Anyone out there ever rebuilt top end/bottom end/anything else of the 250x?
I just got one that needs work and need some pointers
thanks
Will

 

I have tinkered with a few including my 410cc stroker. What do you need to know?

 

Ive got a about half dozen total rebuilds and a 406 stroker motor and a 352 stroker. Need HP parts?

 

I have professinally rebuilt at least three of those you should replace both intake valves and cam chain and maybe the sliders new piston rings gaskets while you have the left side cover off to replace the cam chain you should replace the clutch plates and fibers. good luck

 

How about boring out the cylinder-is it just the skirt that gets bored? .020, .040 or .080? Can I get this done at any old machine shop or do i have to take it to a atv dealer or something?
How necessary do you think it is to do anything with the bottom end? I dont think I really think I have the time/money/experience to do that, especially if it isnt too necessary
Besides that, can I do most everything else with the right tools, like replacing valves?
thanks a lot guys!
Will

 

You need acouple of metric hex sockets for the head bolts and plugs and a flywheel puller . Dont even think about splitting the cases unless you have a factory service manual to show how to put all those gears and bearings in. I agree about the timing chain for high milaeage engines. Boring out the cyllinder is easy and you dont have to split the cases but you dont really get any real cc increase but if it is time for a rebuild them I would bore it to the max . Be careful not to damage the crankshaft oil seal when installing the right side cover.

 

It is not worth ruining your cylinder by boring it to the max. Any machine shop can do it, but I would recommend a good atv engine builder. Pull your cylinder off and see what size piston is in it now. It will be stamped on the top if it is overbored. Such as .05, 1.00, 1.25, etc. This number is mm of overbore.

Splitting the cases is easy.

Valve and cam chain replacement isn't always needed, but is a good idea. The right side cover is the one you must remove to replace the chain. The chain for the 250x is a high performance type and is very expensive. I am thinking something like $70 from honda. If you must replace the valves, a valve job will be needed. This will have to be done at a shop unless you have the capabilities to do it (most people don't).

What makes you think you need to get into the bottom end anyway?

 

thanks a lot guys!
Will