Title: just a thought?
250rnewbie - October 2, 2006 04:46 AM (GMT)
Hey I was wanting to know has any thought of putting a rm 250 motor in a lt frame? If they have is there any performance plus to this? Oh and what parts could you use off a rm motor to fit the lt motor? Just a thought !!! <_<
silversurfer5090 - October 2, 2006 06:33 AM (GMT)
here is one on e-bay. I have been told it will vibrate pretty bad and may crack frames. It will have a great performace gain if using newer rm motor with exhaust valves that open extra ports. I would think a well tuned 87-92 quadracer motor would be about the same without the headaches. better yet a lt 500 motor. If you have a rm motor could be fun for the hell of it.I have seen some dynos on rm motors ported not much over stock.rm,yz had about 40-45 hp but dynos vary so who knows. I wonder how they set them up on the race quads before the 450s came out. they would have used race bike motors without counterbalancers also. Some one use to race a banshee with a yz250 motor in the 250 class don't remember who. anyway :)
Zilla529R - October 2, 2006 04:44 PM (GMT)
Certain year RM250 cylinders interchange with the 87+ LT250r bottom end. I think it was either the 86 or 87 RM250 cylinder that would bolt right on (Shawn knows the answer to this one). You dont want to throw the bike bottom end into the quad. As everyone will tell you (I cant speak from experience) but non counter balanced engines vibrate like hell when mounted into quad frames. As stated above a well tuned LT250r engine would be the way to go. They share a simaler bore and stroke to bike engines of the same displacement therefore simaler perfomance numbers and curves can be obtained through modification.
250rnewbie - October 2, 2006 04:47 PM (GMT)
Hey thanks guys it was just a thought ! I just wanted to kinda throw that out there and see what was the diffrence!
sblt500r - October 2, 2006 05:35 PM (GMT)
the 86 rm250 cylinder and hear will fit on the 87-92 lt250r bottom ends. the rm has a different port layout, so it can make more power then the lt cylinder.
the 85-86 lt250 is close to the 83-85 rm 250's. but nothing much really swaps. the lt engine was basically built for the quad. i read somewhere that the rm250 transmision will fit, giving you a different gear ratio.
silversurfer5090 - October 2, 2006 05:53 PM (GMT)
here is a link to show you the port diff it is a upgrade but i think you could get the same if you ported the lt cylinder.the rm has a intake bridge but not a exhaust bridge. wouldn't an 87 lt cylinder be better. you would have to buy a reed boot ,reed block. l :)
sblt500r - October 2, 2006 06:16 PM (GMT)
thats the page i was thinking of.
has anyone ever put a 88 rm cylinder on the lt bottom ends? i'd like to try it, but it probably won't ever happen :rolleyes:
250rnewbie - October 3, 2006 04:12 AM (GMT)
Well time will tell shawn I just picked up a bottom end for the 85/86 lt complete ! I am in need of a jug and head so are there any rm years that fit this rascale before I strip it !!
250rnewbie - October 3, 2006 04:48 AM (GMT)
Well looks like I am in the market for the jug off a 83-85 rm!!!! Hey if turns out I will let you know!!! I must also say if this is just a slap in in the slobber maker I will let you know too!!! Thanks guys and if any one finds that top end let me know!!!!
tlm52 - October 3, 2006 02:00 PM (GMT)
I put a 1991 rm engine in a 85 quadracer.The bottom end is an rm and the top end is a rmx and it doesn't virbrate very much. It runs great
sblt500r - October 4, 2006 01:41 AM (GMT)
|QUOTE (250rnewbie @ Oct 3 2006, 12:48 AM)|
| Well looks like I am in the market for the jug off a 83-85 rm!!!! Hey if turns out I will let you know!!! I must also say if this is just a slap in in the slobber maker I will let you know too!!! Thanks guys and if any one finds that top end let me know!!!! |
darris, i was wrong. i was thinking of the rm125. the rm250 never had a cylinder like the 85-86 lt. the rm250's all had conventional reed cages. the early rm125's had a cylinder like the 85-86 lt250. so i guess you had a short search! :D i have a few extra lt cylinders, but they need sleeves.
250rnewbie - October 4, 2006 04:03 AM (GMT)
Hey Shawn , Thats ok I was just looking for something to keep my busy this winter! That quad sport is just about done and I hate just stittin' around (drives me nuts) I like to stay busy and I thought building a motor would be something FUN :) Well thats ok I might hit you up on those jugs do you have the heads too? Thanks Darris
sblt500r - October 4, 2006 04:29 PM (GMT)
|I might hit you up on those jugs do you have the heads too? Thanks Darris|
yup, i have extra heads too. a rm250 head should work, you might just have to get the dome cut wider to fit the different size piston.
|I was just looking for something to keep my busy this winter! |
i know where theres a 86 honda 250r for $600. its all apart. i was thinking of buying it, but i have enough quads apart all over the yard! and that would just get added to the pile.
250rnewbie - October 5, 2006 04:04 AM (GMT)
Hey Shawn get me that cats number!!! I would LOVE to have a honda 250r!!! I belive your in Mass Right ? I got family up there Just out side of Woooster !! This could be a sweet deal!!! Thanks Darris!!
sblt500r - October 5, 2006 04:48 PM (GMT)
|QUOTE (250rnewbie @ Oct 5 2006, 12:04 AM)|
| Hey Shawn get me that cats number!!! I would LOVE to have a honda 250r!!! I belive your in Mass Right ? I got family up there Just out side of Woooster !! This could be a sweet deal!!! Thanks Darris!! |
i've wanted one to, just don't have the room or the time right now. :(
you have a pm!
apachepride - October 23, 2006 02:04 AM (GMT)
the 86-87rm250 clutch basket works in the 87-92 lt