smoky ped

I was riding my tomos targa lx today, it has an airsal 70cc kit and a deltoro 15/15 carb. Round twoards the end of my trip, about a quarter mile from my house it started acting up a little. I figured it was just the wind because it was blowing really hard today. But when I was about two minutes from my house it started to have very little power and I noticed that it was spitting out grey smoke like a son of a bitch. It looked alot like transmission fluid smoke because it was really grey and hung around till the wind caught it. Why would my ped be burning atf? Is it burning atf at all? And what can I do to fix this? I'd appreciate any help you guys can offer.

Thanks in advance,

Greg mullis

Re: smoky ped

I don't think it is ATF since it really can't get to the engine. Maybe you put ATF in your oil accidentally or you put to much in your tank.

Re: smoky ped

I am not going to speculate to what the problem is, I am just here to state the it would be very possible that it is ATF, and bassman ATF doesn't have too far to go to get to the motor, there is only one seal on the clutch side seperating the bottom end(ATF) from the top end(crankcase), there should be one other seal between the case halfs that is also the only barrier between the crankcase and the tranny

If a seal went you will be tearing the motor down, but wait around for the Tomos experts.

Re: smoky ped

greg m /
OP

I know I didn't put any atf in the gas tank, I'd have to be pretty drunk...... Anyway, I'm fairly sure it's atf, too much oil and the exhaust would be blue, too much gas and it'd be black, and since there is no coolant in a tomos then the only fluid that would burn grey is the atf. I don't mind tearing the engine down, I'd just like to know what I should be hunting down when I do so. In other words, what seal or gasket would be causing this problem?

Thanks for the help guys,

Greg mullis

Re: smoky ped

My only guess is that a seal may have gone bad, I wouldn't tear into the motor for a bit, wait for the tomos experts to help you out, but for now I would check the tranny fluid make sure you didn't lose much if that is what the problem is

Re: smoky ped

sometimes 2-stroke burns grey. if you had a dramatic loss in power i would suspect the piston rings especialy if you have a big bore kit and even more so if it has been put in recently. i highly doubt its a gearbox seal. but i have been wrong before. but i would pull the head first off, for its pretty easy to do and if that is your culprit you will know right away

Re: smoky ped

greg m /
OP

Ok, I tore down the top half today, and it looks peachy. I checked the compression before I took it off and it was fine. What part of the gearbox should I be going after now, and how far am I needing to tear it down?

Thanks in advance,

greg mullis

Re: smoky ped

try this first..

assemble everything and pressurize the crankcase.. use an air hose and a regulator and push about 20 PSI of air into the sparkplug hole.. You should see or hear air bubbles in the gearbox filler hole if a gasket is blown.

(20 PSI is a wild guess, but i think it's enough.. and it seems safe since a running engine develops way over 120 PSI in the case.. If someone can make a more educated guess, have at it.)

That broken gasket would be the one that splits the engine case down the middle, and that joint would cut right through, into the crankcase. If ATF is getting into the crankcase, it would get in by being sucked through a break in that gasket.

Re: smoky ped

oh yeah.. you have to plug up the exhaust and/or intake port to pressurize the crankcase, but you get the idea.

Re: smoky ped

Gregory Mcintire /

The crankcase pressure is nowhere near 120 psi. When the piston goes up the crankcase pressure goes below atmospheric pressure in order to suck in the air/fuel mix. When the piston comes down the crankcase is pressurised in order to force the mixture up into the combustion chamber. The combustion chamber may reach 120 psi but the crankcase is very low, maybe 5-10 psi. If it were as high as 120 psi, it would be hard to rotate the motor with the spark plug removed, which of course it is not.

The gasket between case halves can leak and cause the ATF burning problem, but it is more common for the crank shaft seal to be the leaking culprit allowing transmission oil into the crankcase..

Re: smoky ped

Yeah..that sounds about right..

and if a crankshaft seal is wet on one side, the ATF would probably enter there before it came through a gasket.

And a pressure test may not be sucessful since the seal may pass ATF in only one direction...

OK.. so pressurize the gearbox and look for liquid in the bottom of the crankcase.

Re: smoky ped

greg m /
OP

Ok, The seal is definatley leaking. I'm gonna have to remove the clutches and gears to get down to it, Is there an easy way to hold everything steady while I'm taking off bolts? Or do I need to buy some specialty tools, and if so, where should I get them from?

I really appreciate all the help everybody,

thanks,

Greg Mullis

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