I may be missing something basic, but it seems as though where the harmonic intake mounts to the carb, there is metal to metal contact. How does that create a perfect seal so all of the intake air goes through the filter?
This is why RUclips is gold. The presenter builds alliances bike-by-bike. It's good because it corners big industry into electricity as used bikes increase in value in money and culture. The utilities send bills so they aren't outside a broad scrutiny, which is good for bringing in different means of power generation. One efficiency generates another.
So your main jet is actually smaller than the original one? 122.5 vs 115-120? I bought a dead sr250 today for 100 euros haha. I want to fix her up again, thanks for the vids!
Correct! With the long harmonic intake the fuel mixes much better with the laminar air flow through the carb - meaning less fuel is needed for a good power producing mixture. All this is worked out on two different dynos with two different operators by the way, so it's not just throwing grass in the wind ;)
@@JadusMotorcycleParts you always want the ideal stoiciometric balance for max efficiency. So either the stock sr is running rich (which it isn't, I've been racing these engines for a decade...) or your kit makes it run lean. To get 20% gain you need a lot of work in the head, different piston, bigger carb, different cam and programmable ignition. Show us the print out from a dyno...
@@sipke All the relevant info is available up on our website on our performance parts page: www.jadusmotorcycleparts.com/performance-parts You are incorrect about needing to do all that work for a 20% gain. We are 100% transparent with all of our testing and results, if you want any further info, don't hesitate to send us an email, we'll send you all the original dyno footage and graph printouts. You are also very incorrect with the assumption that best power is achieved at stoich, not even if you want maximum efficiency. Every engine is different and especially old, air-cooled carburetted engines have different needs. Best fuel efficiency can be up to 16:1 while best power, depending on application can be as low as 11:1. Out of curiosity, do you have a link to some of the work you have done for the past decade? We would be very curious to see what you have done and achieved :) Anyway, cheers for your interest! - Jadus
Hi Matt, unfortunately there are no tanks that are direct bolt on. Many people have adapted other tanks to fit, but then they have fabricated their own brackets and welded them on.
Good question, we actually have no idea sorry! It would be highly unlikely though, sadly. Engine exhaust port angles and bolt patterns differ a lot from model to model.
There are a few more factors that play into the equation so you are best to check our jetting guide here: www.jadusmotorcycleparts.com/post/2018/05/17/yamaha-sr250-carb-rebuild-maintenance-tuning Cheers!
Unfortunately not (that we know know of). We called our first pipe 'Low Slung' because we had intensions of doing a high pipe. But sadly it never happened... I wonder how much interest there would be in such a pipe?
Hi! Due to the fact that the intake is a harmonic intake, the distance from the valve opening to the opening of the intake itself is the most important. Then second to that is the smoothness of uninterrupted flow through the intake system. So adding a coupler may affect both the length of the intake path plus increase turbulence slightly. Hard to know the exact effect but there would be a reduction in effect for sure.
@@JadusMotorcycleParts thank you for the fast response. If I were to make a modification to your intake by adding a 90° bend while mantaining the same overall lenght, do you think it would still have any benefit or I would be better off just leaving my steel conical filter?
@@haythamfpv Difficult to say man. There is a lot of theory behind this kind of stuff, then it is another thing in reality. We tested this particular design for many hours on the dyno to get these results, so an introduction of something new to the system would likely effect the result and would need to be tested.
Hi Patrick! That is because we have been out of stock for a very long time - trying to develop and source our own silencing core. But now they're here! And in stock so you can choose that option now if you like :)
Change filter and exhaust !!! Come on bro ,, we know that if exhaust block bike will loose power nothing new but for filter ,, how could it gives me more performance????
We got really good results with this kit - you can see a video of the testing here: ruclips.net/video/y1NuDUXWREw/видео.html And if you are interested you can learn about the parts here: www.jadusmotorcycleparts.com/performance-parts There you can see a bit about the special 3rd wave harmonic intake bell mouth ;)
Your hate toward that exhaust clamp had me laughing so hard
Haha, when you have installed countless aftermarket silencers with that clamp, you come to hate it!
I may be missing something basic, but it seems as though where the harmonic intake mounts to the carb, there is metal to metal contact. How does that create a perfect seal so all of the intake air goes through the filter?
Sherman T. Potter good tolerances :)
This is why RUclips is gold. The presenter builds alliances bike-by-bike. It's good because it corners big industry into electricity as used bikes increase in value in money and culture. The utilities send bills so they aren't outside a broad scrutiny, which is good for bringing in different means of power generation. One efficiency generates another.
So your main jet is actually smaller than the original one? 122.5 vs 115-120? I bought a dead sr250 today for 100 euros haha. I want to fix her up again, thanks for the vids!
Correct! With the long harmonic intake the fuel mixes much better with the laminar air flow through the carb - meaning less fuel is needed for a good power producing mixture. All this is worked out on two different dynos with two different operators by the way, so it's not just throwing grass in the wind ;)
@@JadusMotorcycleParts ok, thats awesome man! Never thought about that effect! Thanks for your answer👍
@@JadusMotorcycleParts you always want the ideal stoiciometric balance for max efficiency. So either the stock sr is running rich (which it isn't, I've been racing these engines for a decade...) or your kit makes it run lean. To get 20% gain you need a lot of work in the head, different piston, bigger carb, different cam and programmable ignition. Show us the print out from a dyno...
@@sipke All the relevant info is available up on our website on our performance parts page: www.jadusmotorcycleparts.com/performance-parts
You are incorrect about needing to do all that work for a 20% gain. We are 100% transparent with all of our testing and results, if you want any further info, don't hesitate to send us an email, we'll send you all the original dyno footage and graph printouts.
You are also very incorrect with the assumption that best power is achieved at stoich, not even if you want maximum efficiency. Every engine is different and especially old, air-cooled carburetted engines have different needs. Best fuel efficiency can be up to 16:1 while best power, depending on application can be as low as 11:1.
Out of curiosity, do you have a link to some of the work you have done for the past decade? We would be very curious to see what you have done and achieved :)
Anyway, cheers for your interest!
- Jadus
@@sipke If you're interested, you can read about air/fuel ratios here: www.carmo.co.jp/index.php?main_page=chiptuning_ecuflash_tuning
Hey bro. I badly need info on how high should be correct compresssion test value (2003 Sr 250). Thank you!
Min 130psi. Preferably 140+
@@JadusMotorcycleParts Thank you very much!
I'm really trying to find a gas tank that'll fit this bike without having to modify the mounts. Do you know of any or a good place to look?
Hi Matt, unfortunately there are no tanks that are direct bolt on. Many people have adapted other tanks to fit, but then they have fabricated their own brackets and welded them on.
@@JadusMotorcycleParts ya I rewelded the mounts and made an old xs 650 tank work. Really wasn't as bad as I thought it would be
Hi @jadusmotorcycleparts team! Would 2 of your exhausts fit an MG250 (dual port exhaust) to give my bike that simetrical look?
Good question, we actually have no idea sorry! It would be highly unlikely though, sadly. Engine exhaust port angles and bolt patterns differ a lot from model to model.
Hey dude, what size main jet should I use with no air cleaner?
There are a few more factors that play into the equation so you are best to check our jetting guide here: www.jadusmotorcycleparts.com/post/2018/05/17/yamaha-sr250-carb-rebuild-maintenance-tuning Cheers!
Is there a high pipe available for a scrambler type sr250?
Unfortunately not (that we know know of). We called our first pipe 'Low Slung' because we had intensions of doing a high pipe. But sadly it never happened... I wonder how much interest there would be in such a pipe?
Would this work on a xt250, with a different exhaust?
Hi there, unfortunately not. The intake kit would not fit the XT carb.
Hi, I was wondering if the intake would give similar advantages even mounted with a 90° coupler, thank you!
Hi! Due to the fact that the intake is a harmonic intake, the distance from the valve opening to the opening of the intake itself is the most important. Then second to that is the smoothness of uninterrupted flow through the intake system. So adding a coupler may affect both the length of the intake path plus increase turbulence slightly. Hard to know the exact effect but there would be a reduction in effect for sure.
@@JadusMotorcycleParts thank you for the fast response. If I were to make a modification to your intake by adding a 90° bend while mantaining the same overall lenght, do you think it would still have any benefit or I would be better off just leaving my steel conical filter?
@@haythamfpv Difficult to say man. There is a lot of theory behind this kind of stuff, then it is another thing in reality. We tested this particular design for many hours on the dyno to get these results, so an introduction of something new to the system would likely effect the result and would need to be tested.
@@JadusMotorcycleParts thank you!
Where is the best place to purchase your parts in the USA?
Hi Eric! We have one reseller that serves the entire globe: modelikocaferacers.com/gb/248-yamaha-sr-250 :)
Amiggo cómo puedo comprar esos accesorios para mi sr y que me los manden a mexico
how much would it be to get one of these kits to Malaga,Spain ? I recently bought one of these babys
Standard shipping for the kit to Spain is around 35Euro :)
Could your kit works for a suzuki gn250 as well? (With proper carb tuning)
No sorry man, completely different engine and carb design!
Why can't I select "with silencer" on the website?
Hi Patrick! That is because we have been out of stock for a very long time - trying to develop and source our own silencing core. But now they're here! And in stock so you can choose that option now if you like :)
What size is that crank case filter?
Roughly 35mmx35mm
Bobs yer uncle!
Change filter and exhaust !!!
Come on bro ,, we know that if exhaust block bike will loose power nothing new but for filter ,, how could it gives me more performance????
We got really good results with this kit - you can see a video of the testing here: ruclips.net/video/y1NuDUXWREw/видео.html And if you are interested you can learn about the parts here: www.jadusmotorcycleparts.com/performance-parts There you can see a bit about the special 3rd wave harmonic intake bell mouth ;)
@@JadusMotorcycleParts
Thanks bro
You are the best