I got me a brand-spankin' new 2001 Scrambler 400 2x4. It's all stock except a kill switch. I have a verry verrrry low spending amount for mods. I need a first mod, and Ideas? My limit for money is about $400 So far my list of choices includes ( RCR stage 1 kit with Top-end Pipe) (Wiseco piston bored 0.20, or 0.40 over) That's about it for now, what exactly is boring over pistons, and how much does it help? Please help me, all info welcome. Thanks

 

Adam Scramblr 400,

The increase in bore size won't do a thing for you except to lighten your wallet. By increasing the bore size by .5mm-1.0mm you are in effect lowering the ports slightly. By doing this, you'll get a little more low end. Not that much that you'll notice it though. This is in direct conflict with a top end pipe. A trail pipe might be better for you either way. Unless you have the motor ported for top end power, it won't make much of a difference over a trail pipe.

Seriously, I wouldn't go with a Wiseco piston until you have the money to get it ported. Another option would be to get a better reed valve or even some decent back tires for it. It's better to get the motor to breathe from both the intake and exhaust sides. Before even getting a port job, you'll need to get a bigger carberator for it. The motor and exhaust may flow great, but unless you get it breathing right from the intake side, you might as well save your money.

 

Hey, thanks for the info. I know a trail pipe would do good with my stock engine, but I plan to modify it more sometime, so would a top-end pipe be good? Because I don't want to have to buy a new pipe after I mod it some more. Wil I have to get a new carb? couldn't I just re-jet my stock one? I'm pretty sure now that I'm going to get a RCR stage 1 kit, which includes Top-end pipe, Silencer, Jets, Clutching, and Air-box mods for $325. Does that sound good for a first?

 

ive got the stage one kit on my bike and its a great first mod.and the 325$ is well worth it..

 

Hey Thanks, that helped me decide that's what I want, but what Pipe do you have on your Trailboss? Top, Mid, or Low?

 

Adam,

Frankly, I wouldn't do it. The stock cast piston is fine up until around 7000 RPMs. Anything past that (like what a top end pipe would do) is asking for trouble. And if you're going to replace the piston, then why not get it ported too. There so much you can do to increase horsepower without going to a top end pipe (i.e. different reed valve, carb, porting, higher compression heads etc...). The motor in mine is a full trail mod. As an example I had to add a longer swingarm to keep it from standing on end when I gave it gas, even at 30 mph! If that isn't enough power, I don't know what is. Most of the guys I know of, who've modded their engines, have gone to longer swingarms too. The only reason most guys go with a top end pipe is for duning and drag racing. I'm not trying to warn you away from the top end pipe, but I believe you'll be happier in the long run with a trail pipe. If you ever decide to take the next step up from a full trail mod (race mod running $5.00 a gallon race gas) then the cost of a pipe will be the least of your worries.

Hope this helps!

 

as for my pipe i didnt have any choices .i guess they only make one pipe for my boss.but from what i can tell its a low end pipe .i can pull wheelies quite easly with the kit,which i could barley do stock.as for you if your gonna be trail ridding or hill climbing i would go with either the low or mid end pipe ,mostlikly the low end.if you and gonna be drag racing long distances then its obovious to go with the topend pipe.hope i helped just choose what will fit you best.if you have any other questions just ask, i will be more than happy to help.

 

trry a K&N airfilter then put in a green polaris drive spring and a blue Aaen driven spring i have this set up on a 400 2 strokee sportsman and it iss a good cheap starting point.On my 425 i run aa white sprong insteed of a green one.It is better on trails but the sportsman will beat it in mud and speed.