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Jetting... Rookie needs help!


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Ok... Here is my setup...

 

Bike & Environmental Info:

 

06' Stock Banshee powerplant & carbs...

FMF Fatty Pipes (Ceramic Coated)

FMF PowerCore1 Silencers

K&N Filter

Airbox Snorkel Removed

T.O.R.S Removed

Fuel 32:1 Klots Supertechniplate2 mixed with 93Oct

Plugs NGK R BR8ES Gapped at 0.023

I live in Central PA elevation is around 1,400ft MSL

 

Jetting Info:

 

Main Jet(s) are 250(s)

Pilot Jet(s) are stock

Needle is on 3rd Clip (stock)

Air Screw is out 1.5 turns

 

What I notice is that there is a bit of a bog off idle to 1/4 throttle.

After it gets really warmed up it started to run like shit 1/4-3/4 but

ran like a champion in the power band. When you let off the throttle

and decel its seems like it sputters or is choppy with a bit of bog until

it gets back in the power band when it then runs ok again.

 

When I jetted with this setup it was like high 70's low 80's... When I

noticed it running like shit and took these plugs out it was like 95 out

and pretty humid. I changed the plugs and rode again the next day.

It seemed so-so but when I hit some open trail and got into it it seemed

to act up again but not as bad as the day before. Below are some pics

of the new plugs with an hour maybe an hour and a half on them.

 

They look strange because on one half of the plug it seems very dark

and on the ofther half seems light? Both plugs are identical in this way???

Maybe its normal until you get more time on them???

 

ANY help or comments would be awesome...

 

Thanks for helping a 2-stroke rookie! See pics below

 

Mike

 

 

Please click to open images to full size!

 

 

OLD SPARK PLUGS with 2-3 hours of Riding...

-----------------------------------------------------------------------

 

This picture is in natural sunlight...

Old_Plugs.JPG

 

-----------------------------------------------------------------------

 

This photo is in sunlight with flash...

Old_Plugs2.JPG

 

 

 

Below are the new plugs...

 

 

 

NEW PLUGS 1 -1.5 hours on them...

-----------------------------------------------------------------------

 

These side of the plug looks muchlighter???

New_Lighter1_Side.jpg

 

-----------------------------------------------------------------------

 

This side of the plug looks much darker???

New_Darker1_Side.jpg

 

 

~end

Edited by mdhc500
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Old plugs look decent, on the rich side but that's safer than way lean or something. New plugs look good to me, again rich-ish but not horrific. It would be way worse to see light gray (lean) or silver specks (piston/ring damage). Plus in the conditions you're ridin' in where you might not have a whole lotta opportunities to get air flowing over the radiator, on the rich side will help keep the motor cooler...

 

Not to sound condescending but it IS gonna run alot different than garden-variety 4-strokes...shee's don't like lugging and are only really happy when wailing (clutch slipping skills are essential in trails to keep it in the sweet spot of the power, up to that point there's not much to speak of). That said, 2-strokes also will give ya a shot of adrenaline and a half if you take the time to tinker with the jetting, don't be afraid to try different jets (just don't like drop in 420 mains and think you're gonna get more power because there's more fuel heh, work with one circuit at a time and one step at a time).

 

Ok, if it was mine, I'd start with the airscrews and get rid of the bog off idle; try going out (leaner) a half turn and see if it improves, if so try a little more until you like it, if not try going in (richer). It doesn't take much adjustment to make a difference so don't go crazy on them, and keep in mind when the temps/humidity take a big swing you'll probably need to play with them again. Next see if it still bogs in mid-throttle, if so try adjusting the needle clip position and see if you can eliminate it, if not you may need to concentrate on the mains and make 100% sure they are dialed in before returning to the needle clip position. Your jetting is probably close just looking at the plugs, maybe rich but in tight trails the last thing you want to do is go too lean so be careful dropping your main size...at the very least be very wary of any indications of leanness like backfire, overheating, revving high & fast with no power. Since it sounds like you've still go the airbox lid on, you could try 240's and see how it does, it might be perfect or it might be too lean, give it a shot and if there's any question switch it back. Hope this helps man, good luck.

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Old plugs look decent, on the rich side but that's safer than way lean or something. New plugs look good to me, again rich-ish but not horrific. It would be way worse to see light gray (lean) or silver specks (piston/ring damage). Plus in the conditions you're ridin' in where you might not have a whole lotta opportunities to get air flowing over the radiator, on the rich side will help keep the motor cooler...

 

Not to sound condescending but it IS gonna run alot different than garden-variety 4-strokes...shee's don't like lugging and are only really happy when wailing (clutch slipping skills are essential in trails to keep it in the sweet spot of the power, up to that point there's not much to speak of). That said, 2-strokes also will give ya a shot of adrenaline and a half if you take the time to tinker with the jetting, don't be afraid to try different jets (just don't like drop in 420 mains and think you're gonna get more power because there's more fuel heh, work with one circuit at a time and one step at a time).

 

Ok, if it was mine, I'd start with the airscrews and get rid of the bog off idle; try going out (leaner) a half turn and see if it improves, if so try a little more until you like it, if not try going in (richer). It doesn't take much adjustment to make a difference so don't go crazy on them, and keep in mind when the temps/humidity take a big swing you'll probably need to play with them again. Next see if it still bogs in mid-throttle, if so try adjusting the needle clip position and see if you can eliminate it, if not you may need to concentrate on the mains and make 100% sure they are dialed in before returning to the needle clip position. Your jetting is probably close just looking at the plugs, maybe rich but in tight trails the last thing you want to do is go too lean so be careful dropping your main size...at the very least be very wary of any indications of leanness like backfire, overheating, revving high & fast with no power. Since it sounds like you've still go the airbox lid on, you could try 240's and see how it does, it might be perfect or it might be too lean, give it a shot and if there's any question switch it back. Hope this helps man, good luck.

 

 

Thanks for the input... I can see now it will be just some trial and error... Thanks again...

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BUMP...

 

I bumped this because I was reading in another thread how members were telling a guy

in another thread with a similar setup to mine he may be too lean... I too have some bog

in the low/middle end... Someone also mentioned a jetting calculator somewhere? Do my

numbers look abnormal? I dont want to burn up the shee...

Edited by mdhc500
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there is no theory. and that's not that lean on the oil mixture. there are trail bikes by me that run 80:1. the reason yamaha says to run 20:1 or whatever, is cause the oil was such shit back then ('87 when they came out w/the shee), but the oil quality has greatly gone up since then and they just left those premix recommendations the same. if you are running a good quality synthetic oil like amsoil dominator, then you will still be getting enough lubrication at a 50:1 ratio. 40:1 would be more rich than you would ever be wanting to go. you will also be spending less on oil, cause the quart will last you longer, seeing as you don't have to mix it as rich:)

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ive read alot of posts on here and E2s, about amsoil being total crap and motors lookin like crap after using it and tearing down after the season, and there being absolutely no advantage (except saving money_) to running such a lean ratio mixture, some of the more knowledgeable guys ive seen post that bikes they have tested actually make more power wiith a 32:1 mix, please dont attack me, im only stating what ive read from alot of knowledgeable guys- either way i wouldnt wana risk blowin/lockin somethin up over an ounce of oil per gallon

 

and to the OP - read the plug chop thread and it will explain how to fine tune your main jett, no one can tell you anything from looking at a 2 hour plug, get your main jet dialed in and go from there with the rest,, if i were you id ditch the ai4r box lid and jet accordingly, they cant breathe with the lid on, weather the snorkel is on or off

Edited by Michael Jackson
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at the small motors shop that i work at, i tore the top end off a ktm 50 that was in need of a rebuild. it has seen nothing its whole life, but klotz oil and i've never seen such carbon, and funky buildup in my life...ever. the dome of the head, piston crown, and rod, were just all covered in a hard dry carbon. in the bottom of the crankcase, was a weird black/grey oily mixture. a buddy of mine also started using klotz oil in his snowmobile and its also creating a greyish/black residue in the crankcase. from what i've seen klotz is junk. don't get me wrong, its smells good. my shee that i tore down for porting, had no blow by what so ever on either piston, and its seen nothing but amsoil dominator its whole life. engine was nice and clean, w/a nice amount of oil coating on all the engine parts. dome of head and piston crown had a slight oily residue that could easily be wiped off and it was not hard carbon. i'll continue to run amsoil and stay away from klotz. i'll use what i've seen to be good and stay away from what i've seen to be bad.

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i shouldnt have slipped in the comment about reading alot of bad reviews from guys about amsoil, i should have known better than to open that can of worms, haha my bad, everyone has their preference as far as premix, amsoil and klotz seem to be the top 2, premix isnt your problem though, and if your running rich and fouling plugs, runnin less oil in your gas isnt gona lean it out, thats not how it works

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i shouldnt have slipped in the comment about reading alot of bad reviews from guys about amsoil, i should have known better than to open that can of worms, haha my bad, everyone has their preference as far as premix, amsoil and klotz seem to be the top 2, premix isnt your problem though, and if your running rich and fouling plugs, runnin less oil in your gas isnt gona lean it out, thats not how it works

 

 

Yeah, its easy to get side tracked on other topics...

 

I am just going to do a plug chop... I have no where to do it, so I am just going to take it out on the main road and do it... f-it right... I know I can at least get wound out thru 5th on the paved road near my house... Its the only way I am goin to get my mains dialed in.

 

I know something is off because to get my low/mid to run at its best (which still sucks) my airscrew is only 1/4 turn out... I see my future setup as being 260 mains, moving the needle clip down to the 4th slot, and air screw out to 1.5 turns... Oh well, we shall see!

Edited by mdhc500
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