CRF450R Fowling Plugs? Valves and electrics are okay!

KICKERMAN360
Edited Date/Time 5/4/2014 9:31am
So the last two times I've taken the 450 out it has lost spark. The first time I had a spare sparkplug (only IFR811s have been used) on stand by so I put it in and kept going. The next time I didn't have a spare (and we were in the sticks so the nearest bike shop was an hour away). The sparkplugs lost spark and/or had an orange spark. It looked like the CDI was stuffed but I have a complete set of electrics for the bike so I know everything works (also checked over everything with a multimeter (compared the coils to each other, near identical), everything except peak voltages were checked since my multimeter isn't quick enough to read it and I don't have a peak voltage tester, but it did pick up some voltage so it was getting something). Anyway, after putting in new plugs they lit up like normal. I put the old one back in and it was sparking this time at least, but orange in colour (not blue). So I did some internet research and people say check the valves. Well the motor is ~5hrs old and the valves were re-shimmed during the rebuild but I checked them anyway. Near perfect and within tolerance. The carb was also set at OEM specs (it has an aftermarket exhaust but some brand I've never heard of before, not FMF or PC) and it runs well, no popping or fuel starving. I'm gonna clean it though because it has sat while I worked away for 10 months and maybe lean it out a touch. I also am thinking of doing a leak down test just to check the condition of the valves (didn't have it at the time of the rebuild) to make sure it isn't sucking in fuel when the intake valves are closed. It has plenty of compression; Enough to snap a kickstarter!

TLDR: Read below:

Would a dirty carb and leaky intake valves cause fowling of the sparkplug? I have an IFR811. Should I run a IFR911?

Any other ideas? At $30 a pop from my Honda dealer (literally the only place that has them) I don't really want to keep putting new ones in each ride. And not to mention the reliability of the bike becomes questionable.

Edit: Would also like to mention that with good spark it fires up quite easily. I decent kick from TDC with choke does the trick.
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Paw Paw 271
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Paw Paw 271 4/24/2014 4:50am
4/24/2014 4:50am
The orange color spark indicates you have a grounding issue with the coil.
What were the ohms reading on the primary and secondary side of the coil?
Also your carb float needle may not be sealing.
Also the fuel screw may need adjusting.
Excess fuel and weak spark yields a bike that stops running.
KICKERMAN360 4/24/2014 7:38am
4/24/2014 7:38am
Paw Paw 271 wrote:
The orange color spark indicates you have a grounding issue with the coil. What were the ohms reading on the primary and secondary side of the...
The orange color spark indicates you have a grounding issue with the coil.
What were the ohms reading on the primary and secondary side of the coil?
Also your carb float needle may not be sealing.
Also the fuel screw may need adjusting.
Excess fuel and weak spark yields a bike that stops running.
Well I literally swapped over the new and old spark plugs and got blue and orange spark respectively so I'm not sure a grounding issue is the problem (but I won't rule it out).

I'm gonna pull the carb off this weekend and triple check everything. I'll post up the resistance readings tomorrow (i'll have to redo them).
Paw Paw 271
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Paw Paw 271 4/24/2014 9:30am
4/24/2014 9:30am
You can also order the spark plugs from sparkplugs.com at a real good price.
xnationalwrench 4/26/2014 8:08pm
4/26/2014 8:08pm Edited Date/Time 4/26/2014 8:09pm
The kill switch on those have been known to fail, so that could be your grounding problem.

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KICKERMAN360 4/27/2014 5:15am
4/27/2014 5:15am
xnationalwrench wrote:
The kill switch on those have been known to fail, so that could be your grounding problem.
I did check the kill switch for continuity and it seems to be fine. I also have another one and it works the same. And I removed the kill switch from the circuit, same problems.
KICKERMAN360 5/2/2014 11:52pm
5/2/2014 11:52pm Edited Date/Time 5/2/2014 11:54pm
So I went ahead and gave the carby a good clean. The only dirty part was under the CR Flat cover at the top of the carb. Otherwise it was pretty clean down in the bowl area. So I had tested it a few days prior and she was sparking up nicely. Fast forward a few days til now, I clean the carb, put her back together and kick her over slowly in the driveway. Then, I kept getting a little kickback when trying to start it. Not much, but the engine didn't seem to pack a punch. Anyway, I bump started it down the driveway, it starts up and I drive out (reasonably long drive way), turn around on the road and then drive back in (barely above idle since the idle seemed a tad high) and park it. Then I put it on the stand and see if she kicks - nothing, no signs of life. So I lean out the mixture more (1 turn out now on the pilot screw) and still nothing. I take the plug out and she's a bit dirty but sparks up once. Then I swap in a brand new one and it also sparks up once, then nothing. The only thing I can see being the problem is the stator (tried to avoid it since I don't really want to chase new gaskets) but everything else checks out. How it can go from working perfectly to not working perfectly seemingly at random is driving me insane! With all the screwing around with the 450, I reckon I could have rebuilt the 125 motor by now.

Also, I will add, when I actually try and kickstart it I give them a hard kick. Either way, I usually could start it with one foot on the ground so when it does work, even a small kick will spark up.
KICKERMAN360 5/3/2014 1:29am
5/3/2014 1:29am




As you can see, it looks a bit stuffed. Not sure if that has any effect on it, but doesn't look good. I guess I'll try and fix the old one and if that doesn't work, buy a new one.
Paw Paw 271
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Paw Paw 271 5/3/2014 3:09am
5/3/2014 3:09am
OK, so now the question is where did the metal piece come from?
KICKERMAN360 5/3/2014 9:16am
5/3/2014 9:16am
Paw Paw 271 wrote:
OK, so now the question is where did the metal piece come from?
No idea, there was no debris of any kind inside the cover. Also, the bit of metal is stuck onto the stator (not held in by oil etc).
Paw Paw 271
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Paw Paw 271 5/3/2014 6:06pm
5/3/2014 6:06pm
I would take a look at the cam chain tensioner and the bottom cam chain guide to make sure they are not broken. Also check you stator side crank bearing for up and down play. That part had to come from an engine part as the engine oil is isolated from the trans oil so no trans or clutch part could be there.

Paw Paw
KICKERMAN360 5/4/2014 1:29am
5/4/2014 1:29am
Paw Paw 271 wrote:
I would take a look at the cam chain tensioner and the bottom cam chain guide to make sure they are not broken. Also check you...
I would take a look at the cam chain tensioner and the bottom cam chain guide to make sure they are not broken. Also check you stator side crank bearing for up and down play. That part had to come from an engine part as the engine oil is isolated from the trans oil so no trans or clutch part could be there.

Paw Paw
Well the next thing I'm thinking of doing is removing the fly wheel and doing exactly that (and install the spare fly wheel, even though I have no idea how it would stop "working"). The thing is though, I had the engine completely apart when I rebuilt it. Like I said, only have 4-5 hours on it so the insides were clean as a whistle. I haven't checked the crank movement yet though, but there have been no unusual noises to indicate anything wrong.

I fixed up the other stator I had (I wire to the pickup was exposed so I cut it, soldered it and heat shrinked it and tested it with a multimeter. No problems with the intregity of the wire). Got spark on the first kick and then nothing for a while and then a couple of faint sparks. Really frustrating! I guess I'll install the other wiring harness and see. I know the CDI works, I know the coil works and the stator is fine now. I have checked the grounds as well, they seem good.
fulltime wrench 5/4/2014 9:31am
5/4/2014 9:31am
Did you check for stator shorted to ground? You need to find a known working stator to borrow because that one has been damaged. It doesn't take much to kill them.

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