[Lathersr]

Alright Im totally unsure what to do... Ive got a crf450 hybrid build Im doing.. I took the engine apart to check the valves and piston.. I noticed some scoring on the rod.. Im assuming the crank rod bearing is on its way out.. I was looking into possibly building the motor somewhat.. I was thinking a 3mil stroker and maybe big bore... Maybe standard bore..where would you guys take this..saving money is always nice but this is going to be a mx race bike taking a beating
. I mean i could always use and love the extra power but i do need a certain reliability. Where would you guys take this
.. There is 3 mil stroker and 511cc big bore on ebay that looks good but i figure that would need a sick cam and probably some port work... Help me out!! Lol

 

[DnB_racing]

my opinion on the 450 crf is it has plenty of tourqe and a big bore and stroke will defiantly add cost, along with loosing some of great snap that the motor has...
I personally like the way they feel with a good port, and high compression along with a web cam, and stock stroke and bore has the feel I like...

but some like a tractor type of power that a big bore stroked motor has,

I like the faster revving that stock stoked and bored high compression motor has, along with the lighter flywheel compared to the trx,
it has the acceleration were I like it..

but its a matter of opinion on how you like your motors to perform and how you like to use it

 

[Lathersr]

Im going to be buying a piston and Crank rebuild anyway... Im looking for a bit more power but still having a season of some hopeful reliability.

 

[Donny]

i would just keep a standard stroker, and big bore. that way itll give you the ballsy bottom end, along with 4-stroke top end without blowing the trans gears through the cases.

 

[tbone07]

I've never ridden a bored out or stroked out 450 that I liked. Made it feel sluggish for some reason.

An excellent 450 builder is Baldwin and not too far from NY

 

[fast350r]

i would leave it stock stroke and bore and you can add these mods 13:1 piston, port work , bore your fcr, cam, and get those valves checked and adjusted that motor has 2 weak points ( valves and rod) keep your reliability with the stock stroke and bore.

 

[344RDuner]

i would leave it stock stroke and bore and you can add these mods 13:1 piston, port work , bore your fcr, cam, and get those valves checked and adjusted that motor has 2 weak points ( valves and rod) keep your reliability with the stock stroke and bore.

x2 ^^^^

 

[Lathersr]

Hmm i was thinking the hot rods hd 3mil crank which requires no modifications..standard bore piston 13.1.. Possible port work and cam? Defibetly going to have the head and valves checked.

 

[june]

Here's a pic of my friends old crf hybrid with chassis built by Legacy ATV before they went outta business. I don't think he did much to the engine.

 

[rockingkfarms]

Keep it stock bore and stock stroke for reliability
You have to keep in mind the cost to rebuild/maintain a 4 stroke motor vs a 2 stroke
For headwork and all around motor work I'd give Baldwin or DC Cycle a call

 

[american opel]

x2 on calling mark Baldwin.he will gladly talk to you and let you know the best route to go with your build.