24HP Honda Burning Oil...

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TheCartDude

Cartaholic
I seem to have a rather nasty problem with my 24HP Honda GX670TDW getting a lot of oil into the cylinders, primarily when letting off the throttle (usually from about 3600RPMs). It's annoying because it's consuming a lot of oil and it makes a fog-advisory grade smoke cloud, looks like a phosphorous bomb detonating. The engine is very new, maybe 12 hours runtime on it. Valve lash is set correctly, I do have rev springs in it.

Any ideas?

Thanks,
TheCartDude
 
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TheCartDude

Cartaholic
Ok, what exactly should I be looking for? Didn't see anything amiss after I finished respringing it and other than the deceleration burn it works fine with no oil burning. It will hold 2000-ish rpms for about 30 minutes no problem, did this once to recharge the battery.

Oh and the first time it did this oil was sprayed out of the muffler/exhaust manifold connection, which made me initially believe I had an oil hose leak. But that didn't explain the engine bogging down.

Great way to carry on a conversation across two forums btw :)
 
Keyguy

Keyguy

Overworked, underpaid :o) R.I.P.
If the seals were gone completely it wouldn't do what you're describing.
Might be time to consider taking it to Honda for warranty look see....

Jimmy B.
 
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ubercart

New Member
With those new springs his warranty is bye bye. Could have a bad set of rings and are getting blow by into the chamber. The bad thing about these hondas the parts are sometimes hard to find and always expensive.
 
T

TheCartDude

Cartaholic
I could always put the old springs back in. But I doubt that's the problem being that they shouldn't impact the oil entry at all. On further inspection it seems that making a hard left turn (and sloshing the oil toward the flywheel) also causes it to blow smoke.
 
Keyguy

Keyguy

Overworked, underpaid :o) R.I.P.
TCD,
Don't know what else to tell you.
Mine doesn't smoke and I've run the dog doo out of it at times...

Jimmy B.
 
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TheCartDude

Cartaholic
Almost none. It's more level than the stock engine in a stock cart. Do need to get a new cradle snubber though since my old one disintegrated.

Only other thing is the crankshaft has a bit of in and out play in it. Normal? It's enough play to see and feel. About 1/8" by my guess.
 
T

TheCartDude

Cartaholic
Ok I got the new springs out and put the old ones back in. No difference, still smoke bombs. I checked the valve guides as best I could for looseness, didn't see anything amiss with what I think were the oil seals.

I've had some vertical shaft engines suffer the oil blowing problem, don't know what was wrong with them either but the carbs and air filters certainly got gunked up with oil sprayed out of the cylinders.
 
HotRodCarts

HotRodCarts

Cartaholic
If its oiling as bad as you say TCD it doesn't sound good. Does it run ok? Is it making any noises it shouldn't be? I don't have much experience with the Honda V-Twins but if it's oiling as bad as you say I'd look at these areas

No crank case ventilation
Hole burnt in piston from detonation - (advanced timing)
Cracked piston, cracked head, cracked cylinder
Broken Ring(s)
Bent valves(s)

You could do a compression test and a leak down test on it to help figure out where the problem is coming from. Are both spark plugs oily? I'd consider the Honda shop now that you have the stock valve springs back on it....
 
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TheCartDude

Cartaholic
Crankcase ventilation: Vent line to Carb clear
Detonation: Negative. Do have advanced timing but run 93 octane always.
Cracked: Not sure. Still got good compression on both compression strokes.
Broken Rings: Most likely according to results across three forums.
Bent valves: Got good compression, doubt they are bent.

Right now I'm guessing that since I still have compression, and from another post, that when the engine was built someone forgot to put the rings at 180* from each other so oil can slide right up one side of the cylinder. I haven't pulled my plugs yet, that might help determine whether or not the oil is getting in one or both cylinders.
 
HotRodCarts

HotRodCarts

Cartaholic
How do you know you have good compression if you haven't pulled the spark plugs? :unsure:
Good luck with it and keep us posted on what you find...
 
T

TheCartDude

Cartaholic
Turning by hand is hard as all heck on both compression strokes. Holds pressure (Resistance at shaft) too throughout the stroke. Been my way of testing for ages, never got around to making a pressure meter connection.
Got a chance to talk to Jacob this morning. Apparently the Honda has a PCV breather connected to the carb that can inhale oil from the crankcase due to weak baffle design. It's on the top of the engine, on the flywheel side. Solution is to cap off the breather line with a vacuum cap and filter to keep oil out the the carb.

That would explain the oil I found in the carb throat this morning.
 
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