KymcoForum.com
Scooters - 125 to 300 => Bet & Win 250 => Topic started by: OGBillyT63 on January 29, 2014, 11:43:36 PM
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Can anyone tell me the correct size jets for a 2006 Kymco Bet and Win 250. Mine has a 35 slow jet and a 102 main jet. I have seen specs that say 38 for the slow jet and 108 for the main jet. So what size should they be?
Thanks all.
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The official service manual says 38 slow jet and 108 main jet. That sounds like one size up for both jets from what you're using now. Are you at higher altitude?
Is your Bet and Win 250 running just fine?
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I live near Valley Forge PA so I don't think altitude is a issue. I bought it used , Dec 2013 . I was having problems with stalling out when coming to a stop and and some hesitation on initial throttle up so I took the carb apart for cleaning thinking that could be the issue. While cleaning I looked at the jet sizes and discovered that they were different than those seen in several specs. Could that difference in jet sizes be an issue? After reinstall I am still having same issues. My next steps are to check bystarter then valve clearances and cylinder compression.
Thanks
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I have a two brothers cf250 on my bike I am using 38 slow and 125 main but I haven't put on a breather filter yet my bike came with a 35 and a very small 102
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So rice10562, What do you mean by two brothers cf250? How did your bet and win 250 run with the smaller jets ? I haven't tried mine with larger jets yet. How did you end up with using a 125 main jet and how does it run with that set up?
Thanks
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Did everything else check out okay on your bike? My Bet and Win 250 had 16000 km when I sold it. Never had any running issues, but it was my daily commuter. Throttle very crisp, hardly any warmup time. For all I know, it might have come with the smaller jets.
Check all hoses and connections in case you have a vacuum leak making you run lean? I can send you the service manual if you need a copy.
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So far I have put the 38 pilot and the 108 on the main jet after another carb cleaning and checked the bystarter which checks out OK hooked up to my battery and on the carb . I also drained the gas it came with and filled the tank up with 93 octane gas. The bike is outside with a cover on it surrounded by snow and I have not had a decent warm day here to reinstall the carb to check the newer jets, so once I do that I'll see how it runs and if I still have a problem I'll go on to checking out for vaccum leaks, then valve settings and then cylinder compression. .I do have a service manual. I will keep you posted.
Thanks again all!
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The exhaust I have on it is this one Honda CRF250R V.A.L.Eâ„¢ Slip-On Exhaust Systems: made by twobrohers they usually go in ninja 250 bikes but I got a sweet deal on a used one so i cut the original exhaust off made a bracket slipped it on the exhaust manifold then tested for back pressure then I welded it on since it is a bigger exhaust I needed more gas on high end for it to run right with out being to lean once I change the air filer to a breather filter I might have to up jet again
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After reinstall of carb with 38 slow jet and 108 main jet , new irridium dr7iex-9 ngk plug, new gas ,new fuel filter, I started my scooter up today. After adjusting the idle knob and idle mixture screw I got it to keep running . After warm up I pulled the plug that i just installed which was sooty on the end . I then checked the compression with WOT and cranking it over where it reached 180 on the gauge, which seemed good to me. I reinstalled the same plug after wiping off some of the soot and restarted and turned the mixture screw in thinking that it should lean it out some and as I turned the screw clockwise it did'nt change how it ran. There is no hesitation when throttling up, but sometimes acts like it is going to stall out at sitting idle. I have not had it out on the road yet for a run, so all my tests have been with the scoot on its stand. Still need to check for vacuum leaks, but a vacuum leak would make it run lean , right?
Thanks all.
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I think the service manual suggests an idle mixture screw setting of 1/2 to 1/4 turns out from fully seated when used with the #38 pilot jet. Start there.
If 1/4 turns out is still too rich, then go back to the #35 pilot jet and start with 1.5 turns out, adjusting up to 1/2 turn more inwards if too rich or 1/2 turn more outwards if too lean. Use how well the bike takes to throttle as your indicator. Slow to return to idle, slow to rev up or high idle after revving = too lean; too fast of a rev drop or stumbling idle = too rich.
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Today I took all the air side apart ( air cleaner , the tube and air box that runs from the front to the air cleaner compartment , the oil evaporater tube coming off the valve cover, drip tube form that tube),. When I took the air box off which sits up front there was evidence of a mouse nest ( pieces of fabric , wood shavings etc, which one mechanic found in the air cleaner compartment right after I bought it . So the mouse went into that compartment , then through the 1 1/4 inch dia tube , then through the air box and built a nest in front of that. I figured I would check the bystarter so I took it off and measured the length of the plunger before warmup. After all that I started it up with out the air cleaner in and the other tubes off and it started up fine, so I reinstalled all the air air cleaner system and it seemed to run ok still. I was going to take the bystarter off to remeasure after warm up , but could not pull it all the way out, which I assumed meant that the plunger went down as it was supposed to do, so I re installed. I then rechecked the mix screw and found that I could turn in some more from where it was and after turning in I found that it did change how it ran . I now have it at at about 3/4 to 1 turn out from seating and it seems to be running ok now, but I need to take it out on the road once the snow an ice are off the roads to see how it performs .
Thanks again!!
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Update on carburetor on my 06 Bet and Win 250.
I found a manual choke to replace the electric bystarter and installed it and finally had some warmer weather to take it for a run. I found that the scooter runs great with the 38 slow jet and 108 main jet with the choke is still engaged. However if I push the choke cable all the way in even after warm up it will stall out . I'm thinking this could be a sign that the idle mixture screw is not working properly, especially since after seating the screw and backing it out 1to almost 4turns doesn't seem to change the idle and I think the fuel should be coming from idle mix screw after the choke if shut off , so hopefully that will clear up after some riding. If not I'll take the carb apart and make sure the idle mix line is clear and see if it changes anything . So for now I'm adjusting the choke as I ride.
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It sounds like the idle circuit on your carb is still plugged somewhere. You may have to clear the passages that the pilot jet and the idle mixture screw sit in. Try some compressed air.
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Update: Since I last posted I put seafoam in my gas tank and adjusted the manual choke that i installed as I rode in hopes that the idle mixture circuit would clear up eventually. So today I went for a long run and when I got back I pushed the choke all the way in to see if it would idle and not stall out. To my surprise it kept running at idle while just sitting on the stand, so I'm thinking it is at least starting to clear up. Kinda made my day 8).
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... So what size should they be?
My 2005 GV uses 38 / 102. Due to a hesitation resulting from a clogged passages as a result of sitting I experimented with different jets.
Increased the pilot jet to #48 seems to get rid of the hesitation completely. I set the pilot screw mixture set 1 1/2 turns out.
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2005 GV my oem Keihin CVK30 has 38S / 102 stamped in to each jet. Due to a hesitation that I have not been able to fully get rid of even after 5+ cleanings (improved but not gone) I experimented with different jets from jetsrus and found that increasing the pilot jet to #52 seems to get rid of the hesitation completely. #58 was too big and seemed to result in an overly rich mixture and smell from the exhaust. #42 was not enough of an increase over stock. Also, I have the pilot screw mixture set 3 turns out.
Sounds like your idle circuit is not working.I'd pull, and Completely break down the carb. Spray Carb Clean thru ALL the ports, ans go back to the OEM jet.
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There you are... I replied to the post in the other thread.
Fantastic Post!!! Well done sir!
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You all have gotten way too good at helping people here. Now I have to step it up, and get rid of this little Chinese kid that types for me.
I'm keeping the Irish one that gets my beer tho.
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The correct Fuel screw setting for almost any of the CVK carbs is 2-1/2 turns out. And I think a few of you have it backwards, on the CVK carb the "air/ fuel" screw is actually a fuel screw, clockwise leans the mixture out, anti-clockwise makes for a richer mixture. Base setting should be 2-1/2 then adjust from there for best idle and throttle response.
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Spot on.
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Update on my 2006 B&W . I have now been running my scoot up to this date with just the use of manual choke that Iinstalled in place of the bystarter and it has worked out great so far. So my question , does the bystarter circuit and idle circuit feed into basically the same main passage in the carb and if so why can't I just leave it the way it is and just open the manual choke just enough to keep it at idle and set the idle mix screw at 1/2 turn essentially bypassing the clogged idle circuit altogether?
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I recommend watching my carb videos. They will show you exactly what to do to get the carb back to oem original condition and you can put the auto bystarter back on. To answer your question - choke passage is separate from the pilot jet / idle screw circuit.
Kymco Grandvista / Grand Dink / Bet & Win:
http://youtu.be/uE3d9QI2m2Y (http://youtu.be/uE3d9QI2m2Y)
Carburetor Cleaning & Theory three part series:
http://youtu.be/w4vW4zh8g0Q (http://youtu.be/w4vW4zh8g0Q)
http://youtu.be/ig0qHhdxJFE (http://youtu.be/ig0qHhdxJFE)
http://youtu.be/EjCmiZ5xoeU (http://youtu.be/EjCmiZ5xoeU)
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Thanks mrbios for the info.
OK , I took the carb off once again and I drilled out the brass plug and ran a thin wire (very thin wire ) through to where I could see it in the pilot jet hole along with spraying with carb cleaner so hopefully this will clear the idle circuit as you showed in your video . One question though , What is the charcoal canister purging that I saw on the close up of the carb openings in video 3 ? Is this something I need to do or just clean everything out with the cleaner and then blow it all out with compressed air? ???
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Thanks mrbios for the info.
OK , I took the carb off once again and I drilled out the brass plug and ran a thin wire (very thin wire ) through to where I could see it in the pilot jet hole along with spraying with carb cleaner so hopefully this will clear the idle circuit as you showed in your video . One question though , What is the charcoal canister purging that I saw on the close up of the carb openings in video 3 ? Is this something I need to do or just clean everything out with the cleaner and then blow it all out with compressed air? ???
Your welcome OGBilly! Glad you made use of the videos. Yes you are right to descirbe the wire as a "very thin wire" I think the passage is too small and makes the carb prone to clogging if the scooter sits. The set of 4 carbs in the video the passage is about 5x as wide as our scoots making cleaning easier.
Charcoal canister purge - No need to clean it. it works the same as all cars (carb & fuel injected). Basically, the EPA does not allow the vapor from warm / hot gasoline after the car / scooter is run and then parked to vent to the atmosphere. So the vapors vent to the charcoal canister. Once the motor is started a valve allows clean air to enter the canister and get sucked into the carb / motor to be consumed by the motor. It is important that the vacuum line leading from the canister to the carb be sealed - no leaks and if it is disconnected then the carb hose connection must be capped off. So just treat it the same as any other vacuum lines - no leaks as leaks lead to lean burn.
Pilot jet: After fully applying the cleaning methods in the videos I reinstalled my original pilot jet #38 and the scooter worked fine and no longer felt like it wanted to stall on take off (especially when cold). However, I feel the scooter benefits from a larger pilot jet because it provides smoother off-idle hesitation-free acceleration. So I recommend purchasing a few sizes from an aftermarket vendor such as #42, #45, #48. I currently running #48? and thinking about cutting back to #45. Mid range feels much stronger and fuel economy might be reduced by 1 or 2 mpg not sure. I tried increasing the main jet but decided #102 (stock size) is best and there is noting to be gained.
Please continue to post results and I hope you get your scoot running great like mine is. I just passed 14K miles.
Paul
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Your welcome OGBilly! Glad you made use of the videos. Yes you are right to descirbe the wire as a "very thin wire" I think the passage is too small and makes the carb prone to clogging if the scooter sits. The set of 4 carbs in the video the passage is about 5x as wide as our scoots making cleaning easier.
Charcoal canister purge - No need to clean it. it works the same as all cars (carb & fuel injected). Basically, the EPA does not allow the vapor from warm / hot gasoline after the car / scooter is run and then parked to vent to the atmosphere. So the vapors vent to the charcoal canister. Once the motor is started a valve allows clean air to enter the canister and get sucked into the carb / motor to be consumed by the motor. It is important that the vacuum line leading from the canister to the carb be sealed - no leaks and if it is disconnected then the carb hose connection must be capped off. So just treat it the same as any other vacuum lines - no leaks as leaks lead to lean burn.
Pilot jet: After fully applying the cleaning methods in the videos I reinstalled my original pilot jet #38 and the scooter worked fine and no longer felt like it wanted to stall on take off (especially when cold). However, I feel the scooter benefits from a larger pilot jet because it provides smoother off-idle hesitation-free acceleration. So I recommend purchasing a few sizes from an aftermarket vendor such as #42, #45, #48. I currently running #48? and thinking about cutting back to #45. Mid range feels much stronger and fuel economy might be reduced by 1 or 2 mpg not sure. I tried increasing the main jet but decided #102 (stock size) is best and there is noting to be gained.
Please continue to post results and I hope you get your scoot running great like mine is. I just passed 14K miles.
Paul
Better yet, rip that cheap emissions system off!!!!!!!!!
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After watching Paul C 's you tube video about different levels of cleaning carburetorsi I decided to drill out the brass plug which gave me access to thoroughly clean the idle circuit with the use of a very thin wire. I put the carb back together and plugged the hole I made with JB Weld and let it set for a day and then reinstalled the carb. I started up the scoot and got it warmed up and then pushed the manual choke all the way down essentially stopping the choke circuit, and to my delight it didn't stall out as in the past. So once again thanks for your help Paul C.. I'm still running with the 38 slow jet for now ,but I may experiment with larger slow jets later. The idle screw is now at 2-1/2 and it seems to be happy there. Also checked my valve clearances since I had the seat off and set them at .1 mm . So I ordered a new bystarter since I broke the original trying to get it out of the socket when the brass plunger stuck in the hole so the only way to get it out was to pull on it when the plastic parts fell apart. ;).
Thanks all for your help.
OGBillyT63
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Thanks all for your help.
OGBillyT63
Your very welcome. ;D
I went through all the same stuff and I stumbled on the idea of drilling the pilot jet plug for direct access. Want to share it with my fellow scoot enthusiasts to show that carbs still work great and the problems with them can be put to bed once and for all. When the "lambs stop screaming" (silence of the lambs movie) you many want to bump up the pilot jet in time - you will be very surprised how nicely it improves off idle and early mid range power. But the most important problem is solved and all with the best performing stock / oem parts. No dangerous lean burn and endlessly aggravation off idle hesitation. For me it has been about 2.5K miles and not a single hesitation.
Long live our affordable and dependable Kymco scoots! :)
-Paul