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It might be rich.

It might also be water in your floatbowls that only gets sucked up when your carbs are pulling lots of vac, like at full throttle... or something else equally obsure.

Pull the plugs and look at them. Rich will probably leave them black and sooty, oil.... black and oily. Coolant usually leaves leaves fluffy-looking but hard, white-ish or grey deposits. Water will often leave rusty looking (surprise ) deposits on the plug.

Another great suggestion that I can actually do myself. I'll pull the plugs & take a look.

I'm still at a lose on this one. I went to the dealer and he adjusted the idle and tightened the choke. He said possilbly the choke was out a little bit. He told me the white smoke is unburnt fuel. After the adjustments he instructed me to ride the bike hard and it will go away.

After doing this I still have the same problem & it seems like my mileage has dropped. (I was getting 55-60 mpg now I'm getting 48 mpg)
I have also been checking the oil & coolant every couple days. Still no changes in levels or color.

Of course the dealer can't duplicate the problem unless he's willing to ride out on the hi-way for 20 mins full throttle. Thats when I notice the smoke after coming off the hi-way. Absolutely no smoke when idling.

Anyone know of some shadow VLX specific forums ?

FWIW, the dealer told me that he has never replaced head gaskets or piston rings on any Honda bike engine with less than 10,000 miles in his 20 yr career. My bike has 4,200 miles.

If the bike is burning oil or antifreeze, you should notice a drop in the fluid level of one or the other. If you never have to add oil or antifreeze, then it has to be a problem with fuel mixture. I agree with the other posts, oil burns blue, a rich gas mixture burns black and antifreeze burns white. Antifreeze burning has it's own particular odor, I'd think you would notice that right away.

True I don't smell anti freeze. The guy with the Ninja 250 that you responded too kinda sounds like my problem too. (Ruff idle when cold) Except I have the white smoke after engine is warm.

I'll check for air leaks.

Very often when a bike is serviced, they inspect the air filters, and never get them seated properly again. Bikes are designed to operate in proper tune with air filters and mufflers in place as designed by the factory. As I mentioned on the 250 Ninja post, if the filter is not properly seated then it will introduce non filtered air into the carbs and disrupt normal air/fuel mixture, generally causing a lean burn situation. You might check that too.

xsyamahadg wrote:Very often when a bike is serviced, they inspect the air filters, and never get them seated properly again. Bikes are designed to operate in proper tune with air filters and mufflers in place as designed by the factory. As I mentioned on the 250 Ninja post, if the filter is not properly seated then it will introduce non filtered air into the carbs and disrupt normal air/fuel mixture, generally causing a lean burn situation. You might check that too.

I checked the air cleaner today. I found quite a bit of oil in there. Altho the oil was clean. I don't think my air filter requires oil I'll have to check the owners manual later. The filter is paper.

After discovering this I went back to the dealer. We discovered that I have lost 1/2 quart of oil over the last 1,300 miles. Which he said is ok.
He topped off the oil and told me to drive 500 miles and bring it back to see if the oil consumption has increased. He also mentioned that the white smoke could be the oil burning off. According to him burning oil doesn't have to be black smoke. He also said that its probably not worth trying to diagnose if I'm only seeing small amounts of smoke during certain conditions. I'd tend to agree since I don't want to be spending money on random parts/fixes.

I still haven't noticed any decrease or change in performance. The lower gas milege I was talking about before is probably because of the conditions I ride in. (I've been riding on the hi-way alot and into the wind) Thats gotta decrease mileage.

Keep us posted, I'm curious about whats going on with the bike. XS

Just for reference. Black smoke is almost always excess fuel (i.e. too rich on the mixure). Burning oil can be a bluish color if it's just a little seeping past the rings, or solid white if there's a large amount entering the combustion chamber. Coolant usually shows up as white smoke (steam actually) and has a distinctive smell.

Three things make me think the smoke is oil. The fact that you've burned 1/2 qt. in 1,300 miles (a bit excessive for a modern water cooled engine, IMHO). The fact that you found "quite a bit" of oil on the air cleaner (if there's any, it should be a super-light film). And lastly, that the smoke shows up at higher rpm.

Most bikes have hose that ventilates crankcase gasses to the airbox. An abnormally high level of oil, or abnormally high crankcase pressures can result in oil going to the airbox instead of just vapors. High crankcase pressure is often due to blow-by past the rings, which will increase as cylinder pressures increase.

I'd recommend giving your airbox and filter a thorough cleaning. Then ride for 100 miles or so and make some smoke. Check the airbox again. If it has returned to its excessively oily state, then you have to find out why the crankcase breather is sending oil to the airbox. The next logical (and not very expensive) step would be a compression check to see if your rings are OK.

flynrider wrote:Just for reference. Black smoke is almost always excess fuel (i.e. too rich on the mixure). Burning oil can be a bluish color if it's just a little seeping past the rings, or solid white if there's a large amount entering the combustion chamber. Coolant usually shows up as white smoke (steam actually) and has a distinctive smell.

Three things make me think the smoke is oil. The fact that you've burned 1/2 qt. in 1,300 miles (a bit excessive for a modern water cooled engine, IMHO). The fact that you found "quite a bit" of oil on the air cleaner (if there's any, it should be a super-light film). And lastly, that the smoke shows up at higher rpm.

Most bikes have hose that ventilates crankcase gasses to the airbox. An abnormally high level of oil, or abnormally high crankcase pressures can result in oil going to the airbox instead of just vapors. High crankcase pressure is often due to blow-by past the rings, which will increase as cylinder pressures increase.

I'd recommend giving your airbox and filter a thorough cleaning. Then ride for 100 miles or so and make some smoke. Check the airbox again. If it has returned to its excessively oily state, then you have to find out why the crankcase breather is sending oil to the airbox. The next logical (and not very expensive) step would be a compression check to see if your rings are OK.

What your describing would probably be "blow by" If that is the problem I would have expected it to show up right away when i first bought the bike. I bought this bike with 650 miles on it from a private seller. I didn't see any smoke until I hit 3,800 miles. Also, if blow by is really the problem that would be an expensive fix.

Couldn't it be possible that the breather is partially blocked ? As I understand it an engine won't run if the breather is completely blocked.

These carbs are annoying. Next time its fuel injection for me.