Jetting on WR400 with Mossbarger reeds

Well, I've got it running. It idles well but is hard to start. Anyone have experience wihththe Mossbarger? Does the jetting stay the same? Needle in middle position, air screw 1 1/2 turns out for summer temps?
Thanks in advance for the help.
Pete

I'm not sure the reeds would call for too much jetting change. My experience with hard starts is the pilot is too small, or timing issue. Did it run before changing to Mossberg?

need more info..pilot size.....wheres timing at? the mossbargers might be a step leaner or richer. regardless, you will need to fine tune.

is the needle and seat ok? ol mates leaks like a sieve and if you leave the fuel on for a micro second too long, its a full throttle and 10-20 kicks before it blubbers into life shooting a litre or so of raw fuel out the back if the fuel is kept off, its a 1 or two kick hot or cold affair.
I cant see that a reed block should alter jetting much, may need more or less on the top end or mid range is my guess. if everything is ok, 1 size up on the pilot should account for the bigger reed assembly.

Ditto on the needle and seat. If it leaks you will never jet it. Check the float level too. If the system is gas rich the sleeve adjustment rpm screw can be too far turned in to make it run. This causes hard starting because we're off the low circuit.

Specs 86/400
Pilot jet #35
Main jet #400
Needle position #4 slot
Balance screw 1.5 turns out from bottom. Starting point for the best, smoothest idle.

With boyzeen reeds they run a tad rich so jet it a tad lean. Installing the UFO in the bottom of the carb sleeve also makes it rich because the gas/mix is flowing in a staight line not hitting the wall in the sleeve.

The '86/400 is one of my favorite WR huskys.

Jetting,

Make sure the carb is clean. Make sure the choke passages are clean.
Check needle and seat for leakage.
Check float level.
Put a few drops of 2t oil on the sleeve.
Bottom the balance screw and back it out 1.5 turns. This is a starting point.
If not sure I install the needle clip in the third groove.
Make sure the mounting grommets are free of cracks in the rubber.
Make sure the air filter is clean, free of tears and lubed.

Start it up. Warm it up, clear it from the choke from being on.
You turn the balance screw in looking for the highest rpm speed. If it doesn't react turn the screw out. If your out past 1.5 turns go smaller on the jet size. The sweet spot your looking for is 1 turn from the bottom on the screw. The adjustment span is between 1/2 to 1.5 on the screw. The 1 turn setting is perfectly in the middle which gives us room to tweet it in the final adjustment. Your looking for the highest, smoothest idle.
And the balance screw being open 1 turn. Change pilot jets till it's achieved. Next is the main. I go larger till it's blubbery. Then go smaller till it's running clean. Next is adjusting the needle. How's the transfer off the pilot to the main jet feel? If it's rich, not a clean transfer drop the needle. If it feels lean raise the needle. Now if it's running fine your ok. But if the bottom doesn't feel right open or close the pilot screw a tad not much to clean it up.

Don't think you will get this right on the first shot. Take your time. The carb can be so messed up on the upper area it may take two or more times to get it right. Remember you will get it jetted about 90% and that last 10% is the tough part. It's a learning process.

Jetting might be slightly different with a Mossbarger reed but not by much.

Bikes, especially big bore two strokes of any brand, are easier to start when they are set so they will not idle. When the slide is set so it will idle the choke/enrichener circuit does not work as well. On all my big bores I have them set to die after about 2-3 seconds instead of idle.

Does it start easily with a push? if so it could be the electrics rather than fueling..........

Thanks for all the replies!
The bike wasn't running when I got it. The stator and coil tested good. I added another ground and cleaned all mounting areas. Nice spark. timing is at 1.6mm BTDC.
Mossbarger was on the bike when I got it. New carb boot.
I did flood it a few times before it started. The comment regarding the needle not seating occurred and has been fixed.
before starting I dipped and cleaned everything.
It is currently set up to idle, which it does well. I will reduce the idle a bit and see if that helps. I'll check jet size too. The needle is currently one notch above the middle. When I started it, it responded well to the throttle. Just picked up a chain so I can ride it and see how it feels.

try 2.0 plus BTDC and see if it starts on kicker?

Never had a starting problem or an idle problem once the jetting is close or at 90%. Like I said before if the pilot jet section is too rich we raise the sleeve to add more air so the rich lower end will make it idle but at the same time the sleeve is too high so the choke system makes it hard to start. Your off the pilot jet area.

I'm not off anywhere, my bikes are jetted perfectly. You said it yourself that if you raise the slide too high the choke system does not work, well, it works in the other direction also, the lower you set the slide the more vacuum the enrichener circuits sees and the more effectively it will draw out fuel. I do not need, nor do I want, my bikes to idle I want them to start and they do start 1st or 2nd kick.

my 400 idles beautifully (in gear) , starts first or second kick hot or cold and goes like shit off a shovel, I even used it this morning to amble an unwanted cow back through the hole in the fence...lots of idling... whats the issue???

I would suggest that what you ride and how you ride it decides how you like you tick over, trials, trail, enduro and Autos = tick over, motocross =no tickover

Recently I got involved in arrowing a round of the Husky Series here near my place and the other guys asked me to turn my 400 off cause it would just sit there idling all day.
Idling , idling , idling , idling .
Ping a pinggg ping ping .
They may have been jealous with their moderns boiling and stuff.

Well, interesting comments...
Some of the initial difficulty may have been an unseated float valve adding extra gas. They're all a little different. My 07 KTM 300 (Sorry but I have sinned) needs to be laid over until gas comes out, then choke and start. My 85 250WRX started on a few kicks with choke. Going to try and ride it today- see how it goes. I have a small weather window-we are going from low 60's to heavy snow and 30's by late tonight. Wish me luck!

Well, I rode it around, started on the third kick. The rr axle broke(?) when i adjusted the chain but I made spacers for the axle to keep the chain on.
Sure does vibrate when you rev it but the low end is excellent!.
I may need the rear brake assembly- the brake stay that fits into the swingarm is 1/2 missing. Is it magnesium?

yes the backing plate is magnesium.
your axle broke? or the chain adjuster bolt?
if a lot of vibration is present its likely you need to inspect/tighten the front/rear motor mounts.

Harder to fix if the backing plate is magnesium. I need to weld the swingarm too-the lower brake stay slot is also broken off.
Thanks, I'll check the motor mounts. Have to go through the whole bike this winter.

Welded magnesium before. You turn up the argon flow to make a argon atmosphere in a cardboard box using the TIG torch then weld it with magnesium TIG welding rod. I welded Honda clutch covers. I'm also a welder , fabricator too. Big stuff, little stuff. I'd like to setup a welding shop someday just for bikes.