40:1 or 50:1

[Barton]

My gasser is leaving some oil deposits on the silencer and the spark plug is very black, now I don't know if this is because i rode it for an hour on the wet map or if i need to lean it out, The previous owner run 40;1 and the jetting is main jet 178, slide 7, needle n1ef second groove from top and 38 pilot jet.
was thinking just change to 50:1 as it will be less oily and then check plug again or would the wet map retard ignition enough to effect the burn time of the fuel

 

[iamovru]

I have always run my 2T`s at 50:1. There is nothing wrong with a little bit of spooge, it is normal and a good thing.

 

[liv2day]

I have always run my 2T`s at 50:1. There is nothing wrong with a little bit of spooge, it is normal and a good thing.

+1; have run 50:1 for a long time and haven't had any issues.

I've been trying to reduce the drool on my EC200 since picking it up; switched to a leaner pilot jet and it helped, but still have the issue. My plug shows she's still a bit on the rich side, but I can live with it as the throttle response is great.

You didn't mention what bike you have? Also - what type of terrain do you ride and what's the elevation & temp range?

There's a ton of good advice on this forum; Jakobi has lots of good input, as do several of the seasoned members. You'll probably do better with posting in the jetting sub-forum too...do a quick search and you'll find a bunch of stuff

 

[sweeper]

This forum especially has some very experienced riders who obvuously know bikes.And seem to have solved a lot of the Gas Gas jetting issues that have come along.We hear a lot of talk about flash points,mix ratios and different brands of oils.Although these things play small roles in the overall jetting scheme they aren't the primary issurs.When it comes to jetting for me and my personal approach,criteria whatever make model bike weedeater all the same.It isn't right until the plug burns cool and has that beautiful chocalate brown coating.Bottom line for me.The bike should never foul a plug.I mean never.If you get a bike properly jetted for the area you are riding,the temperature whatever.When its right.You could mix 32-1 40-1 50-1 use amsoil,redline,castrol whatever and that baby is gonna run clean have a beautiful plug and very little mess and won't foul plugs.Another bike that isn't jetted properly,fouls plugs has a black oily b.s. plug makes q mess runs pk some days and fouls everydamn plug and your buddies too the next day.Don't matter 32-1 40-1 50-1 amsoil,redline flash point this flash point that.Its still gonna run like crap.

A lot of you will disagree with me on this but some of you know why.I never jet a bike to idle.Maybe a death cough or 2 but when I chop the throttle that baby is shutting down.For me that works the best.The bike is fully utilizing its 3 technically 4 jetting circuits if you count slide cutaway and critical as it may be cancel air scew.I say that because it isn't a set jetting.The bike will pull harder off the bottom it will truly shut down for corners.It wull have no over rev that is trying to carry you just a little farther into that corner then you wanted.The same bike that. you hear roaring around the track or out in the woods with that instantly on and back off sound is not the same backcthats gonna be going ding a ding ding ping cough ding sittin at an idle.Or worse it dors that so guy just raises slide and needle to fix it.Right their imo you've lost the battle.If you eant a bike that pulls off the bottom hard that's where you gotta start.Sorry a bit long a I already know.

 

[sweeper]

Seen a lot of posts on here discussing leaner pilot jets as a cure not only to some jetting issues but also for less mess.Wrong.Very little fuel is being burned on the idle circuit.Also and this is more critical.If you want torque you jet richer on the pilit.If you want the bike to start easy.You jet richer ob the pilot.Not boggy richer just on the richer dide of the line.If you want a bike that pings,keeps going well aftet you wanted it to stop if you like a hard starting bike with no grunt.Then the lean pilot jet is the ticket.The cylinders on the bikrs these days are much more efficient but it wasn't that many years ago you could seize a bike on a cold crisp day because of a lean pilot jet.

 

[Barton]

The gunge out the tailpipe isnt a real worry but the plug is black with oil. Ive always jetted two strokes to get a tan colour on the centre of the spark plug at flat out and worked back to the pilot jet. Has the previous owner as gone one size smaller on the main, dropped the needle one clip and gone down on the pilot jet he seems to have been trying to lean it off. But when in the wet map, if this retards ignition could that give the impression of running rich.
Im going to switch to 50:1 even though the previous owner ran 40:1.
Then ill try again with plug chop from flat out. As sweeper says the pilot system does nothing just above idle.

 

[Barton]

Forgot to say the idle screw is all the way in to allow it to idle which mak3s me think that I neee to up the plot jet from 38 back to stock

 

[adv rider]

running rich

I would do a search of the jetting for your model bike. Most likely it will run best with a different needle/pilot/and main jet combo. You didn't mention year/model, so its hard to give you a better idea of what you need.

 

[webmaster]

Forgot to say the idle screw is all the way in to allow it to idle which makes me think that I need to up the plot jet from 38 back to stock

The carb is "pulling over". You have a lean pilot - so you crank in the idle to provide more fuel through the nozzle/needle.

Start by getting a better needle - the n1ef is not good - richen up the pilot and be sure to back out the idle screw from being "coil bound" when you switch to your updated jetting. #7 slide is okay, depending on needle - 42-45 on pilot.

This will separate the circuits in the carb - making the jetting less sensitive to environmental changes, etc. it will idle and start much better - fuel mileage improves as well.

As others have said - don't jet for spooge. I like seeing oil out the tail pipe - let's me know that the motor is getting some lube.

On the subject of mixture ratio - I used to run more oil than most 36:1 - but I was riding it hard all the time. More oil in the mix gives better ring seal, more lube to crank bearings, and the oil helps transfer the heat away from the piston. So in mind - sticking with 40:1 is fine. I have always viewed the 50:1 recommendation by the mfgr as having to take euro emissions into account. And besides pro honda synthetic racing stuff recommended 36:1 -> I trust honda... Racing - more oil -> putting around -> less oil...

If you have a little money to spend - having Ron at RB-Designs mod your carb and dial in the squish on the head is money well spent. If you only have $$ for one of these - have him machine the head for you (dial in the squish).

jeff

p.s. I am such a fool to respond to a jetting thread - kind of like talking politics in a bar... ;-)

 

[Barton]

2009 ec250 sixdays

 

[webmaster]

I see that roscoe (aka Reverup) was using the following :

36mm Air striker 2 carb Slide #6.5 with notch.
Yamaha YZ 250 2 stroke factory carb needle N3EJ clip in center position #3
Pilot jet #40
Main #180
1 turn out on air screw
----
For me, and probably for you - I would tweak this slightly...

Slide #7.
N3EJ - center clip position
Pilot : 42-45
Main : 178
Air Screw : 2 turns out (maybe 2 1/4).

Two reasons for this - Roscoe is a mighty fast dude and not many are that fast - so you can go leaner on main. And secondly - I like to move more fuel and air through the pilot circuit and turn down the idle - this better separates the idle and the needle (mid) ckts in the carb.

Another needle that others use is the cck...

jeff

 

[sweeper]

That's all good stuff.Barton deffinately on the right track.Workin your way back down.Usually when I get jetting stumped and I got it close but can't get her dialed it turns out to be a needle fix..

All of this jetting talk doesn't mean squat until the pipe has a good seal at the barrel.Good seal between the silencer and pipe.Packed silencer and a clean and reasonably properly oiled filter.I always over oil them.Just crank on it really hard for a day and it will self adjust the filter oil level.

 

[iamovru]

I see that roscoe (aka Reverup) was using the following :

36mm Air striker 2 carb Slide #6.5 with notch.
Yamaha YZ 250 2 stroke factory carb needle N3EJ clip in center position #3
Pilot jet #40
Main #180
1 turn out on air screw
----
For me, and probably for you - I would tweak this slightly...

Slide #7.
N3EJ - center clip position
Pilot : 42-45
Main : 178
Air Screw : 2 turns out (maybe 2 1/4).

Two reasons for this - Roscoe is a mighty fast dude and not many are that fast - so you can go leaner on main. And secondly - I like to move more fuel and air through the pilot circuit and turn down the idle - this better separates the idle and the needle (mid) ckts in the carb.

Another needle that others use is the cck...

jeff

Jeff is correct! I know, because I own this bike now. It is a fire breather that I am trying to tame a bit. Everything else I have read so far is also correct. It is all based on jetting and where you begin and where you end. How you mix oil is really based on what the manufacturer recommends. 50-60:1 is normal now. There are also oils that claim 100:1, but that would make me uncomfortable.

Jeff, what are you trying to accomplish with the jetting you suggest? I may look into that.

 

[Barton]

Been out and changed oil ratio to 50:1, plug is good chocolate brown colour. Have also changes pilot jet, had a 45 pilot kicking about so fitted that and wound air screw out two and a half turns. Now take two kicks to start, and on road sections in top gear at 35mph it surges a little but on the road if you shut off the throttle, on overrun there is an occasional pop from the exhaust so may need to go 42 on the pilot.
One other thing, I removed the power valve cover from the coil side and loads of spoge came out, and the thread / bolt that is sticking out the power valve can be turned a little, may be 5 or 10 degree's is this normal?