ninja12
Needs a job
Posts: 3310
|
posted May 22, 2006 05:55 AM
quote:
For What its worth...
I have been running a 1290 with a 125 shot, megacycle cams (100/105 timing) and headwork. I beat the snot out of it every weekend at the dragstrip, and once in a while at Maxton. I overtorque my headbolts by 5 ft lbs and have never had a problem with headgaskets. I even frequently reuse the headgaskets as well. No problems. In contrast I have never been able to keep a cylinder head for longer than 1 season. Spring pressure is now up to 70 lbs and I still manage to drop, float or melt off valves.??? I think the rap against 3mm overbores comes from the Busa guys. They have always had problems with gasket leaks at bigger bores.
Damn, a head ever year!
Bike sounds badazz, tell us a little about it.
How long, times and mph would be nice?
  
|
mlb
Novice Class
Posts: 48
|
posted May 23, 2006 09:01 AM
I'm also curious about why you think your eating the valves. Do you data log any of the passes at the strip, what's your A/F on NOS? Have you done anything to the heads other than springs? Are you running the stock valves or SS units? When you eat them is the head a throw away or is it fixable and if so what's it look like / how much $ to fix? I know that's a lot of questions I'm just really curious about your opinion of why your having this repeating problem.
Thanks
|
TRNorBRN6001
Needs a job
Posts: 2021
|
posted May 23, 2006 09:09 AM
Maybe a lot of the juice all at once?
____________
TFA 200MPH CLUB MEMBER!
|
mlb
Novice Class
Posts: 48
|
posted May 23, 2006 11:04 AM
So your just hitting the button for an instant 125HP, if so yea that may cause problems ater a little while. Have you thought of putting it on a controller to ramp in the NOS?
Any idea of the kind of HP you're putting down without the NOS?
|
NOS1290
Expert Class
Posts: 103
|
posted May 25, 2006 09:07 AM
Compression is dropped a bit with a .060 spacer plate and 5 degrees of timing pulled. I have the motor mapped for 12.5 to 1 with 104 race fuel, but I could do better by using the specially formulated fuel for nitrous. Detonation hasn't been a problem for the rods, but its been hell on the vavle train though with the extra heat...
|
|
|
HOME
NEW TOPIC