Dirt Bike FAQ

Ok if you go on ebay and search under guides for dirt bike or 2 stroke vs 4 stroke, I just wrote an entire guide on buying bikes, you will probably find it helpfull.

But, if you are 5'1 and 140, a 250 4 stroke racing bike might be a bit too big, Im 6'1 and 150lbs and my 250f fits me pretty well, maby a tiny bit big but I have alot of riding under my belt. I'd say your best bet if you can afford it is a CRF150R (not the crf150F ). Dont bother with 2 strokes unless you cant afford a crf150r. If you cant go with a kx100 or a YZ85. I wouldnt suggest a 2 stroke 125 though because you aren't really heavy enough to keep much traction on the back tire when it kicks into the powerband.
So CRF150R or a KX100

Ppl agrivate me. the reason he and i asked these kinds of questions in this section is cause it is about motorcycle racing. we want people's opinion that motorcycle race and we figured that ppl who mx race would be most likely looking in this section. anyway answer to your question…. i would go with honda cuz honda rox!!! size is your decision tho!!!!

You havent stated your age, height and weight,

i will assume you are an adult >>(involved with Harleys)

anyway if you want a good muck around bike with power and speed check out these models: the ones in brackets r road registable

Honda (Xr 250) > Crf 250 these are four strokes
Yamaha Yz250f > (Wr 250) these are 4 strokes

Honda Cr 125 Yamaha Yz 125 Kawa Kx 125 Suzuki Rm 125

These are the 2 stroke range if your starting out theres more than enuf speed and power in these to keep you satisfied,

These are all potential bike you will want to move up from after a while so i suggest buy an old model, still reliable and thousands cheaper

Check these up on ebay so you know what they are > the most common reliable

gd luck

Enter as many competitions as you can.

Here is the quick rundown fellow rider. 2 strocks have exsplosive power and don't hook power to the grown as well as 4 strokes, a lot of wheel spin. If you want to go balls out most of the time I suggest a 2 stroke. Get a 4 stroke if you want to do some putting in woods or trails. Both types can be light bikes for getting air. Now maintance and rebuilding…2 strokes are cheeper in both area, 4 strokes can be bank breakers when it comes time to rebuild the motor. Buy a used bike, they're are plenty of great ones out there. Don't waste your money on insurance, it's a dirt bike!

4 stroke 250cc. You are already too big for a 125 and will outgrow even more very quickly. I dont think a 250 is more dangerous for you. The geometry of the bike and suspesion should be more suited for you in a 250 anyway. Even your weight i would look into getting the suspension set for your weight. You could probably handle a 450-500 weight and geometry wise, but too much power for a beginner.

The four strokes refer to intake, compression, combustion and exhaust strokes that occur in a four stroke engine.
1 Intake: the fuel and air are brought into the cylindar
2 Compression: the fuel-air mixture is compressed.
3 Combustion:this mixture is ignited by the spark plug to repel the cylindar back and thus giving the energy to drive the engine.
4 The Exhaust stroke: The resulting fumes are expelled on the cylindars return.

In a two stroke engine the strokes combine these mechanisms so that on all four of these can be combined into two strokes.

You may want to check this out too: http://science.howstuffworks.com/two-stroke1.htm

It needs to be a 4 stroke, not 4 cylinder. The turn signals need to be a certain distance from the centerline of the bike. You probably can not take it on divided highways, I think it's a 250cc minimum. The lighting kits can be quite expensive if it doesn't already have the necessary lights, especially the tail-light and license bracket. If it came with the correct lighting then it is probably already titled as a street legal bike. You will just need a safety inspection and insurance.

Go to BBRMOTORSPORTS.COM and get a Powroll Thrust Chamber and you will get the performance of a aftermarket exhaust without spending 300 bones. Then get a rev box. It will let your motor rev past the stock limit witch will give you more hp. That is a good hp gain for under a 100 bones.

If you want to spend a little more money you can have the flywheel lightened at BBR for a hundred bucks. This will let you motor rev like a 2-stroke and make it pick up RPM's fast. If you do alot of wide open riding, this is the thing to do. "This will take away some of your bottom end."

If you still want more than get a big bore kit. If you do go with the big bore kit thin you will need to go with 26mm carb. The stock carb was not made to handle a bigger bore than stock.
P.S.- It is better to buy a complete kit than have the stock cyl. bore. Watch e-bay for these items and do not buy a china knock-off.

Depends on what your style is me personally would get a 250 sice your pretty big and only thirteen you will grow pretty fast. a 125 was made for a 180 or lighter person so you will weigh more than that in the future probably. Also, with racing a 4 stroke is alot more work in the long run. So if you you have someone to service it or if you know how definetly go for the 4 stroke (crf250) If not cr250 or yz250.