new puzzled member

What would happen if the motor had a 87 clutch side case and someone had replaced the flywheel side case with an earlier one because the chain had come off and busted the clutch actuator shaft hole.
This can and has been done because I have done it on a 87/Wr250 , the last bike in my avatar in fact.

Some thing that shows a 400/430 cylinder is a little drain plug in the cylinder above the ignition.

absolutely dukkman....these things can be mixed and matched so much that for someone new to it all its quite overwhelming im sure...i think it makes them pretty handy bikes!

I think Justintendo nailed my feeling about it on the head. Lol. Its one bike in my closet of treasures that I don't have all the answers to. And probably never will. Meh oh well its a runner for now.

One neat thing is if is a 400, you have the oversizes for the 400 to go thru, then you can bore it out to 430 and use those oversizes as well. Then you can resleeve to 400 and start all over again

You know I've actually been wondering about that. What's a ball park figure loom like if I need to bore it? I'm just curious cuz I think I'm gonna tear it down to the frame and freshen up some stuff. Figure I might pull the head an see how my bore looks.

Looking at your photos I see a 87 or later front end , a frame with no rear loop which looks to be a CR , a 87 kickstart lever , a cylinder with a drain plug.
Looks to me like a 87/400 Cr --> Wr mix .

I have a 87/WR400 here with the engine number of 21410332

i highly recommend you do a compression test on it for shits and giggles before you tear it down...hold throttle wide open and kick till the needle stops climbing..once you know that you can tear it down if you like ...

if it needs bored you will have to talk to a shop that can do the machine work..they will bore it till its perfectly round and defect free and let you know what piston size to get. then they can hone to the proper clearance...it will be a great help to them if they also know what the available piston sizes are for your application..
when you remove the jug you will probably be able to tell what motor you have by reading the top of the piston..

Check out Husqvarna parts, phil has all the bits you will need. get the engine apart and have someone split the cases and replace the seals and bearings. They are cheap to do as they are all standard sizes. get the crank checked for balance as well while its apart. not too expensive and great piece of mind.

I think labor and shop supplies to bore it would be around $75 normally perhaps $45 from someone you might meet in the pits of an event.

I kind of suspect if you want an oversize 400 piston your choices would be pretty limited if they exist at all Perhaps around $250. 430 pistons wiseco and woosner are about that retail but I have dealt with woosner direct on line or at least they have an on line store. The origional one is a cast and those aftermarket are forged (and then machined in more ways) and will likely seize if not bored a bit bigger than the origional spec.

I will take a bit different position about pulling the engine apart. Chances are the bearing at the sprocket is the only one that will fail before the crank/connecting rod roller assebmly. You apparently have the plate to enable swithching that out in place. I suggest riding it a few times and seeing how the oil looks and how much stuff is stuck on the magnet. The starter gears and third gear often are not too good. The surface (on the gear with notches) the needle bearing rides on on the kick starter shaft should be inspected and that is just a clutch cover access. The size of the holes for the swingarm pivot and the rear engine insert should be carefully examined if you pull out the engine.