So I bought a 2006 CRF450R and took it out to the track. For the first half of a lap, it ran perfect :banana:, from idle to redline (under load) it ran perfect. At about half a lap, it started to bog when the throttle was opened past 1/8 throttle, as if it was out of gas, or another way to describe it is that it was as if the kill switch was being pressed. After letting the bike sit for a couple of minutes, I fired it back up and it worked great again for a few seconds, but then the same thing happened. It is VERY repeatable and didnt happen during practice (light riding) but did happen during the race (heavy loading).

I have completely gone through the carb and hoses to make sure the it's not a fuel delivery issue: everything checks out, no hoses are pinched, jets/ports are clean. After reading other posts on TT I believed it was the TPS. I replaced it (b/c after testing, I found that the old one was faulty and non-linear with resistance). Thinking that it was fixed, I entered an enduro race today, but had the same thing happen :banghead: It seems to definitely be an ignition problem. Again, from start the bike runs perfect, no issues at all, but as it is driven around the track (and warms up...) it bogs as if its out of fuel when I give it anything above 1/8 throttle. I can still drive it ONLY if I keep it under 1/8 throttle, but once I open it up it sputters and dies. Also, once it acts up, it will continuously bog until I shut off the bike and let it sit for a few minutes. But upon starting and riding a short time it happens again.

Any ideas? My next guess is that it is the coil or stator...? Please tell me there is someone out the that's had the same problems?!?! :thinking:

have you tried a new plug?

Have you removed the fuel cap breather if fitted and/or made sure the cap is not blocked as thats what it sounds like to me

Check fuel cap breather check valve if equiped like johnnyboy suggested. If that checks out ok, you may want to remove your stator cover & inspect for shavings that accumulate on the pickup coil . check where the wires attach to the sensor. there is 2 solder spots that make the connection (2wires) Any shavings found can short the pulse giving the systems you described. Good luck.

I had also already put a new breather on the gas cap and made sure it was installed in the correct direction, so I have eliminated that as being a contributor to the overall problem. I'll try the new plug and definitely take a look at the pickup coil. Shavings? Is that indication of a bigger problem? BTW I really appreciate all your help!

what if you put the old breather cap back on.. or next time it does it instead of waiting a few minutes to start it, open the cap and quickly restart. Sounds like your not getting ventilation of your tank.

erichshonda said:

exactly my thoughts. And if you do have shavings, time for a new crank!!! that is where the metal shavings are coming from

MELK-MAN said:

At one point I took the hose off the gas inlet to the carb and opened the petcock to see the gas flow. It had plenty of flow. Another time, I rode it until the bogging down occured and immediately shut off the petcock, then I drained the carb bowl and there was plenty of fuel that came out. So I am pretty convinced the carb is getting enough fuel. Whenever it does act up (bogging down while throttling) it'll still idle, but anything above 1/8 throttle it bogs and dies thus making me think it's purely electrical.

Man, hope it's not the crank :shocked:

So here's what I have found out so far, sorry for the delay... I tested the ignition coil primary peak voltage, exciter coil peak voltage, ignition pulse generator peak voltage, and ignition coil resistance. The obtained results are as follows (minimum/standard values per Honda factory service manual given in parenthesis):

Ign Coil Primary Peak Voltage (PV): 428.0 volts (100V min)

Exciter Coil PV: 58.6 volts (50 V min)

Ign Pulse Generator PV: 7.28 volts *this one is based on memory as I forgot to write it down* (0.7V min)

Ign Coil Resistance: 0.28 Ohms (0.1-0.3 standard)

Ign Secondary Coil Resistance: 15.6 Ohms

When I checked the spark plug, it was a DENSO, but was not one that was suggested by the manual, so I replaced it with an NGK IFR8H11. I have not fired it up yet since the replacement. Lastly, I took off the left engine cover and did not see anything unusual. The only thing I had questions about was the stator. The shellac had a slight crack near the soldered poles. Could this be causing a problem?

Basically everything checked out good, which is really no surprise since the problem only occurs when the motor is hot and revved high in the RPM range (refer to the above).

I hope to ride it sometime soon and see if the spark plug took care of the problem (not too promising...).

Anything else to check? I think at this point, I'll be looking around for someone who has another bike that is good running condition and I'll put on the ign coil and see if it fixes the problem, put on a diff ICM, etc..

Thanks a lot for all your help!

The ignition coil could start breaking down once it gets warm, and loosing secondary current. I've had plenty of small engines that would idle all day, but put any load and they'd fall flat on their face. Almost always ended up being a weak coil.

You need to get the bike warm and check the stator resistance. It can test fine when cold, but when they get hot, the breach is in the mag wire will open up and you loose the alternators ability to make enough voltage to fire the coil/plug under load.

Could be a bad CDI box too. Its the easiest swap if youve got access to one.

Remove the one-way valve on you tank hose, if you have one. They clog.

Lead Head said:

Update: I got ahold of a brand new coil from Honda and put it on the bike along with the "correct" (according to the Honda Manual) spark plug to no avail. I took it out and the exact same symptoms kept occurring as stated above. This week, I am going to try to swap out a buddy's ICM and put it in place of mine to see if that solves the problem. If not, I believe the problem lies in the stator or the flywheel...?

A few weekends ago, I replaced my ICM with a buddy's. No change. Bike still went through all the gears great until about 300 yards when it died exactly like it's always done. Turning my attention to the innards of the bike, I noticed it has a larger (than stock) Trail Tech flywheel (with a stamp 331L). In fact the flywheel was so large, on the left engine side cover, an internal "fin" was modified to accommodate the larger weight.

Has anyone had problems with these flywheels? It has plenty of magnetism. So does this safely say it is my stator?

Just to answer some above questions: I intentionally rode w/o the gas tank vent on (on a blacktop road just to test the theory of a clogged hose/valve). I even cracked the gas cap open and rode the same route. Same results. Definitely not a fuel delivery issue, I am certain the problem is electrical.

I believe the Trail Tech flywheels should only be used with Trail Tech stators because they have stronger mangets. You're probably overheating the ignition module.

Check with Trail Tech to verify if that flywheel can be used with a stock stator. After that, the only thing left is the stator.

Try completely disconnecting the kill switch! I know it sounds crazy but just fixed a bike last week that had one go bad and have the same symptons as yours and as soon as I disconnected it, no more dying...

Try this link. It sounds familiar.

scooter12, on 25 January 2012 - 04:03 PM, said:

Always check the simple stuff first. I've seen that problem on more than a few occasions, but I'm leaning towards the stator on this one.

Quote

Thats the trail tech +15oz flywheel. They call out the same flywheel for lighting or non lighting but you wouldnt be the first guy to have an issue with the flywheel over driving the CDI and having it cut out.

If you can get your hands on an OEM flywheel that I think would be your next test. You need the correct puller to pull the flywheel off other wise you'll ruin the end of the crank...and that headache I dont think you need.

Finally figured it all out : Once I confirmed that the flywheel was indeed an aftermarket TrailTech (non-lighting), I called Justin at TT and he gave me his $0.02. He was pretty sure it sounded like a stator. Convinced, I decided to buy one, but from an OEM parts store. Seconds (literally) after placing the order, I got an email from TT saying they sell an OEM replacement for $100, or a 40W lighting one for $144. The guys at TT are top notch, I purchased the lighting stator (b/c I have plans to add a light in the future for trails), installed it, and the bike runs perfect! No more cutting out after 300 or so odd yards! Thank you all for the help, it helped steer me in the right direction.

Now if I could only make time to get out on the track before the St. Valentines Day Massacre Enduro...

PS - please to anyone out there that finds the solution to their problem posted on ThumperTalk, please please please post the solution! I assume most people are uber-jubilant when their "dead" motorbike runs again and forget to hop back on and share the solution with the two-wheeled community, Keep ridin'!