Any ideas welcome

[ianisme]

Update

You guys were spot on with your advice. Due to other commitments I was not able to spend any time on it until today. I found that both gas taps were leaking and have managed to fix those. I then discovered that the outside carbs were also leaking due to dirt on the float needle housing O rings.

Having sorted out those issues and having done an oil change, I now find I still have a problem.

The bike starts (reluctantly) and runs, but there are clouds of smoke coming out of the exhausts. Almost immediately large quantities of oil pour out of the airbox drain pipe. I guess the crankcase is being pressurised though I have no idea why. Once again I throw the ball back to you guys. Any ideas gratefully received.

Geezer, I lost my PC due to a dead motherboard so apologies for not getting in touch. I would still appreciate any help you can offer.

[Geezer]

Re: Update

Originally posted by ianisme
[B
Geezer, I lost my PC due to a dead motherboard so apologies for not getting in touch. I would still appreciate any help you can offer. [/B]

Don't run your bike any more until we can check it out together. I think your carbs have flooded the case with gas. I'll eMail you tonight.

Geezer

[sixtysix]

Your crankcase is full of gas! Do not run it! You will do serious engine damage! Take off your air box and then turn on the gass if petcocks or carbs are leaking you will see it pour out of the affected carb(s). After the petcocks and carbs are fixed change your oil and filter and then life should be grand. Wait for Geezer.

[TopCatGr58]

Hey Gary and Geezer,

He says he did an oil change "after" sorting out the carb and petcock issues. I'm wondering if he might have just overfilled the oil? With all of that oil flowing back into the carb intake, he could be getting lots of it back into the combustion chamber that way, hence the heavy smoke and poor performance.

A tip someone posted was to take a stick and dip it in your oil filler opening very far down, then pull it out ensuring you have fluid on the end. Step very far away from the bike, preferably outside, then take a lighter or match to the stick, if it lights and burns, then you DO HAVE GAS in your oil! If it doesn't light, then you just have oil, but somehow you probably overfilled it.

OR, you've got serious compression ring failure. Have you done a compression test on the bike? Good luck!
T.C.

[ianisme]

As TopCat spotted, I did do an oil change after sorting the fueling problem out. I'm not sure where you are supposed to drain the oil on this engine but I ended up removing the filter housing. The "oil" was very heavily contaminated with gas and I didn't need a stick to tell me, due to the strong smell and the thin consistency.

I guess it is possible I overfilled it. I put in 3 litres of oil as it has that amount stamped next to the filler.

I have not done a compression check yet so was planning to do that first thing today. I'll let you know what I find.

[John]

Oil drain plug

It's located just to the left, and behind the oil filter cup. I believe it is a 17 or a 19 mm size. You'll be able to see it in the oil pan.

[TopCatGr58]

The oil drain plug faces forward on the front edge of the oil pan, not directly down!! It's just to the right of the filter chamber looking at the chamber, or just to the left if looking "thru" the bike!

3 Liters is the correct amount, but you didn't drain the engine by just removing the filter chamber!!!!! So...now you still have gas in the oil, and you probably have 6 quarts of it now in the engine case!!!! You'll need to drain it from the drain plug, and again from the filter chamber, and then refill with fresh and you'll probably notice it behaving much better!

T.C.

[ianisme]

TopCat, did you sneak into my carport last night?

You were dead right; I drained (from the correct drainplug!) about 2 1/2 gallons of fluid. The stick and match test confirmed it was full of gas. Filled it with fresh oil and it started and run much nicer.

There is a little oil coming out of the drain and it runs smoky still, but I think that may be because the level is still a little high? I plan to try routing the crankcase breather straight to atmosphere and see if that cleans up the exhaust.

Once again you guys have come up trumps. I must admit I was about ready to throw in the towel on this one. If nothing else I now know a little more about carbs and XS engines than I did before (though thats not hard). Thanks one and all.

[sixtysix]

Well ok then...guess I was right

[Geezer]

Originally posted by ianisme

Once again you guys have come up trumps. I must admit I was about ready to throw in the towel on this one. If nothing else I now know a little more about carbs and XS engines than I did before (though thats not hard). Thanks one and all.

I wouldn't leave the tank connected until the problem is resolved with the carbs. I eMailed you my phone number, give me a call or eMail me back and I'll give you a hand with it. In my years as a Yamaha mechanic I've done hundreds of these.

Geezer