Crf300l full intake test must see. Surprising results

I test the crf300 airbox design and add a few little twists

[@luke3892]

I've watched all the 300l videos over the last few months and this is hands down the best content. Really appreciate the experimental method to suss out the air intake. Great work mate. Now you got me thinking I ask 550 to send me the stage 1.5 tune instead of the stage 1!

[@ronald8673]

I just took the rear snorkel tube out. Cut that panel section out leaving a rectangular hole on the left and a triangle shaped hole on the right with a thin strip of plastic in the center for support. Silicone adhesived in a glassfiber screen door mesh to cover the holes. Took the reso chamber off and rubber glued in a shaped plug to smooth the inside of the intake boot wall. Lastly, cut the front snorkel tube flush with the inside of the air box to create a still air box. Stock filter was retained, it is not restrictive even with the backfire guard. Made a big difference in response.

[@Offthevoltz]

Thank you so much for the testing.

[@razvanniculescu1027]

Thanks a lot, great explanation and idea how to test the restrictions

[@joediesel8267]

Awsome, Awsome video. Very well explained. Thankyou so much for going to the effort in setting up this experiment.

[@not_A_racer]

Great work! Keep it up

[@Impedancenetwork]

F()cking nice. I have my bike tore apart doing these modifications right now. Removed the evaporative control system. Removed in intake snorkel then enlarged the intake. I added the CBR300 High Flow Airbox Velocity Stack and the air box lid with the "frog skin" from 550 Performance. I have a stage 1.5 ECU coming next week. Added the full RS-4 Yoshimura exhaust (which I highly recommend). I might add the CBR cams but I doubt it. I'm loving this bike, but if I want more power the only real option is to install the big bore kit from 550 Performance which I will never do. After I fix this all up I'm going to ride it for a while then buy the KTM 500 EXC-F for more power. I will never sell my CRF 300L but sometimes I need more power and speed so I'll get on my KTM 500 for that. But for longevity, durability, and low maintenance I will ride my Honda. I have a BMW 1250 GSA but I ride my little Honda 300L much more than that 600 pound BMW.

[@colmhaughey7001]

Makes sense can’t argue with the facts I’m working on my air box at present undertaking a similar modification next step with be the exhaust system thereafter review the fueling/ECU really interesting all your modifications so far excellent…!!!

[@RozalynVeersma]

Thanks for doing the exercise! Greatly appreciated! 😁🙏🏍💨

[@Azzaslife]

Thanks Roz , glad I can give you some content as you’ve entertained me for a long time 😁👍

[@Efabulous22]

Amazing video!

[@Jason-fn5ke]

Great video!! Thank you

[@lespatterson2430]

Extremely well done. Wondering if you have the gear to compare the emissions from the engine after modification.

[@ShonkyProductions]

Great work Aaron, that confirms what myself and others have suspected. I am about to do some similar modifications to my airbox in order to take advantage of the CBR300 cams and 550Performance ECU. I like your pod style air filter, does that fit under the seat ok?

[@marcochavanne]

I know you buggered your shoulder, but when you’re able, can you give some feedback on your mods now that you’ve given it the beans in a rally? I’ve been on the fence and have been waiting until you reported back as to it being worth the trouble. I’m at 4,000 miles and haven’t checked the valves yet. Figured I’d replace the cams and intake if in going through all the trouble if it’s worth it.

[@ShonkyProductions]

@@marcochavanne Hi Marco, I am getting ready to do just that. I'll probably need another week or so until I'm good enough to get back on the bike... but it is coming.

[@user-de4ew8cz1g]

Very good info and video. any info on using twin air filter

[@michaelanderson3771]

I have seen other guys put the Unifilter snorkel sock on the end of the inlet like a dunce's hat and that seems to work better. However i agree your modded 4" inlet mod seems to be most effective. I have seen the 550 performance side cover with frogskin also - wonder what that mod would provide on your Manometre. Also testing the unifilter foam main cage air filter.

[@mt1885]

Can you do an update video on the MODS and what you think on the New Twin-Air filter and the new UNI Filters ?

[@guestappearance3211]

But whats the max airflow that actually achieves max hp, by the principle you are working to a 6ft x 6ft airbox with a 4” velocity stack will give more more

[@janqueski]

Excellent ;)

[@240LTS]

... 19:00 ... Is that red filter oiled? If it is not, that will cause even more restriction. Loving this video. Thank you for doing it. . Jeff .

[@marcochavanne]

Curious about your impressions after a few months and if you’ve had any notable loss in torque.

[@daletroy3348]

Thanks for sharing, it’s very interesting. It seems like a lot of modifications and I wonder just how much benefit there is at the end of the day compared to a stock bike , I’m a 110 kg guy and tend to think that I could chase incremental gains till the cows come home spending heaps of money when I should go on a diet 😂😂 but very still interesting none the less 👍

[@Azzaslife]

For a 300 , big difference. I’ve also heard a lot of good feedback.

[@phantomshtter]

It's not about gains, its about getting the bike properly fed instead of malnourished.

[@dickappel337]

Hi Aaron, nice check over of the air box/ airflow for more power, I’ll see what I will chance. I’m only 67 kg 77 full gear, it goes alright as it is right now. BTW where are you located in Australia? Greetings Dick.

[@mcdonaldslover52]

are you worried at all about the air coming in being less filtered? Or are you chasing pure HP for street use? Especially in australian conditions a couple of sessions in the desert destroys the stock air filter.

[@cwalnut]

Bingo...ive done a lot of testing as well..i run a 41mm TB with stage 2 race cams (my bike is track-race only) and it makes the most power with no airbox or intake stack (nor even cbr 300 intake) just a unifilter!

[@dodgierogie68]

awesome video,are you going to go with a 550 ecu? and is it restricted between the throttle body and the engine? i hope you have the time to do follow up vids to the mods,keep up the good work cheers from WA

[@Azzaslife]

Yes 550 performance is almost finished with the new 1.5 modified tune , should be a winner.

[@dodgierogie68]

@@Azzaslife awesome

[@luke3892]

@@Azzaslife anywhere I can find info on their new tunes?

[@Bruneello]

Which block plate you used for the PAIR valve? Cannot fined it for the 300L, but it seems same shape as the 450L

[@1964mjc]

Nice work - would the stock ecu adjust the fuel air ratio correctly to allow for the extra air or do you need the 550 performance tune ecu to compensate for the extra air ?

[@Azzaslife]

ECU tune is a must. Tune is lean from factory, only gets worse with mods.

[@gregjetnikoff7124]

The throttle body intake of the CBR may be a bigger diameter, considering it's length you will lose acoustic reinforcement flow at about half the revs that the original will have. There is no testing of the pulse performance. Now having said that you have cammed it for the CBR cams. This setup should give you a good boost. BUT if you are using the wide range CRF camms I suspect the low end power will suffer. The higher volume cbr intake will exaggerate that as the air velocity at lower airflows will be a lot slower. The air flow overall is useful for us with std cams I think, but I am not so much a fan of the throttle body inlet without the cam change. I had a feeling the extermal intake socks were way too restrictive . Thanks for the confirmation! My dBkiller modded ( larger holes in the killer) to intake cross-section MotoX , I have noticed that the 550 ECU is running rich even with two stock external intake tubes. So I may go to a much larger external intake and put a foam filter over them. I will probably make a couple of aluminium or carbon fibre Blair shape tubes there, but may just try simple larger diameter ones. Thanks for the effort.

[@Azzaslife]

Thanks for the insight, I did a great deal more with testing (some things you mentioned) but I cut it shorter to reduce Boring content. I think this setup most people can relate their mods to.

[@IRQ1Conflict]

Can you just toss the airbox all together and just run a filter straight to the throttle body? Or would that be too much airflow?

[@lindsayfinger4262]

What did you actually use to cut the hole for the 100mm? What was it that you heated up to cut the hole?

[@koshtie]

Hi Aaron do you have a part number for the cb300 iintake please, as every time i look this up it shows an angled inlet ? Yours hopefully Wayne UK....

[@killshot7041]

A lot of people say Honda did this for emissions but the CB300 is also honda's and it has the better air intake and cams, could it be that the intake snorkle is long to avoid water getting into the engine easily? By being so long it dumps water at the bottom of the intake box and avoid it getting sucked through the filter

[@kiler2death]

why would honda make the box restrictive? I don't understand why they chose that. is there a benefit?

[@Johnsmithabcde]

Hi Mate, Where are you located Do you do any crf300L work for others for money?

[@brodiedahms4675]

Be keen to see what HP you make after a tune. Big question would be what exhaust you running to match intake?

[@Azzaslife]

Motox as 550 performance has a specific tune for all my mods.

[@benconverse6158]

I had a thought, and I know the CBR300 intake boot it like $20, but could you just cut the snorkel off the CRF intake and get a similar result and spend no money? Would there be a performance upgrade vs. stock? Also, then you wouldnt have the fitment issues with the CBR intake. Id love to see that in another video with the Muppet Manometer! I saw a Jake the Garden Snake video where he did the CBR intake mod and measured the ID of the 2 intakes, at they are the same at the throttle body end, but the CRF snorkel end is much narrower. Just wondering if anyone else had thought about this.

[@jesseduplantis3369]

I've thought the exact same thing... still haven't seen if anyone tried it.

[@benconverse6158]

@@jesseduplantis3369 I did end up doing it, and using the cut off piece to add another air box hole. My butt Dyno says it helped, but I do t have any numbers to back it up

[@240LTS]

... 2:45 ... do you mean the resonator will not be installed? It is not needed? It is there "to take intake noise out of the bike"? Yeah, I'm confused.

[@507sounds]

Has anyone used a 3d printer to make an adapter plate to fit the cb300 velocity stack to the throttle body/airbox so we don't have to make our own seal out of epoxy or something?

[@steveeichelberger806]

No dyno results?

[@Supersoldier398]

Which uni filter is that? I’m about to do the 4in fitting mod to the stock snorkel

[@Azzaslife]

4 inch unifilter sock for a 4inch 4x4 snorkel.

[@glockmodder]

🤔 i wonder if i could just put a small pod filter straight onto the throttle body if i wasn't worried about mud and water?!

[@Azzaslife]

I thought the same, you so could easily.

[@glockmodder]

@@Azzaslife im gonna do it then im currently running a full yoshimura rs4 exhaust with a 550 performance 87 stage 1 tune wish me luck😋

[@glockmodder]

@@Azzaslife one question ive got the emissions delete done but whats the other hose that goes from the engine to air box is it just a crank case vent?

[@805gregg]

Very scientific????

[@ichebensonstniemand]

Eh probably not so much for two reasons: First, the suction of the leafblower is continuos, while a 4 stroke motor only sucks bursts of air. This is also the reason why airboxes often have those highly engineered shapes, because they want the air to resonate at certain frequencys (=at certain rpms) to produce boost. This video only shows how to eliminate air drag, but does not tell you what happens to all the resonances and other effects of the pulses. E.g. those long small tubes in the intake for sure cause drag, but they also produce a fast moving stream of air while the engine is performing an intake stroke. When the intake valve closes, the fast air has enough momentum to push forward in the tube and accumulate towards the end with a higher pressure. If tuned right, just as the highest pressure is reached, the next intake stroke begins and takes this "boost" in. The very long tube of the 300L suggests its tuned for low frequencys. The second problem with this experiment is how the hose taps into the side of the airstream. It does measure the drop in static pressure when the air is held back by drag, but depending on the orientation of the opening of the hose it could also see a mix of stagnation pressure and static pressure. These behave completely different, as one goes up with airspeed and the other goes down (Bernoullis Law). At last, comparing the pressure of the CB300R and the CRF300L intake is not good practice, because different diameter tubes will have different pressure inside, even if the same amount of air is flowing through (see venturi effect on wikipedia or elsewhere). And its just the amount of air (=mass) that counts in the end. Nevertheless I think its great that this experiment has been done, and its probably scientific enough for tinkering with your enduro bike, i will for sure do some of those mods. Just keep in mind that you are also messing with resonances, which can make you loose some of this boost at certain rpms. And i wonder why no one just cuts of the long CRF300L intake, because getting the CB300 one in there seems to be quite a mess

[@PatchedBandit]

@@ichebensonstniemand "And i wonder why no one just cuts of the long CRF300L intake, because getting the CB300 one in there seems to be quite a mess" EXACTLY my thoughts too! The intake is supposedly the same size from the engine side on both CB300 and CRF so about 40mm exactly. The CRF boot narrowes towards the rear end all the way to 35mm but if you cut 75-80% off the rear end it should be almost exactly the same as the CB300 part. I'm in the process of doing a long video of me tuning my CRF with the ecu, intake stuff and full exhaust swap. I will learn there if it can be done too. I will also do drag runs with RaceBox to see the actual differences.

[@jesseduplantis3369]

@@PatchedBandit following your channel... I've been thinking the same thing. Love to see your results.

[@user-yo1pk4ky4k]

This test does not take into account the resonance of the intake system when the bike is running. This is just backyard "engineering." Not quite the same as those pesky Japanese automotive engineers use with their fluid dynamics testing. Leave engineered products alone!