Need help figuring out what to do next!

[justfun1]

I need some help figuring out what is wrong with my bike before I decide to dig deep into it. I have an '86 venture that has 74 K miles and has an unknown history for most of those miles. Here are some recent repairs: new plugs 1/2 yr ago, new cables & caps this year, new diaphragms last year, carbs synced last fall.

 

My scoot has been underpowered for some time and is getting worse. Tonight I was out looking trying to rule some obvious things out. One thing that is new and significant is that I found a small amount of emulsified oil and what appears to be radiator fluid in the air box (see picture). It seems that it is coming from the engine breather tube that is feed back in to the air box. After the engine is warm you can see a steady stream of smoke/vapor coming out of this tube in the air box. I also do not know what that chamber does that is mounted between the "V", it appears to have both cooling and the engine breather tube. I can't seem to find good documentation on this thing . . .

 

So . . . Do I have a blown head gasket, needs a valve job, or could this be caused by something else??

 

This site is awesome and very friendly!

 

Thanks for your help!

 

Mike

[Yammer Dan]

If you overfill on oil it will come out this tube. With it on center stand make sure it is not over 1/2 way up sight glass. Have you done the Sea-Foam? Sounds like it is time for it. About a whole can in 1/2 tank. head gaskets not often on these things. Gasket could be gone in chamber you talk about can't think of it's name but it has coolant going thru it. Ihave numbers for gaskets somewhere.

[Squeeze]

You should replace both the O-Ring Style Seals on the Engine Breather Casing( The Box inside the V) and this should be gone. Blown Head Gasket ? Nope, i don't think so.

[Guest HdHtr]

If you need to get into the breather, here are some pics that could help.

[justfun1]

Thanks for the insight and the pics! So if I understand correctly: The coolant is probabally comming from the chamber between the "V" and my bike does not run well due to the coolant vapor in the air that the carbs suck back into the cylinders ???

 

It looks as if you need to pull the carb bank to work on this chamber, is that correct?

 

Thanks again for all of you help!

 

Mike

[Black Owl]

If, and I say if, you are getting oil into the coolant fluid, you are also getting coolant fluid into the oil. If you have coolant fluid in your oil, you need to change the oil immediately. Coolant fluid in the oil can wreck havoc on a motor in a relatively short period of time.

[GigaWhiskey]

I am not seeing any coolant color in that pic. Are you running just straight water?

 

 

Nice pics HDHTR.

[justfun1]

I do not see any signs of coolant in the oil, but I did not check the coolant lately to see if there is oil in it.

 

I did not see any green tint in the liquid in the air box either however, a quick touch to my tounge confirmed that the liquid does contain coolant.

 

Mike

[Squeeze]

No need to lick this Gunk. It's mixed up with minor Coolant Portion.

 

But showing this in the Airbox, doesn't mean necessary that there is some Interchange between Oil and Coolant going on.

[93 venture]

Put you bike up on the center stand over night and pull the drain plug, if there is any coolant you should see it drain out first maybe before you get the plug out, im not sure but the cc breather looks like it might also be some kind of oil cooler, it looks to have a coolant line running to it in the part pictures.

[justfun1]

I think I'll order up a set of gaskets for the center chamber and pull & clean the carbs and check the valves. Hopefully this will solve the problem.

 

Thanks for you help!

 

When I get this done I'll let you know how it turned out.

 

MIke,

[Gearhead]

I do not see any signs of coolant in the oil, but I did not check the coolant lately to see if there is oil in it.

 

Coolant in the oil is usually pretty obvious, making the oil look like chocolate milk if you have run the engine for awhile.

 

But showing this in the Airbox, doesn't mean necessary that there is some Interchange between Oil and Coolant going on.

How would the coolant get in the airbox if it's not mixing with the oil, or at least with the breather gasses?

 

It looks as if you need to pull the carb bank to work on this chamber, is that correct?

 

I'm not sure, but it seems like I've read you can get the breather assy out with the carbs in place.

 

im not sure but the cc breather looks like it might also be some kind of oil cooler, it looks to have a coolant line running to it in the part pictures.

Good theory - the breather has crankcase vent, coolant and oil chambers. Does anybody know for sure just what this puppy is for? Why have a chamber with these 3 chambers?

 

Jeremy

[Squeeze]

But showing this in the Airbox, doesn't mean necessary that there is some Interchange between Oil and Coolant going on.

.....

 

How would the coolant get in the airbox if it's not mixing with the oil, or at least with the breather gasses?

 

....Jeremy

 

 

Coolant and Oil can mix up only in the Breather Assembly and this Mixture gets exhausted/sucked up into the Airbox. I had and heard about this Beast so much and more than likely there was nothing more contaminated than the Engine Gases.

[Condor]

Everyone seems to have decided to call this thing a breather, but after looking at the pics, it looks to be more of Yamaha's attempt at an oil cooler/heat exchanger of some sort. Either to warm the oil up during cold riding, or bringing the oil temp down when engine oil gets hot. More of an equalizer. It just don't breath.....

[6m459]

I get green snot in my airbox too. I suspect that it comes up from the "breather".

 

As the bike goes like stink otherwise and since the "breather" is so hard to get at, I have decided just to keep an eye on it and not worry too much about it. Summers are short up here after all.

 

Hope this helps,

 

Brian H.

Uxbridge Ont

[Gearhead]

Won't that eventually allow coolant into the oil?

 

Jeremy