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    2005 RMZ/KXF Issues? Big decision coming...HELP

    For some reason some people are able to put alot of hours on there bike before they see any valve wear. We had valve trouble 3 times on our 04 and had trouble with our 05 with only 10 hrs. on the bike. Replaced valves with wmr one piece Ti valves, conical springs, cam shafts, and there race piston. We also had the seats recut and cleaned up and the head ported and polished. Well the bike was very fast and would pull some unreal holeshots. But! the bike has intake valve failure and zero clearance on both int. valves. The bike has 15 hrs. on it now and is in the same boat as if we would have put it together with stock parts. Hope someone comes up with the correct fix. Until then my son is going to finish the last couple of outdoor races on the 05 kx 125 and race the same bike this winter at some arenacross events. He has turned some good lap times on his 125, last weekend in a 5 lap moto at a local track he turned faster lap times all 5 laps on the 2 stroke. He has to ride more agressive on the 125 and just might stay on it with some mods done to it. The kx 250f is a awsome bike and would be our choice of 4 strokes, just wish the valve train problems would go away!

    05 Kawasuzi 250f

    05 with 15 hrs. and same problem as our 04 with the valves. Still is a great bike.

    regarding 05' rmz/kxf valves

    You could put the stock springs back in and save youself some money this week, only to spend more in the weeks to come. Now that is priceless!

    jetting tech again

    I would also check to see if the hot start is sticking open. We run the 42,r needle 4th clip and anywhere from 165 to 172 main with out any decel pop. Clean and lube you hot start plunger. Hope you get dialed in soon.
  5. Some remove the cover when they ride on wet and muddy tracks. The cover will hold alot of mud up next to the chain.

    The valve fix... I hope

    Bob at WMR has put a great amount of time into testing, and lucky for us he has taken all the work out of the problem and came up with a great fix. we use wmr cams there je 13:1 piston, and we are waiting on there new spring kit with a set of there one piece Ti valves. Bob thamks again for all you hard work on all your 4 stroke development. WMR, the way to go

    jetting tech again

    42 pilot, 172 main, r needle 4th clip from top and 2 1/2 turns out on fuel screw

    air filter

    Twin air filters with no-toil oil and cleaner


    There are only two pipes we would use, The pro circuit lowboy system and white brothers carbon fiber system.

    regarding 05' rmz/kxf valves

    We have an o5 with a bad intake valve, all the other valves are still the same clearance. Left side intake valve. Wmr has done alot of research on the stock valves. They found that out of all the stock valves they tested only about 20% were keepers! Poor quality control, poor valve mat. or poor coating on the valves. The 05 still uses the same spring as the o4 and that is some of the problem. WMR has the best spring kit avail. anywhere !!! If you would like more info, go to there web site or call and talk to bob and he will fill your head with alot of priceless info. WMR 1-866-wmr-race


    We use WMR cam setup with very good results. The bike pulls harder and more responsive all over. Call WMR and they will help get you headed in the right direction. Valve clearance with there cams are 4-6 on the intake with 4 making a little more bottom, but you need to keep a close eye on your clearance when running at 4. The ex. should be at 8. The valve clearance also controls at what degree you cam opens the valves.

    04 KX 250F to 05 KX 250 transition

    Hate to see you give up on a fix to you problem, we had valve problems with our 04 kx. Part of the problem is that it is not getting equal dist. of fuel to both int. valves. The 05 have a longer divider in the int. port to solve this problem. Another part of the problem is the valve springs are getting weak as early as 10 hrs. on bike. When they get weak the valves start to float and bounce around causing more premature wear. Replace with aftermarket spring kit to fix that problem. WMR and Pro Circuit both make a great spring kit. overheating problems are magnified when springs get weak and start to float. If you replace you vavles with new kawi valves DO NOT LAP NEW VALVES IN, check valve seating with mach. blue. If you lap you new valves you will wear the coating off of the valve and it will wear out very fast. Just a reminder, all of the 4 strokes have issues of there own, yes even the yz.

    RM-Z problems

    To be honest, all new 4 stokes have a few problems of there own. They are making alot of power from a small motor and turning alot of rpms. The kx and rmz is a very good bike. The new 05 have several changes made to them. Our 05 has about 10 hrs. on it and my son likes it better than the 04 he raced earlier this season. We have made a few mods to the 05 but it seems to pull really hard all the way from the bottom to the top end. Do not be afraid of buying a new rmz, all of the bikes could have problems, what ever bike you get just try to keep off the rev limiter alot, ride it like a 4 stroke not a 2 stroke and you will be pleased.

    Jetting '05 RMZ250

    We run a 42 pilot and richer needle with a 165 or 168 main, fuel screw is between 1 3/4 and 2 turns out depending on the weather and temps. Pro Circuit sells a kit to remove the back fire screen, with the screen gone you also get better air flow and better perf. Always clean your air filter, very important to a long life with your 4 stroke!

    04'rmz250 or 04'crf250

    The honda is a good bike but does not come on strong and you have to ring it out more so than the kx or rmz. If you are on a 4 stroke on a mx track why would you want to have to rev it out more, take the avg. rider and put them on a kx 250f and then on the crf 250. They would prob. turn faster lap times on the kx with its easy to use power off of the bottom and the mid range. Also the new 05 are with out any ? more responsive and pull harder off the bottom and carry it all the way to the top of the power band. They have changed the head design on the porting specs on the intake and ex. side. Also changed the cdi box to let it rev faster and higher. The 05 kx 250f hands down in the power plant dept. to the crf 250, Honda has been known for there great susp. But the kx is still pretty good if you know how to dial it in. KX 250F IS ONE GREAT BIKE!