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Looking for some guidance here.
Having a strange electrical problem with my 2001 WR250F.
History of the bike, got it in decent shape and rode it for the last 2 seasons. Don't know how many previous owners or what's ever been done to it, although everything looks original.
Guy I bought it from just used it to get around on his farm.

Bike has always been difficult to start.
Spent about $1000 on various carb work this past season and no improvement.
Been through about 3 headlight bulbs this season also (which is the first suspicious thing).
Next, every time I put a new spark plug the bike starts first kick perfectly, after a ride or two, bike takes 100 kicks to start.
When I pull the plug and coil wire and test the plug that has couple rides on it, almost no spark (maybe a tiny one every 20-30 kicks).
Put brand new plug and perfect spark every kick, and when all installed bike starts first kick.

So I know something is going on, doubt it's the stator since the new plug always makes the bike work perfectly.
I know 4 strokes don't foul plugs, but something grounding or going bad seems to be wrecking the plugs.
I did notice the plug comes out little wet and it's not motor oil so could be all the water from riding and washing.
I bought a new plug cap and will try that maybe it just doesn't seal and plug gets wet when riding and washing.
If this is no good will try and new cheapo ignition coil unit from ebay and see if that work.

I guess my question is, without spending allot of time pulling and testing all the wires on the entire harness and bike, is there anyone with similar issue or troubleshooting experience that can guide my to a possible problem I can fix? Heard about ignition coil on these bikes can be bad, also heard of corroded wires. Wonder what specifically is knocking out my headlamp and spark plug?

Thanks for any help and replies.
 

Edited by Serialize

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The '01 WR use a separate coil, and needs grounded.  Pull the coil, wire brush the mounting points to bright metal on the coil AND on the frame.  Check the Wire Tab on the coil and make sure the lug is not loose.  You can squeeze it tighter with plyers to tighten it if needed and plug the wire back on the tab.  Check the high tension lead to make sure its making good contact.  I don't know if that coil has a screw in lead or not, but if it does, you can replace it with a new one, same for the spark plug cap.  That should fix the spark plug issue, but sounds like there's another ground issue with the headlight.  Also, check the socket with the tail light and the connectors with it.

Most times with a headlight, its either the ground, or the light mounting is so loose that vibration is taking it out.  Check the socket and wires for corrosion or loose connection, and then check the plastic housing and just make sure its not shaking around.

Then check the wire harness for a black wire connected to the frame.  The harness ground may actually be thru the regulator/rectifier, but usually not.  Sometimes the connector on the regulator/rectifier to the harness will get a lot of dirt in it because its in a place easily hit with a pressure washer, and people are not careful about keeping a pressure washer away from strategic places.... swingarm bearing come to mind too since I'm dealing with PO bikes lately.  Jump on, hang on, and good luck...

Edited by ronbuell
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thanks for the reply ronbuell.
great advice, and I will try all of those things to see if improves for a more consistent spark.
will also make sure headlamp not rattling lose and wrecking the connection and bulb.

appreciate the feedback.
cheers!!

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Also... if a new plug 'solves' the problem, you need to consider engine health. What does the old plug look like? Any gunk in it? Have you had a leak down test done?

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Thanks for the reply William1.
No gunk or oil on it, just seems wet (likely from puddles and washing).

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36 minutes ago, Serialize said:

Thanks for the reply William1.
No gunk or oil on it, just seems wet (likely from puddles and washing).

Puddles??? You are not clear. When you wash a bike, before you remove the spark plug, you should blow out the cavity with compressed air, any water should exit the weep hole. No water should get inside.

A 'wet' plug (electrode) is a sign of too rich(doubtful) nor possibly (my bet) oil contamination from bad rings/valve seals or possible a head gasket. The leak down test will narrow it down. If it were fuel related, it would, once started, clean out and run fine and start like a new plug. Next time you pull the plug sniff it and then wipe it off, see if it is fuel or oil.

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Thanks for the replies freebird65 and William1.
Fuel or oil might be the problem but when I took the plug out it wasn't slik like oil and had no smell to it (didn't smell like petrol or oil).

When it's cold, it tends to start in a few kicks. Then after riding for a while when stopped trail side and go to re-start it then I get into problems (so many kicks to get it going again). 

Recently when I changed plugs I tried starting it cold and wouldn't start. Kicked about 50 times. Then loaded on the trailer and brought it home about 2 hours later (was stored at my friends house). On the drive home went to the coin op to clean it.
When pulled the plug it seemed to have water on it. Maybe coincidence.

For the carb, spent $700 recently at a supposed to be reputable local bike shop and they said they cleaned and tuned the carb. They said was too lean and they put it back to factory spec. I took it to them to get rid of the bog, which they didn't and it just became harder to start. They also said they notices it needed valve clearance done so they did that so it's back in spec. Figued after that plus some other costs, about $1000 towards the carb should have sorted it.

Now it seems, for whatever reason I'm going through spark plugs (bike only likes to run on a fresh plug which is weird for a 4T I would think).

Edited by Serialize

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You need to find someone else, to work on Your bike !

Sorry, I am not trying to be rude , but damn, $1000 for this problem.

 

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On 1/31/2018 at 8:23 PM, motorock said:

You need to find someone else, to work on Your bike !

Sorry, I am not trying to be rude , but damn, $1000 for this problem.

 

oh I know lol... Just went with who was highly recommended and been in the business 30+ years around here.
was total BS and bike ran worse then when I brought it in with hopes of paying a professional to help with the "bog".
I could have messed with it to get to this point lol, just figured take it to the pro's and get it done right (spent big money and worse off now).

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On 1/31/2018 at 0:32 PM, William1 said:

A 'wet' plug (electrode) is a sign of too rich(doubtful) nor possibly (my bet) oil contamination from bad rings/valve seals or possible a head gasket. The leak down test will narrow it down. If it were fuel related, it would, once started, clean out and run fine and start like a new plug. Next time you pull the plug sniff it and then wipe it off, see if it is fuel or oil.

^

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How You are describing the spark problem has Me confused !

Just how long is the motor running on these rides before the problem shows up ?

Have run in to bad electronics that when heated enough start to degrade and do screwy things, a bad CDI can be hard to find.

If this bike came to Me at this point in time to repair, I would begin with the basics ( especially after other fingers have been in there )

I would check

valve clearance and how the timing marks lined up ( chain stretch )

fuel screw adjustment

leak down test

This 17 year old bike could have more than one problem going on to figure out.

 

 

 

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