Bike runs on.....
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Stellar HDF Member
Joined: Sep 2011
Posts: 3,126
Likes: 1,755
From: In The Woods, PA
Bike runs on.....
You've all seen my threads about the efi to carb conversion on my 98 Ultra. I appreciate all the help and feedback from everyone.
I finally got to spend some time on tweaking the carb and ignition and the bike starts right up, I have it idling right at about 1k rpms when warm. The problem that I am having is that after I turn it off the bike runs on for a couple seconds. Could I have the timing too advanced?
Just to recap. I put an Ultima 53-644 ignition, and H-D VOES, and an S&S Super E Carb (still has he jets that came in it).
Any advice would be appreciated.
Chaz
I finally got to spend some time on tweaking the carb and ignition and the bike starts right up, I have it idling right at about 1k rpms when warm. The problem that I am having is that after I turn it off the bike runs on for a couple seconds. Could I have the timing too advanced?
Just to recap. I put an Ultima 53-644 ignition, and H-D VOES, and an S&S Super E Carb (still has he jets that came in it).
Any advice would be appreciated.
Chaz
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,115
Likes: 7,638
From: Poolville
Hey Chaz, I pretty much run the same setup but with a dyna ignition. I am using curve 3 but I don't run the idle to 1k. I keep it at 850 and no problems at all. Not even on hot days....
Thread Starter
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Stellar HDF Member
Joined: Sep 2011
Posts: 3,126
Likes: 1,755
From: In The Woods, PA
Thanks. You have lots more hp than me! I'm all stock except for a EV-27 cam and muffler pipes. I think I may be hearing some spark knock in the front jug. Maybe I'll just retard the timing a few degrees and see what happens.
Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
You've all seen my threads about the efi to carb conversion on my 98 Ultra. I appreciate all the help and feedback from everyone.
I finally got to spend some time on tweaking the carb and ignition and the bike starts right up, I have it idling right at about 1k rpms when warm. The problem that I am having is that after I turn it off the bike runs on for a couple seconds. Could I have the timing too advanced?
Just to recap. I put an Ultima 53-644 ignition, and H-D VOES, and an S&S Super E Carb (still has he jets that came in it).
Any advice would be appreciated.
Chaz
I finally got to spend some time on tweaking the carb and ignition and the bike starts right up, I have it idling right at about 1k rpms when warm. The problem that I am having is that after I turn it off the bike runs on for a couple seconds. Could I have the timing too advanced?
Just to recap. I put an Ultima 53-644 ignition, and H-D VOES, and an S&S Super E Carb (still has he jets that came in it).
Any advice would be appreciated.
Chaz
Mine does that sometimes when I run regular gas.
It doesn't do it ever when I use super unleaded (93 octain).
Club Member
Joined: Apr 2011
Posts: 5,816
Likes: 7,847
From: SE Louisiana
If it still runs on after dropping some timing, you may have some carbon build up, a few tanks with some MM oil,
or spray some water in the intake followed by seafoam or MM oil and let it soak, change your oil if you do that though.
or spray some water in the intake followed by seafoam or MM oil and let it soak, change your oil if you do that though.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
The running-on is due to something inside the cylinder getting hot enough to ignite the incoming air/fuel mixture. As Schex points out that can be due to a build up of carbon, or more seriously a very hot spark plug or valve.
As for idle, that should be set at the correct speed of around 1,000rpm, not lower. Why? These engines ain't shovels with barn-engine sized flywheels, they need a little extra speed for the crank to rotate at a uniform speed. Lowering idle speed introduces fluctuating crank rotation, with each piston slowing down as it approaches compression, then speeding up as that cylinder fires, etc. If allowed to carry on like that it can introduce damage to the various crank and conrod bearings, as well as making the pistons slap.
As for idle, that should be set at the correct speed of around 1,000rpm, not lower. Why? These engines ain't shovels with barn-engine sized flywheels, they need a little extra speed for the crank to rotate at a uniform speed. Lowering idle speed introduces fluctuating crank rotation, with each piston slowing down as it approaches compression, then speeding up as that cylinder fires, etc. If allowed to carry on like that it can introduce damage to the various crank and conrod bearings, as well as making the pistons slap.
Last edited by grbrown; May 8, 2015 at 11:56 AM.
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Stellar HDF Member
Joined: Sep 2011
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From: In The Woods, PA
I had the top end done just before I decided to do the switch. It has new rings, a fresh hone, and the heads were checked and cleaned. Anyone have contact info for Ulitma? Nothing on the web site.
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From: Picayune, Ms.
I would change spark plugs first to RN12YC's. Set the gap at .038 to .040.
Do this first because it is cheapest route. Then follow grbrown and Schex advice.
You may only need to re-gap the plugs and increase the idle RPM's.
Also make sure the carb is correctly set-up ie: WOT is at the stop, the idle is adjusted properly. This to make sure the engine is using all the circuits in the carb. Start, accelerate, cruse, coast down, and idle. A combined combination of needle adjustment and push/pull cable adjustments. (easy to do and not nearly as complicated as written)
Incoming fuel "cools" the valves, spark plugs; thus preventing "hot spots".
Do this first because it is cheapest route. Then follow grbrown and Schex advice.
You may only need to re-gap the plugs and increase the idle RPM's.
Also make sure the carb is correctly set-up ie: WOT is at the stop, the idle is adjusted properly. This to make sure the engine is using all the circuits in the carb. Start, accelerate, cruse, coast down, and idle. A combined combination of needle adjustment and push/pull cable adjustments. (easy to do and not nearly as complicated as written)
Incoming fuel "cools" the valves, spark plugs; thus preventing "hot spots".