I have had my quad about four months. This is the first quad I have ever owned and I am looking for some experienced advice. I really love it and am very pleased with its performance. I would like for it to have just a little more pep out of the hole. It would be nice to be able to bring the front end up when you punch it. I know its not a performance machine but it is a 378cc 2 stroke. I read one post that talked about a shift drum giving almost instant upshift and backshift. Is a shift drum the same thing as a roller clutch. I know there are all kinds of things to consider, clutch kit, pipe, carb, jetting. I am looking for how you guys have modded your Explorers, what you've done to it, the costs, parts manufacturers, and the results you got. If I wasn't able to do anything to this bike I would still be very happy with it. But I know there should be a few simple things to give it the extra pep I'm looking for. I can't say how much this machine has impressed me. I have been through all kinds of terrain and it has never let me down one bit. One of the things I like the most is when we hit the open trail and I can punch it down and catch and pass any other 4x4 I've road with.

USMC

 

As you can see by my signature I own an Xplorer and a Scrambler. I have added a pipe to the Scram but trying to keep the Xplorer quieter and better for deep woods, hunting and trail riding with the family.
To my Xplorer, I added an EPI clutch kit and saw amazing improvement in acceleration and "pep". After adding bigger tires I stuck on V-Force reed valves which also helped get back some power. If the uni-filter/air box mod works as good as on my Scrambler I will do that too. It adds a lot of throttle response. Hope this helped a bit!

 

Xplor,
I have seen you on other posts and was hoping you would reply. I plan on using my quad for alot of hunting situations and would like to keep it quiet also. Could you tell me which clutch kit you put on ( I know you said it was an EPI kit but is that standard, aggressive,ect. those are the kind of things I really need. I need educated) and do you know anything about a shift drum? I am planning on bigger tires but not until the stock ones are wore out. Which won't be long with the time I spend on it. I'm not sure I know much about the reed valves. Any info you could give me on that would be appreciated. You could definately call me a beginer when it comes to talking about modifications, but I wanted to come here to get info from the owners and riders vice a dealer or product company. I have been out of the riding loop for about ten years and I just can't believe the changes and the progress theese machines have made. Thanks for your inputs.

 

As for knowing about mods I too am a beginer. I did not even know what reed valves were 5 months ago. It is surprising how much a guy can learn in such a short amount of time. Maybe its the 2 to 3 hours a day I spend looking at ATV sites on the net and fiddling with my rides. I am an addict!!

I have the standard EPI clutch kit. It came with a new helix and springs and gives my quad better acceleration and low end. The difference was amazing for a utility quad! It gets me where I want to go a lot quicker. I know nothing about shift drums??? The V-Force reed valves, at least I think, help air flow better and definately give a better throttle response. My Xplorer sounds smoother now too. I hear they add up too 2 HP. These are good mods since they do not void your manufacturers warrenty on the quad.
If you want to get a pipe in the future do not waste the money on the clutch kit because it usually has to be changed to match the pipe. I will stick with no pipe for now because it really is much noisier.
On my Scrambler I have a Uni-Filter. Some say a good filter can add HP to your quad. I noticed about a 5 to 10% drop/difference in the "feeling" of acceleration and performance when I stuck the stock filter back on after wanting to clean my Uni. The Uni is a real improvement.
As for the air box mod I am not so sure it is necessary on the Xplorer. I have a pipe on my Scrambler and did the mod because it seemed to need more air. Just adding a better filter should bring in more air.
As for tires I have 26" mudrunners. I really like them in the spring for muddy trails and can't wait to try them out in the snow. The only regret I have is on hardpacked when trying to follow faster riders. The quad bounces around more and doesn't feel too great over 35 MPH in curves. Gonna get stock size for fast summer trail riding.

Hope this helped a bit. I am sure there will be more responses from others that know much more than I about the mods in question.

 

Xplor,
Thanks for your input, its just the kind of things I'm looking for. I really hope that I will get some more inputs from other Explorer owners, I know there are many out there. I read about some terrific performance that they are getting from their machines and would like some specifics on how they got there. Thanks again.

USMC

 

skidkid,

I have a 2001 Xplorer 400, and just ordered a Boyesen Rad valve, as you've probably noticed from my post on it. I had noticed alot of people had chosen the Delta V-force instead of the Boyesen, and that may be the better reed of the two. However, the Boyesen cage is made of aluminum instead of plastic, they have had no problems with reed breakage or chipping, and if not completely satisfied, all you have to do is return it for a full refund. The Delta V-force may be a great product, but I couldn't see going wrong with the Boyesen. The Delta has had some problems with reed chipping/breaking, has the plastic cage, and I don't know about their return policy. The technical assistance guy I talked to at Boyesen said that his rad valve typically added 5-6 hp. He recommended going to a 200 main instead of the 210 stock main jet in the carb. I got the jet for $5.00. I wonder if the smaller main jet will increase operating temperatures of my bike. I used to have a '99 SP500 that would overheat when mud riding, and bought the Xplorer due to the fact that they have much less overheating problems(I haven't heard of any overheating, even when mud riding). My Rad valve is supposed to be in tomorrow, and I'll install it tomorrow afternoon. Tuesday, I'll be posting results on it. Best of luck with your mods. The reason I chose a reed modification is due to the fact that I want a little more performance(not that it doesn't already meet my expectations), but I don't want it to be any louder. I also understand that changing reeds doesn't void the warranty. I'll keep my stocker around just in case I have problems, and will put it back in if I need any warranty claims. Later,

Waylan

 

The first and simplest thing I would do is change the air filter to a K&N or UNI, this will give you a little better throttle response. It accomplishes this mainly by leaning out the jetting. I changed to a K&N in my 400 Scrambler but I'm keeping the stock filter to go back to when the weather gets down to about 50 degrees. Make sure if your going to buy a clutch kit that the engagement is not raised too high. I don't think you will be happy with it for low speed crawling and hunting if the engagement is too high. It's going to be tough to get your explorer to wheelie easily because it will be more prone to spin than wheelie.
Just my two cents!
Rob Culp
2000 Scrambler 400 2X4

 

Walexa,

Be careful with that 200 main jet as the temperatures begin to drop. You do not want to meet "Mr. Squeeky"

The 200 main jet was standard equipment on the 1995 Sportsman 400s

If you go with a K&N air filter I would put the stock 210 jet back in or maybe go up to a 220.

My dealer said that he had to rebuild a fellows engine who installed a K&N (which he sold) and did not rejet in the richer direction.

Skidkid,

You would be surprised what a difference tuning the air screw on your carburetor also makes for performance. Try some 1/8 turn changes and see what happens.

 

Depending at what elevation you live at, the best mod you can do to get better low-end and keep it quite is have the head milled. Where I live we loose so much power from lack of air. Depending on elevation you could have the head milled a little or a lot and still run pump gas. It is not very expensive either and is pretty simple to do. The other things for good low-end and mid-range are reeds, air filter, and carb. I just bought a pipe for my Scrambler. It was loud, had no bottom end what so ever and just plain made the bike no fun to ride on technical trails. If you get a clutch kit definitely don't get one that engages too high. I also had that and it really made climbing hills and tough terrain a work out. You would just start to get a little movement then it would kick in all at once making throttle control very difficult. If you ask any of the local shops make sure you explain to them the type of power you are after. Most places think you just want more speed when you say you want more power. You have to tell them you want more power at the same RPM and speed as before (ie more torque) or you might end up with a setup that requires you to be at half throttle before your quad even moves.
Hope this helps.

 

Geezzz guys after reading this, I want a UNI filter. Where is a good place to get one? Do you have to rejet the carb to match the filter?

Thanks
Andy G