1984 WR400

100%!- busted

Hi John yes I do have 84 CR250s as well but yes my question was aimed at this WR400 lol
I love my 250s but want to build the 400. I like the 84 chassis and want to try it with the bigger engine!!

its a great engine and check out my rebuild thread on here for any info. I tweaked mine a tad and its like a 125 on steroids but still pulls nicely off the bottom. great engine. you will need to re do the damping stack as they are soft as for a plush enduro ride. a bigger rear sprocket will see you holeshotting in 2nd gear ok. great engine ...if you didn't pick up on that.... it will probably be an 85 as most of them were badged 85 for some reason tho everyone thinks they are 84's

Hi what rear sprocket are you running ?? I was thinking of running a 54?

Had the angle grinder out today!!

Removing the 'rock bar' , grab rail and all the extra brackets on the swing arm that I do not require!

i have a pile of cr frames i would have traded you a few of to get a good frame with that stuff attached..swingers too..its so much harder to weld that crap on, they dont make these anymore..

Bit of bad news the swing arm bearings were pretty seized and it has elongated the frame holes.

The swing arm bolt is knackered too. Big grooves where it's grinding in the frame.

Will fabricate some 'washers' and get the welded on and get a longer swing arm bolt made to compensate

how good of a welder are you? plug welding it is an option long as you can get the hole where its supposed to be again. clamp some alum or better yet brass to the back and fill, then redrill. then no messing another hardened pivot shaft, a cardboard template is handy for finding your hole again. this worked well for fixing some of my frames. we plug weld at work quite a bit.
i know you mean about the gouges on the inside, filling with weld and grinding smooth is the only good way to fix it.

i think HVA has a kit to fix that

Sorry I realise I'm 'butchering' a 30 year old bike but I need all the rad fittings and geometry that the 84 WR frame has.

I am going to atleast be bringing her back to life!!

But I understand your perspective

54 will be good as im running a 52 and its bit of a jump from1st to 2nd.

The bottom end is split now and new bearings and seals going in.

barrel is off being rebored for its new piston.

Today got a package from the USA of the uprated rear springs and preload kit. Feeling lucky as these springs seem to have suddenly gone on 'back order' now. Hope Ohlins are willing to make some more!!

Slow progress ....

looks like a package from arizona! nice stuff!

Well the barrel took a double bore to bring it back into tolerance. So kindly HVA exchanged my piston and supplied me with a CR430 head gasket. Not sure if we are still a 400! 405? The new piston won't work with the 400 gasket.




Got a few other little bits too.

Water pump rebuild kit and sprocket plate

Note for others,
Anytime these sit for who knows how long with gas in the crankcase change the cylinder base gasket. The gas softens the base gasket.

My '86 400 was awesome very smooth. It had low use on it.

V = 3.14 x( R x R) x H

V = 3.14 x (42.25 x 42.25) x 74 = 414.98 cm3

P= 3.1416 I got it.

The 390/400 is the best running engines I had so far.

Port those transfer ports.

Put a piece of brass with a clamp on the rear side of the elongated swing arm hole and weld some of the elongation up. Then remove the brass. The dremel or file it round again..

You have the wrong base gasket if it doesn't fit. It's from a earlier 360/390?