| Author | Message | ||
     Mark_in_ireland |
Well after a long period of time my 1998 S1 Lightning has been brought back from Ireland and after being worked on by one of the top Irish engine tuners it produces 90rwhp and 90rw lb.ft torque. It has Wisco pistons, gas flowed head with 536 cams (IIRC) and uprated springs etc. It has a 42 Mikuni on and the race module. He didn't believe me when I said the exhaust could be the reason it wasn't making the 100rwhp I wanted. So anyone have any idea what sort of gains can be made by replacing the standard headers and V&K end can with a full Buell Race System?   | ||
| Firemanjim |
Got the dynocharts so we can see fuel curve.90 on torque is good but only 90 hp is down on whay you should have.Is your present exhaust the 2 1/2 collector or the smaller 2" ? If it's the smaller that could be a bottleneck. Jetting and timing adjustments may get it up also.Were you there for the dyno runs and did they do tuning in these areas? | ||
| Blake |
What kind of dyno did they use and are the results corrected, meaning "SAE" or "STD" factored? At what RPM did the dyno run stop and was it run in 4th or 5th gears? Was the operator heavy and sitting full-on the bike? What rear tire pressure? A heavy operator, heck any operator sitting on the bike will rob a significant amount of HP from the engine. Forcing the rear tire to deform severely in order to follow the diameter of the small cylindrical drum takes a significant amount of power away compared to if the rear tire were on a flat surface. Why didn't your question initially garner any response? It may be that it was extremely specific requiring intimate knowledge of your specific engine and exhaust configuration. Without first hand knowledge of such an issue, it might be difficult for most folks to answer? If you can put up a copy of the chart like Jim mentions, that would be great. If that is you can find your way out of the wilderness.  (Message edited by Blake on July 09, 2006) | ||
| Blake |
I agree with Jim in that a bike making 90 FT-LBs ought to be making better peak power than what you are seeing. My cams are tailored for big low-end and mid-range but fall off after 5400 rpm and my 90 FT-LB cyclone with stock 40mm CV carburetor made 100 STD RWHP or around 98 SEA RWHP on a humid day in Louisianna. | ||
| Blake |
I do run an old Brian Nallin 1250 kit though with his ported heads. That with the larger 2.5" header and a Borla CF muffler. |
