Buddy 125 w/ mixture screw all the way in

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vdubclub74
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Buddy 125 w/ mixture screw all the way in

Post by vdubclub74 »

Hey, y’all. Runs okay, but not right.

Crashed it, parked it for six months.
Wouldn’t start. Gas in in oil.
Changed oil/filter. Drained gas, replaced fuel filter, cleaned carb,
Started. Tried to tune in. Seems to run best with mixture screw all the way in.
Boggs on slight throttle and full throttle from stop.
Dip stick still smells like gas.

Vacuum leaks? Float valve?

Any of this sound familiar?

Thanks!
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babblefish
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Post by babblefish »

With the mixture screw turned all the way in, you've got the idle mixture set for maximum richness. Maybe that's where the fuel in the oil is coming from. The factory setting for the mixture screw is 1.5 turns out from closed.
The float level setting may have been changed after your crash. Perhaps the fuel level in the float bowl is too high which can cause flooding. Check that too.
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vdubclub74
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Post by vdubclub74 »

Thanks for your reply. In another thread, you said “turning it clockwise would lean the mixture.� This is what I’ve been assuming.
I’ll look into the float as well.
vdubclub74
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Post by vdubclub74 »

Took the carb out and poked around.

One of the jets was mostly clogged. Swapped it with another and that fixed the hesitation.

Looked at the float level (looked about right) and tested it by blowing into the fuel inlet tube while engaging/disengaging the float valve. Seemed to be working.

Mixture screw is now one turn out. Any further out and the idle seems to be too high, spinning the wheel. This seems wrong. Maybe compensating for a rich condition? (Still assuming IN is lean and OUT is rich)

I’ll probably change the oil again and see if it still smells like gas. Anyone had trouble getting rid of that smell?

It’s running pretty well, but I’m still a little concerned about gas in the oil. Is the float valve the only cause of this?

Thanks y’all.
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tenders
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Post by tenders »

Assuming the cause of the gas in the oil has been remediated, there are two problems with gas remaining in the oil: (1) the oil becomes thinner than it should be, and (2) if the oil level is too high it will end up in a lot of places it shouldn't be.

(I don't believe "unexpected ignition" is a particular concern with gas in the oil, and I have often wondered if a small amount of gas in the oil simply evaporates itself out when the oil gets hot.)

For a couple of bucks, why not change the oil again. I use a Topsider hand-vacuum pump with all of my small engines, which removes the vast majority of the oil through the dipstick hole without spilling a drop. You could do something like this and not have to mess with the filter or drain bolt this time around.

Then, measure the new oil's level very carefully on the dipstick and see if the level rises over time.
buddys_n_blasters
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Post by buddys_n_blasters »

vdubclub74 wrote:Took the carb out and poked around.

Mixture screw is now one turn out. Any further out and the idle seems to be too high, spinning the wheel. This seems wrong. Maybe compensating for a rich condition? (Still assuming IN is lean and OUT is rich) l.
Couple things:

1) There should be a thumb screw idle adjustment. Don't try to adjust your idle using the air/fuel mixture screw.

2) I'm pretty sure screwing the air/fuel mixture in leads to a rich condition, as it is an "air" screw, and screwing it in blocks the hole for air (at least that's what I thought, correct me if I'm wrong, people)

3) If that is true, and your bike only runs when the screw is in (air is supposed to be cut off but isn't), I would bet you have an air leak somewhere. It's like you're compensating for a leak by blocking the airscrew. Maybe check to see your air filter is in correctly and the housing is on tight?
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babblefish
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Post by babblefish »

What buddys_n_blasters said.

The IDLE MIXTURE SCREW is to adjust the fuel mixture from idle to about 1/4 throttle. It is NOT used for adjusting idle speed. Idle speed is adjusted via a screw that is part of the throttle linkage on the carb. It has a small spring on it to keep tension and is located on the linkage where the throttle cable attaches to the carb. Final idle speed should be adjusted AFTER the correct idle mixture adjustment is done with the IDLE MIXTURE SCREW.

As was already said, the IDLE MIXTURE SCREW adjusts the amount of AIR that gets mixed with the fuel so turning it IN or closing it down reduces the amount of air in the mixture which in turn makes for a RICHER (more fuel) idle mixture.

Procedure for adjusting IDLE MIXTURE SCREW:

1) Put the scooter up on it's center stand (not kick stand).

2) Turn IDLE MIXTURE SCREW all the way in (CW) until it just bottoms out. Don't tighten! Then back it out 1.5 turns.

3) Start the engine and let it warm up for about five minutes. You MUST let the engine warm up to make sure it is not running on the auto-choke.

4) Adjust the IDLE SPEED SCREW until the engine is between 1600 and 1800 RPM. Just slow enough to not die but not so fast that the clutch starts to engage and the rear wheel starts to spin.

5) Adjust the IDLE MIXTURE SCREW in and out until you achieve the highest idle speed. You may or may not have to adjust the IDLE SPEED SCREW a little to keep the rear wheel from spinning too fast. My experience is you'll be turning it in to accomplish this. Probably around 1/4 turn or there abouts. YMMV.

6) Now adjust the IDLE SPEED SCREW for around 1700 RPM +/-100 RPM. The Buddy doesn't have a Tach so adjust the idle speed just below where the rear wheel wants to spin.

Blowing into the fuel inlet does not give any indication of correct float level or float needle operation. Not sure where you got that information.
The attached picture shows where to check the float level and how high it should be: 18mm, +/- 0.5mm
The picture is kind of screwy. The float level should be checked while holding the carb upside down with the float facing up. Make sure the needle valve is in it's correct position too.
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lovemysan
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Post by lovemysan »

Blowing into the fuel inlet will tell you if you have a major problem with the needle and seat. It will not tell you if you have a slow sleeping leak. If the bike has been sitting I would pull the vacuum line off going to the petcock and exercise the diaphragm by blowing and sucking a few times. Even the new ones require this sometimes. Don’t blow too hard you can damage it. If you think the carb is still overflowing park the nose of the scooter uphill and and the overflow will drain out the air box till you get it fixed. I’d use cheap oil to flush it out.
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DeeDee
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Post by DeeDee »

babblefish wrote:What buddys_n_blasters said.

The IDLE MIXTURE SCREW is to adjust the fuel mixture from idle to about 1/4 throttle. It is NOT used for adjusting idle speed. Idle speed is adjusted via a screw that is part of the throttle linkage on the carb. It has a small spring on it to keep tension and is located on the linkage where the throttle cable attaches to the carb. Final idle speed should be adjusted AFTER the correct idle mixture adjustment is done with the IDLE MIXTURE SCREW.

As was already said, the IDLE MIXTURE SCREW adjusts the amount of AIR that gets mixed with the fuel so turning it IN or closing it down reduces the amount of air in the mixture which in turn makes for a RICHER (more fuel) idle mixture.

Procedure for adjusting IDLE MIXTURE SCREW:

1) Put the scooter up on it's center stand (not kick stand).

2) Turn IDLE MIXTURE SCREW all the way in (CW) until it just bottoms out. Don't tighten! Then back it out 1.5 turns.

3) Start the engine and let it warm up for about five minutes. You MUST let the engine warm up to make sure it is not running on the auto-choke.

4) Adjust the IDLE SPEED SCREW until the engine is between 1600 and 1800 RPM. Just slow enough to not die but not so fast that the clutch starts to engage and the rear wheel starts to spin.

5) Adjust the IDLE MIXTURE SCREW in and out until you achieve the highest idle speed. You may or may not have to adjust the IDLE SPEED SCREW a little to keep the rear wheel from spinning too fast. My experience is you'll be turning it in to accomplish this. Probably around 1/4 turn or there abouts. YMMV.

6) Now adjust the IDLE SPEED SCREW for around 1700 RPM +/-100 RPM. The Buddy doesn't have a Tach so adjust the idle speed just below where the rear wheel wants to spin.

Blowing into the fuel inlet does not give any indication of correct float level or float needle operation. Not sure where you got that information.
The attached picture shows where to check the float level and how high it should be: 18mm, +/- 0.5mm
The picture is kind of screwy. The float level should be checked while holding the carb upside down with the float facing up. Make sure the needle valve is in it's correct position too.
Hey Wes, what do you do to adjust the float level? Do you bend the small tab the needle valve slips onto?
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babblefish
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Post by babblefish »

DeeDee wrote:
babblefish wrote:What buddys_n_blasters said.

The IDLE MIXTURE SCREW is to adjust the fuel mixture from idle to about 1/4 throttle. It is NOT used for adjusting idle speed. Idle speed is adjusted via a screw that is part of the throttle linkage on the carb. It has a small spring on it to keep tension and is located on the linkage where the throttle cable attaches to the carb. Final idle speed should be adjusted AFTER the correct idle mixture adjustment is done with the IDLE MIXTURE SCREW.

As was already said, the IDLE MIXTURE SCREW adjusts the amount of AIR that gets mixed with the fuel so turning it IN or closing it down reduces the amount of air in the mixture which in turn makes for a RICHER (more fuel) idle mixture.

Procedure for adjusting IDLE MIXTURE SCREW:

1) Put the scooter up on it's center stand (not kick stand).

2) Turn IDLE MIXTURE SCREW all the way in (CW) until it just bottoms out. Don't tighten! Then back it out 1.5 turns.

3) Start the engine and let it warm up for about five minutes. You MUST let the engine warm up to make sure it is not running on the auto-choke.

4) Adjust the IDLE SPEED SCREW until the engine is between 1600 and 1800 RPM. Just slow enough to not die but not so fast that the clutch starts to engage and the rear wheel starts to spin.

5) Adjust the IDLE MIXTURE SCREW in and out until you achieve the highest idle speed. You may or may not have to adjust the IDLE SPEED SCREW a little to keep the rear wheel from spinning too fast. My experience is you'll be turning it in to accomplish this. Probably around 1/4 turn or there abouts. YMMV.

6) Now adjust the IDLE SPEED SCREW for around 1700 RPM +/-100 RPM. The Buddy doesn't have a Tach so adjust the idle speed just below where the rear wheel wants to spin.

Blowing into the fuel inlet does not give any indication of correct float level or float needle operation. Not sure where you got that information.
The attached picture shows where to check the float level and how high it should be: 18mm, +/- 0.5mm
The picture is kind of screwy. The float level should be checked while holding the carb upside down with the float facing up. Make sure the needle valve is in it's correct position too.
Hey Wes, what do you do to adjust the float level? Do you bend the small tab the needle valve slips onto?
Yes, I bend the metal tab to wherever it needs to be. I've found though that the float level rarely if ever needs to be adjusted, at least on my scooters. I think the only time I've had to adjust the level was on my Blur with a 30mm carburetor that had to be installed rotated a few degrees because it was taller than the stock 24mm carb. The level was reset to stock after I made an adapter for the intake manifold that raised the carb enough so that it could be installed with the correct orientation.
Some people can break a crowbar in a sandbox.
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