YouTube video - carb issue
06-12-2010, 09:05 AM
#1
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YouTube video - carb issue
This is a video of the issue i am having with the Hawk. The qaulity is not the greatest but hopefully you can get an idea. Notice the difference from smooth roll-ons and blipping the throttle. Its like a stumble of some sort. I shimmed the needles +1,+2,back to oem, Numerous air/fuel settings for each,checked the slide boots for damage and proper install,all hoses in the right place(no pvlir)air box tight,v-stacks correct,and i have covered just about everything i thought.(apparently im missing something
) Picking up new plugs shortly. Good gas in the tank. mj's are clean. Slides operate smoothly and i hear the air being moved in and out. TPS done and synch performed. Sych hoses all buttoned up properly. I am at a loss fellas.
http://www.youtube.com/watch?v=e-5z_wukaj0
) Picking up new plugs shortly. Good gas in the tank. mj's are clean. Slides operate smoothly and i hear the air being moved in and out. TPS done and synch performed. Sych hoses all buttoned up properly. I am at a loss fellas.http://www.youtube.com/watch?v=e-5z_wukaj0
06-12-2010, 09:13 AM
#2
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Check your plug wires too. I had one come loose at about 40k miles. Caused all kinds of fits for me. It had loosened up at the boot. They screw on. I had been arcing across some gap for probably 500 miles or more, bike running like crap the whole time.
Did you ever install a Factory or Dynojet kit on the bike? Are you on a stock filter or aftermarket? Some bikes just don't like anything but a stock filter. I was the exception and had no problems tuning mine.
Sounds to me like the slides aren't lifting quickly or soon enough. That could be a vacuum problem somewhere.
"It ran great all the way up until ___________________________." Please fill in the blank.
Did you ever install a Factory or Dynojet kit on the bike? Are you on a stock filter or aftermarket? Some bikes just don't like anything but a stock filter. I was the exception and had no problems tuning mine.
Sounds to me like the slides aren't lifting quickly or soon enough. That could be a vacuum problem somewhere.
"It ran great all the way up until ___________________________." Please fill in the blank.
06-12-2010, 09:29 AM
#3
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Check your plug wires too. I had one come loose at about 40k miles. Caused all kinds of fits for me. It had loosened up at the boot. They screw on. I had been arcing across some gap for probably 500 miles or more, bike running like crap the whole time.
Did you ever install a Factory or Dynojet kit on the bike? Are you on a stock filter or aftermarket? Some bikes just don't like anything but a stock filter. I was the exception and had no problems tuning mine.
Sounds to me like the slides aren't lifting quickly or soon enough. That could be a vacuum problem somewhere.
"It ran great all the way up until ___________________________." Please fill in the blank.
Did you ever install a Factory or Dynojet kit on the bike? Are you on a stock filter or aftermarket? Some bikes just don't like anything but a stock filter. I was the exception and had no problems tuning mine.
Sounds to me like the slides aren't lifting quickly or soon enough. That could be a vacuum problem somewhere.
"It ran great all the way up until ___________________________." Please fill in the blank.
) It ran good,not great id say, but strong before i pulled the slides to shim the needles. I pulled the air box, lifted the carbs from the boots, removed the slides(pita on the front) pulled the needles,shimmed, put all back together,synch, and then problem. Pulled carbs completely after that,slotted the mixture screw,adjusted 2.25 out, put it all back and still the same. Choke out still the same. It has to be a vacuum problem?(gotta pick up plugs and some other stuff-thanks for the responses-be back shortly)
Last edited by dshakes; 06-12-2010 at 09:32 AM.
06-12-2010, 03:52 PM
#5
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I have been chasing a single cylinder misfire for weeks, and finally got it. You have to go down the checklist, seems like you are almost there and have the tough stuff done. This is what I did.
I did find that my vacuum port cap was off the front cylinder, but replacing it did not fix the problem or make it run any better. It probably did not come off until I started messing with the motor, as I had a 8" long vacuum hose and plug on it. I cannot imagine it was off since the last time I rode the bike, it rode perfect for a 200 mile trip.
What I think finally fixed the problem was #9, I had corrosion in one of the choke cables that was preventing it seating the needle fully and it was playing havoc with the motor trying to run with one cylinder on partial choke, one not. My choke cable was kind of hard to pull out, that should have been a big hint to me.
There could have been something in the carb passages as well. I also found my idle mixture screws were not set the same since the last time I adjusted them, my piece of crap d-shaped screw tool that came with the dynojet rounded itself and was not actually turning the d-shaped screw head but felt like it was. I had been running it like that for a year so it was not the problem, but it sure idles smoother now.
It runs great now, eventhough I have not yet synched the carbs again.
- Diaphram in petcock-take out and look for pinholes in light. Check in tank filter too.
- Clean air vent tube in tank, over flow tubes from carbs.
- check, clean, or cut fresh connections on all vacuum hoses especially one on petcock.
- Check spark plug boots. I found my misfiring cylinder had a lot of corrosion between wire and boot where boot screwed onto wire. I cut 1/2" off wire and used my spare new boot to get a pristine connection.
- Check electrode on spark plug for cracks.
- Clean grounds on coils.
- Carbs off, all jets out, cleaned with spray solvent & compressed air, check slides/diaphrams for pinholes. Check floats for cracks, needle seat on float operated smoothly.
- Check cylinder to carb boots for cracks/holes/overtightened or hard rubber.
- Unscrew choke cable from carbs, clean passages, needles, and lube cable.
- Check TPS, at idle and full throttle.
I did find that my vacuum port cap was off the front cylinder, but replacing it did not fix the problem or make it run any better. It probably did not come off until I started messing with the motor, as I had a 8" long vacuum hose and plug on it. I cannot imagine it was off since the last time I rode the bike, it rode perfect for a 200 mile trip.
What I think finally fixed the problem was #9, I had corrosion in one of the choke cables that was preventing it seating the needle fully and it was playing havoc with the motor trying to run with one cylinder on partial choke, one not. My choke cable was kind of hard to pull out, that should have been a big hint to me.
There could have been something in the carb passages as well. I also found my idle mixture screws were not set the same since the last time I adjusted them, my piece of crap d-shaped screw tool that came with the dynojet rounded itself and was not actually turning the d-shaped screw head but felt like it was. I had been running it like that for a year so it was not the problem, but it sure idles smoother now.
It runs great now, eventhough I have not yet synched the carbs again.
06-12-2010, 04:17 PM
#6
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my vote, bad coil. If it happens that quickly, you will be able to pinpoint which cylinder by pipe temp. Get an infrared heat gun and take some measurements while this is occurring and see which cylinder is colder (measuring temp of head pipe). Just my 2 cents.
06-13-2010, 01:01 AM
#8
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Thanks for all of the recommendations guys. Im at my wits end with this problem. To the point of sitting there staring at the carbs and trying like hell to think of what i am missing. TJ, I will run that checklist and see if anything comes up. Thanks man. zmaniv, I have the synch fitting in the front cylinder vacuum hole with a plugged vacuum hose attached. Autoteach, i will see what i can do about an infrared gun and try to get some results. Again, thanks for all of your help guys.
06-13-2010, 02:53 AM
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It appears that there is not enough gas, or too much air.
1. check that the PAIR removal is complete, plug the line from the front carb, use a screw, silicone and a clamp on the end of the hose. Plug hole in airbox. A 5/8 rubber chair leg tip works well for this. Use block off plates on the valve covers, get them from the classifieds - they are the best and cheapest at $15 shipped.
2. remove all sync tubes, just to rule this out. Put the allen screw back in the front sync hole use thread sealer, put the rear cylinder / petcock hose back in place, use a fresh (new) hose. No "T" joints.
3. be sure that all hoses are attached properly, especially the petcock hoses and tank hoses. You may also check the petcock diaphram, but I do not think that is it, but maybe.
see if that works
4. remove the subfilters foam (just to rules this out)
5. remove the air filter element (just to rules this out)
see if that works
6. re-clean out carbs, including slides, check for free movement (do not replace subfilter foam yet)
7. I do not think this is a jetting issue, but return jetting to stock, again, just to rule this out
8. I do not think this is a TPS issue, but recheck for 500 Ohms, the TPS should be rotated almost all the way counter clockwise.
9. check the choke cables. There is a 1-to-2 junction under the carbs. Sometimes the outer cable housings can get pulled from the fittings, causing the choke (ok enrichment circuit) to be on all the time.
see if that works
10. see who lives near by that can help.
JB
06-13-2010, 06:51 AM
#12
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I am sorry, I didn't read close enough (I know, dont say it) and thought that it was an intermittent problem. Make sure that the cvs are moving properly, not "smoothly" which is a measure using ones finger, by blasting some air at the passages that lift the slide. If you have a cv boot pinched, you may not be getting the slide movement you want, even though it is moving freely. The guys have given you a laundry list of items to check (because they read clearly) and I would just run through everything they have for you.
06-13-2010, 07:02 AM
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I ordered the joint boost fitting from bike bandit and screwed it into the front cylinder fo carb synch purposes. I ran a piece of vacuum hose to the left side of the bike and plugged it with a cap while not in use. I attached the hose with a zip tie to the joint boost. It seems good and tight. I cut the rear cylinder hose and inserted a "T" fitting and capped it off when not in use.
06-13-2010, 07:09 AM
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I am sorry, I didn't read close enough (I know, dont say it) and thought that it was an intermittent problem. Make sure that the cvs are moving properly, not "smoothly" which is a measure using ones finger, by blasting some air at the passages that lift the slide. If you have a cv boot pinched, you may not be getting the slide movement you want, even though it is moving freely. The guys have given you a laundry list of items to check (because they read clearly) and I would just run through everything they have for you.
Thanks for the recommendations. I will sit today and go through everything and see what happens. Thanks guys.
06-13-2010, 07:40 AM
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I ordered the joint boost fitting from bike bandit and screwed it into the front cylinder fo carb synch purposes. I ran a piece of vacuum hose to the left side of the bike and plugged it with a cap while not in use. I attached the hose with a zip tie to the joint boost. It seems good and tight. I cut the rear cylinder hose and inserted a "T" fitting and capped it off when not in use.
06-13-2010, 01:23 PM
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I have put everything back to its origanal state. I put myear to the air box and it just sounds like the vacuum is out of wack somehow. I am 100% sure the diaphrams are seated correctly. They have to be. I dont know. It seems also that the right side exhaust is warmer than the left. I know Hawkrider rider said due to jetting differences they will be slightly different but i dont know? Another video maybe to drum up some ideas? http://www.youtube.com/watch?v=0WztitYpQFM
06-13-2010, 03:41 PM
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I may not be understanding your problem but... In your second video you say you are watching the slides move as it's running. I assume you are running it with the airbox off? This creates an extremely lean condition which Will not allow it rev freely. If you're getting the same results with the Devil pipes but with the air box on then you are still having the same issue. Those pipes are huge and flow very well. Moving that much air will require larger main jets.
06-13-2010, 03:59 PM
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These are great videos - very helpful. So when you put the airbox back on with no filter and no subfilter, and start it up, it behaves the same as before? Then put the filters in and try it - same thing?
What number check are you up to on my list?
Side question: what kind of CCTs are those and when did you install them? If my list does not cover it, you may need to check for a jumped cam chain, but that is not for a while yet.
What number check are you up to on my list?
Side question: what kind of CCTs are those and when did you install them? If my list does not cover it, you may need to check for a jumped cam chain, but that is not for a while yet.
06-13-2010, 04:01 PM
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I may not be understanding your problem but... In your second video you say you are watching the slides move as it's running. I assume you are running it with the airbox off? This creates an extremely lean condition which Will not allow it rev freely. If you're getting the same results with the Devil pipes but with the air box on then you are still having the same issue. Those pipes are huge and flow very well. Moving that much air will require larger main jets.
I am still working on it feverishly. Leaving friday for cherohala and deals gap for a nice long 4 day vacation. Need the Hawk running at least good. Thanks for the info inderocker.
06-13-2010, 04:22 PM
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Airbox on, the carbs reset yes, but i did not put the stock mufflers back on. Let me try that and see what i get. I just dont remember it acting up like that even after i put the devils on. Although i did notice a change in the torque curve from the more free flowing pipes. It was running lean to begin with from de-baffled oems. I will take that to the drawing board and see what happens. Thanks Daniel.
Do you know the stock setting for the air/fuel mixture screws? How many turns out? Like a dumb*#s i forgot to record them before i changed it.
Do you know the stock setting for the air/fuel mixture screws? How many turns out? Like a dumb*#s i forgot to record them before i changed it.
Last edited by dshakes; 06-13-2010 at 04:28 PM.
06-13-2010, 04:39 PM
#23
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I had a cv boot out over 1/2" and the slides moved nearly identical. I had to go back in because it wouldn't take throttle like it should. Not saying it was your problem, but that despite my efforts and experience, I had it happen and could not tell a difference between the slides moving by my own hand.
06-13-2010, 04:50 PM
#24
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I had a cv boot out over 1/2" and the slides moved nearly identical. I had to go back in because it wouldn't take throttle like it should. Not saying it was your problem, but that despite my efforts and experience, I had it happen and could not tell a difference between the slides moving by my own hand.
06-13-2010, 05:01 PM
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The technique that I use is:
1. get the spring fully compressed into the cap
2. Insert cap and slide into carb, catching the slide so the spring doesn't shoot out
3. Gently work slide up and down with light pressure on the cap. The pressure will push the boot into the groove.
4. Very carefully check to make sure it is in place.
5. Screw down cap
6. You can verify for a leak by pressurizing the atmospheric vent (use your mouth- otherwise you can tear boot)
1. get the spring fully compressed into the cap
2. Insert cap and slide into carb, catching the slide so the spring doesn't shoot out
3. Gently work slide up and down with light pressure on the cap. The pressure will push the boot into the groove.
4. Very carefully check to make sure it is in place.
5. Screw down cap
6. You can verify for a leak by pressurizing the atmospheric vent (use your mouth- otherwise you can tear boot)
06-13-2010, 05:32 PM
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06-13-2010, 05:57 PM
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These are great videos - very helpful. So when you put the airbox back on with no filter and no subfilter, and start it up, it behaves the same as before? Then put the filters in and try it - same thing?
What number check are you up to on my list?
Side question: what kind of CCTs are those and when did you install them? If my list does not cover it, you may need to check for a jumped cam chain, but that is not for a while yet.
What number check are you up to on my list?
Side question: what kind of CCTs are those and when did you install them? If my list does not cover it, you may need to check for a jumped cam chain, but that is not for a while yet.
