RMZ250 wont start, at all!!!!!!!!!!!!!

hey guys, i bought this 2005 RMZ 250 and the motor was just rebuilt. new valves, piston the top end is mint. this was done by the person that had the bike before me. anyways this bike didnt come with an exhaust but it came with the header pipe. i didnt fire it up when i bought it but took the guys word that it ran good most likly it would i thought because when i took the valve cover off at home it lookd great the feeler guage indicated the cam lobes were perfectly spaced from the buckets. i borrowd by brothers KX250F muffler (didnt fit very good) and kicked, and kicked and etc. but no fire. i checked the spark, it was good, took the boot off the carb had a look down when i opend the throttle the gas was shooting in nicely. this has me stumped. valves are good, its getting fuel , lots of spark, good compression, clean air filter, when i kick it sometimes all i get is the odd pop. any help would be awesome at this point because i have no idea why this bike is not running!!!! thanks


Air filter nice and clean, freshly oiled? Maybe you flooded it and fouled the plug. I would put a new plug in and try again. My son's starts pretty easily if we choke it and get nice, full kicks without giving it any gas. Sometimes if it doesn't seem to want to start I'll use the hot start for 2 or 3 kicks, let it out and kick again and that does the trick. Not sure why.

I would be wary of the bike having new valves unless the seats were cut. I didn't take advice I was given and put new valves in my son's bike without getting the seats cut. They didn't last too long. So this spring I ended up buying a new head AND another four new Kibblewhite valves. My wallet is very thin now. :thumbsup: If your valve clearances are in spec, that is not your starting problem, just offering some food for thought. Keep an eye on your valves once you get it running.

Good luck and let us know what works.

thanks, well today im going to try a new plug, do you guys think not having the muffler properly sealed for good backpressure is making it harder to start for me?

ill tell you how i make out today see if i can get it running.

I was in the same boat you are in. Valves checked OK and everything else too. Turned out my carb intake boot was on backwards. It is supposed to go on only one way, but it can be forced on backwards. If it is it does not seal on the engine side causes vacuum leak.

I hate to say it, but I only got 2 quick rides in when I fixed this though. Just like willierides that head was toast anyway. It had been shimmed to oblivion on one valve. That one valve went quickly and then I was informed by my head guy that the head was basically unrepairable. The ONLY way I will buy one of these bikes used again is with the head off so I can inspect it thoroughly. My new head, valves, springs, seat cut, gasket kit, Etc set me back about $750. And that is a deal according to most around here.

Good Luck!

i just put in a New cr8e spark plug and tried to start the bike and still nothing. i even tried to put a tiny bit of gas down the sparkplug hole after to see if it would fire up and still nothing. i looked to see if the boot that connects the carb to the motor was backwards and its not. this is all so confusing because everything seems like its working. i heard there was a cdi problem with the 04's and they wouldnt start. i was wondering if there was anything like that with the 05's like my bike. or is the reason that its not starting because i dont have a muffler on the bike and theres no back pressure:mad:

What did you gap the plug to?

i didnt gap the plug i just put it in stock

Try your cdi box with another bike, I know you have spark but we had 2 or 3 in the past year same thing and the box was making spark but wasn't fireing at the right point. But like the other guys posted if those seats are bad your going to eat those valves quick.

did you check to make sure the timing was right????

i didnt gap the plug i just put it in stock

Ummmmm, you do know that consistent firing depends upon the plug being gapped correctly? If it's closed too much, there is not enough area of the spark to ignite all of the fuel all of the time, if it's open too much, then the bikes electrical system may not have the voltage to jump the gap.

Im just saying, I always start with the stupid $h!t and work my way up.... Half the time the problem is something really dumb that you just never thought of.

Have you tried to push start it any? Sometimes when mine gives me a hard time starting I will kick it over real slow about 4 times, then get the piston on a compression stroke and give it one good kick and she fires right up.

the problem was the fuel screw it was set differently, the bike came from the states maybe because it was at a differnt altitude when i brought it home the mixture was too lean. anyways i adjusted the screw and it fired right up lol.

That was going to be my next suggestion. Remember reading of someone else forgetting to put the fuel screw back in after cleaning their carb. Glad your up and running.

hey guys, now that i got my bike up and running, it seems as if its got two idles, if anyone knows what i mean. i will start the biek and the idle will be perfect. then when i ride like put it into gear then take off then say i pull the clutch in or put it into neutral the idle will be unconfortablely high. i have to rev the bike for the idle to come back down to normal. this is most noticable when i am going to slow down when the bike is still in gear the motor will want to keep going so i have to pull the clutch in a rev it so it will go down lol. sorry if im being confusing but this is really frustating thanks


Check for air leaks. Possibly running lean on pilot circuit?

Check for air leaks. Possibly running lean on pilot circuit?

These are possible causes. Does it pop or crackle on decel? If so, that's another indication of a lean pilot circuit. If that's it, bump the pilot jet up a size.

To check for leaks, get the bike idling and use an UNLIT propane torch around the boots, etc. If the idle increases, you found your leak.

Also make sure your throttle tube isn't binding on the end of your handlebar and that your cables aren't pinched or binding anywhere.

my rm 125 did that.. turned out it was just a bad clutch.. glad i sold that old peice of crap it died... :thumbsup: i now hae an 04 rmz 250.. it doesnt like to start for me but shen ive kicked it about 50-60 times it finaly starts.. anyone have a solution for that?? :busted::D

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