Hey Sean, RPM is a function of Torque and vice versa. People often get very wrapped around the axles in this topic because they don't understand some basic physics - when people say things like 'torque is the push you feel and power is your top speed' and other generic nonsense like that. Torque is a force acting at a distance (like you pushing a breaker bar, piston pushing on your crank) - Power is the rate or frequency of how many revolutions you have of that torque in a defined time period (RPM - minute for example). I could go into a hundred analogies of this but the implications are simple and possibly counter intuative for some riders. Lugging (high load - low RPM) your bike is f'ing awful for every part of your drivetrain and engine - you're demanding the same amount of force at the rear wheel for fewer rotations/combustion cycles of the engine = more force per cycle required (think about that statement and hopefully it will start to click for some people: more wear of ever part of your transmission, crank/rod bearings getting harder impacts per power cycle. You increase RPM, you proportionally decrease the force(acting at a distance of the radius of each gear/crank (this is torque)) and you can see you're going to take better care of your drivetrain, bearings etc. End of the story when you're dicussing fuel economy and the analogy of demanding less work per stroke of the piston is technically correct but it's not the reason for improved/reduced economy. There is a fixed amount of chemical/potential energy in a given volume of fuel. You get the best efficiency from your engine when your combustion cycle generates the most torque for a given volume of fuel. When you account for real world stuff like wind resistance, bike/rider weight, and then the complexities of the engine design - you just need to accept that at that throttle position, at that speed, for that RPM, the volume of fuel being burnt is exerting more work on the crank and into your rear tyre because in a given time because the engine is simply operating at a better efficiency (they call this Brake Specific Fuel Consumption) i.e the energy the little honda is extractactig from the fuel is more optimal at that specifc RPM, ignition timing, throttle position, proportional to the speed you're travelling. As you can imagine things like cam profiles, ECU tuning and air intake/exhaust can all have impacts on moving this sweetspot so all the work you did on the bike will certainly have an effect. Anyway, hope that helps someone somewhere even if they just take away, don't be afraid to let your bike rev - it's the kinder thing to do than lug the poor little fella everywhere.
Agreed. I havent got the inlet, exhaust or computer mods Sean has and am nearly twice his weight, but I have been considering similar gearing changes before I spend money on those things.
Thanks for the detailed description of what is actually happening with power, torque and rpm. I will keep experimenting to find the sweet spot with gearing for my bike.
... For those of us that are consuming every bit of information about the CRF 300, we know the engine is happier in the higher RPM range. That it why I like this statement, ... ... "don't be afraid to let your bike rev - it's the kinder thing to do than lug the poor little fella." ... . I have a 2021 300 Rally with a lot of up grades including Rally Raid Level 1 front and back suspension. The rest are typical comfort, cosmetic and protection items. . Between yesterday and today, 11/29/2023, I ordered the Yoshimura RS4 full exhaust; 550 Stage 1, Intake boot; DNA air filter and service kit. . The air box will have the snorkel removed. I will either cut the snorkel in half and have another hole cut in the top/back of the box to double the intake flow into the box like "Pommey Biker" ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-tc3M42IXbAc.html or cut one larger hole and mount in a 3" or 4" rubber boot like "Jake The Garden Snake". ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-7EcFTDVPESo.html . . I will most likely replace the 40T with a 42T or 45T rear sprocket and a X-Ring chain. I agree with "Woodzman Adventures" ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Dl-60lsn_Is.html . 42 tooth= better power/torque. X-Ring chains= less resistance than O-Ring chains therefore not robbing power. Andrew when to a 45 tooth and that is a consideration also. Motorcycles Offroad . ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-7AWIkjdrUb4.html . All this seems like a lot to do to a 300 (286cc) bike to get a great dual sport but that is the beauty of the CRF 300, it can be personalized to anyone's liking ... or left totally stock. . Shonky, Thank you for all the research and testing you do plus making the videos to share. I know that alone takes a lot of time and I really appreciate it. I subscribed with a bell as soon as I found your channel. Keep up the great work and #ridewell. Jeff
😮Very interesting indeed I wonder how much the cams have to do with it also. Looking forward to see how you do on your adventure ride. Great video thanks mate I will definitely give it a try on the next change.
Higher rpm can lower manifold pressure. Lower rpm raises manifold pressure. Higher manifold pressure = more rotational resistance and fuel consumption. I noticed this with my Diesel. The automatic transmission short shifts very early lugging the engine. On some roads, I use manual transmission mode. The engine ran smoother! I pulled up the fuel consumption page and the truck was using less fuel at the same speeds/load.
Reminds me of my Honda Fit/Jazz. 6 speed manual but it's geared low. It gets excellent mpg even revving fairly high at higher freeway speeds. I'm trying to decide what gearing to try after installing Motoz rallz on the rear. Between the heavier weight and taller size it's likely to be sapping some umph. Was thinking of going 14/42. No other mods but will likely do 550 stock improved 87 as a start. I like the quiet though would love to shave a bit of weight. Maybe swap the head/mid pipe and keep the stock can w/guard which is great to have with luggage when neededml
Fuel consumption is more closely related to engine load rather than engine speed. If the engine speed is below the ideal torque range, the rider applies more input (throttle) to achieve their desired riding output. In other words, you're simply throwing fuel at it to achieve the torque output that you could otherwise achieve if the engine were sitting at a more ideal rpm. Hopefully that makes sense. Another way to think about it is to relate it to riding a push bike. If you were to pedal around in a tall gear with fewer pedal rotations, you'll have to push on the pedals so much harder to maintain speed up hills than if you were in a lower gear. Anyone who cycles will understand how energy draining that is.
I watched a video where a guy went up to a 15 tooth front sprocket and lost 2-3 mpg fuel but was 500 rpm less on the highway. Taller gearing but it must have been out of the meat of the torque range.
Did you substract that few km more the original meter counted? Your true speed is about 10% off (and more then 10% at higher speeds) also distance traveled and ofcourse true fuel economy too.
At a glance, I didn’t notice any of you sprocket changers mention what size rear tire you’re running. That is going to 100% make a difference in how a bike runs with different gearing on the sprockets. Most people end up placing the stock with a 120/90-18.
It’s all about how much throttle you have to give to sustain speed/rev range. If you’re using the throttle less and you are in a higher average because of your gearing, you’re going to get better miles per gallon that if you were lower range hitting the throttle harder.
I am very pleased with 14 42. I can takeoff in 2nd get to 4th and cruise in town and on the trail. I can stay in 5th as ling as I want on the highway if I use sixth its only at highway speed. The intake ventura smoothed out a lot of the power band
Sean. Engines have a sweet spot where the motor and the torque are in the optimal range and the burn is most efficient. ECU over fuels as it accelerates and leans out as it runs more efficient. (depending on Map settings programmed) I would be interest what you fond if you ran 14-48 as that was what I ran on my XR600RK - top speed of 130 K but way up in revs but the beast pulled like a train at all areas and in all conditions of single track, hilly, muddy, rocky you name it.
I was running 13/40 on me CRF250l Rally... but I found it rev'd a bit high at highway speeds... tried 14/42 and loved it.. still better then stock in the trails, but still decent on the highway.
You should use GPS and navi for both. Speed and kilometers and get liters when you buy fuel. Don't use the bikes own speedo to compare how different gears and tyres needs fuel / kilometres.
Great video but I’m just as confused about what to try. I did an adventure day yesterday with stock gearing and stock rear tire. 1st gear was virtually unusable and I found I was clutching too much in 2nd going up steeper hills. I thought about trying 14/38 but can’t buy the 38 here so a shop said try 15T, but now the case saver won’t fit on. I’ve stuck a 140/80-18 Michelin tire on the back and will put the stock gearing back on tomorrow unless someone can suggest changing to a different sprocket at the rear to get more out of the lower gears.
See how the stock gearing goes with the 140/80 tyre. I've now settled on 15/39 gearing with a 120/80 tyre. I think I trimmed the case saver slightly to get the 15t front sprocket on. It's a tight fit getting it back on, but all works well once on.
Interesting...I'm looking to regear my Rally...is your rear tire stock? I put on the Perelli 120/90-18 and am thinking of 14/43...which would put my gearing back to stock with that larger tire. I would imagine you tire is stock 120/80 with the 14/41 you tested here? EDIT...never mind, I just read your tire size in the comments below. However...with the 41 rear did your chain guide work with it?
Done your proposed mods and this was exactly what’s been next on my mind - so, thanks! No vibration issues at 8k rpm? Think this is your final state or will you keep experimenting?
There is a slight vibration at 7500-8000 but it goes away above that. I will try a few things to improve that and probably keep experimenting with different setups.
14/40 stock gearing would be the best as you already have extra power and torque from the power mods you have done. It will pull fine in 6th in heavy wind with good rpm with 14/40 . 14/41 the bike revs to high in 6th
I will try 14/45. I'd like ro get more torgue to the trails. I don't like to ride highways with Rally so much and like to go slower than 100km/h with soft tyres on highways.
That's almost close to having 13/40 which I'm running on the 250L, yes it rev a bit higher, that means you get into the higher torque range quicker. I sit about 7000rpm on the highway all day long and still have another 30% on tap.
I also really like 13/40 and 13/42 when just off road, I tend to use 2nd gear rather than having to go back to 1st as often. But it does get annoying on longer commutes! I've settled on 14/42 for now at least.
The speed error contributes to a falsely high result for fuel economy. I ran 42 rear for thousands of miles and compared it with other bikes with me to find that. Bike Thinks you went further on less. Please share which 41t sprocket you found to fit the rear
Yeah you need to compare to GPS speed. I have a speedo healer to get the speed spot on and adjust with the gearing for as close to zero error as possible.
Just wondering how many kms the 300L engines are proven to last for with stock gearing ratio? Something not spoken about too much ..compared to say the proven longevity of Honda CB 500x and Kawasaki KLR 650 engines when properly maintained .
I plan to do more highway, so I will go 15/40. I can give up the 7% torque for a higher speed overall (with the ECU flash). You gained about 2% torque with one rear tooth, but lost 2% top speed. One tooth change in the front is equivalent to 3 in the rear. More rear teeth adds torque and gives up speed and vice versa. But adding 1 front tooth is better for the drive train than taking away 3 rear.
That's what I've done with mine at 15/40 with the 550 ECU, it seems fine but I do notice the drop in torque on this hill I need to tackle quite regular but I may be going faster anyway and not dropping below previous speeds as I haven't done a speedo recalibrate as yet to confirm, so losing 7% torque would be the reason for this feeling but the extra ECU power must be making up for most of that loss. Upon fitting the 15T drive sprocket I also needed to use like a die grinder with a carbide burr to grind some metal away top and bottom from this steel ring that is mounted inside the plastic sprocket cover otherwise it would not fit back over the chain. Grind off a couple of mm top and bottom from the inner of this ring. The electric die grinder I had made it quick and easy otherwise you might be swearing about how to remove the material easily. it's a bigger job than a dremel would normally be able to do, they are for grinding flies legs. There was just enough chain adjustment to fit this sprocket without additional hassles.
Just getting caught up here and may have missed it in earlier comments but it seems in essence you have re-achieved near-OEM gearing with the larger rear tire combined with a 1 tooth larger rear sprocket?
@@marshalbird2480 Thanks mate, I'm going to try to do some more ride videos with other CRF300's to see how the different mods and setups work in real conditions.
@@ShonkyProductions Great, more content is good. You might touch of how gearing can affect touring solo vs with other small bore bikes vs a bigger bore. I know you experienced some of this. I did a 3000 mile ‘solo’ loop, Idaho BDR, Canada and Montana, 75% dirt 25% paved. I used stock gearing for the dirt but switched to a 15T for the longer paved sections. The 15 did allow lower rpms (550/opened air box/Moto-X) but hills and headwinds often required a downshift. As a solo rider I could easily adjust my speed and shift to accommodate hills and traffic and rode at a comfortable relaxed pace. However if I had been traveling with someone on a bigger bore I suspect there would have been some stress trying to match speeds.
@@ShonkyProductions Nobody likes a head wind hey, the first thing i do to all my bikes out the showroom is drop a tooth at the front, i will probably do the same to my 300 rally the one that was supposed to arrive on the 19 of september, now it's december and i'm not holding my breath on that either anyways keep the videos coming there much appreciated and enjoyed.......
YES, that's exactly what myself and a lot of other people wish for. Unfortunately, there is no real options for increasing capacity that have proven reliable. Increasing compression maybe my next option.
Hi Sean ! In my off-road use (not Motorally like You) I love the 14 / 39 solution because the engine it's always ready to push in a firts 4 gear / And it's a bit RPM lower in 6th gear for commute / trip at 110 120 km /h ... ////// Maybe the 14/38 choice it's another possible individual choice for all-around Adv-Trail mode - travelling with soft side bags. ★☆ anyway this Honda 300Rally is a really Fantastic dual Bike, I'm really excited about it. Playing on the rear crown teeth, is the best solution in my opinion .... leaving the original 14 teeth in front. Have a GREAT week End Mate ! Enjoy and Fun / Ride Safe \ 🇮🇹Luke🏹🇮
I originally went 14/38 as it was all I could get for the bike. I then went 15/38 and found that definitely just too high to be flexible in top on the road , and lacked pickup at 100 in the dirt. I then got a 39 and went back to 14/39. Definitely a bit too easy sppinning on the bitumen for me. Gone to 15/39 ( which is what I wanted originally. Seems to be the best for me so far.
I have messed around with gearing and came to the conclusion Honda engineers maybe know what they are doing back at stock no mods and mine will run 86 mile and hour all day. My friend has the 550 and we do roll on races he pulls 5 bike lengths then it stops and we stay that way all the way until we top out on speed.
I guess what I’m saying is all the mods don’t equal more then a few bike lengths he also has the L model so it’s lighter I’m also loaded with luggage so mods yield very small gains I would say.
@@ShonkyProductions No, my wife used to own a rental up there, and she had some family there too. We still pop up to Umina now and then but we're Sydney people unfortunately
