| Author | Message | ||
     Mmmmoto |
I have been going over my new (to me) S2 and found that it has dual (spark) plug heads on it. However, only one plug has a spark plug wire going to it for each cylinder. It seems to run good. It this a problem? It seems to me that both spark plugs should be firing in order to have this beauty run right. What do I do? Help!  | ||
| Ratbuell |
Dual plug heads are aftermarket. Depending on what coil/ignition you have, you may not be able to fire four plugs. It is possible that a PO put on dual plug heads, but left the stock (2-plug) ignition on. | ||
| Stev0 |
HD had dual plug heads on the 1200S sportster from '98 on. They were also in their Flaming Chook catalogue. Using one plug as a blank is fine, if you fire both then you're effectively increasing your advance. If it runs OK, then I'd leave it. you could also put 4 fresh plugs in and try just firing two but try each one and see if it makes any difference | ||
| Buellish |
A machine shop can dual plug stock heads.I've had this done a couple of times in the past. | ||
| Ratbuell |
I guess I should have been clearer. Dual plug heads were not stock for any S2. | ||
| Sportyeric |
As mentioned, the heads probably came off a Sportster Sport and will have a the same design as S1 Lightning heads but with an extra sparkplug that really is just a marketing gimmick. Without spending a fair bit of money buying an aftermarket ignition that will provide dual plug spark (coils and all), you don't need to do anything. Although I wonder if carbon buildup on the non-firing plug might become an issue and whether it would be better to try to find a bolt of appropriate length and thread pitch to replace it. | ||
| Mmmmoto |
Thanks for all of your responses. The heads were purchased new in June 1997 by the previous owner (for $995) and put on the bike when he had about $9k of engine work done (Axtell big bore kit, new rods, trans gears done, etc.) The bike runs great and has BIG power, so I will simply take the extra plugs out and find bolts of suitable length to plug up the holes. Thanx! | ||
| Stev0 |
There is specific blanking plugs available.. Although where you'll find them I'm not sure. The SE version of those heads came with two of those plugs so you could use the heads in either configuration. They need to seal in the same way that a plug does, so be carefull just using a bolt. |
