WANTED! 250R ported cylinder!

[stocktires]

I need a 250r ported cylinder (dont need head), it needs to be a bottom-mid port job, good condition cyilnder, can be a big bore, dont need pistion, must be at the most .80 over, please, my friend just got a raptor and i dont want him to beat me!!! i already have a cool head, rad valve, and i NEED a bigger carb also!

Disclaimer: Procede with any engine mods at your own risk, if your not 100% sure about something you need to seek out the information or don't make the change. It's cheaper to have somebody else do the engineering and work than to fix your mistakes!

Before investing in a cylinder you should get some decent tires for the type of terrain that you ride in and get your suspension dialed in. When you are ready to dig into the motor try a 36mm PJ carb, get a good twin stage foam filter, ditch or modify the airbox lid, and a reed spacer(this really helps increase fuel/air velocity and works quite well with the Rad Valve). I would also look at a Paul Turner type 6 pipe or a CT midrange pipe for low end to mid range performance. You could also raise your compression by using a smaller dome in your cool head or a thinner head gasket. This will probably require you to run race fuel but if you want to make power you have to spend the cash! With all of these changes you will need to change jetting in your carb. You will need to know about performing a "plug chop" and read(examine) your spark plugs. If this sounds like greek to you then you should read up on the subject before spending any money on parts. If you can't tell what's happening in your engine you won't be able to determine where you can pick up more HP. Don't overlook sprocket size changes as they can help you tailor your power to your type of riding. With all of these mods you should be in the $600-800 range. Also if you get a mildly ported cylinder you should be able to use all or most of these parts.

If you are into working on your bike and have a VERY steady hand you can match your ports (remove sleeve to cylinder imperfections) and put a decent polish job on the ports (don't forget to wash the cylinder down with warm soapy water to remove any traces of metal, and then dry and oil the cylinder - WD40 works good as it will drive the water out). If you do decide to do any port work yourself be VERY careful as you can destroy the cylinder. In other words if you are not inclined to read up on the subject and talk to senior engine tuners you may want to skip this. I started this type of work(hobby) in 1986 and I learn more every time I build a motor and I have saved thousands of dollars over the years. I started out simple with some emery cloth and plenty of elbow grease and now I have several hundred dollars of tools and test equipment (I don't have a dyno or a engineering department, I'm strictly a weekend warrior) for building and testing quads. Along the way I am learning about the interactions between intake, engine, and exaust. One thing to keep in mind is that balance is the key. A high RPM cylinder with a stock carb and pipe will never reach it's full potential. Likewise a full race pipe needs a good cylinder and and carb setup to provide maximum output.

For low end power you also want to get the idle circuit tuned correctly so you may have to spend a few dollars on some different pilot jet sizes. If this circuit is off then you will notice a hesitation when opening the throttle. There is a adjustment procedure in the service manual, if you don't have it drop me a line and I can run it down for you. BUT if you have your heart set on a new cylinder consider going with a big bore kit or a Duncan Racing power valve cylinder (I'd strongly recommend going with the Duncan Nicasil lined cylinder for reduced friction and use a lighter piston with boost ports,these things will help the bike rev quicker). If you are going this route hold off on pipe and carb mods until you pick a cylinder and talk to the tech support folks at the company and they should be able to guide you on pipe and carb selections. If a 39mm PWK carb is called for I can make you a deal on one that is brand new (less than 1 hour on bike).

Sorry for the long post but I hate to see anybody waste money on "parts" that don't work together or get into a full race motor that is not set up for their type of riding. If I had a dime for every dollar I've wasted over the years on parts that didn't work as advertised I could pay cash for the new Cannondale that I'm looking at.

Current proud owner of 2 TRX400EX's, Prarie 400 4X4, TRX300EX, and my latest "project bike" - an 86 TRX250R that I'm doing a frame up restoration and performance mods on in memory of my favorite riding partner, my father who passed away this year. He loved to ride my 250R's and this bike was going to be his...

[stocktires]

sorry man, im not in pre-school! My R is totaly set up for MX, +2 a-arms, +4 axle, ohlins & works shocks, beadlocks w/ tamers & radials. ect ect!

As far as the motor i have EVERYTHING EXCEPT A PORTED CYLINDER! that mean cool head, boyesen rad valve, fmf exhaust, 38pj carb ect ect. The only thing i need is a ported cylinder and i cant spend alot of money (not over $200) so power-valves and big bores are pretty much out of the question! And I race the 250 class so i dont want a big bore! Thanks for the help but i just want a good ported cylinder! :D

I know a guy that is very reasonable and gets the work done and back to you quick

Jeff at HobbyTime Motorsports 417-777-4576

I buy stuff from him all the time

[rhino99]

Can it be an 86 style cylinder? I have one for sale thats ported and polished for midrange, its also polished on the outside to a chrome like finish. Includes piston and head.
If you are interested, e-mail me at rhino99@hotmail.com

[stocktires]

yes, i have an 86 motor and quad! I'll take either one and I am VERY interested in your cylinder!!! how much?