1984 WR400 help

My 400 is yummy.
Nothing outrageous , just gets faster and faster with no fuss.
Don't listen to Surprize ,his mate got at the exhaust port on his 400 with a grinder and it's not normal.

Got it apart finally. Penetrant, heated outside, and tapped outside while pulling spring enough til I could get pliers on it.

The packing looks brand new. Is that just because it's the back? Just run it?? Looks hard to pack with the sheet style I have here since the tube doesn't come out..

the back always has tight clean packing, the front is where its always missing..or the packing on that one could be good. on that style you will want to pick up the "stringy" style. nice work getting it apart..

thank you sir.....

so then the question is.........
1. buy stringy style
2. run it how it is
3. cut my foam sheet up and make it be a stringy style....
4. run it, order stringy style if needed. can even repack without removing from bike, not that thats difficult.

Also, if this perforated tube doesn't come out, how would the holes be cleaned when needed? Soak in diesel and hope for the best?

If you're accustomed to riding 125's I suggest you improve your grip on the handlebars!

These things have a powerband about as wide as....oh....Utah.

They just keep accelerating. Perfect enduro motor.

Awesome!!

So I'm ready to install muffler
... looks like I can interchange the rear ends. Should I use the my original? Top is old setup bottom is ebayed one. Original rear cap Looks more free flowing

I just put it together with the old rear end. Looks weird but I suppose it how the old one went.

I'm about to paint it and throw it on. I'll paint ebay end cap too incase you guys tell me to switch.

I have found the easiest way to pack the silencer with the fixed tube is to use a piece of steel or plastic pipe that fits over the perforated tube as a nice sliding fit. Have a piece way longer than the silencer. There are a couple of different diameters of that tube. I was lucky enough to find a piece of very thin chromed steel tube from an old cloths hanging thing that the wife never noticed missing ! I always use the mat type packing. Measure the depth of packing required and cut the mat about an inch or so longer. Wrap it around the tube so that it will be an easy (ish) fit in the body of the silencer. Use a couple of small pieces of masking tape to hold it together. Push the tube with the packing into the body. When it is right in, pull the tube out making sure the packing does not follow it. The inch or so extra will be pushed in to the body at the close of play. The masking tape will not last long and disappear after a few hours of running. DO NOT pack the mat in too tight. It should all be a snug fit.
I guess many will also have their preferred method of doing this. But this is mine.

Just test drove and she rips!!

Couldn't even wind first gear out in my buddy's yard but I could tell new power was there. I could actually make ruts and spin the tire on wet pavement. Tomorrow or Friday I'll ride in a real trail

i like the spiral spark arrestor better than the cone with the perforated holes. better flow and less plugging. the spark arrestor does help keep sound under control.
looks like its actually test ride time now! enjoy the swede, its a good machine that will only get better the more its dialed in. its certainly no 125..

The arrestor with holes just has holes on the outside and is essentially a straight pipe through the center. As a pictured above.

The spiral arrestor had a spiral through the middle which wouldve otherwise been straight air with the other arrestor.

Lmk if that changed your opinion. I can swap before I test ride tomorrow.

That's a bloody good idea grouty, filed for future use!

You could take them both and swap to compare performance?

Agreed

So, the long test ride is tomorrow, but the other day the rear tire Sat on a piece of cardboard and on the kickstand, and the rear tire slid out and crack the kickstand bracket. I can weld it back next week, but for now I have the stand the bike straight up.

And since standing it up I'm leaking oil!!! Out of the front sprocket. And maybe other places. Please tell me this doesn't mean a motor tear down....

Sorry pics are bad. I cleaned it off and now it'll sit over night so I'll take new pics in the morning

Tricky fix for that.
1 Remove sprocket
2 remove magnesium cover taking care not to knacker the screws.
3 buy a new sealed bearing from any bearing shop
4 Sharpen a broken piece of hacksaw blade down to a narrow sharp blade like point. [ sort of like a pointy thin screwdriver ]
5 gently remove the seal from the bearing behind the sprocket by inserting the hacksaw blade and turning. [ Practice on a old bearing if you have one]
6 gently remove a seal from the new bearing.
7 pop the new seal into the old bearing.

Or try and figure a way [ it can and has be done by forum members ] to remove the complete old bearing and replace.

Had this on a couple of bikes of mine, no major problem unless the output shaft bearing is starting to collapse. Just check by getting hold of the shaft (with the sprocket taken off if possible) and see if there is any up and down movement there. If its rock solid then you can live with it but keep a close eye on the gearbox oil level, or try to replace the seal as mentioned in previous post. If you do find movement then you must split the motor and replace all the gearbox bearings. If you don't do this you will risk the gearbox exploding and causing major expense to repair.
The oil leaking from the front exhaust port can be easily fixed by removing the pipe and resealing with a decent silicone which should be an automotive product.