I am converting my 250R to a 350RX. I was wondering if anyone has done this and what are their impressions of the bike? Is it worth the money to make the change? I do a lot of desert (Hare Scrambles) racing and some motocross. I like the power of the four strokes and their ease of maintenance.
I am also wondering about extended A-Arms for this machine. I have read that some go with a +2 wider and +1 forward because the 350X motor is heavier. I have also been told that going the +1 forward will cause the bike to wheelie more. Can someone help me answer my about the conversion and A-Arms.

 

Hey ttaylor,

I am building one of these also. In fact there is a long post on this forum about the bikes. I still haven't gotten my chassis back from Rocky Ridge, in fact I may call Ken today.

I will be using +2 arms on the front with stock rear swingarm, with an eliminator axle. Although this is my first RX conversion so I don't really know if I got the "Hot" setup or not.

 

Where is the forum on the 350X conversions. Let me know what you think about your frame from Rocky Ridge Racing I am going to be sending mine to him shortly. How long has it been since you sent your frame to him? I called him and he said that he was out 2-3 months. I was wondering if it has been that long for you? On you arms are you going the +1 forward or just the +2 wider. Who are you getting your arms from? What year is your swing arm? I have an 86 and have been told that the 86 swing arm is an inch longer that the 88-89.

 

Here is the link for the forum I started. Just copy and paste this URL in the address bar.

http://forums.atvconnection.com/thre...FB=1&Tid=24889

Every person I have talked to about Rocky Ridge has basically said the same thing. Good work, slow turn around. He has had my chassis for about six months. Although he told me it is about finished.

The a-arms I will be using are an older set of Roll Design, which are +2 but not +1 forward. I have an 86 style swingarm that I will probably install on this bike, but I also have a shortened 86,87 style swingarm that I can use in case if I don't like the longer one.

 

Let me know which swingarm you like the best and how you like your a-arms. I called JD performance and talked with them and he suggested just going the +2 and that the +1 forward may not be necessary. Let me know how it handles. I hope that it doesn't take six months to get my frame back. That puts me out of racing for most of the season. My wife would be happy but I won't be.

 

No problem,

I personally think the shorter swingarm is going to be the best for racing. Especially flatrack or tt. Although here, everyone with a sport quad seems to be infatuated with drag racing. So that is why I considered installing the longer swingarm on mine. I should be able to leave pouring the gas on and get the holeshot.

 

use a 250x frame w/250r arms, they bolt right on you just have to move the upper shock mounts up or use banshee lenth shocks. 250r swing arms and rear shocks bolt on to just weld a linkage mount to the frame. the 350x engine just bolts into frame with a little triming on the engine mounts. no modifing the frame rails to get the engine low enough. plus these frames have not been raced to death and a complete 250x is cheap.

 

My understanding is that the 250X frame is shorter than the 250R. Using the 250X frame will shorten the wheel base by about 4 inches. The shorter wheel base will cause the bike to swap more in the whoops. I do a lot of desert racing and we have miles of whoops. If I am wrong on the wheel base then let me know. I would be interested in knowing why more people don't use the 250X frame instead of the 250R. Are there any other modifications that need to be done to the 250X frame?

 

to all interested i have a 250r and a 250x/350x. just measured and the 250r mearsures 26" from the center of the swing arm pivot to the uppper rear arm mount, and the x frame measures 24" form the same points. the kick up in the frames are the same, the r is longer from the begining of the kick up to the swing arm.

 

How do you like your 250X with the 350X motor? Do you do any racing or just trail riding? Are far as handling traits between the R and the X how do they compare? Since there is only 2 inches different I have an 86 250R swingarm which is supposed to be one inch longer than the 88-89. If I take that and do the +1 forward on the arms will I get the two inches back and be like the stock 250R? Will this throw the front to rear balance off on the machine?