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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: dowdogg on December 22, 2017, 03:11:13 AM
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Hello fellow motobrickers,
Today I bring you tidings of another (partially) broken K-bike.
The Problem:
When around 20%-50% throttle at any RPM, the bike misfires terribly and sounds like a two-stroke. Other side-effects include constant flames (awesome, but sadly detrimental) during the misfire and of course gratuitous pops and bangs. When cruising on the freeway, I notice that the header collector glows red hot. The effects seem to be exacerbated with less fuel in the tank and during the first 5-10 minutes of riding (warm-up). No problems at idle and WOT feels great. Other than the misfire, the bike has never felt better or faster. I purchased the bike in Spring of 2017, never had this problem until a few months ago.
Here is a video for reference:
https://www.youtube.com/watch?v=u0ILlj-c-bY (https://www.youtube.com/watch?v=u0ILlj-c-bY)
check around the 19 second mark for a small blue flame (cool huh). Its like that but 10x on the freeway cruising and makes for some very scared and inquisitive on-lookers at night-time.
The Bike and its details:
- 1990 BMW K75 Standard
- Unknown mileage (purchased for a hefty sum of $1100)
- Completely removed instrument cluster (tach, speedo did not work, actually, nothing worked except the neutral light)
Parts replaced/fixed (ALL REPLACED WITHIN 5000 OR LESS MILES)
- New battery
- New 4 hole injectors
- New NGK plugs
- New Crankcase Breather Hose
- New Fuel Filter
- New OEM Throttle body Vacuum caps
- New OEM Throttle body rubber bushings
- New OEM Crankcase Gasket
- New Fuel lines (all around) and OEM hose clamps
- New vacuum lines all around
- New FI relay
- New Starter relay
- Fan would not start ever, so I mounted a manual fan switch via a relay to the Temp Switch Relay
- Cleaned air filter
- Cleaned and checked fuel pressure regulator
- Checked and tested current fuel pump (aftermarket mostplus brand)
- Rewired fuel pump connections
- Almost every electronic/connector cleaned with DEOXIT or Electrical connection cleaner.
- Almost every ground (chassis, etc) sanded, cleaned and checked.
- Throttle bodies synced
- L-Jetronic K bike fuel injection adjusted and set
Other things have been changed but mostly non-functional/irrelevant. I beg the community to save my K with their infinite and endless knowledge. I am reaching wits end at this point sadly after much debate and strife (has not prevented me from riding the bike 50+ miles on a daily basis, duh).
Thanks guys, lets hear some hopefully game-changing comments about what the problem is and how to fix this piece.
Cheers!
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What causes most backfiring on these K bikes is a badly adjusted TPS but as you've done so much to the bike it's difficult.
How did you adjust the Jetronic fuel injection?
Sent from my iPad using Tapatalk
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What were the results of the coolant temperature sensor test? Were all the values within range from hot to cold?
When you removed the instrument cluster was it replaced by something else?
What was done to this bike a few months ago before this started happening?
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Did you replace all that stuff because there was a problem you were chasing?
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+1 to what Laitch asked.
In your list of things you did, you mentioned: Fan would not start ever, so I mounted a manual fan switch via a relay to the Temp Switch Relay
This possibly points back to a failing temp sensor to which Laitch alludes. By installing a switch, all you've done is bypassed the symptom without diagnosing the problem.
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+1 to what Laitch asked.
In your list of things you did, you mentioned: Fan would not start ever, so I mounted a manual fan switch via a relay to the Temp Switch Relay
This possibly points back to a failing temp sensor to which Laitch alludes. By installing a switch, all you've done is bypassed the symptom without diagnosing the problem.
Rob, thanks for saving me from having to post that.
Misfiring/backfiring sounds like over rich mixture. Over rich is tolerated at idle and WOT, but not at small throttle openings. First culprit for that mixture is the emgine temperture sensor. The fact you didn't have a functional fan before adding a manual switch points at it.
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rich mixture missing is usually more rhythmic, and the glowing headers would point to a timing issue or lean mixture, wouldn't it? Could be exacerbated by the free flowing exhaust. Also did you ever check the valves, could be tight with unknown history. Jut barking up the tree here, have no idea what's going on.
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I think there would be two possible failure modes for the NTC sensor - fails open or fails short. If it fails open, it tell the temp module that the water temp is stone cold and the ECU will enrichen the mixture. If it fails short, it tells the temp module that the water temp is boiling hot, and the temp module turns on the fan at the same time the ECU should be providing a leaner mixture. Since the fan never turned on, I suspect the temp sensor has failed open. This supports Gryph's theory (unless enrichening only happens at idle speeds and there is a leaner map at mid throttle; don't know).
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My thinking is that at idle a rich mixture will run, and the only thing you might notice is sooty plugs. If the mixture is lean, the engine will also idle, but comig off of idle it will have a tendency to stumble and die.
A lean mixture will also detonate on acceleration, especially at full throttle where the mass of air entering the cylinders under compression can get hot enough to preignite the lean fuel mix.
At wide open throttle engine performance with a rich mixture will probably be okay since the injectors are probably sized to match the air flow with the throttles aide open. They can't flow enough fuel to substantially upset the mixture.
I'm only guessing here, but I suspect that a rich mixture will take longer to complete the burn, and will still be burning as the exhaust valves open, allowing the flame to travel to the headers.
What kind of gas mileage are you getting with all this going on? I would expect that it is down, maybe as far as less than 30 mpg.
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What causes most backfiring on these K bikes is a badly adjusted TPS but as you've done so much to the bike it's difficult.
How did you adjust the Jetronic fuel injection?
Sent from my iPad using Tapatalk
I followed this guide:
http://skylands.ibmwr.org/tom/tech/co-setting.html (http://skylands.ibmwr.org/tom/tech/co-setting.html)
What were the results of the coolant temperature sensor test? Were all the values within range from hot to cold?
When you removed the instrument cluster was it replaced by something else?
What was done to this bike a few months ago before this started happening?
1.
1. I'm assuming you are speaking about this test (http://www.ibmwr.org/ktech/fan-diagnosis.shtml (http://www.ibmwr.org/ktech/fan-diagnosis.shtml))
If so, the temp probe worked within the ohm range described.
2.
I attempted to do so, but after finding the increasing complexity to get the aftermarket dash I purchased to work, I gave up and scraped the whole idea completely.
3.
I will give a timeline of the aforementioned repairs:
REPAIRS DONE WHEN PURCHASED (APRIL):
- New 4 hole injectors
- New Crankcase Breather Hose
- New Fuel Filter
- New OEM Throttle body
- Vacuum caps
- New OEM Throttle body rubber bushings
- New OEM Crankcase Gasket
- New Fuel lines (all around) and OEM hose clamps
- New vacuum lines all around
- Cleaned and checked fuel pressure regulator
- Checked and tested current fuel pump (aftermarket mostplus brand)
- Rewired fuel pump connections
- Almost every electronic/connector cleaned with DEOXIT or Electrical connection cleaner.
- Almost every ground (chassis, etc) sanded, cleaned and checked.
- Throttle bodies synced
- New FI relay
Side note, was running a shorty muffler (essentially a straight pipe) for the majority of this time period. All these repairs were done not necessarily out of necessity but i just wanted a mechanically sound machine.
4 MONTHS AGO:
Hot day, noticed after a 45 minute to an hour ride that the bike was overheating (water pouring out of the overflow). Thought it was a fluke. Realized the situation kept occurring on long rides. Proceeded to do this test (http://www.ibmwr.org/ktech/fan-diagnosis.shtml (http://www.ibmwr.org/ktech/fan-diagnosis.shtml)) because the fan would not run after 10+ minutes of idling. Had never had a overheating or fan problem since purchase. Did all the relay tests and everything seemed fine, when jumped the fan operated normally. Decided to circumvent the situation and installed my own relay (onto the temp relay) with a manual fan switch. Has not overheated since.
2 MONTHS AGO:
Starter relay dies, replaced with new battery. misfire plateaus and doesnt get any worse but continues. I ride the bike to work 50-60 miles a day with no problems other than the misfire.
3 MONTHS AGO:
YESTERDAY:
More troubleshooting. Set the FI according to this guide (http://skylands.ibmwr.org/tom/tech/co-setting.html (http://skylands.ibmwr.org/tom/tech/co-setting.html)) assuming that my 4 hole injectors were ruining the AFR. Misfire still present but I managed to make the bike idle nice and low, maybe too low? Side note: throttle got stuck at WOT for around a second last night after this adjustment, happened the morning as well, so I'm staying off WOT. Only seems to happen at 100% throttle, not 99%. Might adjust the AFR again to previous setting for safety :hehehe
See the new timeline
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Did you replace all that stuff because there was a problem you were chasing?
See the timeline. Some of it was, some of it wasn't, I just wanted a mechanically sound bike.
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+1 to what Laitch asked.
In your list of things you did, you mentioned: Fan would not start ever, so I mounted a manual fan switch via a relay to the Temp Switch Relay
This possibly points back to a failing temp sensor to which Laitch alludes. By installing a switch, all you've done is bypassed the symptom without diagnosing the problem.
I did diagnose and test the temp sensor when diagnosing the fan and found no error within the ohm ranges at the time. That may have changed now, not sure. side note: i love your build, it was part of my inspiration to get a K!
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rich mixture missing is usually more rhythmic, and the glowing headers would point to a timing issue or lean mixture, wouldn't it? Could be exacerbated by the free flowing exhaust. Also did you ever check the valves, could be tight with unknown history. Jut barking up the tree here, have no idea what's going on.
Have not checked the valves yet even though I know I should have :P please dont burn me at the stake.
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My thinking is that at idle a rich mixture will run, and the only thing you might notice is sooty plugs. If the mixture is lean, the engine will also idle, but comig off of idle it will have a tendency to stumble and die.
A lean mixture will also detonate on acceleration, especially at full throttle where the mass of air entering the cylinders under compression can get hot enough to preignite the lean fuel mix.
At wide open throttle engine performance with a rich mixture will probably be okay since the injectors are probably sized to match the air flow with the throttles aide open. They can't flow enough fuel to substantially upset the mixture.
I'm only guessing here, but I suspect that a rich mixture will take longer to complete the burn, and will still be burning as the exhaust valves open, allowing the flame to travel to the headers.
What kind of gas mileage are you getting with all this going on? I would expect that it is down, maybe as far as less than 30 mpg.
My commute to work is around 50-60 miles a day. I get around 2-3 days worth of riding on 4 gallons. My assumption is around 35-40 MPG, surprising, I know.
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I did diagnose and test the temp sensor when diagnosing the fan and found no error within the ohm ranges at the time. That may have changed now, not sure. side note: i love your build, it was part of my inspiration to get a K!
Thanks for the compliment!
If the temp sensor was working properly, the fan should come on when the coolant temperature reaches 217*F. Yours used to come on normally you said and now it doesn't so that's either a bad sensor, bad temp module or bad wiring. The fan diags pass so that should indicate a good temp module and good wiring but doesn't exercise the temp sensor.
You don't mention whether the bike is difficult or easy to start from cold. Is it easy to start? If not, does the engine struggle to keep idling until the bike is warmed up (about 1-2 minutes)? If the bike is hard to start cold and idles poorly until warm, that indicates a bad temp sensor usually.
Your new exhaust system is very open and short. The K75 is very prone to afterfire if the back pressure is low or there is a leak in the first 20" of exhaust. Yours might just be acting the way it should given the components you've selected. Is it possible to swap back the standard K75 exhaust and ride with that for a test? If so, and if the afterfiring symptoms disappear, the diagnosis could point to the new short exhaust as being the culprit. If not, further tests would be required to isolate the failing component.
Your mileage is pretty normal which is pointing away from an enrichened or enleaned mixture IMO.
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1.
Have not checked the valves yet even though I know I should have :P please dont burn me at the stake.
I wouldn't consider it. You'd probably have a tendency to backfire :giggles
Your mileage is pretty normal . . ..
Not where I come from. My bike gets 48 to 50 US mpg running gasohol. If it were getting that little, I'd swap it for a '98 Valkyrie. :hehehe
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Not where I come from. My bike gets 48 to 50 US mpg running gasohol. If it were getting that little, I'd swap it for a '98 Valkyrie. :hehehe
Well, I guess my MPG calculator (i.e. brain and pencil) was not working right. I am getting 50.6 MPG average when I look it up in Fuelly. That's 4.7 L/100km for us Metric folks.
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Thanks for the compliment!
If the temp sensor was working properly, the fan should come on when the coolant temperature reaches 217*F. Yours used to come on normally you said and now it doesn't so that's either a bad sensor, bad temp module or bad wiring. The fan diags pass so that should indicate a good temp module and good wiring but doesn't exercise the temp sensor.
You don't mention whether the bike is difficult or easy to start from cold. Is it easy to start? If not, does the engine struggle to keep idling until the bike is warmed up (about 1-2 minutes)? If the bike is hard to start cold and idles poorly until warm, that indicates a bad temp sensor usually.
Your new exhaust system is very open and short. The K75 is very prone to afterfire if the back pressure is low or there is a leak in the first 20" of exhaust. Yours might just be acting the way it should given the components you've selected. Is it possible to swap back the standard K75 exhaust and ride with that for a test? If so, and if the afterfiring symptoms disappear, the diagnosis could point to the new short exhaust as being the culprit. If not, further tests would be required to isolate the failing component.
Your mileage is pretty normal which is pointing away from an enrichened or enleaned mixture IMO.
Thanks for the reply! The bike has absolutely no problem starting under any situation. Hot or cold, One click of the starter and it fires right up and idles. Starts up faster than my car (2011 BMW 335i) which I find hilarious. As I mentioned before, for the majority of the time before I was running a shorty muffler which is literally a 4 inch pipe with little to no baffling connected to the header collector. Essentially open header. I never had any misfire problems with that set up. My current set up is a 18” muffler with around 3” inch of piping = 21” of exhaust. It was during the more restrictive and longer exhaust set up days that the misfire started. So I’m not sure if the culprit is backpressure. When I get home I will put on the stock system to see if it makes a difference.
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I am getting 50.6 MPG average when I look it up in Fuelly.
Suddenly, envy has taken control. I've gotta shed weight—battery covers, tank bag, handlebar grips, tool kit—maybe even get a gastric bypass.
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Suddenly, envy has taken control. I've gotta shed weight—battery covers, tank bag, handlebar grips, tool kit—maybe even get a gastric bypass.
I don’t know how you guys get 50 mpg. My cruising speed is 85 or so and I feel the need to keep the bike heathly by redlining it at least once a day. That probably doesn’t help. At 70mph maybe? I only weigh 135. That probably compensates a little.
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mine gets about 50mpg at 60mph, but every 10mph faster get a corresponding 5mpg drop in mileage. So 80 mph and 35 mpg is about par.
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Assuming 50-60 miles round trip, and 4 gallons every 2-3 days your mileage is somewhere between 25mpg(100 miles and 4 gallons every 2 days) to 45mpg(180 miles and 4 gallons every 3 days).
I'm going to figure the actual is somewhere about 2/3 of the way from the lowest to the highest. That puts you around 38-39mpg. Compared to my mileage on my commute which is similar(55 miles at 60mph average speed), you are using about 11-12% more fuel than my full fairing K75RT with my 200 pound butt in the saddle. The only time that my K75 gets that low on mpg is when I am doing 80 mph average speed on the interstate with a fully loaded touring kit.
Sure sounds rich to me. Double check your engine temperature sensor.
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I feel the need to keep the bike heathly by redlining it at least once a day.
Judging by the title of this thread, redline running doesn't seem to keep your bike healthy. In fact, it sounds like it gives it a case of the jitters. :giggles
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So it seems that general consensus is that the water temp sensor needs to be replaced. Everybody on par with that? Want to call my local dealer today if possible to place the order. Thanks guys!
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Compare pricing at the dealership to EuroMoto Electrics: http://www.euromotoelectrics.com/TEMPSENS-K197-p/tempsens-k197.htm
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Everybody on par with that?
Not me. According to what you've written, it meets all the benchmarks for resistance along the temperature curve, so why isn't it working if its ground connection is clean? I think you should test it again. :yes
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Thats reasonable. I'll break it down tonight and do some cleaning of the sensor and its ground again to see. I called the dealership and they told me that they don't have any in the country. Their site says its NLA. Awesome. I'll order online from euromoto probably, if this cleaning and check falls through.
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Do not put thread tape or sealant on the threads, as doing so will insulate the sender from earth. The sender relies on the gasket ring to prevent leakage.
Regards Martin.
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My coolant temp sensor tested ok outside the bike, but on the bike, the fan would never come on leading to the coolant boil over you mentioned. Replaced with a new aftermarket one, fan comes on now. I believe there is a thread some where here about getting aftermarket coolant temp sensors - I can't remember for sure though.
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You can get them through Aliexpress but I've seen reports of them failing. But they are cheap.
Regards Martin.
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Not me. According to what you've written, it meets all the benchmarks for resistance along the temperature curve, so why isn't it working if its ground connection is clean? I think you should test it again. :yes
Well, results are in, temp sensor tested at 2964 ohm cold in 52 degree weather. 307 ohm hot (increasing in quick .1 increments with every second it was off). Temp sensor seems to be working fine, however, I ran this test with the OEM temp relay and of course, the fan never came on during idle or riding. Both the connector and sensor cleaned and scrubbed with deoxit. Also, I ran the bike with 3 different exhaust set ups (including stock) to see if there was any change in the misfire. The problem persisted. What now guys :dunno ? I can buy a new temp sensor, but I would rather keep removing variables if possible.
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Sounds like the sensor might be ok. To be specific, how cold is cold? 17°C? How hot is hot? 97°C? There are two NTCs in the sensor but you published only one pair of readings; what are the corresponding readings for the other sensor?
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YESTERDAY:
More troubleshooting. Set the FI according to this guide (http://skylands.ibmwr.org/tom/tech/co-setting.html (http://skylands.ibmwr.org/tom/tech/co-setting.html)) assuming that my 4 hole injectors were ruining the AFR. Misfire still present but I managed to make the bike idle nice and low, maybe too low?
Correct RPM at idle is 950 +/- 50
Side note: throttle got stuck at WOT for around a second last night after this adjustment, happened the morning as well, so I'm staying off WOT. Only seems to happen at 100% throttle, not 99%. Might adjust the AFR again to previous setting for safety
If you replaced the OEM Oetiker clamps with band clamps around the TB bushings, then double check to make sure that the throttle actuator is not interfering with the screws in the band clamps at WOT. There are specific orientations for these clamps in this area of the engine and very little tolerance for deviation.
(https://lh3.googleusercontent.com/0IWpAenbPUxLcGyBvvV-iJGNo1pae-gIH3oeUy-9S3SPBD7jdMHbH8zVtetpePplIWxlg8ahDUp2e0Zsky8UMIWRYOz-pcDMtHjjb2G7MeBj-mwbQCtK3OkQj3oC9aEiMYdN0PZDjvfXqiLYjqRgfrIawmYRORAJVrED_Uo7uoDLgBzxHjnRhMcFwA6Nsip5IzCUMtnfaTi9vX7dYb7GpFQWtY8WsK0iD2PDbSr0iQ52_dcLn32WNOsc1LWOu14R2FPnMNbp1W0yRCS4QEOA47KK1MGtu5siuJ2PuQoqR2xkwEh8bESvvcXBU2Xi_Mxedq4Dt2Ml0HmItDUmSNaHo-CRe1BcNexcLM3hNsHyNp2sMbWYv5Advhf2P07KSZjGY8Uq1vH5ALjSoC1hDiLxfyZK4nenFdQYRnjTsxC4S8EE9IwHBMKki7wkdHdmUxV2L6kQOXFuYdCuEMpKmEoJMyPJ5_ARb33zqGEGuQdHbigwZOhyrarcZArhJApWFcKbMbR0TpBoZy3F_i6mOoR1ebWNnYchm6FhuwwGz7slpAsn36qeZUrTf7Enj-EoC8pDN9oBwSNytn_yHHAjyR2oRC8K5ooZ_y5NRZfaPpg=w1982-h1486-no)
Also, make sure the TPS is not binding the TB actuator throughout its rotation. Loosen the screws holding the TPS and operate the throttle several times to ensure there is no binding. Adjust the TPS if you detect binding. Retighten the screws once this operation is completed and test one more time.
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1. I'm assuming you are speaking about this test (http://www.ibmwr.org/ktech/fan-diagnosis.shtml (http://www.ibmwr.org/ktech/fan-diagnosis.shtml))
Nope. I was referring to Bert Vogel's boiling water test for the coolant temperature sensor in his troubleshooting guide downloadable from this site.
Well, results are in, coolant temp sensor tested at 2964 ohm cold in 52 degree weather. 307 ohm hot . . .
I can't follow your testing method. Perhaps the giddiness of the season is affecting my reasoning. If your coolant were 52ºF then it would seem to me that your cold value is off by 1000 ohms. Is this the test using boiled water? If it is, why would you be using air temperature as a value here?
Consider the tests in this post and the ones following it (http://www.motobrick.com/index.php/topic,6702.msg45770.html#msg45770) in reference to your temp relay function.
Anyway, I'm confident you'll sort this out and admire your ability to gauge your speed without a speedometer. :2thumbup: Not everybody can do that.
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Did you measure the temp sender resistance through the wiring to the computer or at the back of the sender? If there is a break in the wiring, it would create an open and perhaps the computer thinks the engine is always really cold. A faulty wire or connector pin would explain the temp sender measuring correct and the overly rich mixture that results in the backfire. I suppose a break could also be inside the computer but that seems unlikely.
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Have you checked the valve clearances? Have you checked the compression? And spark plug colour is a good indicator to what is going on. Read up on doing a plug chop and report on the spark plugs colour, before and after doing the chop.
Regards Martin.
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Nope. I was referring to Bert Vogel's boiling water test for the coolant temperature sensor in his troubleshooting guide downloadable from this site.I can't follow your testing method. Perhaps the giddiness of the season is affecting my reasoning. If your coolant were 52ºF then it would seem to me that your cold value is off by 1000 ohms. Is this the test using boiled water? If it is, why would you be using air temperature as a value here?
Consider the tests in this post and the ones following it (http://www.motobrick.com/index.php/topic,6702.msg45770.html#msg45770) in reference to your temp relay function.
Anyway, I'm confident you'll sort this out and admire your ability to gauge your speed without a speedometer. :2thumbup: Not everybody can do that.
New results are in!I proceeded with the Bert Vogel's out of bike water temp test (boiling water test). I was using an in-bike test before.
Baseline: 5000 ohm (cold)
55C: 2,500 ohm
67C: 1,000 ~ 1,400 ohm (keeps dropping, hard to get an accurate reading)
77C: 1000 ~ 850 ohm
84C: 730~750 ohm
99C: 580~600 ohm
I'm not sure what the margin of error is for this test, so please advise.
Have you checked the valve clearances? Have you checked the compression? And spark plug colour is a good indicator to what is going on. Read up on doing a plug chop and report on the spark plugs colour, before and after doing the chop.
Regards Martin.
I checked my valve clearances and exhaust and intake were both in spec. Plug color was good. Compression was fine.
Did you measure the temp sender resistance through the wiring to the computer or at the back of the sender? If there is a break in the wiring, it would create an open and perhaps the computer thinks the engine is always really cold. A faulty wire or connector pin would explain the temp sender measuring correct and the overly rich mixture that results in the backfire. I suppose a break could also be inside the computer but that seems unlikely.
At this point, I have checked both.
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Judging from your resistance readings, your temperature sensor is reading low temperature. The jetronic never knows that the engine is up to operating temperature. This could be causing a rich mixture. However, you say the plug color is good. :dunno2:
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These are the values it should read at the given temps:
Baseline: 2500 ohm (if cold means room temp)
55C: 750 ohm
67C: 500 ohm
77C: 400 ohm
84C: 300 ohm
99C: 250 ohm
So, yours looks to be stuffed.
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Judging from your resistance readings, your temperature sensor is reading low temperature. The jetronic never knows that the engine is up to operating temperature. This could be causing a rich mixture. However, you say the plug color is good. :dunno2:
I must state the fact that i just replaced the plugs less than 500 miles ago. So I wouldn't be surprised if they look fine regardless of their actual condition.
So, yours looks to be stuffed.
Yeah, seems to be the case, I just ordered a new one via euromoto. Will update once I get it in.
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I must state the fact that i just replaced the plugs less than 500 miles ago. So I wouldn't be surprised if they look fine regardless of their actual condition.
:hehehe
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When my temperature switch connector played up it resulted in over fueling. The glowing headers and lack of excess fuel which you would have seen when you pulled the plugs suggest the opposite. Suggests faulty temperature switch rather than the connector which has now shown up the resistance temperature test.
Regards Martin.
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So it seems that general consensus is that the water temp sensor needs to be replaced. Everybody on par with that?
Yes, if you have measured the resistance through each element to the housing, and not both elements in serie.
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MORE UPDATES!
I have replaced the sensor, installed everything on the bike and I took it out for a day. The results were... interesting to say the least.
- Firstly, now the bike suddenly has trouble starting cold (a problem that I have never had). If I don't fuel advance at least one click from the get go, it will start up and promptly die and won't want to start again. Once warm, the bike has no problem starting up and it idles perfectly right away.
- As for the misfire, it is (partially) fixed. The bike will still misfire as seen in the video and shoot flames etc as it did before at partial throttle. HOWEVER, when cruising on the freeway, it still sounds like its misfiring a bit (hard to hear with wind, helmet, etc), but no more flames or glowing red hot header collector anymore. So during cruising, the problem went away (from what I can see visually), but when going through the gears and holding any rpm for too long at partial throttle, it misfires terribly just like before.
To be honest, the results are even more dumbfounding than I anticipated.
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Even in Queensland unless it is reasonably warm I have to start on first click of the fast idle. Check for air leaks, check the "Z" hose, check the vacuum caps.
Regards Martin.
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Even in Queensland unless it is reasonably warm I have to start on first click of the fast idle. Check for air leaks, check the "Z" hose, check the vacuum caps.
Regards Martin.
Crankcase breather and vacuum caps have both less than 5000 miles, all vacuum lines as well. I’ll check again, but not banking on it.
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[li]Firstly, now the bike suddenly has trouble starting cold (a problem that I have never had). If I don't fuel advance at least one click from the get go, it will start up and promptly die and won't want to start again. Once warm, the bike has no problem starting up and it idles perfectly right away. [/li]
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I don't think this is a problem but is instead normal operation. If the bike was running rich before (and therefore backfiring from unburnt fuel), it's possible that it would start at ambient temperature without the idle increase lever locked on.
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If it was running rich it would start without having to advance the fast idle. Read up on how to do a plug chop. Take the bike up to where it is miss firing and shut her down as per the plug chop instructions. You might have to do it a couple of times to get the hang of it. Do this on a quiet road somewhere where you can push it safely to a place where you can work on i it. A back up vehicle is handy to act as a buffer. Hopefully reading the plugs after doing this will give some indication of what is going on. What exhaust are you currently running? Have you used DeoxIT on the ECU and FICU. I have just bought the new Deoxit which now comes in two cans, cleaner and a gold coating can. I had run out of the old DeoxIT of which I only had the one can of cleaner. It was given to me many year ago so I'm not sure whether I was missing a can. Even the new DeoxIT failed to fix my 4 pin fuel pump connector that had only ever had one problem in twenty years.
Regards Martin.
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If it was running rich it would start without having to advance the fast idle. Read up on how to do a plug chop. Take the bike up to where it is miss firing and shut her down as per the plug chop instructions. You might have to do it a couple of times to get the hang of it. Do this on a quiet road somewhere where you can push it safely to a place where you can work on i it. A back up vehicle is handy to act as a buffer. Hopefully reading the plugs after doing this will give some indication of what is going on. What exhaust are you currently running? Have you used DeoxIT on the ECU and FICU. I have just bought the new Deoxit which now comes in two cans, cleaner and a gold coating can. I had run out of the old DeoxIT of which I only had the one can of cleaner. It was given to me many year ago so I'm not sure whether I was missing a can. Even the new DeoxIT failed to fix my 4 pin fuel pump connector that had only ever had one problem in twenty years.
Regards Martin.
Sorry for the late reply Martin,
Yes, I have used Deoxit on both the ECU and FICU. This exhaust is custom-made by Iron Cobra Fabrication in Long Beach, CA. It uses a 18" Cone Engineering muffler. If you want more information on it, here is a catalog of their pre-fabricated products, http://www.coneeng.com/pdf/motorcycle/MC-finished-Mufflers.pdf. I did a plug chop earlier, the color of the plug seemed fine. I also just install brand new NGK plug wires. As of recent after installing the new water temp sensor, the bike runs great once warm, no misfires at cruising anymore. However, it really struggles with start up, I need to turn the fuel advance up all the way and hold down the ignition button for a few seconds for it able to maintain idle.
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It probably needs to have the mixture set. The next test is a really cool feature on 2V bricks. If you have the bike idling at 1000rpm once warmed up, press the green starter button. If the mixture is correct the revs need to stay the same or rise slightly, if they rise significantly or drop the mixture needs adjusting. Either get access to a exhaust gas analyser or look up lean drop method on this site.
Regards Martin.