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Thanks all.
The bike runs ok in it's current configuration. Idles well, plenty of power. The mysteries about the mods has me curious. Maybe I will need to research the engine serial number.
I owned a 98 sportster S- loved it! Yes, duel plug heads due to the lumpy short duration cams- and increased compression. The heads didnt have any screamin eagle designation -(no SE label on script on the heads at all). They were called 'thunderstorm' heads from the factory. I think the OP has modified screaming eagle heads. The 1200S had its own ign module, and it own coil specific to that model. I still have an SE coil and SE ign module (6800 rpm).
No, the Thunderstorm head never came with dual plugs.
What the original poster is describing is "Lightning" heads, which first appeared on the 1996 Buell S1 Lightning (go figure). They have a casting number that ends in -96Y (the "Y" was the designation for Buell parts back in the day).
Lightning heads were the first generation performance heads for the Evo XL platform. Really, though, they were identical to the standard XL1200 hemi heads of the day except some material was added to the chambers, bringing the chamber volumes down to 62cc, as opposed to the 67cc of the 1200 hemi heads. Same valve sizes and same ports as the hemi heads, just smaller chambers is all. These smaller chambers raised the compression ratio to 10:1 when used over the flat top pistons that all the 1200's came with. Standard 1200's with hemi heads were 9:1.
Lightning heads were also offered over-the-counter during that era ...
This was before the "Screamin Eagle" branding was born. Although the Buell version was silver in color, the over-the-counter version was offered in black highlighted as you can see above. This was to sell it to the Sportster crowd, and also to the 1995-1996 Buell S2 which came with a black highlighted motor.
Lightning heads found their way onto Sportsters in 1998, on the 1200S models specifically. They were black highlighted and had a second spark plug, but still the same castings, with the same casting numbers. They were also offered as Screamin Eagle heads at this time, with the SE logo emblazoned on the pushrod side. The SE version came with some bolts to plug the second spark plug hole if the application didn't use them. Same heads as the 1200S models were getting though. 1200S models came with these heads through the end of 1200S production for the 2003 model year.
1998 was also the last year Lightning heads were found on Buells. They were standard equipment on 1998 Buell S1 and M2 models. Still straight silver.
But 1998 S1W and S3 models got the all-new "Thunderstorm" heads, which were a massive improvement over Lightning heads. They had much bigger valves and better ports. Chamber sizes went back to 67cc to make room for the bigger valves, but they were paired with a domed pistons that brought them back to 10:1. Then in 1999 all Buells started getting Thunderstorms, and that continued through the end of Buell tube frame models in 2002.
Then the third generation of factory performance heads came out in 2003, in the form of the Buell XB head. It had even better ports than the Thunderstorms and much better hardware, and a compact, bathtub chamber. These heads found their way onto Sportsters in 2004, on all XL1200 models. They shipped on all XL1200's (with some minor changes in 2007 with EFI) through the end of Evolution Sportster 1200's in 2022.
Last edited by aswracing; May 9, 2023 at 10:23 AM.
This motorcycle confuses me.
How would I find out if it is a Sportster S and how could I tell if it had an engine swap out?
VIN indicates it is a 1999 XL883C but it has the 4 plug Screamin' Eagle head, HAD a Screamin' Eagle Ignition module, Mikuni Carb, a fancy Screamin' Eagle Fork Tweek bar and drag bars that appears OEM.
If your heads have "Screamin Eagle" emblazoned on them, on the pushrod side, then those heads are the over-the-counter version of 1200S Sport heads, what's commonly referred to as "Lightning" heads.
If you ever decide to run 4 plugs, be aware that it massively speeds the burn, and you need to pull about 7 degrees of spark advance across the board, to make it run right and make sure you don't create a detonation issue.
I have dyno tested 2 plugs vs. 4 on several different Evo motors over the years, and never found one iota of extra power. But you do have to pull timing with dual plugs.
So, what heads did my buddy have put on his 883 back in 1990? I'm pretty sure they were dual plugged, but I obviously could be wrong, it's been a long time ago. The dealer did the upgrade so I assume it was HD parts.
No, the Thunderstorm head never came with dual plugs.
What the original poster is describing is "Lightning" heads, which first appeared on the 1996 Buell S1 Lightning (go figure). They have a casting number that ends in -96Y (the "Y" was the designation for Buell parts back in the day).
Lightning heads were the first generation performance heads for the Evo XL platform. Really, though, they were identical to the standard XL1200 hemi heads of the day except some material was added to the chambers, bringing the chamber volumes down to 62cc, as opposed to the 67cc of the 1200 hemi heads. Same valve sizes and same ports as the hemi heads, just smaller chambers is all. These smaller chambers raised the compression ratio to 10:1 when used over the flat top pistons that all the 1200's came with. Standard 1200's with hemi heads were 9:1.
Lightning heads were also offered over-the-counter during that era ...
This was before the "Screamin Eagle" branding was born. Although the Buell version was silver in color, the over-the-counter version was offered in black highlighted as you can see above. This was to sell it to the Sportster crowd, and also to the 1995-1996 Buell S2 which came with a black highlighted motor.
Lightning heads found their way onto Sportsters in 1998, on the 1200S models specifically. They were black highlighted and had a second spark plug, but still the same castings, with the same casting numbers. They were also offered as Screamin Eagle heads at this time, with the SE logo emblazoned on the pushrod side. The SE version came with some bolts to plug the second spark plug hole if the application didn't use them. Same heads as the 1200S models were getting though. 1200S models came with these heads through the end of 1200S production for the 2003 model year.
1998 was also the last year Lightning heads were found on Buells. They were standard equipment on 1998 Buell S1 and M2 models. Still straight silver.
But 1998 S1W and S3 models got the all-new "Thunderstorm" heads, which were a massive improvement over Lightning heads. They had much bigger valves and better ports. Chamber sizes went back to 67cc to make room for the bigger valves, but they were paired with a domed pistons that brought them back to 10:1. Then in 1999 all Buells started getting Thunderstorms, and that continued through the end of Buell tube frame models in 2002.
Then the third generation of factory performance heads came out in 2003, in the form of the Buell XB head. It had even better ports than the Thunderstorms and much better hardware, and a compact, bathtub chamber. These heads found their way onto Sportsters in 2004, on all XL1200 models. They shipped on all XL1200's (with some minor changes in 2007 with EFI) through the end of Evolution Sportster 1200's in 2022.
Thanks for the correction, i knew it was one or the other- i read the article from hammer performance after i posted. It really was a cool bike- i did get some headwork done to it, and had larger valves installed. My 1200S
So, what heads did my buddy have put on his 883 back in 1990? I'm pretty sure they were dual plugged, but I obviously could be wrong, it's been a long time ago. The dealer did the upgrade so I assume it was HD parts.
John
Probably somebody dual-plugged some stock heads. It's not terribly difficult to do.
No he has a four plug head only using two plugs and a two plug coil, with the other two plug holes somehow blocked off. I don't think we are sure it's an 883 or 1200 yet.
We're multitaskers, it's tough sometimes.
John
Last edited by John Harper; May 9, 2023 at 03:38 PM.
Got to looking a little closer at this thing and I'm almost for sure it is a 1200S. VIN: 1HD4CJM12XK115598 Engine S/N: CJMX115598 . What threw me off was when I did a VIN check, it indicated that it was a 883.
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