I installed the midrange RCR Stage 1 kit on my Scrambler 400 a few days ago, I decided to try the 270 jet that was included in the kit. I noticed more power but didn't feel like I got as much of a HP boost as I had expected. It was running very well but my low end power was poor and I noticed that it started to "load up" the carb a bit when I was going slowly up a hill. I checked the plug and it seemed a bit rich. Today I put the 266 jet (supplied in the kit) in and took it out. Holy **** this thing really moves now and it wasn't slow before. I climb big hills that were easy with the stock pipe but now I actually have to start to let off the throttle about 50 feet before I get to the top or I feel like I will fly over the top of the hill. Mucho Power!
Bottom line is if you don't want a fast ride, DO NOT PUT THIS KIT ON! By the seat of my pants I feel like I do 5 mph over stock for about 70 top speed. In 2WD I accelerated from a dead stop on a dirt road and at about 45 mph I looked back to see that I was still spinning my tires. In 4WD you launch so hard that you really have to hang on or the machine will leave without you. I also find that while accelerating at full throttle the front end gets very light and will sometimes start to lift. I am impressed and I am not new to the scene either it takes a lot to impress me this much.
The kit took me about 3 hours to install and was easy, if you can work on a lawnmower you can install this kit with no problem. If you want to see a pic of it installed on my ride check it out on http://www.thecardcooler.com/Scrambler.htm . The bads? I feel that I have lost some low end power so it is harder to go slowly on the tight trails. The power band can be abrupt sometimes when trying to go slow, no big deal going fast is funner anyway. Also the RCR pipe and silencer are quite loud, if a loud pipe would bother you you may want to think twice. If you tried to deerhunt from this quad somebody would probably shoot you off it, I kinda like the sound however, it seems to fit the performance. Considering the huge performance increase, the $325 for this kit is a bargain. My '00 Trailblazer is next!

Matt '99 Scrambler 400 '00 Trailblazer

 

I would like to read your impressions on the kit for the Trailblazer as well. Please post it for me after it's complete.

THANX

 

Mayhem,

I think you'll like the Stage one kit from RCR for the Trailblazer. Just don't expect as much gain from just a pipe and primary spring as with your Scrambler. You must remember that a Trailblazer has a piston port motor. The Scrambler has a reed valve and revs much quicker than a Trailblazer ever will.

I've since added the old 34 mm carb from my Sport to my Trailblazer and dropped four teeth on the back sprocket. I added the RCR Top end pipe and the 38 tooth sprocket at almost the same time, trying it with one sprocket then the other. I didn't notice any improvement with the smaller sprocket from it being stock. This isn't as bad as it sounds, it carried the re-geared Trailblazer with as much authority as it did with the stock gearing and pipe (42 tooth rear sprocket).

I then added the carb and a UFO (Ultimate Flow Optimizer). The stock 30 mm carb was too small for the UFO to work so I had added incentive to get the 34 mm carb to fit. I tried the 34 mm carb by itself and the power came back to where it was before I changed to the smaller sprocket, except this time I had more speed. With the UFO the throttle response was much quicker and seemed to add a little more horsepower to the mix. I can now do wheelies where I couldn't do them stock. And this is with lower gearing too. I think that maybe next winter I'll get it ported and stuff a Wiseco piston in it. If the power becomes too much for my girlfriend, I'll just add a 34 tooth sprocket. This will keep the front end on the ground for her.

I'm almost stuck with the gearing on my Sport. I've had all of the engine mods done to it I care for. When it was running it would easily pull the front end off the ground at about 30 mph when the motor came on the pipe. Believe me, it really is five kinds of scary when it comes on the pipe. I'm hoping that the good folks at Sidewinder Sprockets can help me out on this. I'd like to get a one tooth bigger countershaft sprocket or a two tooth smaller rear sprocket. So I know the feeling of having to shut the machine down early on hill climbs.

 

With the RCR low end kit, my trailblazer will wheelie like nothing! Just rev it up and nail it and the front end will keep coming up!

What pipe did you use for your Trailblazer, Mike? What clutch spring?

I have the green.

When taking off teeth on the back sprocket you will lose topend correct? And by adding onto the front sprocket you gain topend?

 

97 Trailblazer,

I added the spring that Rick sent with the top end pipe. This might explain the differences between our springs. It was a brownish color and has a 500 rpm higher engagement point than stock.

If you decrease the size of the back sprocket or increase the size of the front, it will go faster. The opposite is true a smaller front and larger back will make it go slower. The higher number (ratio) the slower the machine will run. Take the back sprocket and divide it by the front to get your ratio. A machine with 12/42 gearing is rated at 3.5:1, while my Trailblazer is 12/38 for 3.17:1. It may not seem like much, but it does make a difference.

 

Which kit are you getting for the TB? Post a message up when you get it!

 

Thanks for the info Mike!

 

Mayhem, put on the Moto Tassinari reed cage and adjust the reeds at the lightest tension, and you'll get that low end back. I had the reeds adjusted at the tightest setting, and the machine kind of shot out at about 1/4-1/3 throttle, no low end. Adjusting the reeds compensated for this with no noticeable mid or top end decrease. I agree, this setup is pretty amazing for the simplicity of it. I totally removed the inner splash guard on my air box, and do not use the rubber top boot on the box, just the rubber snouts (3), that stick out of the box. If you use the top boot and only drilled small holes in your splash guard, this may account for having to go to the smaller jet. My plug is nice and tan after a long fast rip through a hay field and then shutting down. This is with the .270 jet. I am using 87 octane winter fuel and live in PA.

I am convinced the 400 Scrambler/Sport motor is a huge sleeper motor. Sleeper being defined as big HP gains with very easy, affordable and reliable modifications.

Later

 

Thanks for the input guys, just got home from riding the Scrambler really cooks now. I am thinking that I should put the lowend RCR kit on my trailblazer since my wife and daughters drive it most of the time. If the engagement is to high I think it may be to touchy for them to manage safely. MDelby, I actually never performed the RCR airbox mods because I run a K&N with the airbox lid off so I know it is getting enough air. I live at 4700 feet and ride about 1000 feet higher than that so I think that is why I can't use the 270 jet. I may be able to put it back in when it warms up a bit. The reeds sound like a good idea, kinda expensive for 1-2 hp but I'm sure I will end up getting some though. I can't wait to take this machine down to Little Saharah Sand Mountain in Utah to see how it does. Has anybody been there?

Matt '99 SCR400 '00 Trailblazer