Dirt Bike FAQ

Weak spark, possibly just the spark plug .. alot of times people end up putting the wrong plug .. or you just might need a hotter plug then stock or just a new clean plug being twostrokes burn oil ..

weak compression, two strokes need to be rebuilt alot sooner then 4 strokes .. being its an 87 it might be time for an overhaul two stroke motors are pretty simple to rebuild
if compression is the case
you need to mic the cylinder to see if it needs overbored or if you can hone it
piston rings/head gasket base gasket and piston rings.. pretty cheap and somthing like 6 bolts and normal hand tools to get the head off you have no timing to mess with

and then it could be carburation .. if its running too rich it could be fouling the spark plug
if its too lean it might not be getting enough gas to start

being its a big cube two stroke it might be just how your starting it they can be tempermental

try not touching the throttle and slowly pushing the kick start down "not trying to start it" let it come back up and slowly push it down again thus priming it without flooding it

and then give it a good solid kick and barely just barely twist the throttle try that a few times …. it just might start … if it fails
try holding the throttle wide open n kicking the crap out of it … without the priming it stage before it
then you have a problem other then it just being tempermental

when it starts up .. does it run fine? if it wont idle after it gets running and cuts up at anything below 1/4th throttle it might be a cloged idle jet .. might just be a dirty carb

the list goes on and on, i would personaly start with the cheaper things, spark plug .. adjusting/cleaning the carb,

if you have a buddy with a compression gage i would test it ……….a simple way to test compression without a gage would be taking the spark plug off and holding your thumb over the plug hole pressing down .. and push the kickstart with ur hand if air blows past your thumb as u try to hold the hole closed….. you have enough compression for it to run right

Try Ebay motors / parts

Every shop is different and you would only have to rebuild the bike twise a year if you rode it all the time every day 4-6 times a week. If you raced it totaly different story every other race is usally a rebuild. I have an older 2 stroke I ride it about 3 times a week average and I rebuild the top end every winter. New top end is about $45-$65 for wiesco piston kit. Basically a shop is the same only they'd charge labor also. Some shops even pick up the bike and drop it off for no charge which is handy. You have to call around your local shops…expect to pay about $150 for them to do it. It's not hard to replace a top end, do it once and you'll pretty much know how it works. Hope this helps

There are a variety of good options for you. I would recommend a 4-stroke for trail riding for the wide powerband, the low end torque allows them to just keep on chugging. Though there are some perfectly capable 2-strokes out there for trails.
For trail riding, I would recommend against a moto-x or "racing" style bike. The gears are too close and the lowest ones are often too high for real technical trail stuff.
Some of the ones I am familiar with (through ownership) are the
WR-250 and the XR-250.
I moved up to the XR-250 from an XR-200 and it is a WORLD of difference. It surprised me greatly, so make sure you start carefully moving up from an 80. The engine is vastly superior, and it can do 3rd gear wheelies without popping the clutch . It's among the best off road machines I've ever ridden, the powerband is perfect. It also has disk brakes on both tires (unlike the 200), which you definitely want.

The racing derived bikes, like the WR (based off the YZ), is basically a racing bike with different gearing and a few trail oriented changes. Usually they keep the same high-output high-compression racing motors, which can be finicky. Some of them even recommend a rebuild after every racing season (or more frequent!), though trail riding doesn't put as much strain on it. The XR has an air cooled engine, which I've noticed can get VERY HOT in the summer when your not able to move very fast for a while. The racing derived bikes tend to be liquid cooled, but are a tad more high-strung. I've had issues with both bikes with hot starting, especially after being dropped (the XR not as bad, but sometimes it can be stubborn). If you get a bike that uses a decompress to help start (WR does, XR has one but doesn't need it), it helps if you can get one with an auto-decompress exhaust cam (greatly eases starting), or electric start (though I personally won't ride a bike that ONLY has an electric start). The WR I believe has come with a decompress standard for quite some time now (and I think electric start now too), but I had to retrofit my older model with the cam. 2-strokes do tend to start easier, I will concede that to them .

Things you want in a trail bike:
tons of low-end torque
disc brakes, front and back
lower, wide ratio, trail gearing
comfortable (enough) seat
probably more I'm forgetting…

almost all bike manufacturer's make a good trail bike around that displacement class. Hit up the bike forums and reviews and see what people have to say about the bikes your looking at.

best of luck on your decision and have a blast!

edit: forgot to mention, if you like the Honda CRF250, check out the CRF250X model, it is the Honda equivalent to the WR, with the different gearing, etc. from the full out racing bike.

Chapparell motorsports or bto motorsports

Yup. Good deal.

The original Pit Bikes were simply small motorcycles with a 4-stroke, 50cc motor used by adult-sized motocross riders to navigate the pits (an off-track area designated for setting up prior to an event). Pit bikes evolved to look more and more like mini versions of the factory MX motorcycles. Because racers like to race just about anything with a motor, it got to where the “big boys” started racing each other on these pint-sized pit bikes on small impromptu tracks.
Of course, some guys got busy hopping them up with stuff like aluminum frames, tall seats, etc. –– but retaining the over-achieving motors (usually punched out to 110cc), the 10″/12″ rear wheels, and the tossable proportions that make a pit bike such frickin’ fun. Because a track for these bikes doesn’t require a lot of land, backyard pit bike tracks have sprung up all across America.
Pit bikes now have a full race series with numerous classes (even one for young ladies), five AMA National #1 plates up for grabs, and an exciting ArenaCross Pro & Amateur Series.

and then of course the dirt bike is well just your average dirt bike :]

I doubt that anyone can give you an accurate top speed unless they own one. I would guess around 45 mph maybe. If you just want something to play around in your yard I guess it would be okay. It is what I would call a throw away bike. Personally I wouldn't buy it.