Howdy folks, new guy here. long story...get comfy ! I have an 03 ruckus, bought in 08 with only 600 miles on it. Wife drove it to work for three summers, put 6k miles on it. Now, last run about 6 years ago. So, this winter I want it to live again. Start with the obvious, battery, clean carb, clean gas tank, gas filter, air filter, oil and antifreeze change.

So I do all that stuff, carb was really pretty good, gas tank not so much. Got the tank soaking in evaporust, might win...we'll see.
Time for first start...fires rite up, running out of a soup can for now, I was tickled, warmed it up and changed the oil.
Now with clean oil I run it till warm. Starts perfect, idles perfect, stab the throttle open never misses a beat until at wide open throttle. I had the carb snorkel off yet, and at WOT it spits gas out onto the rear fender. Well, air is supposed to go IN the motor, not out, so next I check the valve clearance. Sure enough, intake is tight. I could not feel any play with my fingers, yet the rocker slid sideways easily, so not "tight", but not in spec either. My smallest feeler gauge is 2.5 and that would not go in.
So, I get a shim from the dealer, wrong one really, now I have 6 thou, and spec is 4. So I run it again, same thing, spits gas out at WOT.
Next I want to put some air pressure to the cylinder to see if I have a burnt valve. I cut off an old plug and brazed a fitting on to apply air. I put a cigarette at the carb, zero air movement. same at the exhaust pipe, zero air movement. Sounds like a lot of air coming out the crankcase , so next a compression test.
The hole in the head is so deep that I had to take off the O ring on the tester fitting, and even then only got a thread or 2 to catch, so just slightly more than finger tight and I got 160lbs dry, and over 200 with oil. So not in spec, 202psi , but not terrible either. After all that testing I felt I had run my new battery down a bit, so I set it to a high idle and ran it in the garage for about a half hour. After half hour you could not even tell a motor had been running. No blue cloud, hardly any smell even. I have a hard time believing the rings are bad. It has never smoked or used oil. So why does gas go out the carb at WOT !
Next, I go after the pollution control stuff.
First, I put the whole system back together as I had been doing all this running with the air box off, and snorkel off. While inspecting things I see that the air filter element had not been seated correctly for who knows how long, not good, but I put every thing together and ran it wide open and immediately took the snorkel off and it was full of raw gas.
next, I look at the reed valve on the head, it does not close one way as it should. Next I test the SE valve on the carb thinking maybe its stuck open, tests good and is all free and clean.
I have had many Honda bikes in my life, got my first super sport 50 in about 69. In those days the needle had notches to change the needle height, the ruckus does not, and that doesn't why it spits gas OUT onto the back fender. I am not familiar with this diaphragm type carb, that controls the needle height.
I live near the north pole so no test rides, could it be that the bike will be fine if the throttle is backed off a tiny bit fro WOT? I have had other bike that ran best like that, but the gas going OUT of the head is a first for me. Wake up now, I am done....any idea's ? thanks

 

I found that the reed valve for the PAIR system was leaking, which could blow crank case air backwards, then to the manifold vacuum line, then maybe out the carb at WOT ? So...I replaced the reed valve, no difference, still blows out the carb at WOT. Need to test the PAIR control valve next

 

Todays project was to test the PAIR control valve according to the shop manual. You need a vacuum pump, which I have, but it seems to have died and wont hold vacuum. So, for the heck of it, I blocked the vacuum line to the intake manifold with a drill bit. It seemed to run better, but still blows gas out at wide open throttle...WOT. Since the intake vacuum line is plugged, that seems to me that the only way air could go backwards OUT the carb would be a weak or broken valve spring. Again, the machine runs perfect until WOT, and even then runs fine except for gas spewing out on the rear fender, which is not good when you consider 99% of the driving is at WOT.
No comments here yet, I see this is not a very active site for Ruckus Info. I have spent many hours searching the web for my problem, many other Ruckus sites are more active, but I joined here as I also have several 88-91 civics and crx's. No problem, I will continue to solve the problem for other folks searching the same problem.

 

Replacing the reed valve seemed to be the fix. Finally got to road test it, and I have my old fine running ruckus back. Gas cap breather sticks shut occasionally, and it will die. Open the cap, give it air, and good for a while. I blow compressed air thru the lock, seems clear, but still some times sticks. may need a new cap.