Ignition timing
Thread Starter
|
Advanced
Joined: Aug 2022
Posts: 63
Likes: 4
From: Massachusetts
Ignition timing
I installed a ultima ignition module in my 1988 Harley Davidson Sportster XLH 883 and for some reason I cant get the red light on the module to come on at TDC and I believe the vertical line is TDC for twin cams and Im on the compression stroke on the front cylinder but no matter where I rotate it I cant get the light to come on. Also I tried eye balling the module to where the old module was at and the bike runs when the choke is all out a bit but all the way in the bike dies, and kinda get a weird gas smell when it runs. What am I doing wrong?
Road Master
Joined: Jun 2013
Posts: 1,239
Likes: 1,171
From: St. Catharines, Ontario
Strange the LED wont illuminate, but the fact that it started and is running on 2 cylinders is encouraging. try advancing it slightly and see if there's an improvement. Not sure how long the bike was running before video started but you may have closed the enrichener too soon. gradually squeeze it off to maintain idle ( I think there are 4 steps)
Thread Starter
|
Advanced
Joined: Aug 2022
Posts: 63
Likes: 4
From: Massachusetts
So should I set it to the dot for timing?
Road Master
Joined: Jun 2013
Posts: 1,239
Likes: 1,171
From: St. Catharines, Ontario
Have you negated the VOES? I would until this is sorted. I would also set it to dual fire. Follow the ultima instructions.
How much advance does the unit provide? 32.5 degrees?
I believe your machine wants 7.5 at idle and 40 for full advance@2000 rpm.
The "I" is front TDC so to static time, you want a spark just as the mark appears in the timing hole.
When this is sorted get it confirmed with a timing light and when at 2000 rpm you should see the dot center of the hole.
How much advance does the unit provide? 32.5 degrees?
I believe your machine wants 7.5 at idle and 40 for full advance@2000 rpm.
The "I" is front TDC so to static time, you want a spark just as the mark appears in the timing hole.
When this is sorted get it confirmed with a timing light and when at 2000 rpm you should see the dot center of the hole.
Trending Topics
HDF Community Team
Joined: Dec 2011
Posts: 8,550
Likes: 3,975
From: San Diego, CA
Cutting out when choke pushed in seems like a possible pilot jet/idle mixture issue. Have you checked your carburetor for problems? I work on a lot of used dirt bikes, and clogged idle systems in the carb usually exhibit the same symptoms as you describe.
I would also double check whether you are on compression TDC when setting your timing. I thought the mark should be centered in the timing hole at TDC.
John
I would also double check whether you are on compression TDC when setting your timing. I thought the mark should be centered in the timing hole at TDC.
John
Last edited by John Harper; Jul 22, 2023 at 10:45 AM.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Thread Starter
|
Advanced
Joined: Aug 2022
Posts: 63
Likes: 4
From: Massachusetts
Have you negated the VOES? I would until this is sorted. I would also set it to dual fire. Follow the ultima instructions.
How much advance does the unit provide? 32.5 degrees?
I believe your machine wants 7.5 at idle and 40 for full advance@2000 rpm.
The "I" is front TDC so to static time, you want a spark just as the mark appears in the timing hole.
When this is sorted get it confirmed with a timing light and when at 2000 rpm you should see the dot center of the hole.
How much advance does the unit provide? 32.5 degrees?
I believe your machine wants 7.5 at idle and 40 for full advance@2000 rpm.
The "I" is front TDC so to static time, you want a spark just as the mark appears in the timing hole.
When this is sorted get it confirmed with a timing light and when at 2000 rpm you should see the dot center of the hole.
Road Captain
Joined: Mar 2009
Posts: 654
Likes: 734
I installed a ultima ignition module in my 1988 Harley Davidson Sportster XLH 883 and for some reason I can’t get the red light on the module to come on at TDC and I believe the vertical line is TDC for twin cams and I’m on the compression stroke on the front cylinder but no matter where I rotate it I can’t get the light to come on. Also I tried eye balling the module to where the old module was at and the bike runs when the choke is all out a bit but all the way in the bike dies, and kinda get a weird gas smell when it runs. What am I doing wrong?
One of those TDC's is between the exhaust stroke and the intake stroke ("overlap tdc"). That's not the one you want. The timing LED isn't going to behave correctly if you're on overlap TDC.
The other TDC is between the compression stroke and the power stroke ("compression tdc"). That's where you need to be, in order to static time the motor
So if you just put the vertical line in the window, without knowing which TDC you're at, you have a 50-50 chance of being on overlap TDC instead of compression TDC. Rotate the motor one full rotation and try again.
We see guys make this same mistake all the time when adjusting their adjustable pushrods. When you adjust your pushrods at overlap TDC, you end up with a lot of slack in the valve train, causing noise and generally galling the hell out of the valve tips. We've even seen guys who've done this then go trashing their head porting shop online, claiming they were sold defective parts. One of many reasons we put guys into non-adjustable pushrods and provide instructions for checking their lengths during assembly. Making things more foolproof doesn't stop every fool, but it helps.
But I digress. The answer to your question is turn the motor one complete revolution and try again.
Also make sure your key is on, and your run/stop switch (on the handlebar is on). The latter being another common reason for the LED not coming on.
Last edited by aswracing; Jul 22, 2023 at 11:36 AM.