83-84 250r engine/top end swaps

[monster 84r]

ive never heard of a straight drop in, or at least something that would need some small work to fit in a s frame. other than the 300r kit, what else would fit in there with a little work? big green machiene sheded some light on the 480, im leaning in that direction.

250 cr elsinore air cooled motor or top end?

480 cr motor? would it fit?

oddessey 350 or 250 motor?

i think an air r with a cr 480 motor would tear it up at the dunes. it would be a good sleeper if the motor fits. anyone whose tried an engine swap on 250r's feel free to chime in.

[RideRed250R]

dotn think odessey... wont fit at all and they are automatic.... think 480.... only difference from a elsinor and the 250R is a flywheel, stator, and forward kicker... my bottom end on my 83 R i just found out is a elisnor tranny (reason i only have 4 gears..no the shift forks arent broke...) the 480 is doable, like i told you before i might pull that off with the 3 other swaps iam going to do this summer... the 480 requires the lower cradles to be notched "dimbled" and some guesseting... but when done the thing will rip like no other bike... from factory they made a impressive 55 RWHP and are very capable of hitting 65+ with the right stuff i have even done some research and aim thinking with the right stroke plate you could fit the 480 rod into a 250R bottom end... for a stroked application.... it can be done, all original motor mounts can be taken off.... and its going to take some time to line it all up... but it can be done... remeber these motors where and are known as the first drag motors, suprisingly alot of the people on planet sand are familiar with this motor and i have heard of several of the first drag atc's hittin 4.2's in the 300FT back in the late 80's... i say go ahead try and pull it off... it can be done... but here is the things your going to need and DO..
complete 480 motor
complete wire harness
get a roller take off all motor mounts and strip frame for weld penetration
basically there you are... just make sure all sprockets line up... and make corrections accordingly

Adam

[monster 84r]

awesome, let me know how it goes when you try it. im anticipating the finished bike, it would rip like crazy.

i just got off of the phone with a guy who does alot of work on vintage bikes here in mesa. he said he could bore my air cooler to a 285 or a 300 for less than 150$ total. i made sure he knew i hjad an 84, and not a pumper. but hes been doing this for 35 years, and 130$ sounds like a good deal to me. he also has a hondaline 300 ready to go.

[BigGreenMachine]

Not to be a downer but you might want to try a different trike. Get yourself a pumper and work from there. Better suspension, more power and tons more motor mods available.

[monster 84r]

i know i should big green, but im strapped for cash, and i cant afford a descent pumper...

[RideRed250R]

yah... i know how you feel man like i said been in your spot i just got the chance to keep one of my air R's.... as for the boring your air cooled out... is he doing that on the stock sleeve? i know the sleeves are quite thick on the air foolers... but that might be big enough to warp a cylinder.... who knows... at this point since you dont got the funds i say just have it fully ported... it will kick alot more then it does as of now...
Adam
my 83R since it got ported rips good and fine