My 300 has mediocre low end!

[thumperflipper]

Taylor Park is my second favorite place to ride (second only to Moab). I am having the same problem with crappy lean feeling low end power on my 2011 300. All started after a topend rebuild. No amount of fiddling seems to help get back what I had. Maybe a difference in crown from the wiseco to the wossner piston? I am interested to hear your solution. Keep us posted

 

[GGRider01]

What frustrates me is that in February, on this same top-end and the N1ED on clip 1, the bike wanted to point skyward in 1st gear. This is with the supermoto gearing, I think 14/42. Temperature was 17 degrees. Have you ever been so cold that it made you want to throw up due to the pain of thawing flesh? Yikes. Winter riding is not for me. Plug looked on the dark side of what is ideal, but damn close.

I can tell you from what little I've retained from everyone here is that it is probably going to come down to having the head cut and maybe RB Designs mod to the carb. If it came to that, I'd just get the smartcarb - no point in buying 100 dollars in needles, 160 dollar carb mod, and on and on. But like I was saying, when the jetting and temperature were just right, the thing had power and jerked my arms off so I'm hoping like hell one of these needles will do the trick.

If you think your jetting is close I would consider advancing your timing. I'm holding off until the weekend to do mine. Will definitely report on results. Right now, the CCK is looking like a bandaid fix until the suzuki and yamaha needles show up. Seems rich down low and lean mid (due to clip position??) and nice when wide open. Just feels and sounds flat, but much quicker than before. Still has a nice punch, which I hope the N3xx needles give. No plug chops 'til the weekend.

 

[GGRider01]

N3EH, #2 clip.
38 pilot, 175 main

Hard to start (CCK had this issue too) so went up to a 40 pilot and it's a lot happier but the choke is unnecessary - seems like too drastic of a change for such a small adjustment. However, it seems common for these to start cold without the choke.

After a few runs, dropped main to 172, pulls harder and doesn't seem to sign off any earlier than before. Need to do wide open throttle chop.

The bottom end didn't change at all. Advanced the timing 1mm and it has come to life. Four-stroking is 90% gone at sustained low throttle openings, still need to clutch up the front end in second and above. 1st is too short to get sustained lift but it is quite willing with 14-51 gears. Will be dropping to a 13 for trail riding. I'll be happy with power wheelies in 2nd gear with the 14-51 setup and probably call it quits when it happens (it's close).

 

[95jersey]

try N3CJ 175/178-45/42 this is the best combination for me between 500-1500 meters.

Maybe try a richer slide? Comes to a point only so much you can do with jets and needles. Fix one thing...create another problem.

 

[Getoviq95]

Maybe try a richer slide? Comes to a point only so much you can do with jets and needles. Fix one thing...create another problem.

Yeah N3CJ is leaner ,but i have 4 friends with gas gas 300 and they all ride with this needle and for many years they dont have a problems only in winter put N1EG

 

[GGRider01]

The n3ej is too lean for the as1, as per Jakobi and my own testing, the cj is half a clip leaner. It did work beautifully at extreme elevations, 10k+.

 

[Getoviq95]

N3C_ series which are 1/2 clip leaner than N3E_ but again otherwise identical. With them N3CJ #3 = N3EJ #2.5 .

 

[GGRider01]

N3C_ series which are 1/2 clip leaner than N3E_ but again otherwise identical. With them N3CJ #3 = N3EJ #2.5 .

Correct.

Also, I am rich off bottom - if anything I will be going to a #8 slide. In theory this should pull more fuel through the pilot but get closer to optimal ratio with even more air coming through. Who knows (not me). Could probably compensate by going to a 38 again.

 

[GGRider01]

Currently going nuts trying to lean this bike out. 35 pilot, N3EH #1 with a 170 main.

Smokes just the right amount, cleans up when warmed up. Takes out a chunk of earth off bottom, strongest hit in #1 position. Plug reads slightly dark after aggressively riding around the desert.

Would the needle being in #1 position really suggest dropping the main?? I'd hate to drop the main any more, although some people are using 168s and 165s.. Just scares me a bit. Going to N3CH sounds safer.

I really like these N3 needles, Seem to be pushing to a leaner diameter. N3CH, N3EW and N3CW (this is referred to as an N3CC as well???) are on the way.

I like how it runs now but don't like not being able to drop the needle anymore. At this point the smart carb would've been cheaper.

 

[cvl05]

I've run 165/168's in my 300's but only above 5000 feet, ncej #3, 38 p 165/68 main. stock slide. runs fine 5-9000 feet. tad rich up high but manageable.

 

[thumperflipper]

35 pilot should be fine for our altitude... I was running a 155 main for 2 or three years with a 38 pilot, always rich. I had the same needle problem with no adjustment. Eventually tried the JD kit, high altitude needle and buried it and still annoyingly rich, called them, they said my 07 carb was worn out and needed a much thicker needle. Problem solved, runs clean. Now I run mid clip position which gives me some wiggle room. GGrider01, what year is your bike again?

 

[GGRider01]

I ended up popping the needle back up to #2 and actually pulls stronger, but less of a hit. Probably going to drop mains one size at a time, while leaving the needle in #2 until the n3ch and W diameter needles get here. I might like what I find (i hope)

The bike is a 2000. It's very possible to the needle jet is worn but I pulled the original piston out of the bike and it didn't show that much wear.. the outside of the bike looked like it had 500 times the hours the piston did.

The guy I bought it from bought the bike new from the Denver area - never changed oil, never changed filter, sure as hell didn't rebuild the top end. Wish I had pictures of the air filter..

 

[(F5)]

Ahh.

If the needle jet is ovalised it will always run bad. Next time carb out pull main out and slide, look down there with a strong light. Any oval will be an issue. You can actually buy the removable tower section that holds the jet. Mine got damaged and I slotted in one from a 35mm pwk, same part as 39 it appears.

 

[GGRider01]

A bit embarrassing but that entire time I was running the N3EG. Not even sure how that happens..

Instead of trying the N3EH which is what I was supposed to be running that entire time, I just tossed the N3EW (arrived today) in, #2 clip and warmed it up. Instantly noticed the pilot is too lean (surprise) and very nearly looped the bike off the sidewalk and into the street. I had contacted Jakobi some time ago about which needle I should start with and this was the one he suggested.. I guess I just like to reinvent the wheel in everything I pursue.

Currently at:
N3EW #2
170
35

There is a difficult to consistently replicate off idle bog, but often enough to know I'm lean.

Will be going to a 38 for sure. If all seems happy down low and still a tad rich on the main, I'll definitely be trying the 168. The way I understand it, if I'm running a 35 and 170 and I'm rich on the main, running a 38 pilot will make the main run even richer, since the circuits overlap. In any case, one change at a time.

 

[Jakobi]

There is some overlap in the circuits, but you'd be hard pressed to feel the effects of the pilot jet when WOT.. it's well and truly above the scope of the PJ.

A 38/40 pilot will have the bottom end responding better for sure. With the main you need to focus your balance between max HP (and over-rev) and being comfortably rich (cooling and safety buffer). Going rich enough on the main that you get a burble when holding WOT and then leaning off a size or two is probably the best way to find a safe balance. If chasing max HP and rpm then can't beat a dyno.

 

[barossi73]

With a richer pilot u will also notice a bit more guts right off idle(to a point).most noticeable on tight,technical stuff when engine is at point of stall and you crack throttle,the engine will lug down a little better,where the leaner pilot is want to stall.may be more subtle on the 300 than my 200.
From 1/8 to 1/4 there is a small effect only which can be useful in tuning if your needle is slightly lean/rich in this area and your already in the best overall clip#.
Im on a different needle that tends to feel flat/lean around 1/8 to 1/4 when you roll on.bumping pilot up 1 was a small but noticeable advantage in this area.nothin noticeable beyond 1/4
Point being there may well be 2 or 3pilots that run well but offer slightly different pros/cons in delivery style from 0 to 1/4

 

[GGRider01]

Popped the 38 in today and it seems a little more inclined to idle. The W diameter probably dictates a 40 or even 42..

However, something more pressing has come to my attention now that the bike has shown its true colors. After a quick 2 or 3 minute warm up, the bike is ready to go vertical and tear the knobs off.. after 10 or 15 minutes of riding it loses that torque. Doesn't gradually get worse from there but stays at a slightly lower power level than when first taking off.

What does a warmed up 2 stroke losing power indicate? The scenario above is easily replicated. Did it several times today and always the same results.

 

[Jakobi]

Popped the 38 in today and it seems a little more inclined to idle. The W diameter probably dictates a 40 or even 42..

However, something more pressing has come to my attention now that the bike has shown its true colors. After a quick 2 or 3 minute warm up, the bike is ready to go vertical and tear the knobs off.. after 10 or 15 minutes of riding it loses that torque. Doesn't gradually get worse from there but stays at a slightly lower power level than when first taking off.

What does a warmed up 2 stroke losing power indicate? The scenario above is easily replicated. Did it several times today and always the same results.

Are we talking mid throttle or off idle.

The signing off of power as it heats up indicates you are slightly lean. You need to determine the throttle position where this is happening though and adjust. Possibly the 40/42 pilot may do it. You may find a bigger 172/175 main does it. Otherwise N3CW#3 will put you half a clip richer.

Now you're getting towards the goal!

 

[GGRider01]

I was whacking the throttle wide open trying to get the front up, so it's difficult to tell which circuit is doing what. I'm quite inclined to say 1/4 to wide open is suffering once the bike is hot. Could be lean top to bottom, but the plug is awfully dark.

I spent quite a bit of time going as slow as I could in 5th or 6th gear and popping the throttle wide open. Quite often I would get a bog - but I don't know the validity of this test. Throttle is wide open at idle speeds with a mountain of gearing for it to overcome.

After doing some pretty hard and fast (70+ mph) pulls with the 170 main jet and my plug comes out darker each time.. I'm inclined to discard plug color and go by feel from here on out. If a 172 or 175 makes it pull harder, then that is what I'll use.

I did do some googling regarding a loss of power when a 2 stroke warms up, and the only thing I could find was a motorized bicycle forum suggesting that a rich condition would cause this.. but it doesn't make sense to me. I'll try richer before leaner, that's for sure.

 

[(F5)]

Disregard plug colour.
Well the choke is action of richer for cold is required and lean it up as it gets warm.

. . . but how warm? Bikes lose power if they get too hot. This is why aircooled bikes went out. Bikes should live above 50*c and below 70*. Passed that and you will notice.

Borrow a point and read thermometer. I bought a Chinese one for about $15 and it seems accurate.

Just to check your pump is working.