are jet kits worth it??

[sburton1]

so is it worth it to buy a "jet kit" or is it easire to just buy th idividual jets from some where on line?? if so whats the best kit at a reasonable price for an 450r carb?? thanks guys

[Chino886]

If you know what jet you need, a kit is a waste!

But if you plan on doing lots of mods to a stock bike, then having extra jets to play with is a good thing!

[F-16Guy]

My brother bought me a jet kit a long time ago, and now I have a whole box of jets collecting dust. They're nice to have sometimes for the large selection, but most of the jets will probably be unuseable. If you know roughly what jet you need, buy that one and a couple on either side.

don't waste your time with the dynajet jet kit, or any other company that rebrands their kits(k&n is one)...their jets are listed as different sizes...for example a keihin might be a 138 where the same size jet from dynajet might be a 145(these are just example numbers, not an actual conversion).

try this site...you can pick up a range of jets or their jet kit, both using actual kehin jets... jets-r-us (http://www.jetsrus.com/)

[sburton1]

thanks guys what is the best brand of jet to run and what fits the 450r carb by the way im a F-15guy their F-16guy go usaf!!!!

[redexrider]

Dynojet isn't a rebrand company, there jets are different than Kehin jets. There is no quality issue between the two. You people that swear one is better than the other... they are made of the same material!! the differences are the size number, but that can be converted, and dynojet has an adapter for most quads that goes in first. Where in Kehin jets dont use an adapter. For anyone who travels the country riding different places (as I do) the dynojet kit has been great for changing the main for different places/elevations. It was no waste of money to me. But all of these Kehin fans will argue this and dog on Dynojet as much as possible... Both brands get the job done equally well. The only good point that has been made so far is that if you know what size jets you plan to run then you can buy them seperate and save a little money. If you just want a broad range of jets with instructions that tell you what you will need for what your bike has and what you ride, then a kit is for you. Whether you want to jump on the Kehin bandwagon or not is up to you. I have no problem with Kehin jets or any other brand, they all work the same if you know how to use them!!!

if it is a keihin carb, use kehin jets...did you look at that site i put up? read some of their frequently asked questions...it will help you out a lot

[redexrider]

"if it is a keihin carb, use kehin jets"


That is like saying it is a Honda, use Honda parts. It just makes no sense to insist that they must be kehin jets... And of course that page is going to say ONLY USE KEHIN JETS, its what they sell!! If I put up a site I could make false statements saying only my homemade jets should be used and come up with stories of problems with other compaines. On my GM truck should I only use AC delco spark plugs because that is what the stock ones were? of course not! I am not trying to dog on you, if you believe in ONLY kehin, that is your thing, but honestly there is no proof that they are any better than Dynojet or K&N or any other brand. Just asking you to be more open minded and give out advice that will help him. It sound to me that a KIT would be the way for him. No matter who it is from

did you read my post on why not to use dynojet kits...

if you have to use an adaptor then there is a problem...have you ever tried to get a replacement needle from dynojet? i bent the one in my 400ex last summer when i was cleaning the carb...i dropped it on the floor adn stepped on it. i called dynojet and the fun began.

here is what i had to do...could i just buy a replacement needle from them...knowing that i had a dynojet kit and needle, along with the part number of the needle...no...

i had to send my needle to them adn then they would determine if it was a dynojet needle. after that they would send me a needle and all i would have to pay was shipping. i did this, it took 8 weeks and the return shipping was $10.75. all they did was put the needle in an envelope...

i guess what is houdlhave said when i said use heihin jets were direct replacement keihin jets...not the stupid worthless dynojet jets...

and using your example of goign around the country and needing different jets...that is actually against dynojet...not may delaers carry single dynojet jets...i know wheni was looking for the needle, every one said that they couldn't get just the needle, i would have to get that from dynojet...i kinda get the inpression it might be the same for jets.

so with that being said, i go acrossed country adn don't have the right dynojet, i can't just go to a dealer and buy it...i guess then i am s.o.l. not good, but if i were running keihin direct replacement jets, then most likelya dealer would have what i need...

[GPracer2500]

I'm assuming this for an 04/05 TRX450R carb?

Here's why I prefer factory style jets:

--One thing I don't care for about the Dynojet kit is that for the 04/05 TRX450R carb (and some others) they want you to plug the main air jet. Personally, I don't like that. I've never found a clear answer on why they want that done. It's also a PITA to reverse. I just assume all the carb's circuits function as they were designed unless it can be demonstrated that Dynojet's way is superior. I've not found such evidence...

--Since Dynojet uses a different scale it makes it tougher to soliciting jetting advice from others. Not as many people use Dynojet jets. In my experience those that do tend to have less experience in jetting (now, no one get all upset--I'm just making a generalization I believe to be true). Those two things make getting solid jetting advice a little tougher task. I know there are conversion charts out there but I don't trust them. Dynojet themselves says that the flow characteristics of their jet designs preclude the accurate use of such charts [shrug].

--Keihin-style jets are more widely available. If you loose a jet or just need a different size than you're many times more likely to locally find Keihin style jets than Dynojets. Try finding Dynojet jets out at Glamis, for example.

--You can buy a range of Keihin-style jets that gets you just as much flexibility as a Dynojet kit.

--Instructions are fine and dandy but they're no substitute for a basic understanding of jetting fundamentals. Their instructions for what jets to run are only rough estimates. For example, they make no mention of temperature. I guarantee that 45 degree temps requires different jetting than 95 degree temps. And their elevation suggestions have 3000ft spreads. My point is that their instructions aren't any better than what you can figure out on your own. Plus, you can download the instruction sheets from Dynojet's website and get what little benefit the instructions actually provide without even using their kit.

--One advantage that Dynojet's kits have is adjustable needles. Some carbs don't come stock with adjustable needles. But, even if that's the case you can use shims or get a factory needle that's adjustable.

I don't question the machining quality of Dynojet's parts. It's the practical application that makes me recommend sticking with factory style jets. There's just too many advantages to using factory jets with too few advantages for using Dynojet's kits. Do Dynojet kits work? Sure they do. But is there any reason to choose a Dynojet kit over factory jets? Not in my opinion.

thank you gpracer2500, you summed up everything i was saying so eloquently. i used to be a dynojet kinda guy until iactually started doing this stuff myself and realizing the disadvantages of them...and the 2 months last summer i would have gone without a dynojet needle( the stock one didn't work as well with the dynojet kit), was ridiculous. it is a good thing that i was not a racer witha points championship on the line...imigne missing 7 or 8 races because you could not just buy a needle.

[krt400ex]

Originally posted by GPracer2500
I'm assuming this for an 04/05 TRX450R carb?

Here's why I prefer factory style jets:

--One thing I don't care for about the Dynojet kit is that for the 04/05 TRX450R carb (and some others) they want you to plug the main air jet. Personally, I don't like that. I've never found a clear answer on why they want that done. It's also a PITA to reverse. I just assume all the carb's circuits function as they were designed unless it can be demonstrated that Dynojet's way is superior. I've not found such evidence...

--Since Dynojet uses a different scale it makes it tougher to soliciting jetting advice from others. Not as many people use Dynojet jets. In my experience those that do tend to have less experience in jetting (now, no one get all upset--I'm just making a generalization I believe to be true). Those two things make getting solid jetting advice a little tougher task. I know there are conversion charts out there but I don't trust them. Dynojet themselves says that the flow characteristics of their jet designs preclude the accurate use of such charts [shrug].

--Keihin-style jets are more widely available. If you loose a jet or just need a different size than you're many times more likely to locally find Keihin style jets than Dynojets. Try finding Dynojet jets out at Glamis, for example.

--You can buy a range of Keihin-style jets that gets you just as much flexibility as a Dynojet kit.

--Instructions are fine and dandy but they're no substitute for a basic understanding of jetting fundamentals. Their instructions for what jets to run are only rough estimates. For example, they make no mention of temperature. I guarantee that 45 degree temps requires different jetting than 95 degree temps. And their elevation suggestions have 3000ft spreads. My point is that their instructions aren't any better than what you can figure out on your own. Plus, you can download the instruction sheets from Dynojet's website and get what little benefit the instructions actually provide without even using their kit.

--One advantage that Dynojet's kits have is adjustable needles. Some carbs don't come stock with adjustable needles. But, even if that's the case you can use shims or get a factory needle that's adjustable.

I don't question the machining quality of Dynojet's parts. It's the practical application that makes me recommend sticking with factory style jets. There's just too many advantages to using factory jets with too few advantages for using Dynojet's kits. Do Dynojet kits work? Sure they do. But is there any reason to choose a Dynojet kit over factory jets? Not in my opinion.

u know, i always thought that the stock style jets were better, but u just hit it home!!! u r like a walking dictionary for engines. i always find ur advice knowledgable and far superior to many bike shops around me. thanks....:D

[coryatver]

Dynojets are JUNK. Just spend 10 bucks you can get a bag of 5 or so kehien main jets from Parts Unlimited.

You can't convert the sizes between the two! Dynojets use a totally different scale and it is impossible to covert between them! there is no pattern. Some of the charts floating around are close but they are just estimates. You can't match a dynojet with a kehien jet.

But if you want to be a sucker and spend 100 bucks on a "kit" that you will use 2 of the jets out of go for it. Or you could be smart and get a few kehien jets for a few bucks.

[redexrider]

man man man, first off to the little boy who was arguing this, GP did not say what you were saying at all. He makes very solid points. And for CORY yes you can convert the sizes as I said and as GPRACER said. there are a few posts on here with a conversion chart showing what size compares to what size, pack your bags and go home kid. As for SPEEDY my example of going cross country was that with the kit you already have the jets you need! I wasn't talking about replaing them if one goes bad (which doesn't haooen too often) I was talking about having the versatility that a kit offers. Sit down son. I totally agree with GP's points it is great to have the knowledge to know what range of jets you might need. And to have the knowledge of what to use and when. But as far as some people on here go they are not knowledgable in this are and need an easy fix, Dynojet offers this. And for GPRACER I am by no means saying that Dynojets should be bought over any other, I am simply stating to the Dynojet haters that they should not bash them or dicourage people from buying them if they are looking for a self explanitory easy fix for thier carb. After tinkering with it and reading up on it, everyone can make thier own opinion on what jets they prefer. I don't prefer one over the other...

Little boy? hey mervin, i am 33 and probably have forgotten more than you will ever know. he is saying the same thing i was. i imagine that he didn't have a 5 year old sitting on his lap as we looked at kiddy sites and this site at the same time.

i never said that dynajet were poorly made, but the conversion can be confiusing, is kind of hard to find, and not completely accurate.

as far as using different jets for different locations, it is possible that your glorious kit will not contain the correct dynojet for the temp, elevation, or any of the other factors that affect jetting. and start asking around the locasl as to what dynojet you might need, chances are, most will give you the stock jet size, not the dynojet size. i hope ya carry you current conversion chart.

as for their instructions, well, a monkey could have written better instructions. i think their instructions are too general. most people go with the jet they say to use and that is it. there is no mention that 2 bikes, both having the same mods may need different jets. they meake jetting a carb to cut and dried and it can cause be bad for the motor. jetting is not an easy fix, damage can be quickly done to an engine with incorrect jetting. granted jetting si not as hard as it is tedious, and dynojet gives a fair starting point , but that is all it is, a starting point.

and the website i posted has a jet kit on it, witha variety of jets, but using stock jets that are cheaper than a dynojet kit, plus they even add in new screws for your carb.

so sit down junior and cut the umbilical cord..class has started

[sburton1]

wow thanks GPracer for the good explination! so the Keihin jets are the easiests to use? what is a good cheap web site to get em from? and dose this also apply to the pilot jet? just want to make sure i order compatable jets for the carb cause its going on my 400ex still trying out what jets to get exactly ill be running a full exhausts, wb rev box, uni filter, open air box with outer wears cover and a stage 1 or 2 hotcam. still deciding which cam to get leaning toward the stage 1 whats a good pilot jet starting point and main jet starting point for that setup? thanks again guys dident mean to cause a scuffel though!!

[redexrider]

Alright bud, I am 35 and really I am done playing with you. You did not say what GP did, nor was it anywhere near it. And yes the dynojet does have every jet I have ever needed for elevation. As far as Temp goes, I have never had any problem with the main in any temp, only the pilot, which is not part of the kit anyways. As for the conversion, if you buy a dynojet kit you do not need to worry about conversion, because they tell you what to use, and you can go from there. Really bud I am not trying to get at hardcore or anything here, but some of the comments you have made about the dynojet kit are just rediculous. I mean hell you don't even know what its called... it is DYNOJET not DYNA The kit is simple to use, and the instrustions are very clear, I have a copy if you would like to see them. They explain exactly what you need for your mods, and ELEVATION which is all thier kit involves, it does not involve temp. So now SBURTON good luck with the jetting. Be sure to read up on other posts to see what others have and what jets you may want to get. The site my friend here mentioned does seem like a good site to get jets, infact I think I might order some myself. My whole point to you was that the dynojet kit is an easy to do kit. When I first got into riding, it was the kit I used, and still use to this day. I still have my original kit, and use the array of jets often. SPEEDY where do you live, I might have to swing by if I am in the area sometime and ride with you, maybe get some of this out of the way.... really no hard feelings bud, some of your previous posts had some serious grammar and spelling problems which led me to believe you were just a boy.

[krt400ex]

Originally posted by redexrider
Alright bud, I am 35 and really I am done playing with you. You did not say what GP did, nor was it anywhere near it. And yes the dynojet does have every jet I have ever needed for elevation. As far as Temp goes, I have never had any problem with the main in any temp, only the pilot, which is not part of the kit anyways. As for the conversion, if you buy a dynojet kit you do not need to worry about conversion, because they tell you what to use, and you can go from there. Really bud I am not trying to get at hardcore or anything here, but some of the comments you have made about the dynojet kit are just rediculous. I mean hell you don't even know what its called... it is DYNOJET not DYNA The kit is simple to use, and the instrustions are very clear, I have a copy if you would like to see them. They explain exactly what you need for your mods, and ELEVATION which is all thier kit involves, it does not involve temp. So now SBURTON good luck with the jetting. Be sure to read up on other posts to see what others have and what jets you may want to get. The site my friend here mentioned does seem like a good site to get jets, infact I think I might order some myself. My whole point to you was that the dynojet kit is an easy to do kit. When I first got into riding, it was the kit I used, and still use to this day. I still have my original kit, and use the array of jets often. SPEEDY where do you live, I might have to swing by if I am in the area sometime and ride with you, maybe get some of this out of the way.... really no hard feelings bud, some of your previous posts had some serious grammar and spelling problems which led me to believe you were just a boy.


we r not here to argue about jets!!!! that is just stupid.

u all shared ur info and now u need to let the guy make a decision based on what he has been told.

end of story....

[sburton1]

so do the 04 450r carbs use keihin jets?? or the other ones?? thanks.

[sburton1]

good site very helpful!! ill have to order some new jets the carb swap that site is great shows ya just what you need! now to figure out a good starting point with the sizes.:confused:

[GPracer2500]

Yes--they use Keihin hex head main jets.

i have 2 copies of their crappy instructions...both for my old 300ex and for the wifes 400ex...

so i had a typo...big frigging deal...it isn't easy to type while holding a moving five year old on your lap...i'll go up and clean up the grammar/spelling since she is with "gramma" right now.

What gpracer said was essentially in the faq of the site i mentioned, and i thought i added it all in, after my poor customer service rant, but i guess i did not. Oh well, for that i apologize.

I am in Oil City, PA. You are more than welcome to ride with us anytime you want.

My point is that the instructions are general enough that anyone can do it, and they get you close. But when it comes it comes to jetting and the chances of having a lean situation, they are not specific enough. close is can be bad. if you end up on the rich side, that is ok, err on the lean side and troubles are headed your way.

as far as my rebranding comment. there are a few companies that take dynojet kits and rebrand them as their own, K&N is one of them

If somebody wants to have the adapter and and knows what they are doing and actually does plug reads, instead of just puttin in what dynojet recommends, then the kits aren't that bad.

holy run-on sentence there batman

Originally posted by sburton1
good site very helpful!! ill have to order some new jets the carb swap that site is great shows ya just what you need! now to figure out a good starting point with the sizes.:confused:

what mods do you have...pipe(slip-on, full.stock,with hrc), filter, lid on/off, etc.
let us know and we can give you a few to start with, or you can just order the jet kit from the list

jet kits are not bad, but you need to realize that just putting in the one jet that they recommend might not be the right jet, but it will be a close starting point

[F-16Guy]

Originally posted by sburton1
thanks guys what is the best brand of jet to run and what fits the 450r carb by the way im a F-15guy their F-16guy go usaf!!!!
Shady J?? Where do you work? I have a couple of co-workers that are going there very soon (we are Air Reserve Technicians in the Reserves).

As far as Dyno Jet instructions go, I feel they are pretty far off, especially Stage 1 vs. Stage 2. To run the Stage 2 jetting that they recommend for a 400ex, it would have to be a high compression big bore with port work and all the other crap. I have a 416 with 11:1 piston and HotCams Stage 1 cam, a K&N filter, an E-Series slip-on w/ 16 disks, and a vented airbox, and I just dropped down to a DJ 155 main and I think it's finally close. The instructions say 170 for my elevation, and it was so rich it would barely run. I was at 160 for a long time, but it still didn't feel crisp, so I went to the 155. It feels a lot better now, but I haven't really had the chance to ride it hard yet. Still, even the 160 was a far cry from what they recommended. I say save your money and buy a few Kehin mains and a pilot.

[redexrider]

F-16, yours was really that off??? It reccommended the same thing for mine the 170 main and mine runs like a top, plug looks great. Sounds like you went alot leaner, and its not too lean?? (by the way I am Air Force active duty, worked on 16's in Korea, and C-5/17's now)

[sburton1]

cool cool ya im at shady j not to bad. im at sea level with a full exhausts uni filter air box lid off with outerwears rev box. what pilot should i use with this 450r carb and what main shoud i start out with? ill get a coupple up and down just incase thanks guys.

buy the way lots of places to ride here in nc.

[PismoLocal]

Imho jet kits are not worth it, why spend $60 on a dynojet, K&N, FMF kit with 10 jets and 1 needle when you can buy almost 20 jets for that same amount from a different company? Doesn't make sence to me.