Stock CDI Boxes

[efilnicafesin]

I just picked up my first quad :D ...Its an 87 250x that has been rebuilt with mostly 300ex suspension parts, and I'm getting ready to do the engine over next... I'm gonna keep it basically stock. I've got a megamax2 exhaust, airbox mods, and a few others, but nothing crazy. I think right now I am having trouble with the iginition - specifically the cdi box or coil. It feels like it is hitting the rev limiter at about 1/2 of the rpm range... and it started after I hit a big puddle. I checked the main jet for blockage and it was clear. I noticed that the part #'s for the 250x and the 300ex are different. Does anyone know if they are interchangeable? Anyone have a stock one they want to part with??

[efilnicafesin]

Anyone have any ideas about this????

[ReconRider25]

is it actually hitting the rev limit or is it bogging down? cuz maybe you just got water in ur gas makin it bog down.....

[deathman53]

I think a 350x cdi will work, but you have to be carefull as there is no rev limit.

[efilnicafesin]

I've actually been following this thread here as it is pretty similar to my problem...

http://www.exriders.com/vbb/showthread.php?s=&threadid=116777


I doubt I have water in the fuel as it started in the middle of a ride.... I really feel as if it is some type of ignition problem. the bottom end is good, but it feels like it is hitting the rev limiter about 1/2 way through the rpm range....

I don''t know the history of this quad, but I do know that it was not maintaned at all.... I just got it and we went over it, and rebuilt just about the entire quad except for the powertrain.... I do know the cam/rockers are past their adjustment and need to be replaced... I plan on doing a top end on it next week..Piston and complete head.... While its apart, I'm gonna look into the carb and see if I can find anything in there...... I don't think its a jetting issue as it did run good for about 2 hrs before it slowly started acting up.... It did stall out while idling, and hasn't been the same since...

Things I have tested or noticed so far....
hot/cold doesn't seem to affect performance...
It stalled when I put the choke on like I would expect
Airbox lid off... no difference..
Air filter off...no difference
New plug.... no difference, however the coil wire does look kinda dried out... But it pasted a water test..
Pulled the main jet, and it was clear...
Plenty of fuel to the carb..

I have pretty much eliminated anything but electrical parts... Thats where I am at now...
I have a mechanical background, just not with quads...

Any other ideas, I'm open :D

[2001-400ex'er]

yes all the 300ex parts will work on the 250x (im pretty sure), i have a 250x that was a piece of junk when i bought it and all of the parts i ordered were for a 300ex, oh yah shes for sale too-with extras for round $1100

[gopeddin400EX]

just a quick but yet dumb question... where is the CDI box located?

[FF1O5]

hey efilnicafesin just curious to see if you got the 250x from a place called case racing in jersey?

[efilnicafesin]

Originally posted by FF1O5
hey efilnicafesin just curious to see if you got the 250x from a place called case racing in jersey?

I don't think so.... :eek2: Where are they located??

My buddy found it for sale on the side of the road by an autoshop..... It prolly should have gone to a salvage yard with all the work he put into it, but he wanted to rebuild it.... He did a heck of a good job on it with 99% of the parts from 300ex on ebay...


gopeddin400EX ... The cdi box is located under the front fender above the left tire basically.... Its a small black box that is mounted in a rubber band.


According to bike bandits websites' parts list, they are different parts. I have seen adds on ebay with some saying that it will fit both machines and some adds that say they are not interchangeable...