Crf 450 running bad in neutral on the stand
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Endless Mike
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- Oct 30, 2003
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Someone on TT had the carb go bad on him, nothing he could do would fix it until he got a new carb. Some internal seal must have been leaking. Check out something along those lines.
Antman
Member
- Dec 17, 2001
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Did your air screw fall out. Mine did before and had the same symptoms as yours. If you pull the choke and it runs slightly better, it could be this. The screw goes through the float bowl on the bottom. You can loosen both clamps and twist your carb a little sideways and have a look. Let us know.
- Thread starter
- #30
I went to start it after i got back from colorado, and it took about 30 kicks to get it started, it wosent even trying to fire!! This is the first time it didnt start on the second or third kick. It only sat for about a week.
My airscrew is still in there.
The hot start lever is sticky!! It dosent return very quick. So how can i check to see if that is the problem, Can i just pull the hot start cable off the side of the motor??
My airscrew is still in there.
The hot start lever is sticky!! It dosent return very quick. So how can i check to see if that is the problem, Can i just pull the hot start cable off the side of the motor??
Can't help you on the specifics of the CRF hotstart since I don't own this particular thumper. However, once you get that sorted out check your valve clearances It's a basic mechanical maintenance item and after breaking it in a bit you should do it just to be sure they haven't closed up on you. Especially if the hotstart was indeed sticking meaning you were running lean. Checking them is easy -- it's when they need adjusting that it gets tricky (the intake side in the case of the CRF due to the shim and bucket design).
When a thumper is hard to start it usually means valves have tightened up. However, if the hotstart is stuck open it's negating the effect of the choke circuit.
I have been cracking up reading this post on all the esoteric things that could be wrong with your bike. Do yourself a favor and remember the 3 basics of any particular internal combustion engine: compression, fuel, and properly timed spark. If the valves are off it affects compression, not to mention the basic mechanical timing of the engine.
When a thumper is hard to start it usually means valves have tightened up. However, if the hotstart is stuck open it's negating the effect of the choke circuit.
I have been cracking up reading this post on all the esoteric things that could be wrong with your bike. Do yourself a favor and remember the 3 basics of any particular internal combustion engine: compression, fuel, and properly timed spark. If the valves are off it affects compression, not to mention the basic mechanical timing of the engine.
Antman
Member
- Dec 17, 2001
- 44
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You can unscrew it from the carb. They can get corroded over time. I second checking your valves. The theory lately is that heat is the enemy. My valves are still spot on with my '03 CRF and it has sucked dirt. I live in Hawaii and when its dry and dusty, even a properly oiled filter with a filter skin changed every ride isn't enough to keep dirt out of the carb. Check the intakes . Its as easy as removing your tank and the three bolts that hold the valve cover on. You'll need feeler gauges. Check your owners manual. It shows you how to do it step by step. Good kuck.
Jon K.
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- Mar 26, 2001
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I'm reminded of the old Cheech and Chong bit.
Have you checked the air in the tires man?
I like the stuck hot-start cable theory. And should be very easy to fix if that is the case. But it still sounds like spark to me!
There should be a contest. "Wheel of Unfortunate Problems", or something like that. "I'll buy a valve; Pat".
Have you checked the air in the tires man?
I like the stuck hot-start cable theory. And should be very easy to fix if that is the case. But it still sounds like spark to me!
There should be a contest. "Wheel of Unfortunate Problems", or something like that. "I'll buy a valve; Pat".
Maybe the powerband need a re alignment.. I like the sand in the Hot start cable theory myself. I hav an 04 and I love that suspension it was sweet at the dunes in florence. I think you should take that sticky cable off and get a cable luber to lube it up. Did you bury those bars in the sand?
While you were looking at the plug did you take a GOOD LOOK AT THE SPARK PLUG CAP? Not sure but I belive these have a resistor in the cap.
Go back and check the cap real good look for cracks or any outher damage, also refer to your owners manual and it will tell you what the resistance should be. Then go buy the new cap you need.
Go back and check the cap real good look for cracks or any outher damage, also refer to your owners manual and it will tell you what the resistance should be. Then go buy the new cap you need.
- Thread starter
- #39
Ok, this is what ive done thus far.. I checked the valves, and they are all in spec, I checked the flywheel and it was good also. I put a new plug in it.. I unplugged the tps, i unplugged the killswitch, checked ALL connections, and it has VERY good spark.
One morning i went out, started it and it ran perfect!!!! No missing or backfiring, So of course i went riding, about halfway through the ride, she started acting up again.. Now im back to square one. At least now i know for sure its electrical. My only thought was that the ignition was bad. I wish i new someone with a crf cause then i could swap ignitions and see what happens. I looked on service honda and a new ignition was like 130 bucks, so i guess that is what i will order. I have no idea what else it could be, it has excellent spark, it just misses like the timing is off, and only misses at high rpm's
Anyone think that it could be anything else, or should i order a new ignition and see what happens??????????????????????????????????????????????????????????????????
One morning i went out, started it and it ran perfect!!!! No missing or backfiring, So of course i went riding, about halfway through the ride, she started acting up again.. Now im back to square one. At least now i know for sure its electrical. My only thought was that the ignition was bad. I wish i new someone with a crf cause then i could swap ignitions and see what happens. I looked on service honda and a new ignition was like 130 bucks, so i guess that is what i will order. I have no idea what else it could be, it has excellent spark, it just misses like the timing is off, and only misses at high rpm's
Anyone think that it could be anything else, or should i order a new ignition and see what happens??????????????????????????????????????????????????????????????????
Jon K.
~SPONSOR~
- Mar 26, 2001
- 1,354
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You can ohm the ignition, but an intermittent problem probably will not show up in the readings. Even the service manual will most likely have a "replace with known good parts" phrase in it somewhere. The ohm meter is better at finding components that are completely dead, not just wounded.
I gotta say that it sounds more like stator than CDI box. Can't really say why, and could easily be wrong, but that is just what it smells like.
Either way, you are right; you need a good buddy to swap CDI boxes and maybe the coil with. If it still acts up; you know it is not the box. Swapping stators requires an even better buddy. Nolan Husser once asked me to swap stators on my KDX200; as he suspected that his was bad. I broke one of my magnets while removing my flywheel (it was a bit hard to get off) and I got screwed real good on that one.
I gotta say that it sounds more like stator than CDI box. Can't really say why, and could easily be wrong, but that is just what it smells like.
Either way, you are right; you need a good buddy to swap CDI boxes and maybe the coil with. If it still acts up; you know it is not the box. Swapping stators requires an even better buddy. Nolan Husser once asked me to swap stators on my KDX200; as he suspected that his was bad. I broke one of my magnets while removing my flywheel (it was a bit hard to get off) and I got screwed real good on that one.
- Thread starter
- #42
I know i check check the stator with an ohm meter, but does anyone know the specs on the stator???? Also, when i unplugged the tps and it ran crappy does that rule out the tps being bad??? Is there a better way that I can check it than unplugging it??
Thanks
Thanks
- Oct 20, 2000
- 2,969
- 2
You guys are scaring me :think:
You have to get this fixed man... Have you adjusted your fuel screw on the bottom of the carb. I put one of those zip ty fuel screws in my carb and I noticed if it was out too far bout 1.5 turns the bike would backfire and pop and or die over half throttle I started turning it in and it was OK, It is running the best around one turn out under the present conditions. When it ran ok was it really hot or cold out and did the weather (humidity) change as you were out?
High Lord Gomer
Poked with Sticks
- Sep 26, 1999
- 11,790
- 34
Where do you live?
I have about 20 hours plus on my crf. I barely got it started two rides ago it took a lot of effort.. I couldnt get it started last time so I took the plug out and it was really black. I scraped it off and it started first kick. What you described as far as the backfiring and popping and dying out when the throttle is opened sounds just like what hapened before I turned my fuel screw in 1/2 turn. I mean it was pretty violent sounding.. and it was very humid out. Foggy and kinda raining about 45 degrees I think that would amplify it. I think you should lube that hot start cable too. Just humor me and crank that screw in 1/2 turn. You say it was idling OK. That is my theory I would try that before anything. The dunes would want you to have that screw turned out cause it would need a little more fuel then when it was colder and more humid. You would want to move that fuel screw in at least 1/4 to a 1/2 turn in. I have heard the crf is finiky with that adjustment from a few guys and I cant tell you enough that 1/2 a turn difference made the bike run really crappy.
- Thread starter
- #48
I live in seattle, washington
I messed with the air fuel screw today for about 1 hour, i did not notice any change at all when i turned it, either way i went the engine ran the same, i even fully turned it in, then went 1 1/2 turns out like the manual says, and same results. idle didnt pick up or nothing.. So this still leads me to believe it is something to do with spark!
I messed with the air fuel screw today for about 1 hour, i did not notice any change at all when i turned it, either way i went the engine ran the same, i even fully turned it in, then went 1 1/2 turns out like the manual says, and same results. idle didnt pick up or nothing.. So this still leads me to believe it is something to do with spark!
High Lord Gomer
Poked with Sticks
- Sep 26, 1999
- 11,790
- 34
Hey, isn't that Greenbean fella next door in Tacoma?
Going back to basics...if the last change you made before the problem was adding a flywheel weight, have you run it with the FWW taken back off?
Also, that's bad if the fuel screw didn't make a difference screwed in fully or backed out. That suggests to me something blocking a passge in the idle circuit, but that doesn't jive with bad running at 1/2 to full throttle.
