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Discussion Starter · #1 ·
About a week ago when changing my oil I noticed that it had gas in it, and it was discolored to gray. I was told that either it could be some sort of bad gasket, I was running too rich, or a float valve was hanging up and I left my petcock on overnight. Well, I wasn't running rich according to the plugs, though the bike does smell a bit rich, and I'm not sure how to check the gaskets. I have been leaving the petcock on overnight a few times, which I think may have been the cause. This was after a 2000 mile trip...lots of it with the throttle WFO and my bad ignition system slowing me down, keeping me in the 70-80mph range even at wfo (fixed the ignition system after coming back home.)



I changed the oil from 10w-40 valvoline motorcycle specific oil to Rotella 15w-40 after reading so much about it here. I just checked it again this week (wow, I'm horrible, aren't I?) and it smells a lot like gas. Seems a bit less viscous than normal, but I brought it to my mechanic and he said that it feels and looks normal, and that usually the smell of gas will linger after it's gotten into your oil. I've also gotten a lot of comments from people in the past about how much like gas my bike smells, but I think that that's always been the case (people don't understand that the gas tank is RIGHT THERE lol).



So, is it true that the smell will linger, or am I going to have to fix this problem then change my oil again? It definitely isn't discolored now when checking from the dipstick, but I don't want to keep riding with a problem like this. I've been turning my petcock off a lot more frequently now...though not as frequently as I should be, a lot more often than I used to, and it never is left on overnight anymore. I've had this bike for like 17,000 miles or so now, and this is the first time I've seen this and I've always had a bad habit of leaving the petcock on overnight.



Another thing mentioned by the mechanic was that maybe since it's not the stock petcock (only has on off res, no vacuum) it may be dripping when put to off or something. I'm doubtful of this because occasionally the fuel filter will be completely empty when I come out to get on my bike for the day, and the petcock is set to off (Florida sun means the gas evaporates from the carbs, apparently.)



So, should I be worried? Does the smell really linger? How long *should* it linger before I should worry? Is it plausible, advisable, or possible to switch back to the vacuum petcock so I don't stupidly leave my gas on all of the time? Or am I just better off getting better habits?



Thanks all.
 

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Lots to read. The stock petcock for your bike should be on/off/reserve. No vacuum.



The easiest way for gas to get into your engine is a fuel needle that isn't seating correctly.



If you want to know if you petcock is cutting off the fuel when you turn it off then turn it to off and pull the hose at the carb or petcock and see if it leaks.



What does your bike look like? Some people chop the hell out of these things and wonder why they have problems and others seem to have bad luck.





Do you always put your bike on its sidestand?
 

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Lots to read. The stock petcock for your bike should be on/off/reserve. No vacuum.



The easiest way for gas to get into your engine is a fuel needle that isn't seating correctly.



If you want to know if you petcock is cutting off the fuel when you turn it off then turn it to off and pull the hose at the carb or petcock and see if it leaks.



What does your bike look like? Some people chop the hell out of these things and wonder why they have problems and others seem to have bad luck.





Do you always put your bike on its sidestand?
help me here Don,why would a non seated valve put gas into the oil?



surely,the overflow is an easier way out?
 

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Discussion Starter · #4 ·
Lots to read. The stock petcock for your bike should be on/off/reserve. No vacuum.



The easiest way for gas to get into your engine is a fuel needle that isn't seating correctly.



If you want to know if you petcock is cutting off the fuel when you turn it off then turn it to off and pull the hose at the carb or petcock and see if it leaks.



What does your bike look like? Some people chop the hell out of these things and wonder why they have problems and others seem to have bad luck.





Do you always put your bike on its sidestand?


Sorry for being long winded in my OP, I always try and include all details and end up adding too many irrelevant ones.



By it "should" be on/off/reserve do you mean that I should keep it like that, or that's what it was stock? Because my carbs definitely have a vacuum line attachment that is being capped off.



I tested the petcock, it seems to be fine when set to off for the most part....hoping that it's consistent. Unsure of how to test how the needles are seating, other than just yanking the carbs and cleaning them out.



The bike is stock, though it's obvious that the PO has made some minor changes in the wiring, and he also is the one to put on the non-stock petcock. He wanted to cafe it and even had the rear fender/signal lights off, but he was smart enough to keep them and I reinstalled it all with no issue. It is leaking/weeping oil in a few places, almost all of the engine is pretty dirty with oil because I'm too lazy to clean it. I always add oil to keep it level though of course. I don't take good care of the cosmetics, but I take good care of the running bits...or at least I try my best.



Yes, the bike is almost always parked on the sidestand, which is another bad habit I'm trying to break. I used to park it on the centerstand nightly but eventually stopped. I was told that this could be part of the problem though I'm not too sure how. It is ridden every day though, if that makes any difference. It's my daily rider, and is also my long distance rider as well, though I don't do trips that often due to time constraints.
 

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help me here Don,why would a non seated valve put gas into the oil?



surely,the overflow is an easier way out?




Surely the overflow should be the easy way out but lets assume here.

If the carbs are at an angle and the bike is at an angle on the sidestand leaning forward with one carb higher than the other and the petcock open maybe by act of god fuel sis slowly draining into the left cylinder.



Yeah that sounds like a load of crap but I bet like the odds of winning the lotto it is possible. Seeing as several times a year we get the same question. Usually comes up unanswered.
 

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The petcock should be a simple on/off/reserve with no vacuum. I didn't/don't think that the 80's had vacuum petcocks but there's no saying that the carbs couldn't have been changed at some time since all cx500 non turbo carbs interchange.
 

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Discussion Starter · #7 ·
The carbs were definitely gone into in the past, but that's all I could tell about them. Seemed like all of the pieces were still stock, but the float bowls were scratched, so they were cleaned in the past. The fuel out bung on the petcock seems a little bit smaller than the 1/4" fuel hose that fits snugly on everything else, so I always just assumed that it wasn't stock. The fiche here at bike bandit seems to show multiple hoses going to the petcock, though I'm not too sure if I'm looking at it correctly.



The sidestand theory is actually a really good idea. I'll just get back into the habit of parking it on the centerstand and observe what happens next. I've googled almost every thread about the gas in oil problem and none of them seemed to have any definitive answer as you said, so that's why I started my own.



Though if gas does get into the oil, is it true that the smell lingers for several oil changes even if there is no more gas in the oil? That's what I'm wondering now. I'm being told that my oil is completely fine at the moment, even though it definitely smells a lot like gas. People who run it through their fingers (after taking some off of the dipstick) say they think there's nothing else in it, and that they "think but aren't sure" that the smell should linger for a bit.
 

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There are sets of circumstances where Gas/Petrol can get into the engine especially if the bike is left on the side stand and depending on even a slightly none flat ground.



If the Petcock is left open(None Vacuum type or faulty Vacuum type)If the float needle valves are sticking open and low because a float has gone low fuel can build up enough to escape into the engine via the intake manifolds.I know this from experience as I've had it happen once.I left one of my CX on the side stand at the back of my house,petcock open and the ground made the Bike up at the back.

I also checked the Air-filter box which had a fuel smell and there was gunge blocking it's outlet pipes so when I took out the plugs some fuel/oil mix trickled out so there also some back feed into them as well.

From that time on around this time of year and part of a a pre-season service I squeeze some washing up liquid into the filter box(With the filter out of course and the small filter stand) and then with the pipe plugs removed pour a couple of kettles of boiled water into it until I see clean water coming out of the Air-filter overflow pipes then dry it out.

I also have got into the habit of switching off my Petcock which I never used to do as my FNVs never gave me any problem for years but better safe than sorry.

In this case I would investigate the Carburettor floats and needle valves which I also serviced because of this event.



Yes the smell does linger and if unsure change the oil again after a few miles,it's cheap enough and just consider it a good safe engine flush.



HTH
 

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mm,sorry guys,i dont buy it.



the only way is for a bike to be laid down for a decent time period.



Shep,do you remember the email i sent you last june/july?...ref,watery oil
 

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Discussion Starter · #11 ·
Well, assuming it isn't the carbs, a float hanging up, or leaving the petcock on, what else could it be? I think that just shutting off my petcock properly should save me from further troubles but I'm curious as to what else could cause it.
 

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mm,sorry guys,i dont buy it.



the only way is for a bike to be laid down for a decent time period.



Shep,do you remember the email i sent you last june/july?...ref,watery oil


Yes I do.I think that was because those guys screwed up in the transport of the bike including that damaged screen.My situation was different and the only time it has occurred and was definitely fuel in the oil.As soon as I took my oil filler cap off I could smell it hence I started to investigate and found all the other things as per above.
 

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Cramer, you said in the original post that the bike wasn't running well due to ignition problems. And went on to say that the bike "smells rich" when running, but that the plugs look good. When exactly did you look at the plugs? And what did they look like?



If you were riding at wide open throttle with a faulty ignition for a long period of time (which was indicated in the original post), then not all of your fuel was being burnt in the cylinders. Some of this fuel can seep past the rings and into the crank case resulting in fuel contamination.
 

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Only 2 ways to get gas into the oil, save pouring into the dipstick hole, and that's, through the carb, or past the rings. If the gas is draining past the needle seat faster then it can drain out the overflow. You should consider yourself pretty lucky Cramer you haven't "hydo'd" yer motor yet.



Try tapping on your float bowls with a hammer and see if they'll seat. Sounds like you've got some carb issues, which could be mis-diagnosed as ignition troubles.



Might be worth it to do a compression check as well, and at least get 1 burr from under your saddle........
 

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Discussion Starter · #17 ·
Cramer, you said in the original post that the bike wasn't running well due to ignition problems. And went on to say that the bike "smells rich" when running, but that the plugs look good. When exactly did you look at the plugs? And what did they look like?



If you were riding at wide open throttle with a faulty ignition for a long period of time (which was indicated in the original post), then not all of your fuel was being burnt in the cylinders. Some of this fuel can seep past the rings and into the crank case resulting in fuel contamination.
I checked the plugs about 700 miles from home on a 2000 mile trip, around the time I checked the oil and it seemed fine though I may not have noticed the gassy smell. The plugs were kind of a light brown "cocoa" color, a bit white. I was thinking that they looked like I was running lean, and upon asking a friend with a lot of mechanical know-how I was told that that was completely normal, and definitely a little bit lean. Checked them again after I got home, though I didn't check my oil because I knew I was going to change it soon, and they were about the same, maybe a little darker but still in the "somewhat lean" category.



I was exaggerating saying I was at WFO the whole time, though I was definitely pushing it a lot, getting WFO a lot, and running around 70-80 mph with the bad ignition system which required a lot of pushing...not to mention I was riding a bit aggressively as well. You may have figured out my problem, I never thought about it like that. Basically the bike would "cough" after cruising around 70-75mph or higher for a while and I'd have to pull in the clutch and let it "catch up" and then go again. It happened consistently above 75, especially when gunning it to try and pass people. Ever since fixing the ignition system I haven't noticed it, though around town I'm about 50-60 tops...though I did take it on the interstate once with a pillion, and was cruising steadily at indicated 80mph and didn't even realize it for a while. I think that the problem is fixed.





Only 2 ways to get gas into the oil, save pouring into the dipstick hole, and that's, through the carb, or past the rings. If the gas is draining past the needle seat faster then it can drain out the overflow. You should consider yourself pretty lucky Cramer you haven't "hydo'd" yer motor yet.



Try tapping on your float bowls with a hammer and see if they'll seat. Sounds like you've got some carb issues, which could be mis-diagnosed as ignition troubles.



Might be worth it to do a compression check as well, and at least get 1 burr from under your saddle........


Well I've never noticed it before, and I always change the oil at least every 2500-3000 miles. Currently so far it's just the smell, which I guess is supposed to linger. I'll know next oil change as I'm going to pull the filter and see if it is the tell-tale gray.



I've only had one carb ever have a float hang up on me before, and that was shortly after I first got the bike last year. Hitting it with the hammer did fix it, and I've never seen gas overflowing again. Tomorrow I'm going to try and see if the overflows are clogged just to be sure. I won't really be positive if the problem is fixed or not unless I find gas in the oil again. I'm going to be checking it constantly just to be sure that it is just the smell lingering.



I recently installed an ignitech, rebuilt the plug caps with hollow copper rods (they were the biggest contributor to my ignition problems, I learned after taking them apart. Holy crap!) installed tecoparts coils and put in iridium plugs. The bike runs so fast now compared to what I'm used to that I have to constantly look at my speedo to avoid getting a ticket. The ignition system definitely was my initial problem. My only problem I notice in performance now is sluggishness coming from a stop, like giving it gas will make it stutter for a second....but only from a complete stop. There are also a few flat spots, like right around 5-6k, but they are so minor that just a very slight twist of the wrist eliminates them.



I'll do a compression test as soon as I can though. I only have one person that has the tool to do it with, and that's my uncle...and I think that his tool is too short for the CX500 cylinders. Eep. I'll have to look around I guess.



Also, do Iridium plugs change colors to indicate lean/rich mixtures in an engine the same as standard plugs? Never used one before, haven't pulled these yet to look at them....wondering if they will look any different at all.
 

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I have the Tecoparts coils look em up on ebay they are half the size as stock coils mine been working great.now @ Cramer say hello to florida been a while since I been there lived in the port richey area for 10 yrs up until a 2 yrs ago anyway when I was running rich I freplaced coils did a bit of work on carbs and got rid of all the exhaust leaks and put new muffs on fixed the problems
 

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Maybe someone can help me here. What are "TECOPARTS" coils?, and do they work on these bikes?




Bear it's a coil replacement for the cdi bikes.
 
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