Scooter performance in cold weather

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robby
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Scooter performance in cold weather

Post by robby »

Winter is almost here and I notice that my scoot struggles when it gets cold. When I first start it, it actually pushes hard enough at idle to move forward (albeit very slowly) - for about a minute. However, as soon as I get out of the garage and sit at a light in the cold, it gets much quieter, and I have to rev it a couple times to stop it from stalling out.

I know that in large part this is just the physics of a 2-stroke engine out in the cold, but is there anything I can do to help it? I assume it's not running very efficiently in this state. Ventilation isn't the greatest in our garage so running it idle for a while isn't very practical.

My scoot is a Roughhouse 50, but I'm asking here because it's more of a general question.
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Kaos
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Post by Kaos »

That usually means that your carb has leaned out due to the denser cold air.
Unless its a REALLY extreme temperature change, you should be fine with just readjusting the idle mixture screw on the carb.
robby
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Post by robby »

Good to know, thanks. I do ride this thing in New England winters. I've never measured but I would guess that on bad days we're talking high single digits. Is there any good answer for those extreme days or am I just trying to do something that wasn't made to be done?
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Kaos
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Post by Kaos »

robby wrote:Good to know, thanks. I do ride this thing in New England winters. I've never measured but I would guess that on bad days we're talking high single digits. Is there any good answer for those extreme days or am I just trying to do something that wasn't made to be done?
You can do it. I've ridden my Buddy down to 6 degrees before. I usually have to tune the carbs on my bikes around December because they're starting to run rough and stall out on me. A quick mixture adjustment and they're good to go for the winter.
robby
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Post by robby »

Awesome, thanks. May ask more detailed follow-up questions when I get around to doing it if ya don't mind.
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Kaos
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Post by Kaos »

robby wrote:Awesome, thanks. May ask more detailed follow-up questions when I get around to doing it if ya don't mind.
Sure, not a problem :)
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Post by mukaiboston »

Hey, I don't know if the two-stroke Buddys have weird idles. After adjusting mine while the engine was running and not hearing any change in RPMs, I took it to the mechanic.

He adjusted it and said it was fine but that it was a bit odd we couldn't hear the rpms chance.

It's an odd problem but if anyone else has this issue, the scooter is not broken, you just have to keep fiddling with it.
islatron
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Post by islatron »

Having a similar issue with my 4 month old Buddy 50, now that the weather has gotten significantly colder (20 to 30 degrees in the mornings). Starts up just fine but initially revs very high and then drops extremely low. Trying to accelerate causes it to stall out. I let it sit for a couple minutes to warm up when this happens, and it seems to help somewhat, but it will go on to accelerate really randomly - sometimes it zips away as usual but sometimes it just kinda sits there for a while and then accelerates rapidly. This is unnerving because I can't predict when it will happen and other cars seem to not appreciate waiting at a green light while I frantically attempt to get moving.

Obviously a new scoot owner here so any advice would be appreciated!
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Post by mukaiboston »

Islatron,

Shouldn't be a big deal. The high revving is just the automatic choke but you need to readjust the idle for cold weather to send more fuel to the engine. It's normal to have to do this when the weather changes.

Look for a small black knob above the gear box on the right near the air filter and slowly turn it clockwise while the engine is running. The rear tire will eventually start spinning, then turn the knob counter-clockwise just until the wheel stops moving. Or you can leave it a little high if you are worried about the engine stalling.

When the weather gets warm next year, you will have to turn the knob down as the hotter weather will cause the engine to rev too much. You will have the opposite issue.
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craftynerd
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Post by craftynerd »

mukaiboston wrote:Islatron,

Shouldn't be a big deal. The high revving is just the automatic choke but you need to readjust the idle for cold weather to send more fuel to the engine. It's normal to have to do this when the weather changes.

Look for a small black knob above the gear box on the right near the air filter and slowly turn it clockwise while the engine is running. The rear tire will eventually start spinning, then turn the knob counter-clockwise just until the wheel stops moving. Or you can leave it a little high if you are worried about the engine stalling.

When the weather gets warm next year, you will have to turn the knob down as the hotter weather will cause the engine to rev too much. You will have the opposite issue.
I wish I'd known about this last winter! I had the same issues with high revving and then dropping to nearly nothing, and stalling when I'd give my Buddy some gas - it was my first winter with a two stroke, and I thought that was how they behaved in the cold. Good to know it's something that can be adjusted! :)
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kooky scientist
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Post by kooky scientist »

On really cold days, you may have to take the gas cap off to start it. I've ridden all year for the past 6 winters and always get around on my buddies and roughouses.
TVB

Post by TVB »

craftynerd wrote:I wish I'd known about this last winter! I had the same issues with high revving and then dropping to nearly nothing, and stalling when I'd give my Buddy some gas - it was my first winter with a two stroke, and I thought that was how they behaved in the cold. Good to know it's something that can be adjusted! :)
Yeah, especially with winter riding, where you may have slippery road conditions to be look out for, you don't want the added distraction of revving the engine to keep it running.
Stinkdyr
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Post by Stinkdyr »

Ok, so that black knob is the Idle Adjustment. Where exactly is the air/fuel mixture screw? How do you get at it? I can't see it from the side of my RH50. (I can see the idle knob easily).
Last edited by Stinkdyr on Sun Jan 11, 2015 1:28 pm, edited 1 time in total.
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skully93
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Post by skully93 »

On the Buddy the Air/Fuel screw is on the left side of the carb.
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Stinkdyr
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Post by Stinkdyr »

skully93 wrote:On the Buddy the Air/Fuel screw is on the left side of the carb.
By left side, do you mean the air filter side of the carb? So, you don't have to remove the seat/bucket or air filter to get at the air/fuel mix adjustment screw? Does a regular size screwdriver work ok? Do I need a bent one, or really short one to reach the screw?
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Post by Stinkdyr »

Ok, so the answer to these Q's: On my 2009 RH50 carb: The gold colored air/fuel mix adjustment screw is located beside the black idle adjuster knob, but on the inboard side of the knob. So, you need to pull off the seat and storage bucket to gain good access to the gold screw. In my case, the shop that serviced this bike for the previous owner must have snapped off the head of the screw, and then kindly neglected to replace the frozen broken screw before returning it to the owner! (or, do they whack off the top of the screw at the factory to prevent owners from adjusting their carbs for enviro reasons?)

:evil:

Here is an accurate pic of the gold screw location. The yellow cover you see is the air intake port that connects to your air filter box on the left outside of your scooter as you sit on your bike.

http://tinyurl.com/lacq4aj


My goal is to try to richen the air fuel mix. Since I can't use the gold screw (until I get around to pulling out the carb to drill it out and replace it, I will instead try to adjust the height of the main jet slide needle. Wish me luck!
Last edited by Stinkdyr on Sat Jan 24, 2015 10:46 pm, edited 1 time in total.
Stinkdyr
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Post by Stinkdyr »

I tried to adjust the main jet slide needle, but it is clear that the manufacturer did not want this to be an option. Whatever that off-white triangular shaped plastic retainer thing (valve plate it is called in parts diagram) is that holds the needle in place, and however it is installed and possibly removed....it ain't easy. It is clear when you get in there, that the needle is not supposed to be adjusted up or down.

So, my only course of action left is to upjet the main jet. Will do that after I order some jets.
islatron
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Post by islatron »

Thanks everyone who offered tips to dealing with this last year.

I did end up turning up the idle and it seemed to help a little bit, but I was still randomly stalling out in intersections and at stop lights. So I took it into the shop I bought it from (it was still under warranty) and they had it for 6 weeks... eventually told me there was a leaky seal which they fixed.

But apparently not, because now the issue is back and if anything, worse than last winter. Which is sad, because I had a wonderful summer of scooting. I'm going to try to adjust the idle again, but does anyone have any other suggestions? I'm hesitant to take it back into the shop since I assume it will be there for at least a month, it's no longer under warranty, and I need it to get to work (no parking at my building for cars).


Edit to add some more details on what's happening. This morning was the first "cold" morning I've tried to use my scoot (about 30 degrees). One day last week it was around 40 degrees and I noticed it was being a little sluggish (I'd try to accelerate and there would be a slight but noticeable pause before it moved off). So, I had an idea this morning might go badly and I started up my scoot in my driveway, thinking I'd leave it running for a bit to warm up before leaving. It ran for about 2 minutes before shutting off on its own. I tried to go out and start it again, it wouldn't start. Left it for about 5 minutes, finished getting ready and when I went back outside, it started up okay. I went down my street alright but when I got to a stop sign, RMPs dropped really really low and trying to accelerate only made it worse. Eventually got it going again, but it did this 3 more times on the 15 minute drive to work. It finally seemed to be running okay right when I pulled up to my building, so it requires a very thorough warm up before it stops happening.
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skully93
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Post by skully93 »

It really does seem like the idle and fuel mix is off. Since we have such drastic temp differences, I have to adjust ours every late Fall and early Spring.

There will be some hesitancy on the part of the bike when it's truly cold, but it shouldn't need too much warming up. Usually start it, put on my gear and store my stuff, then roll it out, shut my gate, etc. only a couple of minutes, but it's generally functional by then. After a few blocks it should perform pretty well.

Low idle, it'll die repeatedly unless you feather the throttle. With the air leak, it sounds like something else could be amiss.

How recent is the service on it?
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islatron
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Post by islatron »

skully93 wrote:It really does seem like the idle and fuel mix is off. Since we have such drastic temp differences, I have to adjust ours every late Fall and early Spring.

There will be some hesitancy on the part of the bike when it's truly cold, but it shouldn't need too much warming up. Usually start it, put on my gear and store my stuff, then roll it out, shut my gate, etc. only a couple of minutes, but it's generally functional by then. After a few blocks it should perform pretty well.

Low idle, it'll die repeatedly unless you feather the throttle. With the air leak, it sounds like something else could be amiss.

How recent is the service on it?
It has 900 miles right now, it had ~450 when I took it in last spring and they "fixed" the air leak. I got it back from them right around when the weather warmed up again, and it ran flawlessly throughout the summer.

Do you think it's worth messing with the air/fuel mix? I've only tried adjusting the idle. I'm not super mechanically intelligent so I don't want to mess anything up, but then again, it's barely rideable as is.
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