My 300 has mediocre low end!

[GGRider01]

Bike came stock with a N1ED needle. This is with the screw top AS1. I have to run it at the top clip with a 38 pilot and 170 main. It's a rich mess but runs "OK." When it's real cold it's lean enough to pop the front end, in first gear.

I thought I'd go extreme opposite and get a N3EJ needle, it's currently on #2 clip where it seems happiest. With 13-52 gears, it's a tire spinning madman and the plug actually looked pretty damn good but still dark, despite warnings that the needle is too lean - could be the main. But on pavement with good traction this still isn't enough to loft the front to the balancing point. Jug feels too hot. Not sure what to make of it. Feels good everywhere but down low where it burbles between off and 1/4 throttle.

I'm looking for advice before I start buying needles left and right. I have pilots in all steps between 35 and 42, and mains 165 to 175. The 175 gives the bike longer legs before having to shift.

Reeds check out ok, carb is clean, and the cylinder and piston are brand new with a great deal of compression. I haven't done any head mods. Powervalve is sound and visually working. Is a later opening powervalve better for low end power? It seems to open quite easily.

 

[Zman]

If the PV opens too early it can hurt bottom end.

 

[adriano.ro]

N3CJ is to lean for AS1. You need some N3EG/N3CG/N3CH with minimum 178 main jet.
For my ec 300 2008 I use 42 N3CG@4 180 main jet and the bike pulls hard,gear 13-49.

 

[GGRider01]

N3CJ is to lean for AS1. You need some N3EG/N3CG/N3CH with minimum 178 main jet.
For my ec 300 2008 I use 42 N3CG@4 180 main jet and the bike pulls hard,gear 13-49.

I should've mentioned my riding is minimum 4500ft (1371.6m). It's not uncommon to go from 5000 to 12000ft (3657.6m) in one day. However, I realise I'm not going to get jetting that allows me to do such a wide range of elevation with perfection, but getting it dialed in in town would be great.

Based on lots of googling and your suggestion, I think the N3CG or CH you recommend is next. I bought a N3EH this morning, which is coincidentally right in the middle. Will see how it performs when it gets here.

How can I get the PV to open later? Wish I had a tachometer to know when it actuates. Will dig into it tomorrow, hopefully.

 

[barossi73]

Wow,that is some altitude range in one days riding!
would a smartcarb be worth considering?

 

[GGRider01]

Taylor Park is just outside of Gunnison, which is about 7,700ft. Up the hill a ways, so probably at camp the elevation is easily 8,000ft. The top of American Flag Mountain is 12,700f. I guess 4500 to 12000 isn't going to happen in one day, but I would if I could!

It's a trip I take at least once every summer, so if I could track down this pitiful bottom end, I could probably dial it in up there quite easily since I'd have a good baseline that I know isn't garbage down here.

Smart carb sure sounds nice, though. Tearing into the PV tomorrow.

This was last year. Ran the N3EJ up there with no incident, other than a waterpump failure. Rusty impeller shaft caused a transmission full of coolant.

https://drive.google.com/file/d/0BxqrXCEttJJzMlBkNTJDTHQ0bm8/view?usp=sharing

 

[adriano.ro]

Regarding PV you can add some spacer between spring and pv actuator,a washer. Also you can put a spacer on left side power valve cover.

 

[Zman]

I would add a few degrees of ignition advance. If that does not help I would go up a pilot size to 42. I know you said it was rich but if the bike is lean it will also have no bottom end. Is your air screw responsive and where is it set?

If those do not work I would check the squish and get the head cut. My 2000 xc300 had similar problems and they were all fixed by raising the compression. If you really want to add low end you can cut the cylinder base instead of the head but that will sacrifice top end.

 

[GGRider01]

I have a 2k3 stator out of a 1999 EC 200. Instead of the insert that basically dictates the timing, it has a hole in the plate itself which will have to be widened. Might be worth messing with. Maybe the 200s had their timing set differently.

Tried the 42 pilot over the weekend and it definitely seemed worse off bottom. I've been setting the airscrew when changing pilots by starting at 3 turns out. I screw it in slowly until the idle increases then backing it out a quarter to half turn. Currently at 2 1/4 turns out with the 38 pilot. With the 42 I was out 3 and 1/2. It's definitely playing its part and makes a noticeable difference when adjusted.

 

[Getoviq95]

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

 

[Zman]

What cylinder base gasket thickness do you have? You may be able to help the situation by going to a thinner base gasket provided the cylinder is not worn with a ridge.

 

[GGRider01]

I used one out of an Athena gasket kit. Didn't have any measurements on it and I didn't use the calipers. I will say it is very thin and flimsy. There was a thicker one as well as a clear plastic one (??). Picked the thinnest after a lot of stalking around the forums here.

I must be obsessive.. I've spent all day wondering about it. I'm thinking exhaust gases are being severely restricted by the bearings I chose for the PV because they're sealed (old ones were too). Even with a large volume side cover I theorize it wouldn't make any difference unless gas can actually expand into the cover.

Also should note that I've never experienced detonation. Time to open the bearings and modify the stator plate to allow timing adjustments. I feel I'm still operating in the dark and hoping I don't learn anything the hard way, as I usually do. Should probably do a squish test also.

Other things to note, the bike starts with the 38 pilot/N1ED with no choke very easily. When I was using the N3EJ, it required choke every time with 38 pilot. The 42 pilot seemed to be the best companion to the N3EJ in 2nd clip position but mid was flat. In 1st clip position the bike had excellent low end but no mid (lean) until WOT then it would come to life on the main jet. What a headache this gives me. We'll see how the N3EH performs and go from there.

 

[Jakobi]

Your clip position testing shows you need to be richer on the needle.

The PV chambers are linked through the cylinder exhaust port, by the drum valves (open when PV is closed, sealed when PV is open). Sealed bearings won't be having any notable impact on the performance.

 

[barossi73]

Prob not your issue,but what condition is your pipe and muffler in?heavy dings or cracks in pipe seams or a choked up endcan can wreak havoc
Carb to airbox boot ok?

 

[GGRider01]

Your clip position testing shows you need to be richer on the needle.

The PV chambers are linked through the cylinder exhaust port, by the drum valves (open when PV is closed, sealed when PV is open). Sealed bearings won't be having any notable impact on the performance.

I was only guessing so, it's good to know I'm on the right track. I hope the N3EH is close. Will have to work from there.

Prob not your issue,but what condition is your pipe and muffler in?heavy dings or cracks in pipe seams or a choked up endcan can wreak havoc
Carb to airbox boot ok?

I'm betting the silencer is packed. Repacked it last year, but I've been running it rich ever since except for the brief periods where I used the N3EJ. When I got it, the narrow section closest to the header was pretty caved in. I bought a MINO kit and got the dents to turn into small dimples.

Prior to that, I took a propane weed burner and roasted the pipe. Got most of it red hot and let it cool. I did this because I didn't want 90 PSI of fuel and air while working out the dents. When shaken out some pieces of carbon were an 1/8 inch thick.. crazy effective. I did this twice last year and get paper thin sheets of carbon deposits out of the pipe the second time around. Probably wouldn't hurt to do it again but would like the bike to be clean enough to not require repacking and roasting the header constantly.

 

[Zman]

If you have not done the squish then I advance the ignition timing. It is an easy fix for the 2k3 if you have the flywheel puller to get access to the mounting screws.

 

[GGRider01]

I do. But will have to ream the hole. This stator plate doesn't use the centering insert found on other bikes. Shouldn't take much.

Kind of done the opposite of what I'd hoped and ordered 4 needles. All based on the jetting database with AS1. I guess the only way to get the best results is to try a handful. Not looking forward to wrestling with the carb all weekend but should prove worthwhile.

An NEDW slipped in the order some how but might be worth a shot. I've read it's too lean. Also got my hands on a CCK locally which I suspect will be richer than desired but undoubtedly improved results over the N1ED. Will update with a list when not on mobile.

CCK
NEDH
NEDW
N3CG
N3EG

I'd like N3EH/CH as well. Almost forgot, N3EH on the way from an eBay seller.

SmartCarb is starting to sound like a smart purchase! Will just have to settle on one of these for now.

 

[Zman]

I have had good luck with the CCK needles in the older screw top carbs on the 300s.

 

[GGRider01]

This is a step in the right direction! Started in #3. Four-stroking off idle, very smokey idle even when warm. Went to #2 and the bike felt lurchy and is wanting to pick up the front.. getting there! Turned mixture out 2 turns even. Still fat rolling off of idle. #8 slide is something to consider.

Will try #1, because I won't know how it is if I don't.. if the bike likes it and the plug looks safe I'll be inclined to try the next step leaner. I wonder what the next step leaner is to the CCK. Not finding a chart for these KTM needles. CEK?

Still running the 38/175 jets. Not many have reported using 38 with the CCK.

 

[TheLetterJ]

I haven't even kicked my 300 over in damned near a year (!!!) But I do remember that I'm running a CEK (but I don't remember the clip position) with a 38 pilot and 172 main in an AS1. Riding mostly 1500'-6000' with temps in the 70's & 80's.