carb issues
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5th Gear
Joined: Sep 2009
Posts: 9
Likes: 0
carb issues
just got an 83 ironhead,finally got it started and running but the carb is giving me problems.I got it to idle but when i hit the gas quick it wants to shut off and pop.If i qive it throttle gradually it will rev to a point and then start popping and cutting out again,also when i go it gradually the rpm come back down slow.I think its just this carb sucks,its a keihin not sure what model.I plan on getting an s&s carb does anyone have any suggestions on whatelse to get?
I like to try and get it to run rite with this carb so any help would be appreciated!
I like to try and get it to run rite with this carb so any help would be appreciated!
Tourer
Joined: Sep 2007
Posts: 400
Likes: 1
From: se ohio
you need to check for vacuum leak check the intake real good for leaks, check for good fuel flow into the carb,if you are going to change carbs go with a newer cv carb, i believe the ones you want are from 94 to 2003 or so alot cheaper than a s&s
Here are my notes on checking for intake and exhaust leaks. I never use anything except propane for the intake leaks test any more. It is absolutely essential that the engine be free of these problems before doing any other tune up operations.
Intake And Exhaust Leaks Tests
You cannot get a good tuneup if there are intake leaks or exhaust leaks.
1. Check for Intake Leaks
With the engine idling spray WD-40 or propane gas around the carb/intake/cylinder head joints. WD-40 is said to work well because it has very fine spray droplets. Propane is best because it leaves no mess, and is most easily sucked in thru leaks. Be careful to not allow any of either to get sucked in thru the A/C as this will invalidate the results.
Any change in engine RPM is a leak which must be fixed.
EDIT: Experience is that this procedure will identify larger intake leaks, but it may miss very small leaks that also must be fixed. And that propane is definetly the better choice.
2. Check for Exhaust Leaks
Pour about 1/2 ounce of oil into each cylinder thru the spark plug holes. Run the engine at idle. You will get lots of smoke for about 5 minutes.
All smoke should come from the ends of the exhaust pipes/mufflers. Any other is a leak which must be fixed.
Intake And Exhaust Leaks Tests
You cannot get a good tuneup if there are intake leaks or exhaust leaks.
1. Check for Intake Leaks
With the engine idling spray WD-40 or propane gas around the carb/intake/cylinder head joints. WD-40 is said to work well because it has very fine spray droplets. Propane is best because it leaves no mess, and is most easily sucked in thru leaks. Be careful to not allow any of either to get sucked in thru the A/C as this will invalidate the results.
Any change in engine RPM is a leak which must be fixed.
EDIT: Experience is that this procedure will identify larger intake leaks, but it may miss very small leaks that also must be fixed. And that propane is definetly the better choice.
2. Check for Exhaust Leaks
Pour about 1/2 ounce of oil into each cylinder thru the spark plug holes. Run the engine at idle. You will get lots of smoke for about 5 minutes.
All smoke should come from the ends of the exhaust pipes/mufflers. Any other is a leak which must be fixed.
... when i hit the gas quick it wants to shut off and pop.If i qive it throttle gradually it will rev to a point and then start popping and cutting out again,also when i go it gradually the rpm come back down slow.I think its just this carb sucks,its a keihin not sure what model.I plan on getting an s&s carb does anyone have any suggestions on whatelse to get? ...
The symptoms sound to me like a lean condition, especially the popping. Also it sounds like there is a fuel flow problem, which is possibly causing the lean. Another possibility [probability?] is that the fuel level in the carb is set too low.
First is resolve intake and exhaust leaks. Ask if you want some ideas for this. Then check the in-tank fuel filter. It is probably crudded up. Then check the tank for rust. If it is rusty then cleaning the filter is just a temporary fix. Also if the tank and filter have crud so does the carb. If that is the case ask and i'll provide my carb cleaning notes.
Thread Starter
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5th Gear
Joined: Sep 2009
Posts: 9
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well,i checked everything for leaks,the front header was leaking very little but everything else is sealed up.The choke cable is gone on this thing and it looks like there are 3 or 4 adjustments on the choke if i start closing it it starts idling higher,i think i probibly just need to pull the carb off and clean it,the guy told me he rebuilt the carb but i dunno about that it probibly missing some parts,lol.
Thread Starter
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5th Gear
Joined: Sep 2009
Posts: 9
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i just looked at the gas inside,its brownish color i think its pritty old gas,it has some small spots of rust inside but i havent seen any tank that didnt have alittle bit.i think the gas is stale it doesnt have that "kick"to it when you smell it.he hasnt rode it over a year and a half so it might be bad gas?It fires right up as soon as i hit the button tho
Road Master
Joined: Aug 2006
Posts: 751
Likes: 6
From: 500 miles south from Artic Circle
As IronMick wrote you need to check that "intank" fuel filter, located in petcock. So remove petcock and you find it.
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Replace the old gas with new. Highest octane you can get locally. Also change both primary and engine oils - these will have condensation in them.
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Road Warrior
Joined: Nov 2006
Posts: 1,441
Likes: 789
From: Heart of Dixie
I'd say at least part of your problem is old gas - it doesn't burn well and it could have clogged up your carb jets and passageways. Also, check to see if your accelerator pump shoots a stream of gas into the carb throat when you twist the throttle (doen't have to be running to check this). A stall or stumble when you open the throttle quickly can be a result of your accelerator pump not working. I run a modded stock Keihin on mine and it's a decent carb. Yours probably just needs a good cleaning and possibly some fine tuning.
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5th Gear
Joined: Sep 2009
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i took the tank off today and cleaned all the junk out of it.The tank filter was full of crud but the inline filter was fairly clean,i think this might solve the problem.I put a bunch of pennies in the tank and dumped about a half a quart of wd 40 in the empty tank and sloshed it all around,it cleaned the tank out great all the nasty stuff is gone.After i cleaned the carb(wasnt dirty at all) and repositioned the acc pump jet twards the center of the manifold,the only thing i noticed was the jet was pushing all the fuel at once in like 1/8 of a turn is that to much and not enough past 1/8 throttle?