kosson@home.com
Sorry I forgot to list my adsress.

 

Thanks bigdaddy,

Ken at Rocky Ridge has my chassis and is doing the mounts and frame rail mods.

I will have pics and information about the quad on my site.

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http://users.nlamerica.com/dixiebai/atv/

 

BRAD, HOW IS THE PROJECT GOING? LET US KNOW.

 

Well, I still have not received my chassis back from Ken at Rocky Ridge. I called him about a week ago and he said it wouldn't be long, but I am starting to get impatient.

Thanks for asking, I post any news on the project. In the meantime go by my site and check out any updates I may have added.

Thanks

 

Brad, I see in the classifieds where someone has a 350x motor and a pipe set up a 250R conversion. I know it feels like it takes forever but be patient and call him twice a week. You will not be sorry.

 

Brad,

Back in 96' I did a conversion on a 89 250R.

I purchased a brand new 86 350X motor (the 86' motor is better than the 85' version) had it "built up" and stuffed it into the 89' 250R chassis. I found where Honda donated brand new 350X engines to mechanics schools when the government banned sales of 3 wheelers. Honda scrapped their entire inventory of 3 wheelers and donated the engines for training. Some schools did not need all of the motors and sold them to some ATV racers and motor companies. Thats how I found it. Since it was brand new, I knew what I was getting.


This machine is fun. My wife has a 91' 250 EX and the 350RX just waxes that thing. I owned the 250R since new and was looking to make the ultimate trail machine. Well my dreams came true. I sent the frame out to have it modified, sandblasted it and had it powder coated. Put everything back together and love the ride.

The most difficult thing I had to do was melt the bottom of the gas tank so that the tank would fit over the carb. I ended up ruining one tank in the process. I also had the rev limiter removed from the black box since the motor was built up. Also it took alittle work to connect up the new carb intake to the stock air box. The two did not match up and I needed to design a rubber boot connector.

I liked the 2-stroke, however I love the 4-stroke. It is easier to ride when you know that you will not run out of fuel and I especially hated carrying extra gas and oil.

I have not run across any 400 EX's yet. The advantage to the 350X motor is it is a 6-speed vs the 5-speed on the 400EX.

 

Brad, hp500 had some good points. We were able to heat up the bottom of the gas tank with a heat lamp, then we put 1/4"spacer on top of the carb, and as soon as the bottom of the tank was real soft we bolted it on, that was over a year ago and it works fine. We also found that if you happen to use a stock carb(350x) you could also reposition the throttle mount on the carb from the top to the side for extra tank clearance by drilling and tapping the plastic throttle cover . We have done this many times and it works great.
On my 475RX I also added the aluminum radiator shrouds made by PRM, they mount to the frame and not the radiator like the others , it REALLY helps keeping the engine cool, we also added an oversize oil cooler. I do not have any problem with the engine getting hot at all. The old 350x three-wheelers used to be an oven between your legs.


bigdaddy DS650, 475RX,

 

Big Daddy brought up another point.

I also installed an oversized oil cooler with stainless steel braided hoses. The original installation called for hose clamps where the rubber hoses met the stock metal oil lines. Well one day while drag racing it, the oil line popped right off of the metal hoses due to pressure and oil sprayed everywhere. (luckily its a Honda - no harm done). I ended up clamping it several places since I did not want that to happen out in the middle of a forest. No problems since.

Also I had a custom head pipe built (2 into 1) and bought a "supertrapp racing series" that fits any machine with a little modification. I installed that, welded the brackets with the kit so that they fit my trike and it works wonderful.

Lastly the chain was a pain in the ***. The position of the installed 350X motor and the stock swingarm and gears requires a half link to be almost OEM. I did not want this so I had a special rear spocket built so that the half link was not needed. I do not have the full range of adjustment on the chain like the stock machine however it has never given me a problem.

The guys I ride with have always told me if I ever sell it, to give them first shot. So far I have no reason to sell it for a 400 EX.

A YZF426 Quad however may change my mind!!!!

Sparky

 

Alright,

This information is great. Just the kind of things I need to know. Before doing my first RX conversion.

Although now I have come up with some questions.

Why is the 86 350x motor better than the 85? I always thought they were the same.

Also I was thinking that a stock shaped headpipe would fit in the frame rails without modification, but I noticed that you had one made, was it necessary?

I thought about using an aftermarket oil cooler but wasn't sure about oil pressure. In other words would a larger oil cooler cut down on oil pressure returning to the motor? What kind of oil cooler did you use?

Even before I sent my chassis off to be modified I was concerned about gas tank clearance and the carb. I have already done a 350x in a 250x conversion and ran into a little clearance problem when I installed the flatslide carb on it. The 250x has a metal tank though which makes those clearance modifications a little easier. When you were heating your tanks how did you know when you had enough heat? I have a real gift when it comes to overdoing things and I don't want to destroy my tank.

Bigdaddy what kind of quarter inch spacer did you use on top of the carb?

 

Brad , the 350x pipe will bolt in place using the R's mounting brackets!! I heated the bottom of the tank with a regular heat lamp, holding it about 2 inches from the tank. It took a while for it to heat up, but it will become VERY soft, the 1/4" spacer i used was some old split rubber radiator hose and layed it on top of the carb, then quickly bolted the hot tank down in place.
The next day I removed the tank ,took off the spacer, and put the tank back on. worked great. I also had the same problem with the oil lines, I ended up using a flair nut connection.
On my 475RX we removed the air box and mounted the oil cooler on the diagonal rear frame bars where the air box used to be. The K & N filter/outerwear mounts above the oil cooler. This kept the cooler protected and did't add additional heat in front of the motor. It has worked great! (This bike is used strictly on the dunes.)