That does sound bad but it can mean something... If there is no difference by moving that screw and it seems really lean possibly it could it be the rubber boot seal leaking either on the engine side or the airboxside. When you had the carb off did you notice any dust in the boot. maybe the carb boots are not sealing right or something poked a hole in the boot and when you open the slide the extra air and vacuum just really leans it out that could explain the headpipe getting so hot and getting lean at half throttle. I mean barring a clogged passage in the carb. If it was electrical would it heat up the headpipe like a lean condition I think the plug would be wet with gas from a weak or no spark. I would really look closely for a dust trail in the boot and check the boots for holes or nubs of rubber on the sealing surfaces and put black or copper silicone on the surfaces of the engine and airbox seals before reinstall. I would really check the side from the carb to the engine for holes in the boot or casting irregularities and make sure the carb is solidly in there with the notch in the boot aligning with the tab on the carb.
Crf 450 running bad in neutral on the stand
- Thread starter xr284
- Start date
Jon K.
~SPONSOR~
- Mar 26, 2001
- 1,354
- 4
If you are worried about an air leak at the manifold; spray a little WD-40 on the joint while the bike is idling. A leaky manifold should show up right away, as the idle will change dramaticaly when the W-D hits it.
Still, a leaky manifold should show more at very low RPMs and at idle.
I'm still betting on the stator. I hope I am wrong.
Gomer; your matchmaking don't look like it is working!
Still, a leaky manifold should show more at very low RPMs and at idle.
I'm still betting on the stator. I hope I am wrong.
Gomer; your matchmaking don't look like it is working!
- Thread starter
- #53
It idles perfect, so smooth.
It dosent miss at just past half throttle, it misses whenever the rpms get up, and it dosent miss every time, its like every couple of seconds it misses. It dosent overheat at all. I have the stock flywheel weight on now.
I will try the wd 40 thing tonight and let you know what happpend, i just dont want the wd 40 to go under the carb and hit the pipe!! Fire!!
It dosent miss at just past half throttle, it misses whenever the rpms get up, and it dosent miss every time, its like every couple of seconds it misses. It dosent overheat at all. I have the stock flywheel weight on now.
I will try the wd 40 thing tonight and let you know what happpend, i just dont want the wd 40 to go under the carb and hit the pipe!! Fire!!
- Thread starter
- #54
Wd 40 on the airboots did not do anything, i ran it for awhile, then i immediatly pulled the plug, it does not look like its running lean, the plug color looks like its running like it should be!! Which it is running like it should be until the rpms pick up, then it starts popping.
Does anyone know how i can check the stator with an ohm meter???
Thanks for all the input, its getting narrowed down......
Does anyone know how i can check the stator with an ohm meter???
Thanks for all the input, its getting narrowed down......
High Lord Gomer
Poked with Sticks
- Sep 26, 1999
- 11,790
- 34
The manual doesn't mention any way to check the stator. It does for the Throttle Position Sensor and the Coil.
http://20-20racing.com/Gomer/TPS.jpg
http://20-20racing.com/Gomer/Coil.jpg
All of the other electrical tests require a Peak Voltage Adapter and a multimeter with an impedance of 10M Ohm/DCV minimum.
I don't remember...have you run it with the kill switch disconnected? With a different plug?
Did the idle change if you took the fuel screw out to 3 or 3.5 turns?
How is the float level?
http://20-20racing.com/Gomer/TPS.jpg
http://20-20racing.com/Gomer/Coil.jpg
All of the other electrical tests require a Peak Voltage Adapter and a multimeter with an impedance of 10M Ohm/DCV minimum.
I don't remember...have you run it with the kill switch disconnected? With a different plug?
Did the idle change if you took the fuel screw out to 3 or 3.5 turns?
How is the float level?
This is driving me crazy. I wish I was able to get at the bike.
Correct me if I'm wrong but the fuel screw is an idle circuit thing and would have little, if any, effect at 1/2 to full throttle.
LHG, I'm with you on the kill switch and float level check, also the fuel line and filter (if there is one). If you pull the fuel line off, do you get the flow you would expect?
From memory, the plug has been changed. Looking at the plug won't tell you much unless you do a plug-chop at the revs where the problem is occurring.
Correct me if I'm wrong but the fuel screw is an idle circuit thing and would have little, if any, effect at 1/2 to full throttle.
LHG, I'm with you on the kill switch and float level check, also the fuel line and filter (if there is one). If you pull the fuel line off, do you get the flow you would expect?
From memory, the plug has been changed. Looking at the plug won't tell you much unless you do a plug-chop at the revs where the problem is occurring.
Did you loosen the tank cap while revving it up to make sure there isnt a clogged venthose. I had that happen on a brand new street bike. I also had an XL600 with a bad ground on the coil it would cut out at high speeds. Popping and such making me think it was a fuel delivery problem. Really make sure nothing is grounding out like someone else said or make sure the ground wires are solid and not pinched especially near the tank and steering bearings, That would be intermittent. Yes, I am not that far away but I am sorry I dont want to part out my bike yet it is too new and running too well. I had a couple of very very bad experiences with that in the past. I will give you all the free advice you can take though....
- Thread starter
- #58
I have unplugged the killswitch, the tank isnt on the bike right now, its sitting on my workbench and i have fuel line running to the carb, so that rules out wires being pinched.. I have ran it with the gas cap off... I did check the fuel flow.. i went through 4 plugs at $15 a piece.
I totally understand what you mean greanbeen.. I dont think i would let a complete stranger take parts off my bike either!!
The bike has excellent spark, it will arc over pretty far, so i think that rules out the coil, but i will check it anyway.
I totally understand what you mean greanbeen.. I dont think i would let a complete stranger take parts off my bike either!!
The bike has excellent spark, it will arc over pretty far, so i think that rules out the coil, but i will check it anyway.
High Lord Gomer
Poked with Sticks
- Sep 26, 1999
- 11,790
- 34
Jon K.
~SPONSOR~
- Mar 26, 2001
- 1,354
- 4
Ah! I get it!
A peak voltage adapter is sort of like the check valve in a compression tester.
It will allow the meter to "store" the reading for peak volts.
Is this correct? If so, then I certainly learned something; as I had never heard of such. Thanks Gomer!
A peak voltage adapter is sort of like the check valve in a compression tester.
It will allow the meter to "store" the reading for peak volts.
Is this correct? If so, then I certainly learned something; as I had never heard of such. Thanks Gomer!
SLOWPOKE 316
Member
- Jan 9, 2004
- 3
- 0
Hey ar284, you need to check for a cracked header pipe up near the cylinder. Also be sure to check on the back side. Warm it up to help locate. Its your problem. Good luck
- Oct 20, 2000
- 2,969
- 2
Is this your bike? Are you the only person that is or has worked on it?
I suggest that if you can't afford to take it to someone that has the tools and know-how to correctly diagnose and repair the bike that you at least get another set of eyes on it. I'm a service tech by trade (more than 24 years). I can't tell you how many times this has happened to me and most every other rep I've ever worked with, when you get stumped the best thing to do is get a second set of eyes on the problem, someone with a fresh perspective. They may not be a m/c mechanic or even a mechanic for that matter. There have been many times that I've explained to my customer what problem I'm experiencing and as I describe the problem and the usual fix, or simply how the machine is suppossed to work, that it all of a sudden became clear what the real problem is.
Though your problem may be illusive, there is also a chance that you are all over the real problem but not realize it. In other words you may not be able to see the forest for the trees.
I suggest that if you can't afford to take it to someone that has the tools and know-how to correctly diagnose and repair the bike that you at least get another set of eyes on it. I'm a service tech by trade (more than 24 years). I can't tell you how many times this has happened to me and most every other rep I've ever worked with, when you get stumped the best thing to do is get a second set of eyes on the problem, someone with a fresh perspective. They may not be a m/c mechanic or even a mechanic for that matter. There have been many times that I've explained to my customer what problem I'm experiencing and as I describe the problem and the usual fix, or simply how the machine is suppossed to work, that it all of a sudden became clear what the real problem is.
Though your problem may be illusive, there is also a chance that you are all over the real problem but not realize it. In other words you may not be able to see the forest for the trees.
High Lord Gomer
Poked with Sticks
- Sep 26, 1999
- 11,790
- 34
I don't know, Jeff...it sounds like he is more knowledgable than any of the mechanics at most of our local shops.
- Oct 20, 2000
- 2,969
- 2
He probably is. I just know from personal experience that we all can easily overlook the obvious sometimes. What I'm hoping is that as some new blood gets in there to analyze the situation and that it may spark some ideas on xr284's part. In my case I usualy reason problems out as I go through the process of explaining to someone else. It's like the light comes on :eek:
Ol'89r
LIFETIME SPONSOR
- Jan 27, 2000
- 6,961
- 45
xr284.
Have you checked your pick-up or source coil. I have seen these go bad on XR's before and they act much the same way as you describe. Bike runs fine until it heats up then starts to miss. Have also seen one come loose inside the case and the bike acted the same way. Missed on top end, ran fine down low.
Remove it from the case and do a visual inspection. Check for cracks or indication of heat on the insulation. Then check it with an ohm meter. Note, these can check good with an ohm meter and still go bad when they heat up.
On electrical problems the first thing to check is the wire connections. Unplug and inspect for corrosion each and every electrical connection. Before you plug everything back together, go to your local auto parts store and pick up a tube of dilectric grease. Put a small dab of dilectric grease on each connection. This will eliminate corrostion.
Side note. A broken or weak valve spring can also cause a top end miss.
Just my $ .02. Hope it helps. :thumb:
Have you checked your pick-up or source coil. I have seen these go bad on XR's before and they act much the same way as you describe. Bike runs fine until it heats up then starts to miss. Have also seen one come loose inside the case and the bike acted the same way. Missed on top end, ran fine down low.
Remove it from the case and do a visual inspection. Check for cracks or indication of heat on the insulation. Then check it with an ohm meter. Note, these can check good with an ohm meter and still go bad when they heat up.
On electrical problems the first thing to check is the wire connections. Unplug and inspect for corrosion each and every electrical connection. Before you plug everything back together, go to your local auto parts store and pick up a tube of dilectric grease. Put a small dab of dilectric grease on each connection. This will eliminate corrostion.
Side note. A broken or weak valve spring can also cause a top end miss.
Just my $ .02. Hope it helps. :thumb:
how about checking the timing. if its advanced it will run great up to a point then it will start glowing.
also is the carb on the crfs like a streetbike carb? i ran into the same problem on my drag bike when the vacuum style slides werent sealled at the top of the carb. I wouldnt think that it would have a vacuum slide surely.
xr284 did you just turn the air screw in and out while idling or did you do it the correct way by reving the motor constantly and turn the screw out until it burns cleanly on top end too.
Do you remember when it ran great for a few then went bad again while you were playing with the electrical stuff. go play with the things until you can see what playing doesnt help. It
I think that you should carry your bike to greenbeans for him to work on it adn swap the parts. Its a shame you cant even ask a friend for help. We all thought yall were in DC instead of the state!
Good luck
also is the carb on the crfs like a streetbike carb? i ran into the same problem on my drag bike when the vacuum style slides werent sealled at the top of the carb. I wouldnt think that it would have a vacuum slide surely.
xr284 did you just turn the air screw in and out while idling or did you do it the correct way by reving the motor constantly and turn the screw out until it burns cleanly on top end too.
Do you remember when it ran great for a few then went bad again while you were playing with the electrical stuff. go play with the things until you can see what playing doesnt help. It
I think that you should carry your bike to greenbeans for him to work on it adn swap the parts. Its a shame you cant even ask a friend for help. We all thought yall were in DC instead of the state!
Good luck
- Oct 20, 2000
- 2,969
- 2
I once had a cadallac that broke a valve spring. The exhaust manifold looked like it was about to melt it was so hot. There was an obvious "miss" but then again there were 7 other cylinders firing, might be harder to notice on a one cylinder machine. It ran good at low rpm's but as the motor revved the vlave began to float. Do you think that could be your problem?
- Thread starter
- #71
When you say broke valve spring, do you mean broke, or weak spring, because when i checked the valve clearence i no i didnt have a broken spring, but a weak spring i have no idea.
As far as having someone else look at it, most of my buddys know very little about engines. They think my muffler berings are out of allignment...
I have talked to some techs down at the local dealership, but they say they havent ran into a problem like this, and to diagnose what was wrong it would be $80.
I did turn the fuel screw about a 1/4 turn at a time, pipe it out, then i would let it idle. I didnt see any difference.
I think i am going to go down to the track tommorow and see if anyone wants to swap some parts with me. It will be a longshot, but what the heck!!
As far as having someone else look at it, most of my buddys know very little about engines. They think my muffler berings are out of allignment...
I have talked to some techs down at the local dealership, but they say they havent ran into a problem like this, and to diagnose what was wrong it would be $80.
I did turn the fuel screw about a 1/4 turn at a time, pipe it out, then i would let it idle. I didnt see any difference.
I think i am going to go down to the track tommorow and see if anyone wants to swap some parts with me. It will be a longshot, but what the heck!!
- Thread starter
- #72
This is my bike, and ive had it for about 8 months, ive probably put 40 hrs on it, just because i dont really have the time. It has always been garaged, and it looks cleaner than the ones on the showroom floor.. That is what puzzles me the most about this, its not like i beat the hell out of it, and things got broke. Its more of i woke up one morining and it ran like a 1973 station wagon!!
- Oct 20, 2000
- 2,969
- 2
Mine was broken into 3 peices but like I said, it was in a car. What was happening was at low rpm the valve would open & close fine but at higher rpm's the valve wouldn't close fast enough so it was staying open longer than it should. My guess is that unspenat fuel was passing through the cylinder and burning in the exhasut manifold. I'm sure it would be a long-shot for the same thing to be wrong with your bike, especially since the spring isn't broken, but I suppose the possibility exists that the valve may not be closing all the way. I doubt that is even the problem anyway but it may be an avenue to consider since you are banging your head against the wall on this one. Good luck tomorrow, I hope you get that thing fixed soon. I sure am interested to find out what the problem is.
- Thread starter
- #74
I started it up and started messing with connections, and i grazed by the hot start cable and tweaked it a little, it made it miss more, i then pushed it back and it missed less, so i then took the cable off the carb, it wouldnt start without it, and it wouldnt start with my finger covering the hole where it threads into, so then i put it back in and it started up, so i decided to mess with the freeplay of the cable, this seemed to help a little but now it idels very high, and before when i would pull the lever when it was running it would die, but now the idle picks up???
I am pretty sure my hot start lever is the problem, but how do i fix it???
I am pretty sure my hot start lever is the problem, but how do i fix it???
Im just happy to hear some improvement. good luck again.
Lube it up and work it a lot. Blow some air through the hot start system and get that sand down in your motor. sorry. I hope I didnt just curse it.
Check the mechanism and see how it works. clean it up when you get there.
Im interested in your findings!!
best of luck
Lube it up and work it a lot. Blow some air through the hot start system and get that sand down in your motor. sorry. I hope I didnt just curse it.
Check the mechanism and see how it works. clean it up when you get there.
Im interested in your findings!!
best of luck
