does anyone kno anything bout the Dial-A-Jet. i want to put on my 2000 400ex fmf slip on exhuast and k&n air filter and i dont kno to much about it. does it give good horsepower gain or throttle response. is it hard to put on or dial in. the people who sell it says it easy to dial in. i want to kno what people think about it.
jrock31
The Dial-A-Jet system allows you to adjust your fuel flow without taking the carb apart or even touching it. When properly installed, the Dial-A-Jet draws extra fuel into the intake system. Depending on the engine load, the Dial-A-Jet automatically adjusts the amount of extra fuel that is needed. The extra fuel is pre-mixed to an atomized state with incoming air before it reaches the carburetor, similar to a fuel injection nozzle. Also, for severe altitude or temperature changes, you can stop the vehicle and make a dial adjustment of about four different mainjet sizes to compensate for the different conditions. To achieve this, five different sized holes on the dial help additional fuel that is needed in the carb.
It is very simple to install and the instruction are easy to follow. Depending on what you have done to your quad you might need to change your mainjet one or two sizes. Mine is still stock for now so I went from the stock 148 to a 142 mainjet. Usually about two sizes leaner then what your mods would call for.
You will also need to make one hole in the rubber air-boot between the carb and airbox. On the EX you remove the stock drain screw from the float bowl and replaced it with a hollow fuel delivery tube supplied with the kit. You will also need to modify your choke lever by shortening it or as I did removing it and lightly heating and bending it. The choke level is not mentioned in the instructions, but easy to figure out what to do with it. If I knew about this before hand I would have had them add a threaded float bowl fitting, which doesn't come in the kit for the EX. This fitting you'd need to drill a hole in the float bowl drain nut on the bottom of the carb and thread it for the fitting.
This setup will only affects the main jet and will not effect the idle. There’s a small increase in mid and top-end power, but it’s only about two horsepower. An average rider might not even notice a thing. This might be different depending on what mods you have.
The main reason I got it was cuz I run elevations from 800 to about 7000 ft and year round. It now takes me about 5 seconds to rejet my carb.
You will also need to get a Snorkel for it and might want to get a One Way Check Vavle and a deeper Float Bowl Nut.
Hope this helps.
It is very simple to install and the instruction are easy to follow. Depending on what you have done to your quad you might need to change your mainjet one or two sizes. Mine is still stock for now so I went from the stock 148 to a 142 mainjet. Usually about two sizes leaner then what your mods would call for.
You will also need to make one hole in the rubber air-boot between the carb and airbox. On the EX you remove the stock drain screw from the float bowl and replaced it with a hollow fuel delivery tube supplied with the kit. You will also need to modify your choke lever by shortening it or as I did removing it and lightly heating and bending it. The choke level is not mentioned in the instructions, but easy to figure out what to do with it. If I knew about this before hand I would have had them add a threaded float bowl fitting, which doesn't come in the kit for the EX. This fitting you'd need to drill a hole in the float bowl drain nut on the bottom of the carb and thread it for the fitting.
This setup will only affects the main jet and will not effect the idle. There’s a small increase in mid and top-end power, but it’s only about two horsepower. An average rider might not even notice a thing. This might be different depending on what mods you have.
The main reason I got it was cuz I run elevations from 800 to about 7000 ft and year round. It now takes me about 5 seconds to rejet my carb.
You will also need to get a Snorkel for it and might want to get a One Way Check Vavle and a deeper Float Bowl Nut.
Hope this helps.
Spot on
This came in real handy
I just picked up a 2000 trx400ex a couple months ago from a guy who did the pipe and added a K&N. He also did the D-A-J but as I have owned mostly Polaris bikes I assumed it was some sort of tree hugger California fuel emission deal.
After I got the bike the throttle was breaking up real bad mid throttle, after tearing the carb apart I realized the previous owner had the needle set to the lowest notch. after resetting it to center I got rid of the mid throttle break-up but still had it from 3/4 to full.
While I knew it wouldn't help much, or at all, I went ahead and turned the pilot FM screw back in a 1/4 turn to try and lean that and also raised the needle 1 notch above center. (hoping possibly the carb was out of whack and leaning both might help the top end).
Same problem. So I was looking through Rockymountainatv.com and saw the dial a jet and was like dude that's what's on the honda!!! After a bit of research I stumbled across this forum and think I may have found the holy grail for this bike!
I went ahead and ordered the 145 and 142 mains, just in case the 142 is too lean.
IT's been a long couple months getting this thing running right, I work a lot and when I play I want to go out and play, not fiddle with a bike the whole day. Which is one thing I have loved about my polaris bikes, they are bullet proof and dependable.
Hopefully after getting this sorted out the bike will run a bit better and I won't have to fight with it anymore.
Certainly appreciate the detailed thread Awesome!!
This came in real handy
I just picked up a 2000 trx400ex a couple months ago from a guy who did the pipe and added a K&N. He also did the D-A-J but as I have owned mostly Polaris bikes I assumed it was some sort of tree hugger California fuel emission deal.
After I got the bike the throttle was breaking up real bad mid throttle, after tearing the carb apart I realized the previous owner had the needle set to the lowest notch. after resetting it to center I got rid of the mid throttle break-up but still had it from 3/4 to full.
While I knew it wouldn't help much, or at all, I went ahead and turned the pilot FM screw back in a 1/4 turn to try and lean that and also raised the needle 1 notch above center. (hoping possibly the carb was out of whack and leaning both might help the top end).
Same problem. So I was looking through Rockymountainatv.com and saw the dial a jet and was like dude that's what's on the honda!!! After a bit of research I stumbled across this forum and think I may have found the holy grail for this bike!
I went ahead and ordered the 145 and 142 mains, just in case the 142 is too lean.
IT's been a long couple months getting this thing running right, I work a lot and when I play I want to go out and play, not fiddle with a bike the whole day. Which is one thing I have loved about my polaris bikes, they are bullet proof and dependable.
Hopefully after getting this sorted out the bike will run a bit better and I won't have to fight with it anymore.
Certainly appreciate the detailed thread Awesome!!
Welcome to the forums...
The 142 is too lean.. factory is 148 main 38 slow.... depending on the mods you would start from 148
The 142 is too lean.. factory is 148 main 38 slow.... depending on the mods you would start from 148
Easy to install, not much of a pain to adjust. allows you to ride just about every elevation in the continental USA. I live at 5K altitude, normally ride to 8K, and adjust for anything over 11K or near sea level.
I'll be putting one on the 300 in the future.
JR
I'll be putting one on the 300 in the future.
JR
trx250, Yeah the bike has the 148 on it but it is breaking up at full throttle and spitting black smoke, which is a sure fire sign that there is unspent fuel and it is too rich.
As I mentioned earlier it already had this dial a jet on it, that's how I bought it. Along with the K&N and White bros exhaust.
As my problem is the bike running rich, I have purchased both the 145 and 142 jets. if 145 is still too rich I will drop down to the 142 but not unless I absolutely have to.
Once it is jetted properly I am done, I live and ride here in vegas and have no plans of going up higher nor down to sea level, so I should be good (hopefully)
If it's too much of a pain, I'll just sell it and get a reliable predator. The bike suits me though So I would like to get it to a state where it isn't just adding weight to my trailer to and from the desert.
Thanks for the input guys
As I mentioned earlier it already had this dial a jet on it, that's how I bought it. Along with the K&N and White bros exhaust.
As my problem is the bike running rich, I have purchased both the 145 and 142 jets. if 145 is still too rich I will drop down to the 142 but not unless I absolutely have to.
Once it is jetted properly I am done, I live and ride here in vegas and have no plans of going up higher nor down to sea level, so I should be good (hopefully)
If it's too much of a pain, I'll just sell it and get a reliable predator. The bike suits me though So I would like to get it to a state where it isn't just adding weight to my trailer to and from the desert.
Thanks for the input guys
That's good stuff for folks who are unaware of the 3 stages of carburation.
However my pilot and midrange are set fine. I am not breaking up in midrange nor at idle.
Unfortunately I can adjust the fm screw until the cows come home and that will have little to no effect on the top end.(which if you read my original post you would see that I tried that) The fm screw only adjusts from idle to 1/4 throttle.
The problem I am having is the bike breaking up at FULL throttle which is handled by the main jet, not the Fm screw nor a needle adjustment.
It is rich due to the increased amount of fuel being dumped by the main jet.
Which is why I am going down either one to 2 sizes 145 first then 142 if 145 is still too rich.
Check out the Dial a jet website they state that you must create a lean condition in order for the dial a jet to function, as this bike carb is stock I am going to have to create the lean condition via the main jet.
However my pilot and midrange are set fine. I am not breaking up in midrange nor at idle.
Unfortunately I can adjust the fm screw until the cows come home and that will have little to no effect on the top end.(which if you read my original post you would see that I tried that) The fm screw only adjusts from idle to 1/4 throttle.
The problem I am having is the bike breaking up at FULL throttle which is handled by the main jet, not the Fm screw nor a needle adjustment.
It is rich due to the increased amount of fuel being dumped by the main jet.
Which is why I am going down either one to 2 sizes 145 first then 142 if 145 is still too rich.
Check out the Dial a jet website they state that you must create a lean condition in order for the dial a jet to function, as this bike carb is stock I am going to have to create the lean condition via the main jet.
Basic Carburetor Tuning Guide - ATV Forum - All Terrain Vehicle discussion for Honda, Yamaha and more ATVs
Here's a thread for how basic carburation works for folks that may not be aware, I know it has helped others I have pointed to it.
Here's a thread for how basic carburation works for folks that may not be aware, I know it has helped others I have pointed to it.
I understand how a carb functions. But that plug chop is for top end throttle I didn't get into a lot of detail of the 3 stages if the carb. That thread was for anyone who wanted to know how to run a plug chop on their bike. I read your post you raised the needle clip I think you are dumping too much fuel from mid to upper circuit. I would drop the clip back to center and start at ground zero with the DAJ... it's obviously pulling too much fuel in the intake with the main when your making the transition through the circuits. My thread was in 2 sections. The first covering the plug chop. The second being how to set the F/M screw. Starting with the slow jet and working your way to the main is the only way to get a carb set up correctly, because all the circuits intersect at some point during operation. eg. Idle circuit(Slow jet) to mid throttle (Needle). And mid throttle to WOT(Main jet).
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