[ChrisC]

I am in serious need of some guidance! I feel like I am arranging deck chairs on the Titanic! I did a stator and R/R replacement right after I bought my '89 due to charging problems, both were fried (I posted a pic in the gallery to show what a fried stator looks like!) While I was waiting for parts to arrive, I did a bunch more work including coastering and a de-goat. After I got everything back together, and resolved the additional charging problems, yikes, while test riding the bike to observe the voltage, the bike started to run rough, lost power, and I had to keep it throttled up to keep it from stalling. Long story short, back in the garage I noticed leakage and smoke from the rear cylinder manifold. :wow:

I immediately thought of a couple of scenarios, a stuck float, crud in the carbs, and a blown head gasket. I pulled the plugs from both sides of the rear cylinder to begin to confirm what I was thinking, and they were both wet. I checked the spark for both, it looked weak to me initially, but I checked them against the plugs in the front cylinder, that looked absolutely normal (not fouled), and the spark looked the same. I drained the carbs and it came out absolutely clean (I have been using Seafoam since I bought the bike). I did not notice if the amount of gas was the same from each carb; I just realized that I didn't check that. I was going to try to "burp" the carbs (I think that was the term used describe turning off the petcock a couple of times to try and clear gunk out of the carbs) just in case the float was gunked up, and then I noticed an additional symptom, the bike never stopped running when I shut the petcock off!!

I did some research on the forum and found a few references to leakage and vacuum troubles on a de-goated bike, caused by the back pressure differential, resulting in similar behavior to what I was seeing. So assuming that the de-goat was part of the problem, I re-goated. I also drained the oil and there was gas in the crankcase, which kind of confirms the free flowing gas due to a vacuum issue scenario. I checked the air filters and the vent hose to the right ear; all fine, and dry. All of the boots on the carbs seem to be in place. No additional leakage around the carbs that I can see.

Okay, I am not sure what to do at this point! I am very new to wrenching and I am feeling a bit lost in the woods. What do I need to do? How do I clear the rear cylinders? Do I need to replace the plugs that were fouled? Can this still be a blown head gasket, or a problem with the rings? How do I get all of the gas out of the crankcase? I am chasing a red herring, and the problem(s) are really elsewhere? I could really use some advice!! Sorry for the long post. Thanks.

 

[hyperbuzzin]

Gas in the crankcase? First thing I'd check is what kind of compression you're getting. Might be worn piston rings.

 

[Duck]

gas in the crankcase is usually caused by an overflowing carb dumping raw fuel into the intake. port.

 

[ChrisC]

Gas in the crankcase? First thing I'd check is what kind of compression you're getting. Might be worn piston rings.

I'm going out to pick up a compression gauge so I can check, I'll post the results.

 

[ChrisC]

gas in the crankcase is usually caused by an overflowing carb dumping raw fuel into the intake. port.

The 2 things I am guessing that would cause the carb to overflow (at idle, since that is when I can see it) would be the pilot screw being set way too rich and a stuck float needle. Correct? Anything else? I have the pilot screws on both sides set at 1 and 3/4 turns. I guess even if the gas from the drain plug is clear, I can still have gunk causing the needle to stick.

I do not have a fuel level gauge. Is there a different way to check? Can I do it by ounces, rather than trying to determine "1.5 MM above float chamber"? I let the carbs fill up this morning and drained them to check if the amount was the same on each side. The right side had more fuel than the left.

 

[rckmtn]

Concur with Duck. Usually gas in the oil is from flooding.
If the plugs don't fire gas can't burn and some or most of it will puddle and wash past the rings to the crankcase. Change oil, change the fouled plugs, and the start troubleshooting. Checking spark with the plugs out is not truely an indicator of plug condition. Plugs can fire when out but totally fail under compression. Some of the other "oldies" in here might remember spark plug testers that used compressed air to load the plug for spark testing at different pressures. Now days most modern plugs are cheap and would not stand up to the old blast cleaners.

 

[Duck]

I remember the old pressure plug testers. I'd love to get my hands on one.

Another consequence of a flooding bowl, is the excess fuel washes down the cylinder wall causing wear and loss of compression. The compression or most of it, will come back whith fresh oil and a little easy running, but if left too long some serious scoring can occur.

 

[750Doug]

I guess even if the gas from the drain plug is clear, I can still have gunk causing the needle to stick.

It is very possible, and likely to have some piece of debris jammed up in the float seat keeping it from closing, OR, the tip of the needle worn so it can't seal closed when the float closes it.

Both of these are not things that can be indicated by the "color" of the gas flowing out of the drain valve.

Somewhere in these Forums are some threads about reverse cleaning by spraying up into the drain. That might work for you, as a last try before pulling the carbs.

And yes, both carbs should have the same amount of fuel in them.

 

[ChrisC]

Thanks for the feedback! I tried to do a compression test after changing the oil, but the tester I have only had adapters for 14MM or 18MM openings. Since ours is only around 11MM, I picked up a "universal" tester with rubber plugs. Theoretically these would only need to be pressed into the opening to get a compression reading. Even these were too big at the tapered end to fit. I am going to make an adapter by using an old spark plug tomorrow morning and try again. I am also going to spray carb cleaner through the drain plug to see if that helps, as long as the compression tests between 129 and 199 PSI, and is within 10% among cylinders. If I am not getting good compression, I'll wind up giving the carbs a thorough cleaning while I have the engine out to address the rings/gasket issue. Clymer's also mentioned possible valve problems, so I'll have to check all of that out if I have to do a tear down.

By the way, does anyone know the part number for the autolite or champion plugs?

 

[Crobins365]

By the way, does anyone know the part number for the autolite or champion plugs?

Autolite's are 4164.

I had the same stuff going on with Orleans when I first put the rebuilt engine back in - Duck may have to refresh my memory as to what I did to fix the problem, but I actually had gas just blow right out of the front manifold. Quite a surprise! I do believe (here's the thread: http://www.vn750.com/forum/showthread.php?t=7047) that mine turned out to be a timing issue. Once I got the timing set, I obviously still had some issues, but gas spewage was not one of them.

So, unless you've pulled the engine and done soemthing with the timing, go with the simpler things like stuck float bowls, bad compression, etc. One easy way to tell if you have *some* compression in the cyl is to pull one spark plug, pull it off the wire, and put the wire far, far away from your person. Take the wire off the other spark plug for the cylinder - that just keeps the cylinder blocked, but prevents any sparking from blowing you up. Then put your finger over the empty spark plug hole and see if you get push-back when you press the ignition switch to turn the engine over. Again, this doesn't tell you how much compression you have, but if there's a massive problem, it'll let you know that.

Oh, BTW, the engine will continue to run on whatever fuel is in the float bowls, even if you've turned off the petcock. That's how i finally got Orleans to run - dumped fuel directly into the lines, turned the igntion, and she ran until the bowls emptied out (about a minute and a half).

 

[Duck]

Thanks for the feedback! I tried to do a compression test after changing the oil, but the tester I have only had adapters for 14MM or 18MM openings. Since ours is only around 11MM, I picked up a "universal" tester with rubber plugs. Theoretically these would only need to be pressed into the opening to get a compression reading. Even these were too big at the tapered end to fit. I am going to make an adapter by using an old spark plug tomorrow morning and try again. I am also going to spray carb cleaner through the drain plug to see if that helps, as long as the compression tests between 129 and 199 PSI, and is within 10% among cylinders. If I am not getting good compression, I'll wind up giving the carbs a thorough cleaning while I have the engine out to address the rings/gasket issue. Clymer's also mentioned possible valve problems, so I'll have to check all of that out if I have to do a tear down.

By the way, does anyone know the part number for the autolite or champion plugs?

Make sure you've changed your oil, and circulated it a bit by cranking the engine, This should get some fresh oil on your cylinder walls if they've been washed down at all.

 

[ChrisC]

Well the compression checked out fine!! About 170 - 175 PSI on all 4 cylinders. Looks like I can rule out valves, rings, and head gasket. I'm going to try to back wash the carbs through the drain plug tonight. If that doesn't work, I'll pull the carbs for a thorough cleaning, and replace whatever necessary.

As far as the timing goes, the way I understand it, there is not much in the way you can do to adjust things besides resetting the chains. One question though, if all was running well for the first couple of hundred miles I had the bike on the road, would a problem in the timing show up suddenly? I mean, if the chain broke, or a sprocket, or something else major, I would expect other noise and symptoms. I'm not ruling anything out at this point without thoroughly testing, but since I am in a learning mode, I am trying to understand this stuff as best I can.

 

[ChrisC]

Make sure you've changed your oil, and circulated it a bit by cranking the engine, This should get some fresh oil on your cylinder walls if they've been washed down at all.

Good advice! I changed the oil and let the bike idle for a minute or two before running the compression tests.

Also, since I had no difficulty with the dry test on a cold engine, I saw no need to do a wet test. Should I have done one?

 

[Duck]

Well the compression checked out fine!! About 170 - 175 PSI on all 4 cylinders. Looks like I can rule out valves, rings, and head gasket. I'm going to try to back wash the carbs through the drain plug tonight. If that doesn't work, I'll pull the carbs for a thorough cleaning, and replace whatever necessary.

As far as the timing goes, the way I understand it, there is not much in the way you can do to adjust things besides resetting the chains. One question though, if all was running well for the first couple of hundred miles I had the bike on the road, would a problem in the timing show up suddenly? I mean, if the chain broke, or a sprocket, or something else major, I would expect other noise and symptoms. I'm not ruling anything out at this point without thoroughly testing, but since I am in a learning mode, I am trying to understand this stuff as best I can.

These are 2 cylinder engines. The dual spark plug setup is confusing you, The timing si pretty much set as it is, and a bad chain will make a racket before it gets bad enough to jump a tooth
Clean and synchronize your carbs and make sure the necessary vents are opn

 

[ChrisC]

These are 2 cylinder engines. The dual spark plug setup is confusing you, The timing si pretty much set as it is, and a bad chain will make a racket before it gets bad enough to jump a tooth
Clean and synchronize your carbs and make sure the necessary vents are opn

The dual plugs were throwing me! As much as I looked at 2 pistons in the manuals, I kept thinking 4 plugs = 4 cylinders. Thanks for being gentile! I am an idiot! :doh:

Will focus on cleaning the carbs from here.

 

[Crobins365]

Definitely follow Duck's advice - if the bike was running fine, there's nothing that should've thrown off the timing. So most likely it's a stuck float. Cleaning carbs is really a fun job. Really! Fun! Good luck - you'll get it going. And for a self-described newbie at wrenching, you sound like you're doing great!

 

[hyperbuzzin]

The dual plugs were throwing me! As much as I looked at 2 pistons in the manuals, I kept thinking 4 plugs = 4 cylinders. .

You're not the first to be confused by the 4 plugs. It is deceiving

 

[ChrisC]

Thanks to everyone who chimed in on this problem! I flushed the carbs from the drain plug a few times and it seems to have resolved the problem without having to pull the carbs! :rockon: I'm going to pull them at the end of the riding season to give them a thorough cleaning, assuming the problems don't return before then.

Rode to work and back today, about 70 miles, and aside from having to dial in the idle adjustment, everything worked great. Pulled the plugs when I got home and there was absolutely no fouling, they looked great. No smoking from the manifold and no leakage. I am one VERY happy camper! :smiley_th

As an aside, I was still getting alot of popping after I coastered. Now, after the re-goat, all of the popping is completely gone, and the low end power is back (at least it feels that way). I think I wasn't getting a good seal with the Scootworks kit. I really never seemed to get the right side to fit properly.

Thanks again for the input!

 

[Duck]

Glad its running good for you

Enjoy

 

[hgree]

I had this problem on my '97 when I degoated due to a stopped up vent tube going to my tank causing a vacuum problem to my petcock letting gas flow while it was sitting not running into my cylinders then on into the crankcase. After regoating the problem still existed until I cleared the vent lines. On late '96 and early '97 models one of the vent tube fittings on the tank is smaller and plugs up easily, KAW figured out the problem and corrected it with only a few bikes released with the small vent tube. Mine is one of them.

All of this being said just to tell you to check your vent lines to tank and petcock!