03 crf 450 problem

[lrrs428]

problem with my 03 crf 450. It runs fine on the stand but one you get on the start line you have to slip the hell out of the clutch to get going. i have replaced the whole electrical system exept for the stator. the gearing i have actuall reduced for more bottom end prior to the problem. im wondering if its a clutch problem. any sugestions? Thanks Clark #428

[lrrs428]

just thought about it some more. what about the stator and fly wheel?

[OreoGaborio]

... and it runs & shifts fine otherwise? Your only problem is when starting from a stop?

[Kitt]

why would this be electrical? sounds like a glazed clutch to me.

[butcher bergs]

Is the motor breaking up when you begin your starts or are you simply having to do like you said and slip the clutch excessively?

[lrrs313]

motor is breaking up under load, not just on starts. sounds perfect on the stand, but the minute you put it under full load it breaks up bad, no power at all. I watched bikes blow past him on the front straight and up the hill out of 3-4 that he walked past before the problem.

[KB]

motor is breaking up under load, not just on starts. sounds perfect on the stand, but the minute you put it under full load it breaks up bad, no power at all. I watched bikes blow past him on the front straight and up the hill out of 3-4 that he walked past before the problem.

With the history of that motor I would first check timing and then the carb. How's the valve adjustment? You may thing they are in spec but it won't hurt to take 5 minute and put a feeler guage to then.

Last but not least I would go with the ecu. I have an 03 if Clarke wants to pull my ecu out and try it on his bike. That entire engine has been a part.

More I think about it...................make sure the auto de-compression adjustment is in spec.

Holla nukka.

KB

[lrrs313]

KB - Timing's been checked (several times, by different people), ECU's been replaced, carb's been cleaned and inspected and seems to be functioning properly. I'm still thinking stator. It's about the only thing left from the original motor. Otherwise I'm running out of ideas.




Besides lighting a match.......

[OreoGaborio]

I bet ya 20 bucks it's only running on one cylinder.

[butcher bergs]

I'd like to hear the condition you describe but in the mean time, have you checked the float height?

Based on what I've read so far, the bike sounds like it idles fine. If the stator was bad it's highly likely you'd hear a misfire even at idle. Since it sounds as if the bike is stumbling under any kind of load that would initially suggest to me fueling and I would be checking for kinked lines, tank vent, float height, etc. I would go to the electrical after fueling and check/ inspect the coil pick up as well as the associated parts.

[OreoGaborio]

Since it sounds as if the bike is stumbling under any kind of load that would initially suggest to me fueling and I would be checking for kinked lines, tank vent, float height, etc.

I'm no 'tard head, but I'm thinking fueling as well. While you're at it, check the petcock if it's got one.

[KB]

I'm no 'tard head, but I'm thinking fueling as well. While you're at it, check the petcock if it's got one.

You scare me when you work on things.

KB

[lrrs428]

wow thanks guys, ill check the carb again tomorrow and the pick up for the stator. I agree now if it was the stator it would suck at idle to. i have replaced all the electrical already i will check the clutch but they are new plates from when i grenaded the tranny. if all this dosen't work i have my local onda shop looking for an 07 left over. Like Brian said its just frustrating because i get passed by bikes i would normally walk away from down the front. I appreciate all the help fellas. KB its not so scarry when i work on bikes i just have that good old fasioned bad luck. like when you forget a part of your exhaust at home. ha ha thanks

[lrrs428]

the bike feels like i am trying to take off in third gear but its not a gear issue you cantput that together wrong and once you get going it skips and sputters. i checked the valves and the exhaust is spot on but the intake is 1 thousands loose and the other is 1 or maybe 2 thousands tight. would that create that big of an issue?

[BLACK SQUIRREL]

I have an 02 with a Brand new rebuilt motor(stock bore) PM for details

[butcher bergs]

wow thanks guys, ill check the carb again tomorrow and the pick up for the stator. I agree now if it was the stator it would suck at idle to.

Check for any cracked components while you're in there. Look for signs of arcing anywhere around the electrical and related engine cases or perhaps some kind of contamination at the pickup and stator points. Any kind of sooty deposit would suggest arcing.

I'd be checking the float height spec and other fueling-related items first and then go to the other stuff.....but that's just me.

[Kurlon]

A lil tight on the valves will reduce working compression, but if you're idling ok the compression shouldn't be low enough to cause it to miss. If it's not jetting/carb related, have you replaced the plug and coil? (Does that bike use a coil over plug stick, or a separate coil?) Breaking down under WOT with load, but not on the stand sounds like a weak spark?

[lrrs428]

yes i replaced the coil. im going to dig in the stator today

[lrrs428]

hopefully its ready for the next weekend