250r mods

[rob1badbanshee]

i am looking at a 86 250r it now has a fmf pipe and silencer what mods can i do to get good low end and bretty good top end. what kind of riding do you guys do with your r's will a piped R out run a piped 400ex thanks

[Live2Ride300]

My piped R out ran my friends stock 400 by alot, I wouldnt doubt it out running it if it was piped either.

[AndrewRRR]

Originally posted by rob1badbanshee
i am looking at a 86 250r it now has a fmf pipe and silencer what mods can i do to get good low end and bretty good top end. what kind of riding do you guys do with your r's will a piped R out run a piped 400ex thanks

port it, mill the head (or get a coolhead), get a better reed cage, get a different carb, get a different pipe, etc. All the usual 2 stroke tricks.
If you want to spend more money go with a big bore and/or stroker and pump out some real power.
When my R was stock except for a pipe (a really crappy answer one or something), it didn't have a problem with piped 400ex's.

[wilkin250r]

For a two-stroke, the powerband is all in the pipe and porting.

I'm going to go out on a limb here and assume that you know how a two-stroke works, and why you don't have a camshaft.

You can gain alot of power with a good port job, but it is typically top-end power, at the sacrifice of low-end power. And it's not cheap. If you're looking to save your low-end power, you can probably skip the expense of a port job.

Althogh you may hear differently on here, there isn't much difference between aftermarket 4-stroke pipes. However, there is a HUGE difference between aftermarket 2-stroke pipes. I suggest you visit the tech section of this website on how a two-stroke pipe works. (http://www.exriders.com/techarticles/twostroke.html)

Basically, the pipe helps build power. Based on the pipes design, you can have strong mid range, or strong top-end. Or, you can spread it out, and get decent (not strong) mid AND top-end power, but you can't build power everywhere. So, find a pipe that fits your particular riding style.

Here's a little tip if you are struggling with terminology, or just tryig to find the best pipe to fit your riding style. Low-end power is typically more useable and ridable, and it will give you a nice, broad, easty-to-use powerband, but the power will begin to fall off at high RPMs. MX stands for motocross, but if your looking at a pipe, an MX pipe is a low-end pipe. Midrange has a little more peak power than a low-end pipe, and is still very ridable. A very good all-around pipe. A top-end pipe gives the most PEAK horsepower, but it is over a very narrow RPM range. You really have to be spot-on with your shifting to be able to keep your quad in the powerband. A top-end pipe will have that "light switch" feel to it. It will bog and sputter, then suddenly do a wheelie and take off screaming when you hit the powerband. A TT pipe or a Drag Racing pipe are both top-end pipes. If you want to get the most out of a top-end pipe, I suggest a port job to go along with it.

A set of aftermarket reeds are a MUST! You can't build power if you can't pull in enough air.

[AndrewRRR]

You definately don't want a top end port job if you are looking for low-mid power, but you can get port jobs for R's that are for low-midrange power. They are basically a mild port, smoothing out major flow restrictions without hogging out ports or altering timing. You can usually get it done for about $200 and it does make a difference.
LRD does pretty good MX and woods type porting. I'm sure there are other builders that are good as well (I have first hand experience with LRD, but I can't speak for others).
I would do compression (head), pipe, and carb, then worry about porting. You should talk to whoever does the porting about which pipe will work best for you type of riding first though.

[powerslider]

Check your compression to see if it's normal, 150psi minimum. A good reading on a stock motor is 170 using a Snap-On gauge. Raising the compression will give more power everywhere, if you can run race fuel (110) bump it up to 220 or so. Installing a Rad valve will help also. I wouldn't change pipes just yet, the FMF's aren't as bad as some people make them out to be depending on which # pipe you have. Repack the silencer, it's important to keep it maintained. If your interested in porting talk to Sandtrix, their cylinders make big power and they are very reasonable pricewise.

You would be wise to go completely through this motor if your going to add substantial power output. You don't want to rebuild the top end only to have the lower end fail....