1998RM250

Member
Nov 5, 2008
426
0
Hey guys, I kind of put this project on the back burner as my health hasn't been the greatest this spring.... My CR 250 rebuild is complete, other then now it has no spark at all. When I got it running after the rebuild it had "decent" spark except the RC electronic powervalve was not working, suspected the new electrosport stator as the issue as it ran fine before I ruined the oem one. Got a replacement stator and cleaned up the contacts on the ecm behind the front number plate (they were clean to begin with) and also noticed there was some rust on the actually coil pack where bolt's and grounds to the frame. I cleaned the contact path up really good, thought for sure that was my problem but still no spark at all. My guess is that at this point the coil is probably bad? I'm just hoping the ECM brain isn't dead... Any input? I really want to get this bike running bad!
 

arnego2

Member
Mar 8, 2008
271
1
On the electrical circuit you go from the bottom to the top, OHM values are what you need for your bike so a manual comes in handy.

Check if the stator is good, than the coil and if all checks out get a new or borow a CDI of someone if you are lucky enough to have a mate with a similar bike/make/year.

On thing to look into is the kill switch, disconnect it and see if you get sparks.
 

1998RM250

Member
Nov 5, 2008
426
0
Well I tried unplugging the kill switch and still no spark. I'm just hoping its not the ecm because I can get a coil on ebay for around $30 or so....
 

1998RM250

Member
Nov 5, 2008
426
0
Okay well I bit the bullet and ordered a new oem coil just now, my guess is that would be the problem as spark was diminishing and the RC valve stopped functioning. I did however take the connections off the ecu and clean them with rubbing alcohol, and tried starting it. Hope the brain isn't fried or I give up.... ps these forums are dead lately what gives?!?
 

arnego2

Member
Mar 8, 2008
271
1
Get a second bike, that gives you a great advantage. Never let the two bikes down in maintenance so if one has problems fix it right away and ride the other.

If the coil still not fires it will be the ECM (ECU or CDI) as long as you have checked all wires. Did you?
 

1998RM250

Member
Nov 5, 2008
426
0
Okay the new coil arrived today, it was not oem (purchased online) go figure and the spark plug wire is a mile long (great to test for spark though lol). Got it installed and NO spark still... I have checked all the wire connections and they are clean & secure. The wiring itself appears to be in good condition. Would the ECU slowly fail over time, because first the rc electric powervalve would not open, but still had "decent" spark. I say decent because the spark didn't appear as strong as it should be, and it was a bear to start. The only thing I could think of is when I wash the bike which i do alot (no powerwasher though) it could somehow leaked inside? The connections themselves are spotless, I'm stumped... ECU's aren't exactly cheap and I just spent over $850 on new bottom end, top, and linkage/suspension bearings and new electrosport stator!
 

arnego2

Member
Mar 8, 2008
271
1
sorry to hear that, do you have any one over there who could lend you the ECU?

I had it happen to me on my YZ250 all tested, bought a vortex Ignition and it started the first kick.
 

1998RM250

Member
Nov 5, 2008
426
0
I don't know anyone with an ecu I can borrow to test.... I'm guessin any 02-07 ecu will work, or are they different because some model's don't have the electric powervalve? :bang:
 

1998RM250

Member
Nov 5, 2008
426
0
I just purchased a ecu from a running same year bike off that popular auction site for a good deal with the rubber mount too!
Hopefully this solves my problem now.... Has anyone else heard or seen the cdi/ecu fail over time? Seemed as if first the electronic powervalve stopped functioning all a sudden, then the spark slowly decreased till there was none. Sounds like failing electronics? Let's hope so in this case.... I miss my manual powervalve :coocoo:
 

arnego2

Member
Mar 8, 2008
271
1
I had a cdi failure but I still believe I was to blame for that.

Went through some pretty deep water about carb height and did not clean the stator after that not thinking that dirt could well tamper with the electric current. So I think due to producing less and lesser electricity I starved the cdi to death.

Needless to say that now I take off the flywhell every now and then and clean the stator.
 

1998RM250

Member
Nov 5, 2008
426
0
CDI/ECU came today and still no spark, what else could possibly go wrong? Could a bad servo motor not complete the circuit or something? I heard of the "bad green wire ground"? I'm getting frustrated and really want to ride this thing!
 

arnego2

Member
Mar 8, 2008
271
1
Ok but used, there is guarantee that it would work.
Have you tried your old cdi with the new coil?

You only need one naked wire touching the frame.

At this stage I'd pull the cable tree and test each wire, I trust you have a tester.

What happens if you disconnect the PV? Have you tried to start the bike with kill switch off?
 

1998RM250

Member
Nov 5, 2008
426
0
The part was guaranteed off a running bike, and I've triple checked all wiring (none is bare or worn anywhere I can see). I've narrowed it down to these boxes, can anyone explain what they are and do? If these were to malfunction due to water etc would that cause the no spark issue? Thanks

2vmak4k.jpg
 

1998RM250

Member
Nov 5, 2008
426
0
I'm not sure what it is, that's what I'm trying to find out... Sorry the pic is sideways, tinypic did that! These are the only electrical components I have yet to replace, that rubber looking box and the metal box. I believe one is a capacitor or resister for the electronic powervalve? Kiind of odd off how the power valve stops working, then slowly the spark got weaker until it went out. I replaced everything except these part here on the left frame rail behind the shroud.
 

1998RM250

Member
Nov 5, 2008
426
0
Seems like this is a lost cause and nobody has any personal knowledge on the electrical system on the RC valve honda's.......
 

1998RM250

Member
Nov 5, 2008
426
0
Ok well I figured out that it is a Voltage rectifier and capacitor setup. I know that before I started having issues I washed this area on the bike very well, and the powervalve was the first thing to stop working before the no spark issue. My last and only question left, would a bad rectifier and capacitor also cause no spark, or does that just supply power to the rc valve?
 

arnego2

Member
Mar 8, 2008
271
1
I don't own or owned a CR so far but I think on RMs and YZs there is no Voltage rectifier and capacitor or it is incopororated into some other devise. What does the manual tell you?
 

1998RM250

Member
Nov 5, 2008
426
0
It tells me absolutely nothing about my questions. Just need to know if these componets are bad, if that would cause no spark on top of the non working electric power valve.

EDIT: Spoke with the honda dealer who rebuild my bottom end and we went over the electrical system and what all I had replaced, he said it should still have spark at least. I think at this point since nobody knows anything about these electrical systems I'm going to bring it in for diagnostics.....
 
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