It's behind a brass plug between the carb and the intake manifold. You don't have to take the float bowl off to see it, if I remember.
It is in a tubular extension which protrudes downward from the carburetor, just ahead of the float bowl and just behind the rubber connector leading to the cylinder head. The bore in the tubular extension is plugged by a brass plug of about 5 or 6 mm. Easiest way to study it is to loosen the two hose clamps which secure the rubber connectors (cylinder head and air box), then rotate the carb's bottom to the right side. Take care not to over do this and damage the throttle cable, but no problem in rotating far enough to access the plug for drilling. The removal has been described here and in the manual. A definite "must do" IMO. A carb adjustment tool or nimble fingers are desireable for making adjustments. In a pinch, turn the idle mixture screw out one full turn more and try that. HIH Norm
What is the standard adjustment on the mixture screw? I mean how many turns out after seating the screw?
Most idle mixture adjustment screws are set at 1-1/2 turns. This means that the screw is turned in gently until it just touches the seat and then is turned out 1-1/2 turns. Apologies if you already understand the "gently" and "just touches" but have seen hundreds of small engine carburetor screws damaged and/or carburetors ruined because someone turned the screws in with similar force to that which one would use to tighten a common screw of that size. The mixture adjustment screws have a tapered tip which adjusts the size of the passage formed by the space between the tapered tip of the screw and a metered hole in the carburetor's casting. Carburetors are made of aluminum or an alloy such as "pot metal" which is a zinc combination, none of which are very strong but which resist corrosion well enough. The mixture adjustment screw makes a fine adjustment of the flow of air and fuel bubbles within the idle passage. The main control of fuel flow is by the idle pilot jet which is a brass insert (screwed in in this case) having a metering hole and often some emulsion passages. The pilot jet meters the amount of fuel flowing in response to the pressure drop across the throttle valve. Since the thottle valve is only restricting air flow to a high degree at idle, and since the idle passages are positioned to take advantage of the idle conditions, there is flow in the idle circuit only during idle and lower throttle operation in most cases. In order to provide a more accurate adjustment, the mixture screw is added to the circuit but if the mixture screw must be turned in an excessive amount or turned out an excessive amount in order to set mixture sufficiently, the pilot jet needs to be replaced accordingly. FWIW, people sometimes misunderstand the role of the idle speed adjustment screw and the idle (fuel air) mixture adjustment screw. We are referencing and discussing the idle (fuel air) mixture screw in this case. This screw is usually placed near the cylinder head (intake) end of modern motorcycle carburetors. These mixture screws use a coil spring to provide tension to the screw threads so as to prevent the mixture screw from rotating in response to vibration. In most modern bike carbs the spring is around the screw inside the carburetor. If the screw is removed the spring will usually come out on the screw but care must be taken to avoid having the spring fall out and be lost. Further inside the carb adjustment screw bore, beyond the spring will be a small washer into which the spring bears and beyond the washer is a tiny rubber "O" ring. The "O" ring fits tightly to the adjustment screw bore and to the body of the screw. In addition, the pressure provided by the spring, squeezes the "O" ring to tightly seal to the screw and body. This "O" ring is intended to prevent air entering around the adjustment screw. The washer and "O" ring are often displaced and lost because someone does not expect that they are there. If you lose these, and the spring will still provide sufficient tension to the adjustment screw, you may be able to dispense with them until new ones can be obtained. Usually people don't even notice. The other idle adjustment screw is the idle speed adjustment or curb idle adjustment which is intended to provide sufficient throttle opening so that enough air enters to allow the engine to run without the throttle being held by hand. This is simply a stop to hold the throttle open a small amount. This one is most often external to the carb body and bears into the throttle linkage. People have had some very interesting times because they did not understand the very basic difference between these two adjustments. Look at a parts break down or idle adjustment picture in a manual. I may have something somewhere or can take a photo if someone is needful. HIH, time to sleep, Norm Forgot to mention: one does the idle mixture adjustment and or changing the idle pilot jet before experimenting to find the desired main (main metering) jet and jet needle because the idle contributes to the part throttle fuel delivery in conjunction with the main metering system. So, if one has a very lean idle as is common, works out and installs the correct main jet and needle, then adjusts idle mixture the main metering will be rich during partial throttle operation.
incorrect. always tune for best main jet and then everything else. if tuning your way the bike will always be too rich at 1/8 to 3/4 throttle. not my opinion but Marc the owner of www.factorypro.com read their CV carb tuning section. I have followed his tips on a few bikes and it always works, even my valkyrie which has a modified OEM airbox and after market exhaust system. Following FP will give the power and great part trottle/cruise MPG.
Thinking about stripping down the DR and adding a kick starter, to turn it into an enduro bike. Question: if I remove the battery, rectifier, and all the lights; will the bike still run? In order words, does the ignition use DC power from the battery or AC power straight from the stator?
Thanks for the info, Norm. When I installed the new jets I was careless enough not to count the stock screw setting. I set it to 2 1/2 turns out after rejetting it. I am thinking about moving it to the stock position and working from there. Btw, I put my air box lid back on and I am glad to be back to "normal" noise levels. The one obvious improvement from the new, larger jet install is at startup. I no longer have to use the choke from a cold start. I previously had to use the choke no matter what the outside temperature. That's not conjecture but a fact. I thought the little DR was just really cold-blooded. I did have to use a "notch" of choke this weekend when it got down into the 50's. It was only for a couple minutes and then it settled to it's normal, "putt, putt, putt," after I pushed the choke back in. I am curious how the jetting change will affect gas mileage with "normal" riding. The last tank got me 65 mpg. Every tank so far has included several hours of WOT or lots of stop-and-go riding. Maybe that is normal for me?
Did you change the idle pilot jet also? If that's the case then 2-1/2 turns out may be on the rich side. Simple enough to check as an engine reacts more to adjustment to the lean side of stochiometric (ideal) than to the rich side. How to explain.....an engine produces more power with a slightly richer mixture than with the ideal mix. Stochiometric for "normal" gasoline is 14.7 parts of air to 1 part of fuel by weight however that changes when using other fuels than gasoline. Alcohols, for example, have lower mass to volume and contain less energy by volume. For this reason, an engine running alcohol requires much larger flow volume of fuel, so much larger sized jets. When one considers an engine which has been jetted for an ideal mix with gasoline, adding alcohol to the fuel produces a less "dense" fuel and so requires larger jets or what we might call a richer mixture despite that it is not in fact richer. In order to reduce emissions to an acceptable level which is laudible, IMO, manufacturers have had to compromise by jetting to the lean side. Adding fuel injection, advanced combustion chamber design, catilyst, etc. would add to much to cost for the market to bear. So, we find these machines to be jetted to an air fuel mixture which is on the short end of fuel and on the long end of air. Gasoline droplets mixed with air has a range of concentration within which it will burn. If the mixture is ideal then all gasoline should find sufficient oxygen to burn the fuel completely. This is the theoretically ideal (stochiometric) ratio of air to fuel. The limitation for maximum power is the volume of air which the engine can aspirate in a given amount of time. Since an engine is, in effect, simply an air pump, spinning the pump faster will pump through more air, resulting in more power to a limit. So, we want more power we can add a bit of extra fuel to the mix we can add a bit of extra fuel to insure that all of the available oxygen is consumed. Remember that the amount of oxygen (air) is the limited factor. Of course the better the quality of the atomization of the fuel: tinier droplets, more evenly dispersed the better the combustion. If we begin with an ideal fuel/air mix and add a bit of fuel percentage (richer) power will go up as the percentage increases up to a certain point. After that point the added mass of fuel, which does not contribute to combustion because of the limit of oxygen, reduces power output because the added mass of fuel requires heating and so diminishes the expansion of the combustion gasses. So, let's consider your DR200 which is warmed up and idling, turn out the idle mixture screw which increases the amount of fuel entering the air stream. The engine speeds up because there is more fuel available to insure that the available oxygen is consumed. Since you have not opened the throttle, the amount of oxygen available remains the same. I know this is a bit of an over simplification but the scenario works well enough in practice to illustrate and can become more subtle later if desired. So, what to do? Keep adjusting the mixture screw out while listening/measuring engine speed. Engine keeps speeding up so keep opening until the engine speed no longer markedly increases. This is about the best mixture to produce power during idle but this is not the ideal adjustment. Now, let's assume that we leave the adjustment there and correct idle speed, then go for a ride. The engine will likely perform better than before but the biggest effect will be when the engine is cold. A cold air fuel mixture combined with cold engine surfaces make for a much less efficient combustion. Ever notice how much more difficult it is to start a cold, worn engine? Starting, intake, compression, power, exhaust: requires intaking a mixture of air/fuel, compressing the mixture, igniting the mix at the best time so that combustion is completed just before the piston reaches the top of the compression stroke, then experiencing the effect of the high pressure pressing against the piston to create the power stroke. The piston then moves up to clear (push out) the exhaust (burned air-fuel mix) so as to begin again. A cold carburetion tends to produce larger fuel droplets, and compression produces a lower temperature and so pressure. People often do not recognize that the compression of the air-fuel mix serves to elevate the temperature of the mix to quite high temperatures. The higher the temperature, the easier for the spark to ignite the mix and the quicker it will burn. Hotter mix burns faster, colder mix burns slower. So the worn engine produces lower compression pressures which are cooler and harder to get burning and to burn completely. What to do about that? Well, there's more: as the droplets of fuel (think of a plant mister fog) travels down the intake tract, past the intake valve, into the combustion chamber, when ever the droplets touch the cold surfaces and stick there (impinge). This means that, in order to have a decent mix, we need to add extra fuel (richer) in order to still have enough droplets to burn effectively. Start a cold engine, we need a richer mixture so the choke or starting enrichment circuit. We've adjusted the carb to the rich end of the range when warmed up so the mix will be richer when cold, also. A richer when cold mix will require less extra fuel to run than a leaner mix. That's why we notice that the engine needs less "choke" or may start and run without the choke when cold. People sometimes assert that this is much better because the engine runs well without the choke but one should consider the obvious which is that a fuel/air mix which is rich enough to serve cold operation will contain more fuel that is required to consume the available oxygen, especially when warm. Such an adjustment must produce poorer mileage than an ideal one although one might wish for the compromise. Staying with the rich side of adjustment, let's consider other effects: The extra (more than can be used) fuel, especially combined with larger droplets and cold surfaces and lower compression pressure/temperature must result in even lower combustion temperatures than ideal and so less efficiency. Fuel which touches the cooler surfaces will tend to stick there for longer and some will remain as a liquid film which runs down/is blown along the intake tract and drops into the combustion chamber. Some of the liquid fuel will encounter the piston rings and cylinder wall from which the fuel will wash some or all of the oil, reducing lubrication. Cold engines wear far faster than warmed up engines for these reasons. Air cooled engines of simple configurations such as the DR cannot control engine temperature and so are at the mercy of heat output versus heat loss to ambient. If one were to ride one for short trips, especially under colder conditions engine wear will be much greater. If one operates with an overly rich mixture, engine wear must be higher. Let's see if this is still small enough to post. Obviously, dumping in one big blob of gasoline will result in poor burning so this brings the topic around a bit further. I love it when people make simple pronouncements regarding fuel delivery systems. On the other side of the coin, one can begin with explaining one facet of operation only to meet oneself returning. :) If we
OK, that posted so let's move to the idling engine which has been adjusted to the rich end by finding the fastest idle speed. OK, so we begin turning the idle mixture screw inward and notice that the idle speed begins to drop gradually but not in direct proportion. If we had left the curb idle adjustment screw in position, we will note that the idle speed reaches the previous speed at the mixture screw adjustment which matched. Continue turning in (very slowly is always the way) and note that the speed keeps dropping until the engine stops. One will also notice that the idle is not as smooth as one leans because a leaner mixture does not ignite and burn as well. What we are doing is to reduce the amount of fuel droplets to increase the probability that each fuel droplet finds enough oxygen to burn. Extra oxygen (air) will help to burn all of the fuel but there is a limit to benefit. As the air/fuel mix becomes leaner (contains a lower concentration of fuel droplets) the amount of available air provides a greater probability that fuel won't go unburned but the extra air needs be heated which reduces the expansion to a similar effect to that of a rich mixture but to less effect. The big problem with a leaner mix, comes from the fact that the fuel droplets are more widely separated which makes it more difficult for a burning droplet to ignite the adjacent droplets. This makes for slower burning than ideal although the quenching effect of a rich mixture may match the burning rate of a leaner mixture, with the normal air-fuel mixture range a lean mix tends to burn more slowly. The lean mix, within normal range also burns hotter than a normal or slightly richer mix. While the effect of a much leaner mixture may reduce output by virtue of the need to heat too much extra air, the practical limit of being able to ignite such a lean mixture will come into play before the extra mass of air becomes an issue. This was the basis of Honda's CVCC automotive engines which were able to use a separate ignition fuel air charge to ignite the main combustion chamber but this is getting really out there. So, adjust the idle mixture leaner than ideal and the speed drops until the engine quits. Adjust richer and the engine speed rises to a limit and then begins to drop slowly. Well, what to do? We could adjust the mixture screw until the warm engine reaches a higher idle speed, then adjust curb idle speed back to normal idle speed, then adjust mixture again until the highest ldle speed is found at the minimum throttle opening. This is what most people do and is a very practical approach for small motorcycles when one has not resort to exhaust gas analysis. "Oh", you say, "but the adjustment is richer than it needs be!" Yes, so I finish adjustment by leaning the mixture slowly while listening for the engine idle speed to drop very slightly- say 50 RPM. Remember that an engine "likes" a slightly richer mix so we can benefit from moving a bit into the more ideal mixture range for better combusion without losing power. OK, now go back to fiddle with the idle mixture to prove some of the above: From a given idle mixture, if turning the screw inward makes the engine speed up the mixture was richer; while if screwing inward makes the engine slow down the mix was leaner. Playing with the adjustment, however, you notice another factor which becomes more obvious as you continue to experiment. Adjusting to the lean end requires more screw turning than adjusting to the rich. The engine reacts "likes" a slightly rich mixture more than a leaner/normal one. Recall the "bit of extra air to make sure all the fuel is burned"? There are some other practical considerations including that some engine designs will operate happily with a leaner mixture than another. This is because the combustion chamber an intake design of one engine will more evenly distribute the fuel air charge, etc. Here's another consideration which we have little practical ability to affect: the intake column of air and fuel makes a turn in order to pass through the intake valve void and to disperse into the combustion chamber. Designers go to staggering lengths to effect charge droplet uniformity because fuel droplets are heavier than air and so intertia tends to drive the droplets to the outside of turns, etc. If the charge is not uniform in dispursion, the burning rate of various areas will not be uniform. Very lean areas may reach extra ordinary temperatures/pressures in which they may explode rather than to burn. This is detrimental to both efficiency and engine survival. It's tough to cover sufficient in such limited time but the consideration of ignition spark timing is another factor which particularly limits these small engines. A cold mixture will burn more slowly than will a warm one which means that the cold mixture must be ignited (begun burning) earlier in order that combustion is completed prior to the top of the compression stroke. If all of the burning is completed too late, some of the effect of pressure increase is lost resulting in less power from the burned mixture. If the mixture completes burning too early, the high pressure acts against the rising piston to reduce power output. More advanced managment designs measure temperature and affect ignition timing to this effect. A given air fuel density will burn more slowly than the same air fuel ratio at a higher density. In other words, squeeze the same mix tighter and temperature rises and the droplets are closer together so it burns faster. Let's say that we adust the point at which ideal ignition timing takes place at one fuel density but then we turn the engine faster. Since that density of mix takes a certain amount of time to burn, turning the engine faster allows less time so we will need to start the mix burning earlier (piston further before reaching the top of the compression stroke) in order for combustion to be completed in time. What to do? Early systems used springs and weights to rotate the ignition timing control in order to compensate. Modern systems use an electronic processor built into the ignition module which counts ignition pulses per second and adjusts the spark timing according to look-up charts of the ideal timing. So, as engine speed increases, the spark is fired earlier in piston position in order to allow sufficient time to complete combustion. If one were to subsitute the ignition module from another machine having a different combustion chamber design and other factors making for different combustion rates, then one may have problems such as engine damage or lower mileage. There is another factor of at least equal import to that of engine speed in influencing combustion rate and that is, of course, fuel charge density. OK, back to that same speed down the road, but now we have an ignition module which changes ignition timing in order to fire the spark at the (more) ideal time for the engine speed. All is perfect, correct? No, remember that our little DeaR cannot include engine temperature? There is another problem also: as we open the throttle (say we are running at 50 mph in top gear and encounter a head wind) in order to maintain the same road speed/engine speed? Opening the throttle obviously increases the air fuel charge density in the combustion chamber which places the fuel droplets closer together and also raises temperature. Both of these effects act to speed the rate of combustion (burning) so now combustion is competed too early and begins to "fight" the piston's upward movement. Efficiency goes down and if we achieve too great a pressure/temperature the exploding charge will loose efficiency markedly and may cause engine damage. What to do? We must fire the spark plug a bit later (retard timing) in order to compensate. How to do this? There are two systems commonly used on motorcyles, the second of which is universal to automobiles. 1) A linkage from the throttle to provide throttle position information to the ignition module. Quite crude but a big improvement over nothing as has the DR. 2) Measure of the intake air pressure which is in direct relationship. In other words, the DR's ignition timing must be adjusted for only one mode of operation and that must be wide open throttle. This must and does reduce the possible efficiency were the part throttle effect considered. Problem? Too expensive and we wouldn't pay for the small effect on such a limited platform. Time to stop now but hope that this has been useful to someone. When one spends a lot of time and energy in order to offer a gift, one always hopes that the gift is worthy of the recipient. Norm
In simple terms, the previous posts suggest making idle mixture adjustment by: 1) Warm up engine having fresh fuel and in good condition. 2) Adjust idle speed to close to recommended. 3) Adjust mixture screw to find the fastest idle speed. 4) Adjust the idle speed as required to maintain near to the recommended speed as needed during mixture adjustmen but not to be too "anal." 5) When maximum speed at minimum throttle opening is found, turn the screw in until you hear the engine just begin to react and then until it slows slightly. 6) Experiment until you determine whether you are most happy with the way it runs as above or whether you prefer for the adjustment to be slightly richer. HIH Norm
How are you planning to add a kickstarter? IIRC, there is an orange and white wire that feeds 12VDC form the ignition switch to the CDI box.
i have 11,000 since 2011 on a 2009( sat in dealers showroom) and have had no problems. changed to 16t gear then i sorta messed up and running a 14t to 39 rear gear has not really improved milage(to lazy to change back) around high 80's on good days 98percent of miles have been over 60mph on pavement running dunlop 404 i think? other than that everything stock except for milk crate tywrapped to rack carries my lunch box perfectlly (btw not a real crate, but a wally world one, not as strong but bigger :)
I don't own my DR200 anymore, but I skim through this thread every so often. Unless you are really stuck with your DR for some reason, I wouldn't bother trying to use it as a platform for serious offroad riding. It's a great little dual-sport for messing around though.
Is there somewhere online that has speed limit listings by road? I'm trying to plan a long trip where the speed limit does not exceed 55 mph. I know there has to be a site somewhere. A GPS has to get it's speed limit information from some database. Riding the DR at 65 mph is not a fun experience for even a short distance. The times I have hit 65 mph, it was on a long, flat stretch of road with no headwind! I've come to realize that the little DR will be confined to riding around town and being hauled to campgrounds. That's the real reason I bought the DR200 in the first place.
Why not? If I can knock 30 pounds off this bike by stripping off the street legal stuff, it would be sweet little trail bike.
Seriously? Cutting a peg off here and there isn't going to add up to 30 lbs. Plus you still have a heavy frame, 14hp motor, and dated marginal suspension. Sure might shave a lb or two removing lights and passenger pegs etc., but then it's a trail bike you want, right? Better install a skid plate (lbs), case guards (lbs), probably want to carry some tools and tubes (more lbs)... The little DR is good at what it does, but based on your goal, wouldn't you be far better off starting with an actual trail bike like a KTM 200SX weighing in at 209lbs to start, there's 68lbs right there plus you get a way more powerful motor, quality suspension that will make the trails fun to ride. Just seems like a lot of work for little to no benefit when much better options are out there. This may seem like a knock on the DR200 but it isn't, my wife loves hers and has a blast on it, I just don't see the point on trying to make it something it isn't.
If you use your gps software, like Basecamp and tell it to avoid interstates and national highways. That's the default for my "Motorcycling" profile, if I'm in the car I just use the "Driving" profile which routes you on the major roads.