retarding exhaust

I've read where four wheeler owners retard the exhaust timing as a mod to extend the power toward mid and top. If you make clearance at the piston to allow for collision, would there be an extended power band? If it's retarded too much would blow down occur so late the exhuast pressure would hold up the rising piston? How bout 112in. 102ex ?? what would it do? I'm looking for an extended high end, I just need to shift the peak up a little more and have good charge right to it. I'm ready to toy with the exhaust but don't know where to go.. Just don't want to make 5 changes when it could be one or two. It's like asking about a rare coin that doesn't exist :blink: :woohoo: found it!! Remember, if know one knows, I'll have to find out. The quest for power. Endless strides through the desert, sun beating down on your back, sweat rolling into your eyes, walking through the valley of one heck of a party fear creeps into your bones, where is your bike? Small voice inside says drink the puke in the helmet and go charge cactuses. :woohoo:

"Small voice inside says drink the puke in the helmet and go charge cactuses." :laugh: :laugh: :laugh: :laugh:

This made me laugh.... Not sure WTF "cactuses" are :blink: but laughed just the same...

I think he meant "cactii" . Drink the kool-aid, put on your Nike airs, and go lay down in bed until the mothership gets here.

nads.com wrote:

I've read where four wheeler owners retard the exhaust timing as a mod to extend the power toward mid and top. If you make clearance at the piston to allow for collision, would there be an extended power band?

Not on my 750 twin. The horsepower peaks at about 7000 and redline is about 7500 so it already peaks right at the top. Bike makers are pretty good at squeezing all the power out of these engines.

VARYING LOBE SEPARATION ANGLE
Tighten***********************************Widen
Moves Torque to Lower RPM ***********Raise Torque to Higher RPM
Increases Maximum Torque ************Reduces Maximum Torque
Narrow Powerband *********************Broadens Power Band
Builds Higher Cylinder Pressure *******Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock *****Decrease Chance of Engine Knock
Increase Cranking Compression ******Decrease Cranking Compression
Increase Effective Compression *******Decrease Effective Compression
Idle Vacuum is Reduced ***************Idle Vacuum is Increased
Idle Quality Suffers **********************Idle Quality Improves
Open Valve-Overlap Increases *********Open Valve-Overlap Decreases
Closed Valve-Overlap Increases *******Closed Valve-Overlap Decreases
Natural EGR Effect Increases ***********Natural EGR Effect is Reduced
Decreases Piston-to-Valve Clearance **Increases Piston-to-Valve Clearance

LOBE SEPARATION ANGLE
Above 114 Deg. = Extremely Wide
114-112 Deg. = Wide
112-110 Deg. = Moderately Wide
110-108 Deg. = Moderate
108-106 Deg. = Moderately Tight
106-104 Deg. = Tight
Below 104 Deg. = Extremely Tight

ADVANCING / RETARDING CAM TIMING
ADVANCING **********************************RETARDING
Begins Intake Event Sooner *****************Delays Intake Event Closes Intake
Open Intake Valve Sooner *******************Keeps Intake Valve Open Later
Builds More Low-End Torque ****************Builds More High-End Power
Decrease Piston-Intake Valve Clearance ****Increase Piston-Intake Valve Clearance
Increase Piston-Exhaust Valve Clearance ***Decrease Piston-Exhaust Valve Clearance


Changing one and not the other causes varying degrees of things from both lists!!! :laugh: :laugh: :laugh:

Best of luck.

NAILED IT! Catii take cover.

Throw in some drop in cams on 116 centers and watch what happens at 4k

larrycavan wrote:

Throw in some drop in cams on 116 centers and watch what happens at 4k

Turn your 4 stroke into a 2 stroke !?! :laugh:

andy9802gt wrote:

I think he meant "cactii" . Drink the kool-aid, put on your Nike airs, and go lay down in bed until the mothership gets here.

at midnight we cut our balls off and then meet up behind the comet...i have my roll of dimes

:laugh: :laugh: :laugh:

trianglelaguna wrote:

andy9802gt wrote:

I think he meant "cactii" . Drink the kool-aid, put on your Nike airs, and go lay down in bed until the mothership gets here.

at midnight we cut our balls off and then meet up behind the comet...i have my roll of dimes

got anything of value you want to leave me? besides the taurus and the projects and the errant bag of shroom' tips under the couch cushions?.....:laugh: and no, i dont want your scrotum contents........

larrycavan wrote:

Throw in some drop in cams on 116 centers and watch what happens at 4k

What is this 4grand happening so spoke of o riddler?