Yoshimura Mikuni TMR-MJN32 Carburetor for the Ninja250R

[ninja250r81]

MAYBE A REPOST but

Yoshimura are going to release aftermarket tunable carburetor's for the 08+ ninja 250r

https://www.yoshimura-rd.com/t-NP_12..._TMRMJN32.aspx

[lgk]

how much?

[GlassAnkles]

man those look good, hopefully that dual stack version spices up the mid range a little more.

its yosh, i bet it cost a fortune the first few years.

[GlassAnkles]

the oil tank breather that is required for these is $242 on its own

Oil Breather Tank Kit (Part No. 532-001-0000)

[flurbadurba]

want

[Racer x]

What is the oil tank breather for? I have had the Keihn CR Specials on for years now. This looks like a good set up

[choneofakind]

How would you be able to rejet with that setup? are there jets you can change?

Originally Posted by GlassAnkles

the oil tank breather that is required for these is $242 on its own

Just get a crankcase breather, and stick that on the hose. $10 from an autoparts store.

[Racer x]

The jetting is simple. The bottom of the fuel bowl unscrews and gives you access to the main jets. the needle is accessed through the top.

Race carbs are easy to adjust and work great. Plus this is a 32mm carb.

The only way to gain horse power is to increase the air and fuel going into the engine. I would rather have a great set of 32mm carbs over a FI system with a 28mm throttle body. Unless you want fuel economy.

[DaBlue1]

OK, a price has been found. Prices range from $1,294.00-$1,498.00 (as of 3-18-12). Of course items from japan.webike.net are expense anyway.

http://japan.webike.net/products/20295995.html
http://japan.webike.net/products/20295994.html
http://japan.webike.net/products/20295996.html

[thisisbenji]

Holy crap, I take it we will only see these on track bikes eh?

[choneofakind]

These seem kind of expensive compared to other 31mm CR carbs.

Keihin ones are around $430. $1,300 seems awfully steep when the competition is 1/3 the price

[Racer x]

over a grand is a bit expensive. My CR carbs where 400 bucks. and I got 34hp with them. Plus other mods

[jmgrande]

MJN Carburetor - Theory meets Practicality. Fujio Yoshimura figured out a way to create a Multiple Jet Nozzle that would be more efficient at atomizing fuel. It took a lot of engineering to develop and test the initial prototypes, but once dialed, the results were spectacular.

The key is a nozzle which replaces the standard tapered needle. The multiple jets spray a fine mist of fuel, which atomizes much better, thus creating a more efficient burn. In addition, the atomized fuel is centered in the bore of the carburetor thus taking advantage of much higher intake velocities creating even more power and efficiency.

Benefits of the MJN:

MJN system atomizes fuel much better than ordinary solid type needles.
The MJN nozzle controls the amount of fuel in proportion to the throttle opening (intake air) by accurately drilled and positioned fuel intake jet orifices.
The resultant more efficiently atomized fuel gives better throttle response as well as better fuel efficiencies overall.
Also, the MJN system supplies the fuel through the MJN nozzle in the center of the bore where air speed is the fastest. This atomizes fuel even better!
Another very important theory of MJN system is when the throttle is shut off and engine braking occurs, very minimal amount of fuel is guided into the intake ports. Therefore, remarkably crisp throttle response is obtained, upon corner exit and transition back to 100% throttle settings.

COPIED FROM SITE, see link for more info:

http://www.yoshimura-rd.com/t-NP_12_..._TMRMJN32.aspx

[Alex]

/merged

[jmgrande]

Originally Posted by Alex

/merged

Thanks Alex!

Just ignore me I thought I found something new, ha guess not!

[Todd250]

that is pricey, but I am sure it works like a champ. Does anyone have any reviews on them? If it is a Yoshimura product you can all but guarantee it will be worth it.

[ninja250r81]

a little dodgy, seems like he is just a reporter and did not know much about manufacturing stuff.

how nice are the carbs . to me worth every cent

everyone needs to support the genuine factories and not just by how light the wallet gets

http://www.youtube.com/watch?v=zlmyVuWi2JA

[jmgrande]

Scott do you have the Yoshi carbs? I thought the 250 was EFI in Australia

[Nemesis]

Big mistake and a waste of research & money on Yoshimura. Mark my words.

[ninja250r81]

Originally Posted by jmgrande

Scott do you have the Yoshi carbs? I thought the 250 was EFI in Australia

i do not have yoshi carbs, will be getting them if i dont upgrade to a zx6r.

aussie gets carb.

there are fuel injection 250's being sold called "grey imports" from a certain "victorian" shop who has brought a few shipping crate loads from a few closed down kawasaki usa suppliers.

nothing but bad comments from people who have brought their bike's from there

from missing parts, braking down, injection parts are only sourced in usa etc

[HKr1]

They look like down draft carbs, interseting they work well mounted level.

[fordendk]

Originally Posted by Nemesis

Big mistake and a waste of research & money on Yoshimura. Mark my words.

Your words are marked and in my opinion completely "wrong". You should not post about things that you obviously have no experience with.

I have these carbs now and they totally rock! I have tested with/vs a friends Ninjette with jetting mods to standard 30mm Kiehins and sports full system exhaust. I have an arrow titanium exhaust (removed DB killer) and he uses an R9 (IMHO probably a similar 2-into-1 full system for Ninja 250). He has a FactoryPro jetting kit in his Kiehins. My only two mods are the carbs and exhaust.

We swapped bikes today for testing (mostly so he can feel the difference with my carbs). I was on his bike watching my bike pull away like I was standing still after I hit full gas on his bike and revved it out in each gear. His bike actually felt like a bit of a pig after riding mine. There is nothing wrong with his bike at all and it definitely has more power than mine was with the standard kit. Mine has not even been tuned properly yet (will dyno and tune before and after CDI goes in over next few weeks).

These carbs and the arrow exhaust totally transformed my bike make a huge difference to the mid range throttle response. You can really feel it pull much harder now from 5K-9K and has a power band after 9K. The carbs are supposed to add 5PS to the intake and I believe it because you can hear the flutes/stacks sucking in the air (almost sounds like a mini-turbo). I am using the single stack model. I am sure that the dual stack model will be even better but I could not find it. My friend was shocked when he jumped on my bike. He is getting his $1500 ready to buy these carbs now. We will test his R9 exhaust with these carbs vs my Arrow exhaust on dyno in a few weeks (we are in Indonesia so now it is the quiet month of Ramahdan and hard to get things done).

The main difference I found when riding with these carbs is that you have to roll-on the throttle, not slam it on (same as most racing carbs) because if you give it full squirt all at once then you get too much fuel etc.. Next step for me is port+polish intakes, put in a JettingPro CDI and tuning. I think will get to near 40hp at rear wheel without engine mods.

BTW we also looked at another ninjette yesterday at the same workshop I installed the carbs at with a cheap single-map CDI (9 stage adjustment... nojikawa or something). This bike was revving out at over 16.5K (off the standard tacho'... probably more like 17-17.5K). It revved smoothly with none of the usual fart/burp at 12->13K and also seemed to get to top revs very quickly. It had all standard engine and carbs with FactoryPro jet kit and Yoshimura USA full system (not Japan).

I am going to go for the JettingPro CDI because it should get the same results and has 2 selectable maps plus a launch control/limiter. This limits revs to a selected limit... say 10,000 when the clutch is pulled in and will release and rev to max when clutch is released.

Anyway... no bullshit and I don't work for Yoshimura.

[lgk]

i would have bought the yoshi carbs, if they cost less than my EFI kit.

[fordendk]

I just went on gut feel because of the results I have had with carbs on other bikes and cars. Actually I am a little surprised at the performance increase.

[lgk]

might just be the response is more crisp.

i suspect my bike doesn't make much power over a well tuned carb, but the response is instant and other riders have said it felt more responsive on both low and high end.

[cuong-nutz]

Can't wait to see the dyno results

[fordendk]

Originally Posted by lgk

might just be the response is more crisp.

i suspect my bike doesn't make much power over a well tuned carb, but the response is instant and other riders have said it felt more responive on the low end.

I was a little surprised at first but I am sure that it is definitely substantially more power and also improvement in the lower-mid-range throttle response. It is very noticeable.

I actually talked to couple of mechanics before I went ahead with these carbs. One of them said that carbs don't make much difference and another said that the Yoshi carbs make a huge difference (obviously the guy selling them to me). I would have been very pissed at him if it didn't and it is not like he can run away because I was there and testing while he did the work and his workshop is just down the street from my house within 3km. He said he has done a few other bikes and got great results too so that is why he recommended it. He told me that just these carbs are worth about 5hp rear wheel on average (remains to be seen).

My previous experience with other bikes is that race carbs do make quite a difference. Anyway I won't be talking to the anti-carb guy much anymore about this or anything else for that matter (... he also tried to convince me about a port+polish and a 280 bore-up kit on a brand new bike instead of trying the carbs first). The same guy told me that FCR carbs will be pretty much the same as the Yoshi MJN's. I very much doubt that now too. Maybe not many people are trying the Yoshi's because of the cost.

When we ran our initial test to compare bikes we were straight line dragging from standing start and I was giving my buddy's bike a serious fist-full of throttle all the way through 1st -> 4th. He was pulling away from me easily on my bike (he was actually quite a way ahead after about 400m and I was getting further behind while still winding out his bike). Bottom line is that my bike blew my buddy's bike off easily. We both have the same wheels and same tires (standard front rim with Chemco 4.5" rear wheel and Bridgestone BT92's) and same standard sprocket. When my buddy got off my bike he said he was quite shocked at the power increase over his bike.

We will do some more testing over the next couple of weeks to confirm at higher speeds and acceleration from each rev range and also try to test against some other bikes also (at least we call it testing ).

I will try and do the right thing by reporting back the results when my buddy gets these carbs in a few weeks to see if he gets the same performance increase because I would hate to see a bunch of people running out to spend $1500 on carbs due to my testimonial. I might also post dyno results if we get it done and get the images.

I have noticed that it is not easy to get good reliable information about these bikes and mods etc. because a lot of guys just rag on in forums about wasting money and buying a bigger bike etc. and all the vendors say that their crap is the best etc. Actually the negative stuff is annoying because it doesn't help anyone. It is far more helpful when people post their real/personal experiences and facts not some BS assumption/hearsay based on their supposed/assumed genetic or intellectual superiority.

For us here in Indo' it is not about bigger bikes and mostly not about money at all. You have to live here to understand why people love 1/4 liter bikes. I have owned many bigger bikes (GSXR, R1 and Fireblade 900 plus a longer list of older bikes both 4 stroke 4 cyl and 2 strokes right back to early days) before in other countries and if I really wanted to own another one here I would just buy one and probably keep the ninjette anyway because money isn't a problem.

The main reasons most people try 250 things more for kicks here in Indo' is because big bikes are outrageously expensive and are not that practical in the insane traffic here. It is also a major hassle with police, registration and gray market imports... quite a mess actually. Also sometimes you have to wait a long time to get the bikes you want imported, spares and mods also and some importers jack up the price so much that it is ridiculous (makes me sick to think about paying some opportunistic jackass ransom like that). So just many pains in the ass with big bikes here whereas 250's are everywhere and easily modded. There are many mods for 250 here which makes for some additional enthusiasm and fun.

The ninjette is a very fun bike to ride (especially with mods... so far these carbs are a very fun mod).

[lgk]

can't wait to be the results.
i have no doubt the yoshi carb is awesome, and easy to tune.

does your friend use pod filters on his bike?

[fordendk]

My friend is using a K&N air open filter which is pretty standard here in Indo.

[lgk]

can you ask him what jets he using?

just trying to form a comparison.

[fordendk]

He is using a FactoryPro jet kit but not sure what sizes. We will find out when he removes carbs next couple of weeks and I will post back. I agree will be interesting comparison.

[dirty nasty]

Not a question so much about these carbs, but would Keihin CR flatslide carbs for a new-gen bolt up to a pre-gen? I realize jetting will need to be messed with (duh), but what else is different?

[lgk]

Originally Posted by dirty nasty

Not a question so much about these carbs, but would Keihin CR flatslide carbs for a new-gen bolt up to a pre-gen? I realize jetting will need to be messed with (duh), but what else is different?

if they work for a new gen it should work for the old gen.
the carb boots look the same.

the intake side would probably need a k&n though

[pomartin]

Originally Posted by fordendk

Your words are marked and in my opinion completely "wrong". You should not post about things that you obviously have no experience with.

I have these carbs now and they totally rock! I have tested with/vs a friends Ninjette with jetting mods to standard 30mm Kiehins and sports full system exhaust. I have an arrow titanium exhaust (removed DB killer) and he uses an R9 (IMHO probably a similar 2-into-1 full system for Ninja 250). He has a FactoryPro jetting kit in his Kiehins. My only two mods are the carbs and exhaust.

We swapped bikes today for testing (mostly so he can feel the difference with my carbs). I was on his bike watching my bike pull away like I was standing still after I hit full gas on his bike and revved it out in each gear. His bike actually felt like a bit of a pig after riding mine. There is nothing wrong with his bike at all and it definitely has more power than mine was with the standard kit. Mine has not even been tuned properly yet (will dyno and tune before and after CDI goes in over next few weeks).

These carbs and the arrow exhaust totally transformed my bike make a huge difference to the mid range throttle response. You can really feel it pull much harder now from 5K-9K and has a power band after 9K. The carbs are supposed to add 5PS to the intake and I believe it because you can hear the flutes/stacks sucking in the air (almost sounds like a mini-turbo). I am using the single stack model. I am sure that the dual stack model will be even better but I could not find it. My friend was shocked when he jumped on my bike. He is getting his $1500 ready to buy these carbs now. We will test his R9 exhaust with these carbs vs my Arrow exhaust on dyno in a few weeks (we are in Indonesia so now it is the quiet month of Ramahdan and hard to get things done).

The main difference I found when riding with these carbs is that you have to roll-on the throttle, not slam it on (same as most racing carbs) because if you give it full squirt all at once then you get too much fuel etc.. Next step for me is port+polish intakes, put in a JettingPro CDI and tuning. I think will get to near 40hp at rear wheel without engine mods.

BTW we also looked at another ninjette yesterday at the same workshop I installed the carbs at with a cheap single-map CDI (9 stage adjustment... nojikawa or something). This bike was revving out at over 16.5K (off the standard tacho'... probably more like 17-17.5K). It revved smoothly with none of the usual fart/burp at 12->13K and also seemed to get to top revs very quickly. It had all standard engine and carbs with FactoryPro jet kit and Yoshimura USA full system (not Japan).

I am going to go for the JettingPro CDI because it should get the same results and has 2 selectable maps plus a launch control/limiter. This limits revs to a selected limit... say 10,000 when the clutch is pulled in and will release and rev to max when clutch is released.

Anyway... no bullshit and I don't work for Yoshimura.

this. he is wrong.
there was not a lot of money spent on research.... this type of atomizing of fuel is well known for ages... they just made one, which works best on 250...
and besides.. bigger carbs do mean more power on high rpm... but also less at lower

[fordendk]

I have no idea about Yoshimura's R&D budget. I thought the original guy was saying that this is a waste of money and R&D also. My post was to reinforce my own experience with these specific carbs after paying over $1500 for them. All I am saying is that these carbs work awesome and I am very happy with them. I got much better than expected results. Maybe you can get similar results on Ninjette with FCR carbs also.

Would be interested to know if anyone purchased them and thinks they suck and why?

[Nemesis]

Originally Posted by fordendk

I have no idea about Yoshimura's R&D budget. I thought the original guy was saying that this is a waste of money and R&D also. My post was to reinforce my own experience with these specific carbs after paying over $1500 for them. All I am saying is that these carbs work awesome and I am very happy with them. I got much better than expected results. Maybe you can get similar results on Ninjette with FCR carbs also.

Would be interested to know if anyone purchased them and thinks they suck and why?

Hahahahhaa!

You had me at "I have no idea..."

I highly doubt a guy who spends $4500 on a current Ninja 250, would be foolish enough to spend another $1500 on carbs just to gain 3-5HP. $6K? Really? Go buy a used 600/650cc for that money.

I say it's a waste for Yoshi to invest all this effort and time, money building these because had they had inside contacts from Kawi they would have known a http://www.asphaltandrubber.com/wp-c...nja-250R-1.jpg was coming out that produces way more HP and has tons of features. And will be priced lower than $6K.

I'm just saying their timing is late, and the costs are too great for US riders/racers to even consider.

Maybe in your country it may be worth upgrading the carbs for whatever government regulations you may have but here in the States...nah, the cost outweighs the benefits.

[fordendk]

Originally Posted by pomartin

this. he is wrong.
there was not a lot of money spent on research.... this type of atomizing of fuel is well known for ages... they just made one, which works best on 250...
and besides.. bigger carbs do mean more power on high rpm... but also less at lower

Just in regards to "bigger carbs do mean more power on high rpm... but also less at lower"... what Yoshimura claim is that the 4 jet/needle approach in MJN they use also adds power in lower and mid rev range. Seems good to me so far. What you said is probably true for most carbs.

[lgk]

Originally Posted by Nemesis

Hahahahhaa!

You had me at "I have no idea..."

I highly doubt a guy who spends $4500 on a current Ninja 250, would be foolish enough to spend another $1500 on carbs just to gain 3-5HP. $6K? Really? Go buy a used 600/650cc for that money.

I say it's a waste for Yoshi to invest all this effort and time, money building these because had they had inside contacts from Kawi they would have known a http://www.asphaltandrubber.com/wp-c...nja-250R-1.jpg was coming out that produces way more HP and has tons of features. And will be priced lower than $6K.

I'm just saying their timing is late, and the costs are too great for US riders/racers to even consider.

Maybe in your country it may be worth upgrading the carbs for whatever government regulations you may have but here in the States...nah, the cost outweighs the benefits.

the carbs were manufactured for a variety of bikes.
they just linked two of them, created some jets, and cnced some different mounting options for the 250.

i dont think they wasted much time on these carbs.
they just figured a new way to make it profitable.

[Nemesis]

Originally Posted by lgk

the carbs were manufactured for a variety of bikes.
they just linked two of them, created some jets, and cnced some different mounting options for the 250.

i dont think they wasted much time on these carbs.
they just figured a new way to make it profitable.

And they want $1500?

[lgk]

Originally Posted by Nemesis

And they want $1500?

lol, i know its expensive.

but if we didn't have fuel injection, they would totally be worth it.
they are way more tuneable than the standard carbs, and the response is way better.

now, its kind of a niche market where you have to want race carbs or compete in a race that forces you to use carbs.