If you find this adjustment inconclusive, just set it at 2 turns out; hard to go really wrong with that. You should also be aware that the engine can stumble at too lean a mixture. One old trick was to find the lean stumble point and the rich stumble point and set it halfway in between. In my opinion, rich is better on this carb because the idle mixture circuit always plays a part well into partial throttle. Rich runs cooler. Google "Care and Feeding of the Keihin Carb". Good reference!
I'm not sure why the recommendation there is for 3/4 - 1 turn out. That is pretty much how they come from the factory, and it is lean. the generally accepted rule of thumb is about 1 3/4 turn out for stock, roughly 2 1/4 turns out for aftermarket exhaust. Those are not exact numbers, but should be a very good improvement over stock.
Thank you so much, really helpful video! Not sure if this is the case for all but my 2016 didn't have a cap on the adjustment screw. With a Lexx exhaust and 2.5 turns out felt a little rich when shifting gears. Think i'll try what you recommended in the comments at 2 1/4. Overall, superb..big difference!!
Drilling the slide will improve throttle response a bit but won't do anything to the mixture, so if you don't want to do it there's no problem. Just put a washer or two under the needle and turn the screw out a couple turns. You should notice an improvement in first gear/second gear roll-ons. Nothing to removing and replacing the cables - just watch that choke cable!
I don't know, Juan. It depends on what else has been done. Two to two and a half turns out is probably in the ballpark, but it all depends on what the pipe is flowing and what intake mods have been done. You see, you can get to the point where you need a larger pilot jet to control the lean pop on decel. I have a very free pipe, a ported heat, and holes in the air box. I needed to go up a couple sizes on the pilot. Try the "cracking throttle" method below ans see where it takes you.
Probably not, with just the pipe. You can start at 1 1/2 and turn it out an 1/8 turn at a time, cracking the throttle each time. What you are trying to do is get the idle running as rich as possible. When cracking the throttle causes a stumble the mixture is too rich; back it off a bit until there is no stumble. Running rich at idle and part throttle should help to prevent decel popping. The engine needs to be fully warmed up for this adjustment.
Great video. When you are showing the outdoor portion of the video you have what looks like a brass thumbscrew in your idle mixture screw hole? Where can we get one of those for future adjustment?
Hi Rick - It's called the 'EZ-Just Mixture Screw' and it is made for Harley Davidson Sportsters that use the CV40 carb. John's Cycle Parts (www.johnscycleparts.com/store/index.php?route=product/category&path=20) has it, as does CV Performance (www.cv-performance.com/). They are about $20. Tom
carmela dominguez lo que está mal con su motor de arranque? Yo creo que debería ser un 'artículo de reemplazo ', no un 'elemento de servicio' a menos que tenga una buena tienda motor eléctrico cerca de usted. Debe retirar la cubierta izquierda para tomar los engranajes del eje, luego cuatro tornillos para quitar el motor de arranque del cárter. Tom
Thanks for the part 1 & 2 videos. I just completed this mod and got rid of the popping at deceleration completely. Woohoo!! But I'm still having a minor problem I was having before the mode: when I keep the bike at 5000 rpms steady (let's say highway cruising speed) i notice a bit of a surge/hesitation in power but when I open the throttle there is a response. If i choke it the hesitation disappears, what can that be?? Again thanks for taking the time to make these video series
Hi Orlando, It sounds like you are still a bit lean on the idle circuit. The idle circuit is active for a fair amount of the small throttle opening. When you are running at an easy 5000 RPM you are really using very little throttle. There are a couple of things things that should help. First, proper idle mixture tuning. There is a pretty tried-and-true method for finding the proper idle mixture that has been used for decades. I copied these words from cv-performance.com because they do as good a job of explaining this as anybody does. They sell the E-Z Adjust idle mixture needle. Good company. "The air cleaner assembly must be installed prior to starting the engine, not only to hold the carburetor in place but to prevent having the carburetor backfire in toward you while tuning. Start the engine as normal and bring up to operating temperature prior to fine tuning. Let the bike idle for no more than 5 minutes. With the engine warmed up and at idle you may now fine tune the idle mixture screw for optimal performance. Acquaint yourself with the adjustment screw location at the bottom rear of the carburetor prior to running the engine. You will need a small screw driver for adjusting the screw unless an EZ-Just has been installed. With the engine idling slow (no more than 900 rpm), turn the screw inward (clockwise) SLOWLY until the engine starts to stumble. You are working with the screw upside down so check to make sure you are turning the screw clockwise or inward. Note that not all engines will stumble or have an RPM change that is noticeable when twisting in the mixture screw. This can be due to the idle jet being too large, installed cams, or ignition systems such as those on Twin Cam 88's. If unable to find the low adjustment point where the idle slows, simply set the screw at 1-3/4 turns out and proceed to the next step. If the engine will not idle on its own during this procedure, adjust the idle set screw on the throttle side of the carburetor until it idles correctly. Now turn the mixture screw outwards (counter-clockwise) until the engine begins to run smoothly, then add 1/8 of a turn. Maintain proper idle speed and repeat the adjustment each time you adjust the idle speed. Blip the throttle a couple of times and observe the results. If the engine responds quickly with a smooth blast and no backfiring through the carburetor, you have your idle mixture right. If a hesitation occurs then adjust the idle mixture screw out another 1/8 turn. Normally, the mixture screw should only require 2 to 3 turns out from gently seated. Anything above 4 turns indicates the pilot jet is too small." Going from a #38 pilot jet to a #42 can really help in some installations, too. Finally, going to a KLX kit instead of the 22-cent will make a vast improvement in the overall air-fuel mixture across all throttle openings. The 22-cent is meant to be a quick and easy way to remedy the factory lean condition in the carb. The KLX is a more aggressive tuning method to improve bot AFR and power. Of course, it costs $50 instead of 22 cents... Tom
@Ian Ferrier, No, you don't. Sometimes you may find a need to fine-tune the KLX needle with one washer; doing so moves the needle by half a groove. Other than that, no. One is a poor man's bit of carburetor tuning and the other is a better approach though a mite spendy. If you don't mind spending $50 I recommend the KLX needle. Tom
great video.my son has a first gen klr 650. i was out visiting him over the weekend. he lives in san diego {sea level}. the bike has a super trapp muffler with stock pipe. it has a aftermarket air filter. i asked him if he has ever pulled the spark plug to check it out. he has owened the bike for 2 years now and has just changed the oil every 1000 miles and clean the air filter, tighten the chain and put gas in it and loves the bike.i pulled the plug and it was real real light in color. i ride a xr650r ,kx500,gsxr 1000 and a 79 bultaco 250 pursang. so i know what a hot plug looks like. i kinda freaked out seeing how hot it was burning. you think the 22 cent mod will help his bike out ? or any suggestions ? thanks
Buzz- KLRs come from the factory pretty lean; it's an emissions thing, I guess. What you are seeing is pretty normal. The 22 cent mod will richen the mixture a bit and take it from about 17:1 and get it closer to 15:1. With today's fuels that contain additive packages and ethanol the old "reading the plug" trick gets a little bit iffy, though. The SuperTrapp being on there is an unknown as far as what it's doing to the mixture. I found that the ST had to have 9 plates in it to flow as well as a stock pipe and was horribly loud. Depending on how many plates he has in it, it may be contributing to the lean condition. Intake and exhaust mods need to be balanced. He might be better served by installing a KLX needle. If he still has the stock exhaust can, a better exhaust mod than the ST is to open up the stock can, removing the baffle. If flows pretty well and isn't obnoxiously loud. All in, I'd say the 22 cent mod would be beneficial on his bike. Do it and check the plug. If it still looks lean, go for the KLX needle. Go down one jet size and start at the second clip from the top, then tune. Tom
thanks for posting the excellent how to. I just bought a 2012 klr and was thinking about this mod. I have an after market slip on and thats it. do i need to turn out the bottom screw 2 1/4 turns? great video, thanks again.
por favor donde va la manguera de combustible tiene dos lugares que van a la cuba del flotante una inferior (abajo) y otra de arriba, estuve mirando diferentes videos y en ninguno dice como van las mangueras , en la parte de atrás del carburador lleva una manguera al multiple y no la tiene se la anularon a mi moto yo quisiera saber donde va? ningún video de web dice paso a paso sobre las conexiones de carburador, al no saber en donde va la manguera de arriba se me complica, pues no soy mecánica y no estoy en condiciones de llevar al taller. ¿se puede remplazar el carburador por uno común de cortina normal? gracias.
Yo sé cómo se hacen las motos USA. Hay dos dimensiones de las mangueras del carburador. Una manguera va desde la válvula de combustible (grifo) hasta el codo de combustible del carburador. El codo es negro y en la parte inferior. Esto debe ser una manguera de combustible de 8 mm. Se va a la salida de combustible en la válvula de combustible. La otra manguera es una manguera de vacío. Es de 3 mm y va desde el tubo de latón en la parte frontal del carburador a la parte posterior de la válvula de combustible. Esto es para operar la válvula de combustible sólo cuando el motor está en marcha. Hay otra manguera de 8 mm que se adjunta al carburador. Debe ser una manguera transparente que se adhiere al codo gris en la parte superior del carburador. Es un respiradero. Yo sé que en Australia tienen más mangueras que proporcionan calor al carburador. Están conectados al radiador de alguna manera. Yo no sé nada de eso.
es factible reformarmar el carburador para que funcione solo con la cortina como las motos antiguas...esta el carburador muy manoseado y piden 100 dólares por la reforma y en Argentina son 1300$, se me ocurre reformar la cortina con un cable y quitar la mariposa trasera ¿podría funcionar? o colocar algún carburador de alguna moto vieja de unos 500 CC, por ejemplo.
carmela dominguez Es posible utilizar un carburador tracción directa como el Mikuni VM38 o algo similar. Eso sería más fácil que la conversión de la CVK40.
Hi there, great vid thanks so much - I'll be working on my 2000 KLR over the winter. Quick question, where can I get a 4 40 washer? That'll sound dumb I'm sure but I've looked here in Montreal and can't find one. Any pointers?
Hi, it is not a dumb question! They can be hard to find, as they are part of a set of very small hardware and they are not metric. What you need to find is a stainless steel washer of the appropriate dimensions. Here we find that ACE Hardware Stores often stock a good supply of 4-40 screws, nuts, and washers. You might try Ace Quincallerie Moussette 1561 Rue Ontario E, Montreal or Quincaillerie Home Hardware 4299 Boulevard Saint-Laurent, Montreal. If you cannot find 4-40 washers then 3mm washers should work. They will be a bit smaller in the inside diameter and outside diameter and a bit thinner. The shaft of the needle is right at 2.92mm. I have used the 3mm washer in the past. Here is a comparison of the two: 4-40 Stainless Inside Diameter 3.25 Outside Diameter 7.75mm Thickness .8mm From my stock, what you find may vary: 3mm Stainless Inside Diameter 3.13mm Outside Diameter 7.15 mm Thickness .63mm Normally two 4-40 washers are used, but people often find that one is sufficient. I would suggest using two of the 3mm washers to start; you can go to three and have a bit more lift on the needle than two 4-30 washers give. Wouldn't hurt anything. Stainless washers are usually well finished with no burrs, so stacking them is not an issue. Make sure that the ones you get have no burrs from the manufacturing. If they do, sand them flat with some fine wet-dry paper, oiled, on a pane of glass or other hard, flat surface. Best of luck! Tom
Holy mackerel, you the man! Thanks a lot Tom, can't tell you how much I appreciate you going above and beyond to help a guy out. Really, thanks. Looking forward (no, really!) to the winter as it'll give me plenty of excuses to get into the garage and start the tear down and eventual rebuild of my KLR - with your help and your videos I feel well prepared. Good man!
You are very welcome; glad to be of help. Are you planning on replacing the balancer lever? If so, and if it gets too cold to work on the bike, I have a set of videos on that job that will chew up an hour of your time. ua-cam.com/video/U3UJIbDOLMQ/v-deo.html If you get really housebound you can while a way a good bit of time at www.souperdoo.com , too. There's some fun ramblings there. Have fun! Tom
You said turn the screw out 1 and 3/4 turns. But I keep reading forums say its 2 and 1/2 turns. whats the big difference. because they dont mention after market exhaust.
It's a ball park figure. The generally accepted rule of thumb is about 1 3/4 turn out for stock, roughly 2 1/4 turns out for aftermarket exhaust. Those are not exact numbers, but should be a very good improvement over stock. The truly correct, and fiddly, way to do it is to turn the screw out 2 turns from gently seated, then turn it in a bit at a time, all the while looking for a peak in RPM. If turning it in from 2 turns doesn't get you to a peak RPM, go back to 2 turns out and look for the peak RPM by turning it out. When the mixture is correct, the RPM peaks. If you're approaching the peak from the lean side, then it will start to fall back off as you go a bit too rich. Vice versa if you're approaching it from the rich side. See how hard that was to read and understand? That's why I say, in the video, to go a turn and 3/4 out ;^) This guy does a pretty good job of explaining ua-cam.com/video/zm5mB3R8Ucw/v-deo.html This guy, too, ua-cam.com/video/YxpQjDQzX7g/v-deo.html Tom
Yes, you can. What that will do is correct the mixture to about the 1/4 throttle open positiion. After that the mixture is pretty much governed by the taper of the needle and the size of the main jet. You'll probably be on the lean side there, as that's the way they are designed. To recap a bit, setting the idle mixture screw correctly will give you the proper mixture at idle and to about 1/4 throttle. Installing the washers pulls the needle out of the jet a wee bit, correcting the 1/4 to almost wide open throttle mixture. At wide open throttle the engine is running off the very small tip of the needle and is quite rich (this is a bit of a safety measure so that you don't run lean at WOT). Drilling the slide allows it to come up quicker as you open the throttle plate, which puts vacuum on the top side of the diaphragm. That improves throttle response. This chart may help you understand what controls the air/fuel mixture, though it has components that aren't in our carburetors: www.carbparts.com/keihin/needles_tuning/calchart.gif. Here's another, presented a bit differently: s1183.photobucket.com/user/NVTrailRider/media/003649c6-0ab5-4fdc-b75a-fc097105f668_zps27583c53.jpg.html Tom
David, Yes, it can be done. The KLR250 carb is a smaller version, but the needle is similar. It should work out all the same, though I think folks start with one washer. Some have reported good results with a main et one size larger, too. There is a thread for the KLR250 over on adv.net. It is rather long, but that's where the smart folks hang out. You might find info there on jetting the carb, shimming the needle, and what a good setting for the mixture screw is, or if a KLX needle works on these carbs. Tom
Why do you promote the idea of doing this mod while carb is still on bike,then do it while on bench? By the time you've got to the point of tilting carb ,how hard could it be to just remove the damn thing? You seem to have found out its just exer to go ahead and remove it!
This mod is often done at tech days and doing it while the carb on the bike isn't that hard, and it can be done easily and quickly. I wanted people to see what was required to do the mod, and that was easier to film with the carb ont he bench. To your point, removing the carb isn't very hard to do, though. If you have the time to remove the carb and get it to the bench, that's also a good opportunity to do a cleaning of the carb, too.
If you find this adjustment inconclusive, just set it at 2 turns out; hard to go really wrong with that. You should also be aware that the engine can stumble at too lean a mixture. One old trick was to find the lean stumble point and the rich stumble point and set it halfway in between. In my opinion, rich is better on this carb because the idle mixture circuit always plays a part well into partial throttle. Rich runs cooler. Google "Care and Feeding of the Keihin Carb". Good reference!
I'm not sure why the recommendation there is for 3/4 - 1 turn out. That is pretty much how they come from the factory, and it is lean. the generally accepted rule of thumb is about 1 3/4 turn out for stock, roughly 2 1/4 turns out for aftermarket exhaust. Those are not exact numbers, but should be a very good improvement over stock.
Thanks for the video! Job done with confidence and gave my bike a little more on the throttle!
Hi Shane,
I'm glad it was useful for you! Enjoy the performance improvement.
Tom
Thank you so much, really helpful video!
Not sure if this is the case for all but my 2016 didn't have a cap on the adjustment screw. With a Lexx exhaust and 2.5 turns out felt a little rich when shifting gears. Think i'll try what you recommended in the comments at 2 1/4.
Overall, superb..big difference!!
Glad to hear it! Interesting that the cap may not be on the 2016; had't heard that before.
Thanks!
Tom
Souperdoo,
Excellent how to video, thank you. My 2011 with stock exhaust is about to undergo this mod this afternoon/eve.
Drilling the slide will improve throttle response a bit but won't do anything to the mixture, so if you don't want to do it there's no problem. Just put a washer or two under the needle and turn the screw out a couple turns. You should notice an improvement in first gear/second gear roll-ons. Nothing to removing and replacing the cables - just watch that choke cable!
I don't know, Juan. It depends on what else has been done. Two to two and a half turns out is probably in the ballpark, but it all depends on what the pipe is flowing and what intake mods have been done.
You see, you can get to the point where you need a larger pilot jet to control the lean pop on decel. I have a very free pipe, a ported heat, and holes in the air box. I needed to go up a couple sizes on the pilot.
Try the "cracking throttle" method below ans see where it takes you.
Probably not, with just the pipe. You can start at 1 1/2 and turn it out an 1/8 turn at a time, cracking the throttle each time. What you are trying to do is get the idle running as rich as possible. When cracking the throttle causes a stumble the mixture is too rich; back it off a bit until there is no stumble. Running rich at idle and part throttle should help to prevent decel popping. The engine needs to be fully warmed up for this adjustment.
what hapends if i modify exaust (wider exaust so easier gas release), but dont do anny modification or adjustment to carb?
Great video. When you are showing the outdoor portion of the video you have what looks like a brass thumbscrew in your idle mixture screw hole? Where can we get one of those for future adjustment?
Hi Rick -
It's called the 'EZ-Just Mixture Screw' and it is made for Harley Davidson Sportsters that use the CV40 carb. John's Cycle Parts (www.johnscycleparts.com/store/index.php?route=product/category&path=20) has it, as does CV Performance (www.cv-performance.com/). They are about $20.
Tom
es muy valiosa la información pero seria bueno también algún video en spañol
Estoy feliz de que lo encontró útil! Gracias.
tengo una klr 650 y por ejemplo en UA-cam no hay información en español y no encuentro ningún video de como desmontar el motor de arranque (burro)
carmela dominguez lo que está mal con su motor de arranque? Yo creo que debería ser un 'artículo de reemplazo ', no un 'elemento de servicio' a menos que tenga una buena tienda motor eléctrico cerca de usted. Debe retirar la cubierta izquierda para tomar los engranajes del eje, luego cuatro tornillos para quitar el motor de arranque del cárter.
Tom
Thanks for the part 1 & 2 videos. I just completed this mod and got rid of the popping at deceleration completely. Woohoo!! But I'm still having a minor problem I was having before the mode: when I keep the bike at 5000 rpms steady (let's say highway cruising speed) i notice a bit of a surge/hesitation in power but when I open the throttle there is a response. If i choke it the hesitation disappears, what can that be?? Again thanks for taking the time to make these video series
Hi Orlando,
It sounds like you are still a bit lean on the idle circuit. The idle circuit is active for a fair amount of the small throttle opening. When you are running at an easy 5000 RPM you are really using very little throttle.
There are a couple of things things that should help. First, proper idle mixture tuning. There is a pretty tried-and-true method for finding the proper idle mixture that has been used for decades. I copied these words from cv-performance.com because they do as good a job of explaining this as anybody does. They sell the E-Z Adjust idle mixture needle. Good company.
"The air cleaner assembly must be installed prior to starting the engine, not only to hold the carburetor in place but to prevent having the carburetor backfire in toward you while tuning. Start the engine as normal and bring up to operating temperature prior to fine tuning. Let the bike idle for no more than 5 minutes.
With the engine warmed up and at idle you may now fine tune the idle mixture screw for optimal performance. Acquaint yourself with the adjustment screw location at the bottom rear of the carburetor prior to running the engine. You will need a small screw driver for adjusting the screw unless an EZ-Just has been installed. With the engine idling slow (no more than 900 rpm), turn the screw inward (clockwise) SLOWLY until the engine starts to stumble. You are working with the screw upside down so check to make sure you are turning the screw clockwise or inward. Note that not all engines will stumble or have an RPM change that is noticeable when twisting in the mixture screw. This can be due to the idle jet being too large, installed cams, or ignition systems such as those on Twin Cam 88's. If unable to find the low adjustment point where the idle slows, simply set the screw at 1-3/4 turns out and proceed to the next step.
If the engine will not idle on its own during this procedure, adjust the idle set screw on the throttle side of the carburetor until it idles correctly. Now turn the mixture screw outwards (counter-clockwise) until the engine begins to run smoothly, then add 1/8 of a turn. Maintain proper idle speed and repeat the adjustment each time you adjust the idle speed. Blip the throttle a couple of times and observe the results. If the engine responds quickly with a smooth blast and no backfiring through the carburetor, you have your idle mixture right. If a hesitation occurs then adjust the idle mixture screw out another 1/8 turn. Normally, the mixture screw should only require 2 to 3 turns out from gently seated. Anything above 4 turns indicates the pilot jet is too small."
Going from a #38 pilot jet to a #42 can really help in some installations, too.
Finally, going to a KLX kit instead of the 22-cent will make a vast improvement in the overall air-fuel mixture across all throttle openings. The 22-cent is meant to be a quick and easy way to remedy the factory lean condition in the carb. The KLX is a more aggressive tuning method to improve bot AFR and power. Of course, it costs $50 instead of 22 cents...
Tom
@@souperdoo thanks again for the info, i will look into this
Do you need to do the 20 cent mod if you're doing the klr needle kit?
@Ian Ferrier,
No, you don't. Sometimes you may find a need to fine-tune the KLX needle with one washer; doing so moves the needle by half a groove.
Other than that, no. One is a poor man's bit of carburetor tuning and the other is a better approach though a mite spendy.
If you don't mind spending $50 I recommend the KLX needle.
Tom
great video.my son has a first gen klr 650. i was out visiting him over the weekend. he lives in san diego {sea level}. the bike has a super trapp muffler with stock pipe. it has a aftermarket air filter. i asked him if he has ever pulled the spark plug to check it out. he has owened the bike for 2 years now and has just changed the oil every 1000 miles and clean the air filter, tighten the chain and put gas in it and loves the bike.i pulled the plug and it was real real light in color. i ride a xr650r ,kx500,gsxr 1000 and a 79 bultaco 250 pursang. so i know what a hot plug looks like. i kinda freaked out seeing how hot it was burning. you think the 22 cent mod will help his bike out ? or any suggestions ? thanks
Buzz-
KLRs come from the factory pretty lean; it's an emissions thing, I guess. What you are seeing is pretty normal. The 22 cent mod will richen the mixture a bit and take it from about 17:1 and get it closer to 15:1.
With today's fuels that contain additive packages and ethanol the old "reading the plug" trick gets a little bit iffy, though.
The SuperTrapp being on there is an unknown as far as what it's doing to the mixture. I found that the ST had to have 9 plates in it to flow as well as a stock pipe and was horribly loud. Depending on how many plates he has in it, it may be contributing to the lean condition. Intake and exhaust mods need to be balanced. He might be better served by installing a KLX needle. If he still has the stock exhaust can, a better exhaust mod than the ST is to open up the stock can, removing the baffle. If flows pretty well and isn't obnoxiously loud.
All in, I'd say the 22 cent mod would be beneficial on his bike. Do it and check the plug. If it still looks lean, go for the KLX needle. Go down one jet size and start at the second clip from the top, then tune.
Tom
thanks for posting the excellent how to. I just bought a 2012 klr and was thinking about this mod. I have an after market slip on and thats it. do i need to turn out the bottom screw 2 1/4 turns? great video, thanks again.
Awesome!!!
por favor donde va la manguera de combustible tiene dos lugares que van a la cuba del flotante una inferior (abajo) y otra de arriba, estuve mirando diferentes videos y en ninguno dice como van las mangueras , en la parte de atrás del carburador lleva una manguera al multiple y no la tiene se la anularon a mi moto yo quisiera saber donde va? ningún video de web dice paso a paso sobre las conexiones de carburador, al no saber en donde va la manguera de arriba se me complica, pues no soy mecánica y no estoy en condiciones de llevar al taller. ¿se puede remplazar el carburador por uno común de cortina normal? gracias.
Yo sé cómo se hacen las motos USA.
Hay dos dimensiones de las mangueras del carburador. Una manguera va desde la válvula de combustible (grifo) hasta el codo de combustible del carburador. El codo es negro y en la parte inferior. Esto debe ser una manguera de combustible de 8 mm. Se va a la salida de combustible en la válvula de combustible.
La otra manguera es una manguera de vacío. Es de 3 mm y va desde el tubo de latón en la parte frontal del carburador a la parte posterior de la válvula de combustible. Esto es para operar la válvula de combustible sólo cuando el motor está en marcha.
Hay otra manguera de 8 mm que se adjunta al carburador. Debe ser una manguera transparente que se adhiere al codo gris en la parte superior del carburador. Es un respiradero.
Yo sé que en Australia tienen más mangueras que proporcionan calor al carburador. Están conectados al radiador de alguna manera. Yo no sé nada de eso.
es factible reformarmar el carburador para que funcione solo con la cortina como las motos antiguas...esta el carburador muy manoseado y piden 100 dólares por la reforma y en Argentina son 1300$, se me ocurre reformar la cortina con un cable y quitar la mariposa trasera ¿podría funcionar? o colocar algún carburador de alguna moto vieja de unos 500 CC, por ejemplo.
carmela dominguez Es posible utilizar un carburador tracción directa como el Mikuni VM38 o algo similar. Eso sería más fácil que la conversión de la CVK40.
Hi there, great vid thanks so much - I'll be working on my 2000 KLR over the winter. Quick question, where can I get a 4 40 washer? That'll sound dumb I'm sure but I've looked here in Montreal and can't find one. Any pointers?
Hi, it is not a dumb question! They can be hard to find, as they are part of a set of very small hardware and they are not metric.
What you need to find is a stainless steel washer of the appropriate dimensions. Here we find that ACE Hardware Stores often stock a good supply of 4-40 screws, nuts, and washers. You might try Ace Quincallerie Moussette 1561 Rue Ontario E, Montreal or Quincaillerie Home Hardware 4299 Boulevard Saint-Laurent, Montreal.
If you cannot find 4-40 washers then 3mm washers should work. They will be a bit smaller in the inside diameter and outside diameter and a bit thinner. The shaft of the needle is right at 2.92mm. I have used the 3mm washer in the past.
Here is a comparison of the two:
4-40 Stainless
Inside Diameter 3.25
Outside Diameter 7.75mm
Thickness .8mm
From my stock, what you find may vary:
3mm Stainless
Inside Diameter 3.13mm
Outside Diameter 7.15 mm
Thickness .63mm
Normally two 4-40 washers are used, but people often find that one is sufficient. I would suggest using two of the 3mm washers to start; you can go to three and have a bit more lift on the needle than two 4-30 washers give. Wouldn't hurt anything.
Stainless washers are usually well finished with no burrs, so stacking them is not an issue. Make sure that the ones you get have no burrs from the manufacturing. If they do, sand them flat with some fine wet-dry paper, oiled, on a pane of glass or other hard, flat surface.
Best of luck!
Tom
Holy mackerel, you the man! Thanks a lot Tom, can't tell you how much I appreciate you going above and beyond to help a guy out. Really, thanks. Looking forward (no, really!) to the winter as it'll give me plenty of excuses to get into the garage and start the tear down and eventual rebuild of my KLR - with your help and your videos I feel well prepared. Good man!
You are very welcome; glad to be of help.
Are you planning on replacing the balancer lever? If so, and if it gets too cold to work on the bike, I have a set of videos on that job that will chew up an hour of your time. ua-cam.com/video/U3UJIbDOLMQ/v-deo.html
If you get really housebound you can while a way a good bit of time at www.souperdoo.com , too. There's some fun ramblings there.
Have fun!
Tom
You said turn the screw out 1 and 3/4 turns. But I keep reading forums say its 2 and 1/2 turns. whats the big difference. because they dont mention after market exhaust.
It's a ball park figure. The generally accepted rule of thumb is about 1 3/4 turn out for stock, roughly 2 1/4 turns out for aftermarket exhaust. Those are not exact numbers, but should be a very good improvement over stock.
The truly correct, and fiddly, way to do it is to turn the screw out 2 turns from gently seated, then turn it in a bit at a time, all the while looking for a peak in RPM. If turning it in from 2 turns doesn't get you to a peak RPM, go back to 2 turns out and look for the peak RPM by turning it out.
When the mixture is correct, the RPM peaks. If you're approaching the peak from the lean side, then it will start to fall back off as you go a bit too rich. Vice versa if you're approaching it from the rich side.
See how hard that was to read and understand? That's why I say, in the video, to go a turn and 3/4 out ;^)
This guy does a pretty good job of explaining ua-cam.com/video/zm5mB3R8Ucw/v-deo.html
This guy, too, ua-cam.com/video/YxpQjDQzX7g/v-deo.html
Tom
Thanks for the reply! One more question. Can you just ritchen the screw without putting in the washers?
Yes, you can. What that will do is correct the mixture to about the 1/4 throttle open positiion. After that the mixture is pretty much governed by the taper of the needle and the size of the main jet.
You'll probably be on the lean side there, as that's the way they are designed.
To recap a bit, setting the idle mixture screw correctly will give you the proper mixture at idle and to about 1/4 throttle. Installing the washers pulls the needle out of the jet a wee bit, correcting the 1/4 to almost wide open throttle mixture. At wide open throttle the engine is running off the very small tip of the needle and is quite rich (this is a bit of a safety measure so that you don't run lean at WOT). Drilling the slide allows it to come up quicker as you open the throttle plate, which puts vacuum on the top side of the diaphragm. That improves throttle response.
This chart may help you understand what controls the air/fuel mixture, though it has components that aren't in our carburetors: www.carbparts.com/keihin/needles_tuning/calchart.gif.
Here's another, presented a bit differently: s1183.photobucket.com/user/NVTrailRider/media/003649c6-0ab5-4fdc-b75a-fc097105f668_zps27583c53.jpg.html
Tom
Can this be done on a 2000 super Sherpa carb? Kl250
David,
Yes, it can be done. The KLR250 carb is a smaller version, but the needle is similar. It should work out all the same, though I think folks start with one washer. Some have reported good results with a main et one size larger, too.
There is a thread for the KLR250 over on adv.net. It is rather long, but that's where the smart folks hang out. You might find info there on jetting the carb, shimming the needle, and what a good setting for the mixture screw is, or if a KLX needle works on these carbs.
Tom
what is that clamp your using to hold the carb?
thanks! great videos!!
is this pretty much the same for a klr250?
Stephen Abner , As far as I know, the carbs are very similar and the procedures ought to be the same.
Tom
Main Jet klr250 = 118-128
Main Jet klr650 = 145-155
Why do you promote the idea of doing this mod while carb is still on bike,then do it while on bench? By the time you've got to the point of tilting carb ,how hard could it be to just remove the damn thing? You seem to have found out its just exer to go ahead and remove it!
This mod is often done at tech days and doing it while the carb on the bike isn't that hard, and it can be done easily and quickly. I wanted people to see what was required to do the mod, and that was easier to film with the carb ont he bench.
To your point, removing the carb isn't very hard to do, though. If you have the time to remove the carb and get it to the bench, that's also a good opportunity to do a cleaning of the carb, too.
Removing Carb.: Unscrew and remove the 2 Clamps, tilt the Carb, then Pull backwards towards Airfilter and twist to the right