Desparate for help

[BigMike]

Sorry it has been a while since I have on the forum. I am having a bit of a crisis. I do as much of my own maintenance on my 92 as I can but I've been having an issue beyond my skill set. Even the mechanics at the shop I have taken it to cannot figure out what is going on with it. They called Yamaha and still can't get an answer. I would greatly appreciate any help on this one.

My bike is pouring smoke out of both pipes but it only starts doing so after about one minute during warm up. Yamaha says that would only happen if the oil is overfilled but I can assure you that is not the case. We made sure of it on 3 separate occasions now and it still starts smoking...a lot! The shop has had it for a month now and I am going ape-**** without my bike. There are no cracks as far as we can tell anywhere and the compression is great. The oil is somehow getting into the air-box and going into the carbs etc. Any thoughts out there???

Thanks in advance all!

Big Mike

 

[Traumahawk]

Do you have a stage 7 kit or is it all stock?

 

[Fire-medic]

I say it sounds like bad rings or bad valve guides/seals. Do a compression leak-down test, that should help diagnose it. Yes, you'd think bad rings would mean low compression, but obviously the sump is becoming pressurized and bad rings is one cause. If you hear air at the oil filler during the cyl leak down test, bad valves, if you hear air at the carbs, bad valve guides/seals.

Correction: I re-read my comment, and would like to cite the Mobil Oil website about 'reading' a leak-down test. My answer was simplistic and not complete, here's a more-authoritative answer about the process:
https://mobiloil.com/en/article/car-maintenance/car-maintenance-archive/how-to-do-a-leakdown-test

Hearing problems
Beyond getting an overall picture of engine condition, the engine leakdown test is an excellent way to pinpoint where problems are before tearing down the engine. Listening for where the air is escaping by ear can isolate the problem.

• Intake valve : Air whistling out of the intake, carburetor or throttle body indicates a leak at the intake valve.
• Exhaust valve : Air heard hissing out of the tailpipe, turbocharger or exhaust manifold means an exhaust valve leak.
• Piston rings : Whistling or hissing out of the PCV valve, oil filler cap hole or dipstick tube means the air is pushing past the rings. Suspect ring or cylinder wall wear.
• Head gasket : Air bubbles in engine coolant seen at the radiator filler cap could mean air escaping into the coolant past the head gasket.
• Cracked cylinder head : Bubbles in coolant or coolant being pushed up out of the radiator neck can also indicate cracks in the cylinder head or cylinder walls.

 

[customizedcreationz]

The air box has a air/oil separator that's supposed to let the crankcase pressure through and trap the oil so it can run back down the tube into the engine when the high pressure in the crank case ceases to exist.

Check the valve it's on the rear where the oil tube runs.

If you have bad rings it will push oil as well. Even though you show compression, a leak down gauge will show you a problem even if the compression shows as the oil may be sealing the rings.

 

[Fire-medic]

Todd, beat you by a minute!:Nixon:

 

[customizedcreationz]

Todd, beat you by a minute!:Nixon:

Yes you did! Great minds think alike!

 

[jfeagins]

...and if your "mechanics at the shop" can't isolate something this major, especially after having your bike a month........................time to find someone else to work on your baby.

 

[customizedcreationz]

...and if your "mechanics at the shop" can't isolate something this major, especially after having your bike a month........................time to find someone else to work on your baby.

Yeah that's probably pretty sound advice as well. Everyone makes mistakes, but after a month of working on it, or did they have it sitting there for a month and looked at it for one day?

 

[95spfldmax]

...and if your "mechanics at the shop" can't isolate something this major, especially after having your bike a month........................time to find someone else to work on your baby.

+1.......what's been suggested here is just basic mechanic troubleshooting.......nothing specific to the Vmax..............

 

[BigMike]

Thanks a ton everybody! Yes I agree that they should have had it done by now but I also think that they probably have been sitting it and claiming to work on it as opposed to the other way around.

This is the last time they will see my bike for sure. If I had more time I would learn how to do this myself but...way too much to do as it is.

Again, much appreciated guys! I'll let you know what it is once complete.

Thx!

BigMike

 

[[email protected]]

Just so happens that I found a '92 vmax for sale at the motorcycle shop 1 mile from my office. It has a problem with oil puking into the airbox. I'm guessing the bike I looked at is BigMike's.

I talked to the mechanic. He said they called yamaha and have been directed to rebuild the crankcase breather assembly. They quoted the owner 8 or 9 hrs to do the work. He supposedly said no way, then bought a new max.

The mechanic said the owner did a compression test and all is good with the motor. They never did a leak down test. it looks like they pushed it in the corner and forgot about it.

they are selling it on consignment. I'd like to to and do a leak down test and buy it if ok but not sure I gave the time right now

 

[Fire-medic]

Yes, certainly sounds like the same bike. Get permission to do a leak-down test, or have them do it as a condition of buying it. As in, "I ain't buyin' it until I see a leak-down test done on it!" And, preferably being present while it's done.

Then you will have a better idea of what's going on.

 

[sdt354]

The problem with compression test is they can be misleading. A lot of carbon in the heads will shoot compression up artificial. I have a HF leakdown tester, it's basically useless for a percentage reading, but great to pressurize a cylinder. It's got a valve and restrictor in it already along with spark plug thread adapters. It's cheaper than making one, if a coupon is used. Like Fire Medic posted, listen for air by passing valve components at the carbs or exhaust ports or oil fill cap for rings. Blowing into coolant-a head gasket or crack. Useful to have and works on any engine. We should start a thread on tools needed to maintain a vmax, what do you guys think?
It might help out some of the new guys that want to learn and take care of their bike.
Steve-o

 

[DMAN999]

^ A necessary Tools thread would be great.

 

[ga_max]

I like the idea of a tool thread. Plus instructional info is always helpful.

 

[wayne z]

So, Can you find out how it ran after more than 10 munites? Did it keep smoking or clear up?. A lot of the smoke you may see is oil buildup in the exhaust cooking off, may take 10 munites or so to burn it out.

Try to find out how much oil it consumed. If it doesn't use much worse than a quart every 750- 1000 or so, or you don't ride a lot, you might get away with adding a catch bottle and just ride it like it is. Just something to consider.

 

[blackandblue88]

I'm no expert but I had a very similar situation on another V4 Honda Magna. Started fine but after a minute or so it smoked out of both pipes. I pulled the carbs off again ( for the third time) and cleaned them extremely thoroughly. It stopped the smoking completely. The bike had been sitting for over a year so it was gummed up and the floats must have been sticking letting too much unburned. fuel into the exhaust I guess.

 

[Rollie]

...and if your "mechanics at the shop" can't isolate something this major, especially after having your bike a month........................time to find someone else to work on your baby.

+1 Big Time.