rm 125 wont rev up

[125rmcrazy]

guys ive gota problem with my rm 125. i replaced the head gasket on the bike recently and didnt route the stator wires properly and they melted onto my pipe. bad news. i found this out when i lost the spark on the bike. i repaired the wires but now the bike wont rev any higher then about 4000 rpm say. its almost like a rev limiter kicks in and it pops and bangs and backfires and wont rev any higher. i checked the resistance in the stator and it was within spec, checked the coil which also was, but the resistance on my cdi as compared to the owners maintenance manual was way out of whack. so i figured when the wires burned somthing grounded out inside. i replaced the cdi, same trouble. it starts fine and idles good but as soon as you try to rev it it hits a certain rpm and breaks down. any ideas? (carb is clean and all brand new parts inside).

 

[tomcat1976]

pulse coil

check the pulse coil, since you did not mention that. also check kill switch and wires leading up to handle-bars. hope this helps.

 

[helio lucas]

when one of my bikes do that the first thing i will do is changing the spark plug... do almost what you discribed... hope you already change it...
then i will check the high tension coil, then the two coils in the stator... then change the cdi...
since you already do this all and forget to mention the spark plug i will bet on it...

do you avance or retard the stator? if you do it too much the bike will do what you discribe...

when i want to see if is a tension problem usualy i set a very little gap in the spark plug, say 0.1mm, and run the engine... if ran good in high rpm then it´s a tension problem...

 

[125rmcrazy]

thanks guys i tried changing the spark plug that was the first thing i done. and i tried disconnecting the kill switch made no difference and it is a brand new unit. i've checked the resistance in the stator wires as per the manual and they are within spec as are the coil on the frame. like i said i tested the cdi wires as per the manual and they were out of spec, so i bought another cdi on ebay to try but i replaced mine with a cdi from a 89 250 (the cdi looks identical same wire colors and connections) but the part number i found out on the online microfiche is different. could this be causing my trouble? can the pulse coil in the stator cause this trouble? im starting to get at my wits end with this and the bike ran so good before this!

 

[125rmcrazy]

well guys turns out that the other cdi i had was a faulty unit too. everything checks out on both units except for the 2 wires that connect to the the pulse coil from the stator show infinite resistance whereas it should be 170kohms and 14kohms oppositely. i've got a new cdi unit on the way i'll let you know how it turns out.

 

[helio lucas]

good luck for the next one...
some times the cdi´s change just one year to another(most of the times realy)....

 

[125rmcrazy]

i pulled my flywheel cover off today and found out that my flywheel key was sheared off completely and sitting in the bottom of the case in 2 peices. replaced the key and the bike is back to working order! thanks guys.