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11-20-2012, 11:42 PM
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#16 (permalink)
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IronButt
Join Date: Oct 2012
Location: Oregon
Posts: 223
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I read that the Mikuni requires vacuum to pull fuel into the bowl. I thought it was gravity-feed.
__________________
1972 Superglide FX: Rebuilt, Super E, Drag pipes (FOR SALE PM ME)
2005 Sportster 1200: Thunderheader, SE ICM, SE carb upgrades, pretty stuff
1985 FXRS-SP: (looks VERY different than the pic. More black now) Dyna 2000 ICM, Twin Tec II Single Fire, Mikuni 42mm, S&S intake, Progressive springs, need money for Thunderheader and mid-controls! Have lot's to trade and $ if you have one for my bike!
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11-21-2012, 01:52 AM
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#17 (permalink)
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IronButt
Join Date: Oct 2012
Location: Oregon
Posts: 223
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Could this also be a timing issue? I didn't adjust the timing after my Dyna ICM because it said if your timing was good before the install that it should be good.
Thanks
__________________
1972 Superglide FX: Rebuilt, Super E, Drag pipes (FOR SALE PM ME)
2005 Sportster 1200: Thunderheader, SE ICM, SE carb upgrades, pretty stuff
1985 FXRS-SP: (looks VERY different than the pic. More black now) Dyna 2000 ICM, Twin Tec II Single Fire, Mikuni 42mm, S&S intake, Progressive springs, need money for Thunderheader and mid-controls! Have lot's to trade and $ if you have one for my bike!
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11-21-2012, 05:06 AM
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#18 (permalink)
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IronButt
Join Date: Oct 2008
Location: Aussy
Posts: 536
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The mikuni is like any other carb in that it uses a float in the bowl to regulate the fuel level in he bowl - Vacuum does not even come into the discussion.
You seem to be all over the place with this problem....
You really need to slow down and check the basics like the ignition timing and jetting. Once you have a baseline picture you sand a way better chance of success.
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I prefer my engine blown not stroked!
D.L.R.A #1174
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11-21-2012, 07:09 AM
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#19 (permalink)
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Lifetime Premium
Join Date: May 2011
Location: Joliet IL
Posts: 495
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I'd get rid of the filter, at least until you've got it running
Do a google search for mikuni hsr42 tuning manual, that will get you a good reference and the exploded view. Big help when dealing with these.
A/f screw is on a/c side facing rider. Easy to get to even with the a/c on. Idle adjust is the big black cable hanging down with what looks like a Phillips head screw stuck in the end.
Once you have the jets set up like I posted (at this point even a 165 main is ok, which is what it should have shipped with ), and the screw set 1 turn, you can try increasing the idle a turn. See where that gets you.
If all this fails, id recheck the setup on the dyna2k, or even swap in the factory ignition just to try it out.
Beyond that, i would think it's a fuel delivery issue, so besides the filter check for any sharp bends in the line, and crack the gas cap loose in case the vent is causing issues (doubtful tho)
__________________
'03 FXSTB -Wild One WO500's, D&D Lowcat, Corbin Hollywood solo, 3.5" extended Fwd controls, Mikuni HSR42.
'94 FXR Superglide - In progress
Last edited by Blackened; 11-21-2012 at 07:12 AM.
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11-21-2012, 07:21 AM
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#20 (permalink)
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Lifetime Premium
Join Date: May 2011
Location: Joliet IL
Posts: 495
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Quote:
Originally Posted by tussuck
You really need to slow down and check the basics like the ignition timing and jetting. Once you have a baseline picture you sand a way better chance of success.
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This is good advice, I would add that in the future add your mods one at a time, that way if there's an issue, you know exactly whats causing it.
__________________
'03 FXSTB -Wild One WO500's, D&D Lowcat, Corbin Hollywood solo, 3.5" extended Fwd controls, Mikuni HSR42.
'94 FXR Superglide - In progress
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11-21-2012, 08:07 AM
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#21 (permalink)
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Seasoned Rider
Join Date: Feb 2005
Location: DFW, TX
Posts: 55
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You do have the Mikuni purge fitting (used with emissions kit only) capped off, correct? It's the nipple directly below where the enrichener cable connects to the carb.
Last edited by cpmike; 11-21-2012 at 08:10 AM.
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11-21-2012, 11:05 AM
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#22 (permalink)
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IronButt
Join Date: Mar 2011
Location: PA
Posts: 1,814
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The VOES vacuum connection is just to any manifold vacuum source. As opposed to a ported source. At this point it's not relevant, just unplug it.
Start the scooter, just as it starts to stall, give it a spray of carb cleaner, if it revs up, you are way skinny on fuel.
So start it again and with the palm of your hand, choke the crap out of it. See if you can keep it running. If it will run, then you need more fuel or less air. Double check for a huge vacuum leak. If not, clear your calendar for the afternoon.
Pull the fuel line and make sure the line flows freely. Then pull the carb. Pull the bowl and make sure the float is set correctly and that the valve flows freely. It's messy, but I'd put the carb back in place with the bowl off and reconnect the fuel line. Open the petcock and see if it flows. It wouldn't be the first one I ever saw where the line internally kinked when the carb was bolted up.
Check the jet sizes, the list above looks good. I'm sure there are internet sites with starting jet lists.
Spray carb cleaner into each jet and verify that it sprays through into the bore.
Just for shitsandgiggles make sure the slide moves, and seats properly.
At this point, it's time for an expert. You'll be checking for drill through errors, blocking plugs, casting defects and such. With no prior experience with that carb, or any other the way I read it, you will be in over your head.
With that said, I'll bet that an old 38mm side draft would look good about now
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"All mankind is divided into three classes: those that are immovable, those that are movable, and those that move."
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11-21-2012, 11:51 AM
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#23 (permalink)
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Lifetime Premium
Join Date: May 2011
Location: Joliet IL
Posts: 495
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+1 to thermodyne for great garage style advice
Tbh I used the mik because I had it, and I'm a stubborn bastard, so I resolved to learn it inside and out and MAKE it work, and that being said, it's a little sensitive to hot/cold weather but it works very good.
If I had it to do over again I probably would have just gone with a super E. Very easy carb, basically set it and forget it.
Just my .02
__________________
'03 FXSTB -Wild One WO500's, D&D Lowcat, Corbin Hollywood solo, 3.5" extended Fwd controls, Mikuni HSR42.
'94 FXR Superglide - In progress
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11-21-2012, 10:23 PM
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#24 (permalink)
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IronButt
Join Date: Oct 2012
Location: Oregon
Posts: 223
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I put a Super E on my shovelhead and it was a breeze. Nothing beats these Mikunis for throttle response in my opinion. I am going to time the bike soon as my first step. I turned the idle screw all the way in and backed it off a few turns. Still no dice. HOping it's something easy here soon.
__________________
1972 Superglide FX: Rebuilt, Super E, Drag pipes (FOR SALE PM ME)
2005 Sportster 1200: Thunderheader, SE ICM, SE carb upgrades, pretty stuff
1985 FXRS-SP: (looks VERY different than the pic. More black now) Dyna 2000 ICM, Twin Tec II Single Fire, Mikuni 42mm, S&S intake, Progressive springs, need money for Thunderheader and mid-controls! Have lot's to trade and $ if you have one for my bike!
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11-21-2012, 10:27 PM
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#25 (permalink)
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IronButt
Join Date: Oct 2012
Location: Oregon
Posts: 223
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I also have the tuning manual, and it doesn't tell you where the standards or "0's" are. Like turn this knob all the way to the right and then left two full terms. I could have had a 2 year old mess with all of these settings and I would really not have an idea where they are suppose to be set from the factory.
__________________
1972 Superglide FX: Rebuilt, Super E, Drag pipes (FOR SALE PM ME)
2005 Sportster 1200: Thunderheader, SE ICM, SE carb upgrades, pretty stuff
1985 FXRS-SP: (looks VERY different than the pic. More black now) Dyna 2000 ICM, Twin Tec II Single Fire, Mikuni 42mm, S&S intake, Progressive springs, need money for Thunderheader and mid-controls! Have lot's to trade and $ if you have one for my bike!
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11-21-2012, 11:10 PM
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#26 (permalink)
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IronButt
Join Date: Oct 2012
Location: Oregon
Posts: 223
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Quote:
Originally Posted by cpmike
You do have the Mikuni purge fitting (used with emissions kit only) capped off, correct? It's the nipple directly below where the enrichener cable connects to the carb.
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Isn't that vent suppose to be open for fuel overflow? Had a tube on it and ran it to the bottom of my frame to drain.
__________________
1972 Superglide FX: Rebuilt, Super E, Drag pipes (FOR SALE PM ME)
2005 Sportster 1200: Thunderheader, SE ICM, SE carb upgrades, pretty stuff
1985 FXRS-SP: (looks VERY different than the pic. More black now) Dyna 2000 ICM, Twin Tec II Single Fire, Mikuni 42mm, S&S intake, Progressive springs, need money for Thunderheader and mid-controls! Have lot's to trade and $ if you have one for my bike!
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11-22-2012, 12:12 AM
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#27 (permalink)
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Lifetime Premium
Join Date: May 2011
Location: Joliet IL
Posts: 495
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Quote:
Originally Posted by Krowbar
Isn't that vent suppose to be open for fuel overflow? Had a tube on it and ran it to the bottom of my frame to drain.
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purge vent is in the back, cap is #83 on this diagram. Should be a black cap on it from factory.
http://www.mikuni.com/pdf/tm42xview121801.pdf
Think it's about time to check your ign timing though
__________________
'03 FXSTB -Wild One WO500's, D&D Lowcat, Corbin Hollywood solo, 3.5" extended Fwd controls, Mikuni HSR42.
'94 FXR Superglide - In progress
Last edited by Blackened; 11-22-2012 at 12:15 AM.
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11-22-2012, 10:32 AM
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#28 (permalink)
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Seasoned Rider
Join Date: Nov 2007
Location: Pompano Beach FL
Posts: 68
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Could be as simple as did you set the Dyna 2000 correctly? As in single fire vs dual fire? Why is the bowl vent pissing fuel? Fuel air spark = bang. Something is missing from that equation. Make sure both sides of the coil are firing. Just pull the plug wire off the plug and stick a screwdriver in. Hold the metal and crank it over. You will know for sure if the coil is firing. Try one cylinder at a time.
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I`m never serious, Seriously
There is a very fine line between "hobby" and "mental illness
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11-22-2012, 01:19 PM
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#29 (permalink)
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IronButt
Join Date: Oct 2012
Location: Oregon
Posts: 223
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Quote:
Originally Posted by crankyoldguy
Could be as simple as did you set the Dyna 2000 correctly? As in single fire vs dual fire? Why is the bowl vent pissing fuel? Fuel air spark = bang. Something is missing from that equation. Make sure both sides of the coil are firing. Just pull the plug wire off the plug and stick a screwdriver in. Hold the metal and crank it over. You will know for sure if the coil is firing. Try one cylinder at a time.
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I think I'll just see if I can get the spark to arc on the head or something... haha
I need to time the bike I think. I have to wait for my rear wheel to get back from the powder coater so I can use to help find TDC easier. Timing could very well be the issue. It only cranks and fires for a second and the bike shakes a little. Could be timing. Hopefully so. I only put 50 miles on my FXR before i started its winter makeover... haha
__________________
1972 Superglide FX: Rebuilt, Super E, Drag pipes (FOR SALE PM ME)
2005 Sportster 1200: Thunderheader, SE ICM, SE carb upgrades, pretty stuff
1985 FXRS-SP: (looks VERY different than the pic. More black now) Dyna 2000 ICM, Twin Tec II Single Fire, Mikuni 42mm, S&S intake, Progressive springs, need money for Thunderheader and mid-controls! Have lot's to trade and $ if you have one for my bike!
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11-22-2012, 01:38 PM
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#30 (permalink)
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IronButt
Join Date: Oct 2012
Location: Oregon
Posts: 223
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Quote:
Originally Posted by Blackened
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My Mikuni doesn't have that purge vent. What's this mean? haha
__________________
1972 Superglide FX: Rebuilt, Super E, Drag pipes (FOR SALE PM ME)
2005 Sportster 1200: Thunderheader, SE ICM, SE carb upgrades, pretty stuff
1985 FXRS-SP: (looks VERY different than the pic. More black now) Dyna 2000 ICM, Twin Tec II Single Fire, Mikuni 42mm, S&S intake, Progressive springs, need money for Thunderheader and mid-controls! Have lot's to trade and $ if you have one for my bike!
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