? I am not sure how the compression release affects the leak down test operation. Is it possible that is holding a valve open?

You share the same head-scratcher that I did. I'm fairly sure my exhaust valves and/or the head are to blame. My acetone and light test had to have been faulty somehow. Heck, I may have even tested only the intake side or tested the intake side twice. When I was building the head back up after the deep-clean, I did the "wiggle" test of the valves in the guides and also the "pop" test pulling the valve out of the guide. Intake valves were both good on that front. Both exhaust valves, however, had a small amount of play in the guides and neither one had a strong "pop" like the intake valves. I didn't think either was was bad enough to call them failed, but apparently I was wrong.

I didn't adjust valve clearance with the latest build-up, but the time before that I did adjust clearances according to spec. I didn't touch the tappets and the clearances still looked/felt correct so I left it alone.

I also thought maybe I wasn't at true TDC on the compression stroke, thus the positive air pressure was pushing the crank and allowing the valve to open. I tried it a half-dozen times at the peak of the piston stroke with both cam lobes facing down (TDC on compression) with the same results. In total, I had to have tested it at least 2 dozen times at varying strokes just trying to make sure my valves weren't opened by the cam and trying to get different results. I know it's frowned upon, but I bumped the key a couple of times while performing the leakdown and I could see the needle bouncing with the stroke but it never passed 90% leakage.

If the brand new head assembly still doesn't solve the problem, I think I'm going to light the thing on fire and bury it in a pit! I knew I was getting a project, but I never imagined it was going to be this bad!