SA50P cuts out after several minutes of WOT

[wilsoniya]

Howdy!

As mentioned in the subject, I'm running a 2001 SA50P. Here's the problem I'm having: she starts up fine and runs as expected to a point. I'll be riding WOT for several minutes when the engine starts sounding labored, and then it cuts out altogether. I can restart, but the engine runs poorly and quickly dies. The weird thing is that I'll leave her alone for 15 minutes or so and she'll start back up and run fine again. *?

Here's the backstory:

Just last week I dusted her off for the first time this season and changed the back tire which was bald. I then took her out for a ride and she died (I was marooned several miles from home ). After walking her back, I was able to restart her and ride again... very puzzling.

I took a wild guess and suspected a carb problem. Being too lazy to disassemble the carb and clean it, I took the pump-a-bunch-of-seafoam-into-the-idle-screw-hole approach. I actually noticed a minor improvement in engine rev performance after this, but again after riding WOT for several minutes she died on me.

I am at a loss and very confused/frustrated and am scared to ride my baby around for fear of being stranded in the ghetto.

Any help would be graciously appreciated.

THANKS, and happy riding!

[bradthreee]

You are going to need to stop being lazy and disassemble the carb to clean it. It really is the only way to do it right.

[wiguy05]

You are going to need to stop being lazy and disassemble the carb to clean it. It really is the only way to do it right.

Agreed.

Also sound like your overheating. Might want to look to see if the fan/shrouding is damaged or missing in any way. Also, what plug are you running?

[scooterwerx]

sounds like it could also be a clogged fuel line, it fills the bowl too slowly for WOT, but letting it sit fills it back up and it will run again. does it have a fuel filter?

[Wheelman-111]

Greetings:

Werx's fuel starvation hypothesis sounds most plausible to me too. Here's another way it can happen. If the vacuum line to the petcock is iffy, the suction goes away at full throttle. The petcock closes partially or completely and the carb bowl gradually empties, resulting in your stall. The rubber in the line can get porous without obvious cracks showing, or a connection can be loose enough to seal at idle, but the vibration from higher RPM causes it to leak. For a couple of bucks' worth of Polyurethane, replace all the hoses and make sure to use the little clamps. That's why Honda-san put them there.

The same process occurs with an obstructed tank screen, a plugged inline filter and let's not forget spooge around the float needle. Do the easiest stuff first before you resort to pulling the carb for a cleaning. A steady flow of fresh gasoline should theoretically clean the carb for you, especially since you added Sea Foam. Since it runs well most of the time, I don't think cleaning the carb alone will solve your issues.

[wilsoniya]

Thanks, all, for your replies.

Also sound like your overheating. Might want to look to see if the fan/shrouding is damaged or missing in any way. Also, what plug are you running?

I've got an NGK BPR6HSA with very few miles on it. The shrounding looks to be fully intact, and it feels as though the fan is pulling plenty of air.

sounds like it could also be a clogged fuel line, it fills the bowl too slowly for WOT, but letting it sit fills it back up and it will run again. does it have a fuel filter?

I honestly do not know. I haven't added one, and I seriously doubt the dude I bought my hog from did either, so If a fuel filter is stock, then I have one.

Werx's fuel starvation hypothesis sounds most plausible to me too. Here's another way it can happen. If the vacuum line to the petcock is iffy, the suction goes away at full throttle. The petcock closes partially or completely and the carb bowl gradually empties, resulting in your stall. The rubber in the line can get porous without obvious cracks showing, or a connection can be loose enough to seal at idle, but the vibration from higher RPM causes it to leak. For a couple of bucks' worth of Polyurethane, replace all the hoses and make sure to use the little clamps. That's why Honda-san put them there.

Ok, so try replacing the vac line, then? Any advice on where those can be gotten?

The same process occurs with an obstructed tank screen, a plugged inline filter and let's not forget spooge around the float needle. Do the easiest stuff first before you resort to pulling the carb for a cleaning. A steady flow of fresh gasoline should theoretically clean the carb for you, especially since you added Sea Foam. Since it runs well most of the time, I don't think cleaning the carb alone will solve your issues.

Without much experience on the matter, I feel as though an obstructed tanks screen or plugged filter would cause intermittent problems, not the very regular type I am running into. In any case, How would I clean the tank screen and do you have any thoughts on flushing the inline filter?

Thanks again, guys. you are all my heroes

[Wheelman-111]

Greetings:

Simple stuff. Look at your cooling fan for obvious missing teeth or gaps in the shroud. Then move on. Open the airbox and see if there's a foam element versus a pile of goo in there. The #6 plug is the correct one if your scooter is still Factory-restricted. Replace it anyway and for $3/90 seconds you eliminate that remote possibility. Plus you have a spare plug.

Small-engine repair places carry hose small enough (1/8ID) to serve as vacuum line. So does Honda-san. For the one foot length, you won't save millions buying from Ace Hardware. Buy a couple feet of fuel line while you're there - it's the next size up. If you find a paper-element inline filter from Lawn Boy, replace with cone-shaped little porous stone job from Autoparts, chainsaw repair or Honda. The paper ones don't drip fast enough to keep up with your Elite's voracious appetite for fuel.

Drain the tank and remove the nut that holds the petcock. Underneath there should be a white plastic cylinder which you may need to pry out with a small screwdriver or pick. It slides on out of there. Wipe off any debris gently, and check the mesh screen for holes. Have a look inside the tank while you're at it. IF it's not covered with sludge, put it all back.

The one thing that could make your issue a heat-related problem is if the previous owner de-restricted the pipe and/or airbox and didn't change the "P" jet, which is very small, like a 68? In that case, the mixture's too lean to stand WOT for long. Should it be so, you will need to pull the carb and find a 78-82 or whatever size the stock SR jet was.

[wilsoniya]

Yo Wheelman:

The one thing that could make your issue a heat-related problem is if the previous owner de-restricted the pipe and/or airbox and didn't change the "P" jet, which is very small, like a 68? In that case, the mixture's too lean to stand WOT for long. Should it be so, you will need to pull the carb and find a 78-82 or whatever size the stock SR jet was.

The modifications I've made are listed in my sig. I have derestricted the pipe, swapped varis (thus removing the vari travel restrictor), and also swapped gears, though I doubt that has any bearing on the problem at hand. So in the long run I really need to upsize my jet is what you're saying... In the interim could I just add a portion of oil to the fuel tank to overcome the deficient oil present in a lean mixture?

Thanks man.

[wilsoniya]

Also, I have a few questions about acquiring a new jet. The Honda shops in my area don't carry many OEM parts for my scooter any longer. For some OEM replacement parts I have ordered from Babbits, but in general find them to be a mega rip off (e.g. the stock jet for the 01 SA50P is $24).

So does anyone have other options. I realize I need to get the jet for the SR due to my mods. Does anyone know the model number for the SR (e.g. my hog is the SA50P1; what would the equivalent model number be for the SR?).

Thanks a bunch!!!

[wilsoniya]

Sorry about the 300 posts in a row.

Am I to replace the jet, or the jet needle??

Grazie!

[Wheelman-111]

Greetings:

Honda dealers have or can get the correct jet from the SA50 (no "P) model number, and it's often the cheapest bet.

Adding oil won't help richen the mixture. On the contrary. I would discourage you from running the scooter at all until the jet's right.

Don't mess with the needle. Just get the # 78 jet. 99101-187-0780. Give that number to the parts guy and see how soon he can get it. They don't have them in stock, typically. However Deepinnaharta gets my stuff in 2 days usually.

[wilsoniya]

Bros:

I noticed some oil on my garage floor right under my scoot. Upon further inspection it appears to be leaking out of the final reduction gear box. Anyone think this could be related to previously described problem?

Many continued thanks

[Lunytune]

Per suggestion to put oil in the gas tank. Is that wise for system designed for injection? Will the oil accelerate carb varnishing? I'm a newby too, so learning 2 strokers. Far different that the big engines I used to make a living at.

[evilone]

Per suggestion to put oil in the gas tank. Is that wise for system designed for injection? Will the oil accelerate carb varnishing?

I don't know if i overlooked it or if someone who isn't a forum member suggested oil in gas tank. Gas cools top end, oil lubes top end. If you add oil to gas you are making it leaner by displacing some of the gas that cools the top end. And you would need larger jet to richen it back up.

If you are still running injector? That should be all you need.

Not sure about accelerating carb varnishing, i haven't run into that?