All 2st Jetting Chat - Need Help? Post Your Questions Here

Sounds like you are starting to confuse yourself PowerKord!!!


Ok start with the basics, the black knob above the fuel inlet is your idle adjustment which only opens the slide up to let more air to increase the idle and that's it, does not effect the rest of the circuit aside from idle. The air screw effect throttle action from idle up to/near 1/2 throttle.

I would twist out the idle knob (lowering the slide), set the air screw out 2.0, start the bike, warm it up and then twist your idle knob in until you are happy with the idle (it should hold idle for at least 2mins). Now, turn the air screw out in small increments.

If the bike doesn't progressively raise it's idle by turning out the air screw e.g out 3 turns and no effect, the pilot jet to way to big. Opposite applies when you can screw in the air screw to .5 and the thing is still idling (too small of pilot jet)

On a nicely jetted bike, you should have the air screw out min 1.5 and idling (warmed up) for around 2-5mins before dying out (probably don't want your 2banger to idle too much as it can cause fouling).

45 pilot jet is too large (rich) in IMO, start with a 38 (lean), middle clip and 1.5 out on the air screw as a base and work from there - no use playing with needle heights or type of needles if you don't have a reliable base to work with especially from idle to 1/2 throttle.

Thanks ohmygewd, it does seem that the 45 pilot and "J" needle are too rich. I ordered an "L" diameter needle as the "K" needle I had in would not run well off the bottom. I'll try to go leaner on the pilot as well.

Hey powerkord, what elevation and temps are you at?

I'm around 1000 ft. above sea level. Temps have been in the 80-90 range...

Hi all, wr250 01
Had a mikuni tmx
32.5
2nd clip 60
slide 4
Ran crisp mostly but tried pwk to see if it could be more consistent.

So Far am on
40
2nd cel
175
slide 7

Question is with these settings right off the bottom is good, just after it's savage and pulls hard right through. While this is fun in the tight, when it's a bit more open or rocky it doesn't feel like productive power or very linear. Also in the sand it feels lean, would richening the clip move it up the range and give it some more torque before getting wild?

Richening it will mellow it out a bit but if you go to far it will start loading up on which ever circuit you make richer. I changed from a stock pipe to a Gnarly pipe and it smoothed out the middle hit. My bike is an 09 WR250.

thanks, will try it

1992 WR360

PWK Airstriker 38mm
Main jet = 172
Pilot jet = 42
Needle = Blue
Clip position = 2nd
Air screw setting = 1 3/4
Slide = 7

Bogs down low and up top.

Starts so easy, second kick cold under choke but hates starting hot.

Gun it off the line and it will just about cut out, picks up the front wheel through the mid then acts sick up top spluttering and carrying on at higher RPM

BP 95 octaine Amsoil Dominator 50:1

Once or twice per ride when the conditions are perfect...(Riding up a long steepish hill with good grip, w.o.t, every now and then it is perfect and revs out well.)

Feels very rich at high rpm and plug is generally wet.

Vid uploading

Any ideas are worth a shot.

Have plenty of needles and jets but only a #7 slide which the majority of people are using on Cafe Husky.

Stu

Got some awesome advice on DBW that is worth posting:

"Its a big pumpin 360 with a high vaccuum off idle. Most skips (aussies) find the blue needle on the rich side, but this would be more noticable on the larger engine. Is it a lean bog, or a burbly wet slow responding mushy feel that then cleans out as you show it more throttle?? What effect does the air air screw have?? I'm thinking rich as it starts easy cold and hard hot. Does it start easier when you open the throttle?

Things I'd be doing. Double check float height. Maybe set the distance a few mm more than stock (lower level/less fuel). Then start over with 40 JD Red#3 172 main. Set the slide manually so its only 1mm open (looking in the throat).

Set the AS at 1.5 turns out. Then shuffle pilots until you get the one that allows the bike to start and idle at these settings once up to temp. Use the air screw to get best repsonse off idle.

Once pilot is setup like this work on clip position, then finally dial the main in to make her scream."

And also this:

"What happens if you screw the airscrew in and out? If you find the idle speed increases as you bring the AS out, then that's a sure-fire sign that your pilot is too big.
Another signs would be if it is relatively easy to start from cold with no choke/being able to turn the choke off soon after a cold start and have it idle fairly happily (remembering that big 2Ts are always cold blooded).

The 'heavy', bogging sound off idle in your vid also screams "too rich".

I'd get a 40, a 37 and a 35 and try them one by one, in that order. My guess is that the 37 is the one to use, but it's gonna be a matter of trial and error. Look for the idle screw to be about 1.5 turns out to give good off-idle throttle response and a regular idle.

If you go too lean, it will be a real bitch to start, especially when the engine is semi-warm. It will also tend to sound tinny. It might sound quite crisp, but will be down on power.
If you get to a point where you've narrowed the choice down to two jets, but can't feel the difference between them, then always go for the larger one.

Don't touch the main jet until you're happy with the pilot. Not revving out is a typical sign of being too rich, particularly if it sounds flat and lifeless.
Too lean on the main will sound great on a free-rev, but will be well down on power, and will often pop under load (as opposed to an obvious 'chug chug chug' misfire).

Again, work your way down in small steps, until you're happy, or you've realised you've gone too far...

Being a WR360, if you're struggling with getting the main jet right I'd also suggest that you check the power valve operation careully, and ensure the ignition works properly (particularly at high revs).

A couple of other things:
1. KTM380 jetting could also be a good guide, seeing as they run a PWK38 stock.
2. Modern fuels seem to need leaner jetting than old and/or American recommendations.
3. My KX250 runs a 40 (IIRC) pilot jet in a PWK38 - it's smaller bore means it needs a larger jet than your 360.
4. If you have an aftermarket pipe/silencer its likely to want leaner jetting than recommended.
5. Make sure its properly up to temp before making changes. "

Stu

Stu,

Do a quick inspection for an air leak around the base gasket, should be visible with an oil weep. Also, pull the carb out, spray carb cleaner and give it a good blow down (inc breather tubes) with an air compressor gun or go down the servo and use their tyre inflater.

From your vid, it sounds like a) the motor isn't up to operating temp or b) it's running rich from idle. You'll find blipping it from 0 to 1/4 it's fine but from 0 to 1/2 it bogs..try this:

Don't over oil the filter...it can richen the bike as it's blocks airflow and can clog the carb.

Screw out the airscrew until you hear the idle rise and now blip the throttle from 0 to 1/4 and then, as the rev's are just coming down, to 1/2 throttle - if the it sounds relatively clean and the AS is out more than 2.5 turns, then the pilot jet is too big.

I've jetted my mates 93 WR360 with the following (PWK38mm)
JD Red needle at middle clip (I use the blue on sand)
172 main
40 pilot
Airscrew out base 1.5 max 2

The only difference with my 96 Wr360 is that l run a 170 - we do a lot of slow speed stuff and the 360 is best when you short shift so you rarely go WOT unless it's long straights...unless your at Beachport then l would run a 175-178main and 42pilot

Come summertime @800m altitude with temp at around 28-30C, move the clip to 2nd from the top and maybe adjust the airscrew in or out by no more than 2.

If you had a crankcase leak it's pretty easy to identify - oil in the water says it's a tranny seal and if it's the stator side, take the stator cover off, spread some baby powder, seal her up and start it then check; if the powder has disappeared then it's sucked into the bike indicating a seal issue...plus the bike will run like shit and foul up.

Well, after shattering my piston last fall, I slowly and carefully rebuilt my 99' WR250 engine. Replated cylinder, rebuilt crank with new rod, bearings, etc, piston is a Wossner forged. Here it is back in the bike. Started 2nd kick and runs awesome. Still carefully breaking it in. However, as before my low end could be a bit crisper. During the rebuild I set the PV at 50.5.

Boysen fiber reeds
Procircuit Platinum pipe (I know not the best for low end)
Stock Mikuni TMX standard jets 400 M, 35 P
After break in I will use 40:1, (currently 32:1 for break-in) with Belray H1R
I ride between 800 and 1200 ft, North East temperatures 45 degrees to 90 F

I didn't see anyone with my combination in the jetting database.

Will a smaller pilot improve the low end? Almost everyone on here has used a smaller pilot.

Should I be running 50:1 instead of 40:1 after break in? I'm old school and have always used 40:1 but am thinking I should go to 50:1

Has anyone on here experimented with adding the Vforce reeds to an earlier engine and with what improvement?

How about Honda CR250 reeds?

Any other suggestions?

P.S. Part of the slowness in my rebuild was from obtaining a Husaberg FE450 that got a bunch of tweaks and tons of happy riding time this year!

I'm running a 30 pilot in mine right now and it has really crisp power off idle. So you definitely need to experiment and see what your bike likes. I run 40:1 in mine. More oil won't hurt your engine!

Thanks PowerKord. I'm going to order a 30 and 32 and try them. What kind of pipe is that on your bike?

I do have the FMF Gnarly and Powercore II on mine, I have had the head shaved for more compression. Other than that it's stock.

Has anyone observed this? I repacked my silencer, which was long overdue and the bike was quieter as expected but also seemed to run leaner... Especially in the mid and top end. It was a hot day so I'm sure it wasn't due to a drastic change in air density altitude.

32.5 for aussie huskies, yours should be similar, usa jetting runs very rich for us

Hows your float level? I have same carb and lowered level to 18-22mm, level with bowl like most do is more like 14mm and waaay too rich.

I did drop it down a bit but when my additional jets come in I will check it to see if it is 18-22. Thanks!

2002 husky 125 wr
stock ,repack silencer , iridium ix ngk BR9EIX plug. good top end, new air filter
v force reeds had oil spooge and changing my stock carb settings to the ..i live in south eastern mass temp right now is 65 degrees F and im at 92 feet elevation..so pretty much sea level. i looked at the chart with the owners manual and it says i should run a 400 main 35 pilot (stock) but i have a lot of oil drip from exhaust pipe... suggestions?


stock------------------changing
-main jet 400 --------------to a 390....(also bought a 380 i can change it to)
-jet needle 6dj8-60-------- staying the same
-jet needle groove 3rd-------up to 2 to make it leaner
-pilot jet 35-----------------30
-idle air screw 1 1/2------1 1/2
-slide 3.0----------------3.0

I would go leaner main and richer needle setting
Lifting needle with clip second to bottom will fix bog