[AUDACIA]

list of mods to engine\carbs

exhaust (36$ muffler)
DYnojet 2193

did stay with directions, 3turns to fuel\air mixture screws and i HAVE NOT synced my carbs it runs just fine no hesitation starts right up.

i have a 102main jet and snorkle removed stock air filter.

i was cooking along and working up to my shift point when i was like f it so i hammered it on at about 6k and ran it up to 12k but it dropped all power after about 10.5\11k ? it hardly pulled as hard so do i need bigger main jets?

the kit smoothed power out now i have pull from about 4500 all the way up to 11 with a big increase in the low end and power.

i can pass somone in 6th with only marginal throttle use.

any ideas? i think Z would be the one to answer this.

 

[spooph]

well, I'm not Z, but what you might want to try is dropping your needle one space.... If that doesn't the desired effect, go up one size in jets and return the needle to the original height...

But what would be really helpful here for us is a video of your tach with the sound to match... As in, get the bike warmed up, then video the tach while you go from idle to red line by twisting the throttle as far is it'll go quickly. Just snap it all the way open... If it "bogs" anywhere, there will be part of the diagnosis.. A warm bike should be able to rev very quickly from idle to red line under full throttle. If you make this video, I'll be able to lend a hand with what you have to do to each point to affect low/mid/high ranges...

Ztrack, Racer X, and Eric know much more than I, but this is what I recommend...

 

[AUDACIA]

well, I'm not Z, but what you might want to try is dropping your needle one space.... If that doesn't the desired effect, go up one size in jets and return the needle to the original height...

But what would be really helpful here for us is a video of your tach with the sound to match... As in, get the bike warmed up, then video the tach while you go from idle to red line by twisting the throttle as far is it'll go quickly. Just snap it all the way open... If it "bogs" anywhere, there will be part of the diagnosis.. A warm bike should be able to rev very quickly from idle to red line under full throttle. If you make this video, I'll be able to lend a hand with what you have to do to each point to affect low/mid/high ranges...

Ztrack, Racer X, and Eric know much more than I, but this is what I recommend...

well thank you! it pulls all the way up to about 8.5k with minimal throttle use even in last gear.

above that i think im loosing power but idk.

so go down the road or while in neutral rev it up?

ill do it when it gets back from the shop im having the valves readjusted, *haha im throttle happy on this bike.

 

[spooph]

I hear ya on the throttle happy..

And if you can do both that would be sick! But standing still in neutral would be just fine too...

It definitely sounds like you're running lean on top though.

I'm willing to bet you could drill out the idle jets one size (not jet size, but one wire guage size - get a 60-80awe drill kit, and measure what size it is now, and then go one up). Which will give you all the pickup you want on the bottom end..

It sounds like you can use a little more fuel in the middle too... You can do this three ways. 1.) Raise your needle a tige more, maybe double what you have now... So 2 more shims, which 4 shims = next jet size up, or 2-3 steps in awe drills.... 2.)Or jet one step up. 3.)Or mess with your air/fuel mixture screw... I have mine at 2.5 turns out, but I'm at 5,000 feet... So I think 3 - 3.75 turns out for you would be a good place to be....

For the top end however you're gonna have to go to a bigger jet, and then drop your needle back down to keep your mid-range solid and not overly rich....

 

[AUDACIA]

I hear ya on the throttle happy..

And if you can do both that would be sick! But standing still in neutral would be just fine too...

It definitely sounds like you're running lean on top though.

I'm willing to bet you could drill out the idle jets one size (not jet size, but one wire guage size - get a 60-80awe drill kit, and measure what size it is now, and then go one up). Which will give you all the pickup you want on the bottom end..

It sounds like you can use a little more fuel in the middle too... You can do this three ways. 1.) Raise your needle a tige more, maybe double what you have now... So 2 more shims, which 4 shims = next jet size up, or 2-3 steps in awe drills.... 2.)Or jet one step up. 3.)Or mess with your air/fuel mixture screw... I have mine at 2.5 turns out, but I'm at 5,000 feet... So I think 3 - 3.75 turns out for you would be a good place to be....

For the top end however you're gonna have to go to a bigger jet, and then drop your needle back down to keep your mid-range solid and not overly rich....

im running dynojet kit 2193

using 3rd setting as they say to use and im running a 102 main which im going to switch out for a pair of 106's i bought.

as for low to mid range its perfect id rather not mess with it, it pulls strong and i hardly have to downshift to pass people now =).

i have a full jet kit so drilling my own holes is something i'd rather stay away from.

 

[AUDACIA]

ok so i did a full throttle test run.

i upgraded from a 102 main to 106 in the thought that it was lean above 10k.

FALSE.

im at elevation of 1300 give or take a hundred.

mods are.

snorkle removed.
free flowing baffled exaust.

dynojet kit 2193.

i still cant rev past about 10k in 6th gear ;(.

im thinking now im to rich, that i should try 100main or the stock 98.

any input?

oh i hit 105 tonight, however i was goign down a hill so racer X your safe... safe for now

 

[spooph]

take a look at your plugs... If they're black they're rich, if they're brown they're right, and if they're white, they're lean...

And just to give you an idea, when I rejetted my Eliminator an I4 600cc motorcycle (150cc's/cylinder/carb), I went from 90 to 148's to get it to run right.. I'm not talking about running, I'm talking about running right... It would fire and stay running with 120's, but was lean as HELL, and didn't come into "the zone" till the mid 40's... at 152's I was just a tad rich, so I backed off a little...

And just for comparison's sake: our 250's are 125cc's/cylinder/carb, which is why X is currently up to a 118. I think eventually you could put bigger jets in there, but I'm not sure why. The numbers just don't seem to add up right... So keep playing with the jetting.

Also, when I jetted my Eliminator, I kept going up in little increments (90-98-112-120-130-142-152)... Now those might not seem little to you, but considering how much I went up, they're little, eh?

Otherwise, without that video, I can't tell you a whole lot more specifically.... I can give you many things to check and stuff, a lot of which has already been covered, I'll see if I can find the threads....

 

[Racer X]

One think I would try is to remove the flame trap from inside the air box . It is a steel screen that keeps the air filter from catching fire if the engine back fires.You need to remove the air box to get it out but it is VERY restrictive,

I would try pulling that and try the 106 again .

Fuel flow in the CV carb goes through overlapping circuits.
the carburetor circuits go from the idle jets to 1/4 throttle then the pilot jets are coming in below 1/4 throttle to about 3/4 from 1/2 throttle to above 3/4 it is the needle and main jet relationship.Then from 3/4 to full it is all main jets

If you have the Dyno jet needle clip in the center and say 105 jets . Ride the bike get up to about 45 mph and drift along then slowly open the throttle if the bike accelerated till about 7/8 throttle then you can open ad close the throttle and nothing happens or you feel a slight power increase when you let off then you are lean . I went to 110 jets before mine felt right . But I had K&N pods.

Carb balance is not done with the pilot screws . They just fine tune the idle . The balance is done by turning the screw between the two carbs that that balances the linkage that opens the carbs together.

http://www.keihin-us.com/tune1.htm

 

[AUDACIA]

One think I would try is to remove the flame trap from inside the air box . It is a steel screen that keeps the air filter from catching fire if the engine back fires.You need to remove the air box to get it out but it is VERY restrictive,

I would try pulling that and try the 106 again .

Fuel flow in the CV carb goes through overlapping circuits.
the carburetor circuits go from the idle jets to 1/4 throttle then the pilot jets are coming in below 1/4 throttle to about 3/4 from 1/2 throttle to above 3/4 it is the needle and main jet relationship.Then from 3/4 to full it is all main jets

If you have the Dyno jet needle clip in the center and say 105 jets . Ride the bike get up to about 45 mph and drift along then slowly open the throttle if the bike accelerated till about 7/8 throttle then you can open ad close the throttle and nothing happens or you feel a slight power increase when you let off then you are lean . I went to 110 jets before mine felt right . But I had K&N pods.

Carb balance is not done with the pilot screws . They just fine tune the idle . The balance is done by turning the screw between the two carbs that that balances the linkage that opens the carbs together.

http://www.keihin-us.com/tune1.htm

understood, thank you for your input! both of you!!.

I noticed around 50 if i open it all the way it pulls different as apposed to a slight increase. it pulls hard all the way till about 9 grand in 6th then drops off very very sharply at that point. I can't accelerate past about 90 it crawls. before doing exhaust and dyno kit i could accelerate all the way to top speed which was 101-102 mph.

im not certain if im running lean or not.

the needles are perfect and air\fuel mixture screws are fine.

like i said pulls hard all the way till open throttle in a higher gear, lower gears it still try's tugging away at 11.5k .

106 is the biggest i have, so i guess when i pull it apart ill pull that wire mesh i saw out and leave the 106 in there, do a test run and see. i should pull the plugs, the shop when they did my valves i had them pull the plugs and they said they looked fine, but then gain im PAYING them for SERVICE if its not fine eventually they will have to fix it.. which means more $$

 

[Racer X]

go with hotter plugs . NGK CR9E .Also. different jets flow at different rates. You can use keihin jets and DJ needle But I only use Keihin jets .They come in a pack of four. Cheap cycle parts has then for 15.00 dollars a pack. what gears are you running? It still sounds lean

 

[spooph]

thanks X, those diagrams are brilliant - they're gonna go in the "secret stache of performance information" file...

Now I don't mean to be a PIA, but I've heard lots of different schools of thought on spark plugs...

I've heard an engine is designed around 2 components, the spark plug and I forgot the other one... But I remember messing with spark plugs in my eliminator once, and once I got the jetting figured out, and went to the stock plugs, everything was spot on....

So, X, could you say more on the spark plug thing?

 

[Racer X]

I wish I knew more. For me it is all about the heat range. When I ran in June of 08 I had like 110 DJ jets and a Yoshi with cr8e plugs. The bike went 101 mph that is like 110 on the inaccurate speedometer .I needed 106 mph. On Sunday I pulled my muffler because I figured the 110 was a touch rich . The bike went 103 104 then 106 but I missed the record by .005 mph .
When I got home I pulled the plugs and the tip was melted down . A couple more runs like that and I would have done some damage.

You have to look very close to see carbon buildup on new plugs with modern fuels.

Check out the NGK web page . There is way to much for me to comprehend .

http://www.ngksparkplugs.com/techinfo/spark_plugs/techtips.asp?nav=31000&country=US

 

[Racer X]

See what I mean about complicated . I meant colder not hotter plug . The 9 is colder . higher number colder plug

 

[spooph]

ooo, that's a good page, I'll be checking in on that for a while...

 

[spooph]

So Audacia, after having read that article, it seems to me that you shouldn't have to worry about plugs at all... The biggest thing that affects spark plugs is timing, especially ignition timing. Even though you modified the bike, you should be able to nail the original fuel/air mixture RATIO. You should have more fuel, and more air coming into the engine, but you should end up with the same RATIO, whatever it was to start with... Which shouldn't affect the plug at all.... If, however you start playing with ignition timing and such forth, as X is doing, you're gonna have to look into plugs and such...

 

[metbandit1]

oh i hit 105 tonight, however i was goign down a hill so racer X your safe... safe for now
[/quote]

cmonnn! i hit 105 on flat and 110 down hill

 

[AUDACIA]

go with hotter plugs . NGK CR9E .Also. different jets flow at different rates. You can use keihin jets and DJ needle But I only use Keihin jets .They come in a pack of four. Cheap cycle parts has then for 15.00 dollars a pack. what gears are you running? It still sounds lean

gears? i just looked at your graph, well defenitly my main jet is out of whack, because until it kicks in the bike runs like a batoutahell.

im running 16\45 stock rear with 16 front.

don't tell me ill never redline in 6th, i got it to go 103 with 16 front before i did these mods.

 

[AUDACIA]

So Audacia, after having read that article, it seems to me that you shouldn't have to worry about plugs at all... The biggest thing that affects spark plugs is timing, especially ignition timing. Even though you modified the bike, you should be able to nail the original fuel/air mixture RATIO. You should have more fuel, and more air coming into the engine, but you should end up with the same RATIO, whatever it was to start with... Which shouldn't affect the plug at all.... If, however you start playing with ignition timing and such forth, as X is doing, you're gonna have to look into plugs and such...

ahh i see, yeah my bro and i have been around carbs for a while, we've both owned dirtbikes or fourwheelers in the past.

he said now that i have more fuel\air i should go hotter, well i decided not to ive heard nasty things with people doing what ive done and melting there top end from hotter plugs.

hmm,, well if i can NAIL the right RATIO of F\A then ill be good to go, its just blind testing as i do not have a dyno nearby ;( .

 

[AUDACIA]

oh i hit 105 tonight, however i was goign down a hill so racer X your safe... safe for now


cmonnn! i hit 105 on flat and 110 down hill

when i said 105 i ment 110 on the spedo... so if your hitting 105 flat on the spedo, ill put all stock on my bike and murder u, i got to 105 with room to go on the tack stock haha, well with a 16 front sprocket.. >.>

 

[Blue Ghost]

Has anyone tried this set up done in Sportrider?
http://www.sportrider.com/features/146_0903_2008_kawasaki_ninja_250/index.html