Jettin OR not Jettin that be the ?
#2
05-31-2007, 06:25 PM
Jettin OR not Jettin that be the ?
<div class="FTQUOTE"><begin quote>Originally posted by: pjb74
How much more power does jettin give and isit worth it and oh yeah easy to do ? 2005 eiger 400</end quote></div>
Simply putting bigger jets will do little or nothing and could even deteriorate the performance and gas mileage. Sometimes going to a smaller jet will get you better results. From the factories most machines are jetted to be a little on the rich side (runs cooler, slower, less chance of a melt down -warranty issues).
You need to rejet for optimum performance and power.
Putting is a new jet is only a matter of taking the carb off the machine and removing the float bowl and replacing the main 'screw in' jet. The trick is to get the right one that gives the best results. Sometimes this can take several jet changes. Unless you have some special diagnostic equipment then you generally go by the color of the spark plug and how it is burning the fuel. Test, change jets and test again.
If you put too big of a jet in then the thing will be flooded - like running with the choke closed.
If you put too small a jet in then the thing will be lean and overheat and burn pistons etc.
If and when you get it to run on peak then changes in weather, altitude, quality of gas etc will be more noticable in power loss. If you get it to peak say at 3000 feet then take it down to sea level - watch out you will be on border line lean. If you peak it at sea level and then go up to 3000 feet, you only loose power from a rich condition.
A marginally rich running engine is less suseptible to serious problems. A lean, mean running machine is very suseptible to melt downs.
My recommendation is that if you don't know what you are doing and your machine is running fine don't mess with it. Because you could end up with a machine that runs worse and also you could damage the engine to the point of major repairs or replacement.
If your engine is running fine then you are more than likely running at least 95% efficent. The other 5% won't mean much to you for general use - maybe in a race situation or timed runs. If you can run 50mph now the other 5% will yield you 52mph. Is the risk of damage worth the extra speed.
Jets are cheap at around $2.00 each. Major repairs are not cheap.
The way that I rejet is that I will bring the jets from a rich mix down to where it is lean and screaming, and pulls through the entire rpm range. Then I go bigger on the jets until it flat spots on acceleration, meaning that it will pull but not strong through the entire rpm range - it will flatten out and just maintain with a gradual increase. Basically ending up with 97-98% efficient instead of 100%. Just a tad on the rich side, to use as a safety buffer. Reality instead of being able to run 54 mph at peak, I will have it running 52-53 mph. If I were racing for money - that may be a different story.
The way you can tell rich is that it will break down like it is wanting more gas, and may even misfire or sputter. Where in fact it wants more air and less gas. And your plugs will be black.
If you are unsure then make a hard run and start to choke it a little if the performance picks up that means you are lean and it needs less air to get the correct fuel/air mixture, if the performance goes down that means you are rich or already at peak. If at full throttle you feel a glitch or it seems like it is running a little rough and backing off the throttle to 15/16th picks up speed or seems to smooth out the engine then you are running a bit rich.
A $2.00 change could cost you $1000 in repairs, so be careful.
How much more power does jettin give and isit worth it and oh yeah easy to do ? 2005 eiger 400</end quote></div>
Simply putting bigger jets will do little or nothing and could even deteriorate the performance and gas mileage. Sometimes going to a smaller jet will get you better results. From the factories most machines are jetted to be a little on the rich side (runs cooler, slower, less chance of a melt down -warranty issues).
You need to rejet for optimum performance and power.
Putting is a new jet is only a matter of taking the carb off the machine and removing the float bowl and replacing the main 'screw in' jet. The trick is to get the right one that gives the best results. Sometimes this can take several jet changes. Unless you have some special diagnostic equipment then you generally go by the color of the spark plug and how it is burning the fuel. Test, change jets and test again.
If you put too big of a jet in then the thing will be flooded - like running with the choke closed.
If you put too small a jet in then the thing will be lean and overheat and burn pistons etc.
If and when you get it to run on peak then changes in weather, altitude, quality of gas etc will be more noticable in power loss. If you get it to peak say at 3000 feet then take it down to sea level - watch out you will be on border line lean. If you peak it at sea level and then go up to 3000 feet, you only loose power from a rich condition.
A marginally rich running engine is less suseptible to serious problems. A lean, mean running machine is very suseptible to melt downs.
My recommendation is that if you don't know what you are doing and your machine is running fine don't mess with it. Because you could end up with a machine that runs worse and also you could damage the engine to the point of major repairs or replacement.
If your engine is running fine then you are more than likely running at least 95% efficent. The other 5% won't mean much to you for general use - maybe in a race situation or timed runs. If you can run 50mph now the other 5% will yield you 52mph. Is the risk of damage worth the extra speed.
Jets are cheap at around $2.00 each. Major repairs are not cheap.
The way that I rejet is that I will bring the jets from a rich mix down to where it is lean and screaming, and pulls through the entire rpm range. Then I go bigger on the jets until it flat spots on acceleration, meaning that it will pull but not strong through the entire rpm range - it will flatten out and just maintain with a gradual increase. Basically ending up with 97-98% efficient instead of 100%. Just a tad on the rich side, to use as a safety buffer. Reality instead of being able to run 54 mph at peak, I will have it running 52-53 mph. If I were racing for money - that may be a different story.
The way you can tell rich is that it will break down like it is wanting more gas, and may even misfire or sputter. Where in fact it wants more air and less gas. And your plugs will be black.
If you are unsure then make a hard run and start to choke it a little if the performance picks up that means you are lean and it needs less air to get the correct fuel/air mixture, if the performance goes down that means you are rich or already at peak. If at full throttle you feel a glitch or it seems like it is running a little rough and backing off the throttle to 15/16th picks up speed or seems to smooth out the engine then you are running a bit rich.
A $2.00 change could cost you $1000 in repairs, so be careful.
#3
06-01-2007, 08:56 AM
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Jettin OR not Jettin that be the ?
wow thanks for all the info. the reason i wanted the jet is cuz i have the bigger tires and i wanted bigger tires but it is very poor in thick blue mud which is not unlike for most four wheelers but a 400 i figure it would be ok it almost a dead stop til i gave it a push. any ideas or suggestion is welcome.
#4
06-01-2007, 11:41 AM
Jettin OR not Jettin that be the ?
<div class="FTQUOTE"><begin quote>Originally posted by: pjb74
wow thanks for all the info. the reason i wanted the jet is cuz i have the bigger tires and i wanted bigger tires but it is very poor in thick blue mud which is not unlike for most four wheelers but a 400 i figure it would be ok it almost a dead stop til i gave it a push. any ideas or suggestion is welcome.</end quote></div>
Gee, I wish I could suggest something for an idea. It would seem to me that the Eiger should do ok with 26" tires. I run 25" but I have the ones on the back that have 1" tread depth that do good in mud, the fronts have 3/4" inch tread depth and also do good. Most OEM tires are 1/2" tread depth.
Only thing I can think of is, yes, you do need more power if the Eiger can't turn the tires. But how to get it is the question. A few mods, probably will not get you enough. What has happened is that with the bigger tires you have changed the gear ratio to the point that your low gear is like a second gear (just too tall of a gear). No matter with a big HP boost second gear will never be like low gear.
The proper way to get back on track is to change the ring and pinion in both the front and rear differentials (this way you get back your first/low gear).
Another option is to sell the 26" tires and get a good agressive 25" tire. You wll maintain your gear ratio (keep first/low).
Besides the problem with mud since you don't have the low gearing (gone until something changes - tires or gears) you will also suffer from slow work and also pulling. Simply adding horsepower won't work good either. If you understand tractors and gearing then you know what I am talking about.
What would I personally do? I would sell the 26" and get some agressive 25" tires. That is the easiest and cheapest way to get the right gearing and the performance that you want. (You are only loosing 1/2" or ground clearance). A set of 'High Lifter' springs would get you 1" more clearance so you would end up 1/2" higher (and they are only about $50 for the front and $50 for the rears). Had you done this first you would have spent about the same amount of money as the 26" cost more than the 25" tires - with the savings you could have gotten the 'High-lifter' springs.
wow thanks for all the info. the reason i wanted the jet is cuz i have the bigger tires and i wanted bigger tires but it is very poor in thick blue mud which is not unlike for most four wheelers but a 400 i figure it would be ok it almost a dead stop til i gave it a push. any ideas or suggestion is welcome.</end quote></div>
Gee, I wish I could suggest something for an idea. It would seem to me that the Eiger should do ok with 26" tires. I run 25" but I have the ones on the back that have 1" tread depth that do good in mud, the fronts have 3/4" inch tread depth and also do good. Most OEM tires are 1/2" tread depth.
Only thing I can think of is, yes, you do need more power if the Eiger can't turn the tires. But how to get it is the question. A few mods, probably will not get you enough. What has happened is that with the bigger tires you have changed the gear ratio to the point that your low gear is like a second gear (just too tall of a gear). No matter with a big HP boost second gear will never be like low gear.
The proper way to get back on track is to change the ring and pinion in both the front and rear differentials (this way you get back your first/low gear).
Another option is to sell the 26" tires and get a good agressive 25" tire. You wll maintain your gear ratio (keep first/low).
Besides the problem with mud since you don't have the low gearing (gone until something changes - tires or gears) you will also suffer from slow work and also pulling. Simply adding horsepower won't work good either. If you understand tractors and gearing then you know what I am talking about.
What would I personally do? I would sell the 26" and get some agressive 25" tires. That is the easiest and cheapest way to get the right gearing and the performance that you want. (You are only loosing 1/2" or ground clearance). A set of 'High Lifter' springs would get you 1" more clearance so you would end up 1/2" higher (and they are only about $50 for the front and $50 for the rears). Had you done this first you would have spent about the same amount of money as the 26" cost more than the 25" tires - with the savings you could have gotten the 'High-lifter' springs.
#5
06-01-2007, 06:07 PM
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#6
06-01-2007, 06:27 PM
Jettin OR not Jettin that be the ?
The Eiger is a sweet machine and very capable (one of my favorites actually). The straight rear axle limits it from being articulate and a mud machine. Other than that it is a good ride. Very capable and a whole lot of fun. It will also go 98-99% of anyplace any other machine will go. Climbing over big rocks, stumps and running mud is only a small phase of trail riding. If you want an articulate or mud machine then you need full independent suspension with plenty of ground clearance and a whole lot of wheel travel such as Arctic Cat.
I avoid a lot of mud and drive around it on the trails quite often, I know what my machine will do and to clean it up after playing in the mud is a pain (takes a couple hours and a whole lot of soap and water). Plus mud holes are a good place to break things (axles etc) and punch holes in the CV boots.
I avoid a lot of mud and drive around it on the trails quite often, I know what my machine will do and to clean it up after playing in the mud is a pain (takes a couple hours and a whole lot of soap and water). Plus mud holes are a good place to break things (axles etc) and punch holes in the CV boots.
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