Hi guys, I asked this on the vintage board, but I'll ask you cats also. I have a 1980 Suzuki RM 250 for post-vintage racing. Nice bike, ran well except for a high RPM miss that slowly got worse. The bike would fire on the first or second kick, idle nice, run great in the mid-range but would miss on full throttle. The jetting is nice, so it's not a lean miss. What I have now is a weaker spark, that fades away after 5 or so kicks. Does that sound like a coil going south or is my stator or CDI box giving up on me. I really don't want to have to spend more money than neccesary if you guys might know or have seen a similer problem. Thanks, maxi
High RPM miss to weak spark...
- Thread starter maxiracer
- Start date
yzbluebeast
Member
- Jul 16, 2003
- 10
- 0
Do you own a multimeter??? There are a few test you can do that will give you an idea of whats going on by process of elimination.
loaded and unloaded stator output.
Stator IB.
Pulser output.
Stator resistance.
Ign, coil resistance(pri and sec)
etc........
loaded and unloaded stator output.
Stator IB.
Pulser output.
Stator resistance.
Ign, coil resistance(pri and sec)
etc........
I had the same problem w/ my 98 cr250, it would be fine off the pilot, but once it got on the main it would...almost like it was hesitating, and not getting on the main. Eventually I took it in after screwing around with it and getting very frustrated, they said it was a stator coil not giving enough spark. After I got it back I had to rejet and it's been fine ever since. I sold it to my buddys brother and he hasn't had a problem yet.
David Trustrum
~SPONSOR~
- Jan 25, 2001
- 1,396
- 0
Do the simple stuff first. Sparkplug, Sparkplug cap, clean or replace airfilter (replace by now) Check that the coil is grounded properly. (clean plug-connector contacts, check with meter etc).
Clean carb out properly esp pilot jet (never poke with wire though). Drain old gas out & check for water replace with fresh if unsure how old.
Wouldn’t hurt to repack the muffler & see how much carbon build up is in the pipe.
Chances are it is your stator but it wouldn't hurt to try another ignition coil first.
Clean carb out properly esp pilot jet (never poke with wire though). Drain old gas out & check for water replace with fresh if unsure how old.
Wouldn’t hurt to repack the muffler & see how much carbon build up is in the pipe.
Chances are it is your stator but it wouldn't hurt to try another ignition coil first.
- Thread starter
- #5
Bluebeast, I do have a basic multimeter, and can get the use of better unit.
What should I look for in numbers? And how should I check the output?Measure output while kicking the bike over? If it's not under load, all I can measure would be static restincence I believe. My thinking is that it is the stator, I switched coils from a another bike and got the same results. Fair spark, not a hot blue spark like I had before. I fear a bigger problem is that my dealer tells me the stator for the 1980 RMs has been discontinued, although the 77-79 and the 81 is available. Does anybody know what the difference between a 80 and 81 stator plate is? And is retrofit a possiblilty? Thanks for all your help!!!!! :)
What should I look for in numbers? And how should I check the output?Measure output while kicking the bike over? If it's not under load, all I can measure would be static restincence I believe. My thinking is that it is the stator, I switched coils from a another bike and got the same results. Fair spark, not a hot blue spark like I had before. I fear a bigger problem is that my dealer tells me the stator for the 1980 RMs has been discontinued, although the 77-79 and the 81 is available. Does anybody know what the difference between a 80 and 81 stator plate is? And is retrofit a possiblilty? Thanks for all your help!!!!! :)
David Trustrum
~SPONSOR~
- Jan 25, 2001
- 1,396
- 0
Will be easy to get them rewound. Check adds in magazines