Do you guys think that a black spring and larger snorkle will make up for the power lose that the 27in 589s will rob from the prairie 650? If you think I'll need to add other mods to make up for the loss in power pleas let me know.

 

1. twin air filter. That may just do the trick with what you said, but why stop there? Go on to 2 and 3.
2. Modify the stock exhaust? No. Nobody here wold ever do that.
3. cdi (available soon).

Make sure the belt is tight, that makes a diff on takeoff and keeps the belt lasting long.
Hey, why stop at being equal to stock with 27" tiires. Get cams from penland after you do the above listed items.

 

The spring and the snorkel will help. But, I know for a fact that if you would add the jets and exhaust mod and a better air filter along with the black spring and snorkel it would more than make up for the bigger tires. When you open them up and let em breath it makes all the difference in the world.[img]i/expressions/face-icon-small-happy.gif[/img]

 

PS. Once you make all of these mods you need to make sure you've got a good set of tires to handle all of that speed and power.[img]i/expressions/face-icon-small-shocked.gif[/img]

 

Good start !! But Im shure you will want more.[img]i/expressions/face-icon-small-happy.gif[/img]

 

Ok I forgot about the air filter and will be adding one of thoes too. But I dont know to much about jetting and how it works. If any one can tell me It would be grate. Also I live in east ky (i can see wv frome my house) but I dont know how mant feet above sea level I am and I think that has to do with jetting so if you can help me out with that it would be good to. Also how do you mod the exhaust? If you all can help me out I will be gratefull

 

Tommyboy 84,

Altitude, temperature and humidity effect the jetting of a carburetor. Here are some simple rules that can help you fine tune the jetting to get the best performance from your machine
ALTITUDE
As you increase your altitude the octane requirement decreases 1-2 octane per 3000 feet elevation. This is because the density of the air is reduced or there is less air available for your motor to burn. The higher the altitude, the richer your motor will run, making it necessary to re-jet the motor in order to lean it out. The fuel volume remains the same and the air volume goes down. If you have a vacuum advance, as the altitude increases, the motor makes less vacuum and the air fuel ratio becomes richer due to the decreasing air to fuel volume.
TEMPERATURE
When the temperature goes up, the air density decreases, thus you have less air available for combustion and your air fuel ratio becomes richer. The same works in reverse. As the temperature goes down, you end up with more air per cubic foot, and without re-jetting your carburetor, the engine will run leaner.
AIR DENSITY
As the air density increases, your engine will lean out. As the air density goes down, the engine runs richer. Like driving up a mountain, at the top, the motor has less power because you have less air to burn.
HUMIDITY
When the humidity increases, octane requirements ease. The formula is something like... for every one gram of water increase per one kilogram of dry air the octane decreases by .25 to .35. WWII aviation engines used water injection and it worked well for a short time by cooling the cylinder temperature. As temperature goes back the effect goes away.

The following link will help explain how each component of a carburetor effects engine performance.

http://www.recreationunlimited.com/air&fuel/jetinfo.htm

You have a lot to learn. You should read up as much as possible to understand why a 142/145 main jet combo on a 650 Prairie in one place will work and in a different part of the country will work poorly. Once you fully understand what all of the effects of jetting are, you will be able take full advantage of making your machine breath better. The more that you research, the better you will be able to get your machine running.

ED

 

Hey Ed, did'nt I see you on Jeopardy like two days ago???[img]i/expressions/face-icon-small-confused.gif[/img]

 

Tommy-- It would be the best $80.00 you ever spent on that bike. Add about $7.00 for a jet, and modify your exhaust, ala nyroc, and you are good to go!