I was wondering if anyone has ever done this before. I have a modified RM 250 bike but I miss my quad. I was thinking of getting a full quad minus the motor and sticking the motor in it. Now would I have too much trouble doing it or is this a common conversion??? If not this frame maybe a banshee??? Any info is appreciated!!!!!

 

theres a guy on the forum whos doin this exact thing right now. his name is 1986suzukiquadracer..talk to him

 

hey, the idea is good, and i'm sure it will work, but, i've experienced motorcycle engines in quads.. we took a fully balanced CR500 and put it in a LT250 frame.. even though the engine was balanced, it vibrated so bad it was hard to hold on to the handle bars.

the reason is this...

the quad motors,, the LT250/500 and the honda 4trx 250r and the tecate 250 4wheeler are counter balanced. (the banshee is a twin so the pistons oppose each other and balance themselve, i'm not very familiar with the banshee motors to know if they actually have a counter balancer)

the motorcycle motors arent counter balanced so they vibrate bad in a 4wheeler frame.

there are too many points of contact to the ground with a 4wheeler.
on a motorcycle there are only 2 wheels touching and the handle bars are rubber mounted

we even tried rubber mounting our LT250 handle bars to help, but it didnt do very much good.

anyway, if i were u, i'd just sell the RM250 and buy a LT250 , but thats me.
good luck in whatever you decide.

check out my website http://kos.realns.com

 

A person who used to race with us did this conversion way back.It was a 1986 LT250 with a 84 or 85 RM250 engine.The thing went OK but the vibration was terrible.Cracking frame etc.One night we were sitting in the pits waiting to go on the track,he gave it a rev and the cross bar of his handlebars fell on to the ground.
A while later I got a free Slingshot 250 engine and slipped it into my 90 model LT.It did not vibrate as bad but it just didnt go as hard as the LT engine.The LT engines are set up for the extra weight etc associated with the quad,so I would advise against this conversion.

 

I t is possible to bolt the 86RM cylinder straight on the 87 and up LT bottom end, power gain is questionable. I have comparative port maps and photo's on my site if anyone interested. If you have access to a good machine shop it would be possible to weld up the LT crankcase, relocate the base studs and us the 87/88 RM cylinder, this would be a HUGE power gain, again see my web site for comparative photo's etc. The 88RM is known to have been one of the hardest hitting midrange roost mx engines of it day........ due to it's exhaust port powervalve, the LT powervalve unit will link straight up.......

kiwi

 

hey kiwi_craig,
i like that tech page for the 250 quadracer. u know where i can get the port designs on the LT500...
thanks, Rick

 

I have an old and somewhat (very) battered LT 250r which appears to have at least a 96 or newer rm cylinder bolted to it. I dont know who did it (I bought the thing used) but they left the stock 32 mm mikuni carb on it. The thing only ran about 3 hours after we bought it (I knew "0" about these things(quads) at the time of purchase, and have since advanced my knowledge to at least "1" on a scale of 100)
When I had the engine rebuilt, the guy who did it failed to notice that the cylinder sported a 249cc stamping on it (as far as I know this can only be a 96 or newer rm cylinder at least according to my catalogues) and installed an "LT" piston of the correct bore I assume, along with a new performance reed valve.

I also have a pair of 350x / 250x conversions, one with a full TC 365 racing conversion with updated cam and cdi in 2001. On the short flat track (1/7 mile) where my son races this bike outruns many TRX 265r's and quite a few of the 330r's as well as most of the 400ex conversions (not all).

All of this said, when I run the 365X against this old lt 250r on our street, the 350 out pulls it for about 100', and then the old LT just slams right up with it. None of the LT's which we race against at the track are even close to this 365X even on the 250' straight. Considering the missmash of parts in this lt, there may well be something to this type of conversion especially if done correctly.

Also heard rumors about someone in NY State who used to build these conversions a few years back. They had a rep for being "untouchable"

 

You are wrong there. It wasn't an RM cylinder most likely. The 1985 and 1986 models of Suzuki quadracers sported 249 cubic cenitmeters of displacement. The later models (1987-1992) Sported 246 cubic centimeters of displacement. I'm guessing that it was an 1986 or 85 model, You said the Carb was a 32mm (and stock) Where as the newer models came with a 34mm carb on them. Im guessing your mechanic didn't know the difference.

 

hnmmmmmmm get some picture up on the net or e-mail. Later RMs are case reed inducted, it would be a HUGE fabrictaion job to get a late RM top end on.......

Kiwi

 

Thanks for the info on the year. The only info source I really had was a catalogue for Wiseco pistons which indicated the LT 250 85/86 as 246 cc. The only 249 cc cyclinder shown in the catalogue was a 96 RM or newer. Several other mechanics who have looked at it decided that it was an RM head as well. But who knows, may have been the power of suggestion.

The bike frame shows as an 86 on the SN tag, but who knows what motor year is in there. The mechanic who worked on it said it couldn't be an 86 because it does not have a power valve.