Modern Buddy

Hello,
Bought a used Buddy 125, appears stock, about 2300 miles on it. It runs good from 0-50% throttle opening, but 50%-100% throttle opening there is a "dead spot". Yes, I know it shouldn't be rode at full throttle, but I don't think it's supposed to be more sluggish at 50% than at 25%. I played with the air screw a bit, and it seemed to be set about right. I checked the plug and it looks normal, not overly white OR dark.

I know that with my dirt bike experience, 50%-100% throttle issues are usually a main jet change.

1) Is a "boggy" open throttle a sign of too rich or too lean on the main?
2) Are these bikes particularly sensitive to temps? In other words, it's been in the 50's - will this bike likely run fine when it's 70 or 80?
3) Is there a standard jet size that you guys run on stock 125's?

The buddy should run fine in any temperature really. I've ridden down in the 20's, up into the 90's. It runs the same for me hot or cold without any adjustment of the idle, air/fuel, or jet.

It's possible you may need to upjet due to the elevation you live in. Certain people have done this for their bike to run properly.

Congrats on your new ride.
Before you go diving into jet changes (you shouldn't need to if the Buddy is stock), check the air filter, fuel filter and float bowl. If any of those is overly dirty, your engine will run as you describe.

The air filter appeared fine, but I've not checked the fuel filter or float bowl. I'll check them out and go from there. Thanks!

Altitude 1000', by the way.

Some do seem to need to up the idle a little when the temps drop. Mine runs fine at cold temps, but I know that is not always true for everyone.

Also full throttle should be fine. If you search around on the site you will find some posts from those that run WOT (wide open throttle) almost consistently.

Also, check your variator weights. they can cause a flat spot that can feel like a misadjusted carb.

To answer your other questions:
Bogging is a sign that you're running too rich at take off.
The stock Buddy jet is a K92, though they usually run better with a K95.

Yeah, I wondered about the variator weights. I need to look into that. It looks like maybe I should upgrade to the Dr. Pulley sliders anyway (?).

And thanks for the input on the main jet!

If you're thinking of making the switch, I give the DP sliders a big thumbs up...

50-100% throttle sounds like it could also be a dirty needle. A good over all carb cleaning should help or just ride the hell out of it for a few tanks of gas.

djelliott wrote:50-100% throttle sounds like it could also be a dirty needle. A good over all carb cleaning should help or just ride the hell out of it for a few tanks of gas.

+1 and +Seafoam.

Don't do a million things at once. Used scooters sit, that's why they get sold.
Does "I just didn't end up riding it as much as I though" or "I rode it all the time until I found X" sound familiar?

Unused carbs have ethanol based gunk that clogs up the tiny openings in the fuel system. A good run down of the scoot with some good fuel cleaner and it'll probably run as good as new.

Sounds like a plugged carb to me. If the bike was otherwise stock, it makes no sense that somebody would change jets, and no sense that the bike would need different jetting.

Stock jetting should make the bike run perfectly fine with no hesitation (although you may see more power from a lean jet change) up to at least 8500 feet or so.

I would take the carb off and blow out the passages, make sure the needle and seat operate smoothly and the like. These carbs are pretty simple and should run ok unless they are plugged up.

Anachronism wrote:Sounds like a plugged carb to me.

^^^This.^^^

Was the scooter sitting for a while before the previous owner sold it? If so, it most likely has some residue from the old gasoline that jelled up inside the main jet.

This is a pretty common thing when one of these vehicles sits for a good length of time.

As Anachronism said, give the carb a good cleaning, and spray some carb cleaner through the main jet and/or some compressed air to get any crud out of it. Be careful about using any kind of wire to scrape/clean out the hole, as the jets are made of really soft metal and pretty much anything put in there can enlarge that hole (possibly making another issue altogether.)

I'm guessing that if there's sludge in there, that's the issue.

Careful taking any of the screws out. There made of butter. Maximum down force, minimal turning force.

djelliott wrote: or just ride the hell out of it for a few tanks of gas.

For a minor issue, adding a detergent additive and riding could help, but for something this pronounced, I really wouldn't suggest this. If the carb is out of whack so far that it won't run at WOT, riding it more like this can sieze or hole a piston.

Just realized another possibility. How is your battery? If the battery is flat, you can see upper RPM problems. If the battery is too dead to run the starter, give it a full charge before going further.

Anachronism wrote:

djelliott wrote: or just ride the hell out of it for a few tanks of gas.

For a minor issue, adding a detergent additive and riding could help, but for something this pronounced, I really wouldn't suggest this. If the carb is out of whack so far that it won't run at WOT, riding it more like this can sieze or hole a piston.

Just realized another possibility. How is your battery? If the battery is flat, you can see upper RPM problems. If the battery is too dead to run the starter, give it a full charge before going further.

You'd be amazed at the healing power of a few fresh tanks of gas on a bike that has sat for awhile. Even without detergent.

Not disputing that, but with a major carburetion issue, you can blow the motor before you clean the carb.

Anachronism wrote:Not disputing that, but with a major carburetion issue, you can blow the motor before you clean the carb.

I'd agree with that on a two stroke but it'd take some effort on a four.

i didn't read through all the posts..

are you using premo gas? made a huge difference in my new scoot. i was running the unleaded low grade and the dealer put some gas crack in my tank and it was bringing to life my 125 cc worth of scooter.