1978 cr 250 to big bore.

hey all, new member here! great place you all have! spend as much time here as my wife does on FB 78 cr 250 motor apart for all new bearing's &seals, crank need to be done ,sooo, 390 or 430? what can/ will it take a to turn this girl into a tundra tosser?!, 250 motor's complete, new jug-head-piston a given..will the 250 ignition fit bigger crank? will the 250 flywheel work? any advice would be great!! i'll try to post a pik from where i'm at so far: thank's in advance,

id say, your best bet is to find a 79 or 80 390..CR or WR., avoid the OR..
the trans in the WR is a little tougher, and likely see less abuse, you will need the swap the pipe as well, yes your stator and flywheel will work..same crank stub.
i have a 79 390 that im going to part, and may sell the running engine and pipe..
if you contact me outside the forum, we can talk about a price and shipping.

old huskychuck, alaskan husky,I'm interested!mvollema@yahoo.com

id say, your best bet is to find a 79 or 80 390..CR or WR., avoid the OR..
the trans in the WR is a little tougher

Whats the faults with the OR trans? I had a 1980 OR390 and loved it, very reliable. Put a 420 kit in it in in 83 and ran it hard the whole time I had it, untill 88. Was I just lucky to never split the cases for trans issues? Thought the OR had WR lower gears then close ratio uppers? or am I backwards?

whats a 390 run like? I've had an rm 500 and a yz 490 loved the snort! 93 ktm 300 was fun also,got 2 of my boys hooked! out here in AK theres miles &miles of quad trail'and huge hills! so looking for more snort than the 250 has to offer, that and I'm old....er and fat...er than I used to be! horsepower to weight ratio you understand!!

I thought the 390 was a awesome engine, very broad power. When the 430 replaced it at the time my 420 kitted 390 would take a stock 430. That was also a long time ago and I was a teenager=crazy. For your 78 chassis I would look for a 390 "WR" or "OR" engine. my 2cents.

I cant, for the life of me, figure out how to pot up pics!! thanks for info guys Iunderstand what you mean huskyfleet, I was once young and crazy! It's just that there's only a few kids out here with bikes,all small bores, I feel I must learn them proper about ''roost'' then of course there's the quads

nothing wrong with the OR,s however,, long story short,,i owned a 79 250 WR, wore it out in the early 80,s picked up a roller 250 OR for a good price, and thought, just swap the engine, and be happy..
well, i found out the front ports were a little smaller, and my WR pipe wouldnt work, and i didnt get the OR pipe, so i had a muffler shop weld a smaller end on my pipe,
id did run great for another year, and then i picked up my first single shock Husky..
so, on the 250,s anyway, the OR seems to have its own intake and exhaust port sizes,. maybe to help low end,.not sure..
admited, i have never looked close at the 390 OR porting..i cant imagine Husky not doing the same for the 390 as the 250,s
in hindsite,,had i just swapped out the manifold it might have fit ok without welding.. i was 18 or 19 then...and really didnt use my big head much..

this is me,,,what stud,,and after i swapped the engine,,
man i was skinny thin, and look at all the awesome hair....boy do i miss that,,lol come to think about it,,i think was closer to 22 years old then.

this is cool,after years of fiddling with everything possible, we still have to fiddlle with everything, we need a switch to turn our brain off or on!!If my sweety reads this