Street Fighter update

[dbran1949]

That's not the Streetfighter...

Sorry - I thought it looked a lot like my bike, looks like an S4

[Fox]

Any Updates on this project?

I was at Will's shop yesterday to check on the progress. He just got the frame, wheels and swing arm back from powder coating. It looks great. The engine should be back from SF soon. It looks like it's going to be a mad dash to get the bike ready in time for Laguna Seca.

[DesmoTull]

5) Slipper Clutch!

Just for my own education, you still would need a slipper with the traction control??   

[Triple J]

Just for my own education, you still would need a slipper with the traction control??   

A slipper keeps the back wheel from locking on hard downshifts...something TC can't help with.

[yotogi]

A slipper keeps the back wheel from locking on hard downshifts...something TC can't help with.

Well, unless you wanted the computer to apply power to the rear wheel for you trying to guess your intentions. 

[Triple J]

Well, unless you wanted the computer to apply power to the rear wheel for you trying to guess your intentions. 

That could get interesting as you're flying into the hairpin at your local track...or on your local back road! 

[mitt]

A slipper keeps the back wheel from locking on hard downshifts...something TC can't help with.

I am pretty sure the latest gen TC can.  Adding a bit of fuel, or keeping the throttle bodies open to decrease engine braking.

mitt

[yotogi]

I am pretty sure the latest gen TC can.  Adding a bit of fuel, or keeping the throttle bodies open to decrease engine braking.

I don't see how that would work most of the time and it seems that a slipper clutch would do a better job of it anyway.

[Triple J]

I am pretty sure the latest gen TC can.  Adding a bit of fuel, or keeping the throttle bodies open to decrease engine braking.

mitt

Hmmm, that would be interesting...I was under the impression TC only kept you from spinning the back wheel.

[Spidey]

The MV F4-1000R has a system kinda like mitt's talkin' about.  I think.  I only understand how it works when I read about it.  Then I promptly forget, until the next time I read about it.   

Here's a blurp from their website:

The Magneti Marelli 5SM ECU manages the widely acknowledged EBS system (Engine Brake System) that is fitted to MV Agusta engines for controlling torque under deceleration. The concept is based on a solenoid-activated bypass valve on cylinder N° 2 intake duct. The bypass is situated downstream from the feed throttle that has a suitably shaped air intake. This device allows cylinder N°2 to produce torque even under deceleration (when the feed throttles are closed) thanks to a signal sent by the Marelli ECU.

The advantage in terms of engine braking at high and medium engine speeds is self-evident. It is also very clear that the engine management system could allow more demanding riders to adjust and optimize engine braking at different engine speeds to suit their individual riding styles.

[mitt]

I don't see how that would work most of the time and it seems that a slipper clutch would do a better job of it anyway.

TC, or really the ECU, can also control engine rpm, and can help bump engine speed to gearbox speed during downshifts, possibly making a slipper clutch unneeded.

mitt

[mitt]

I don't see how that would work most of the time and it seems that a slipper clutch would do a better job of it anyway.

A slipper is mechanical and only works after the fact that there was a serious mismatch in drivetrain speeds.  An ECU could predict the event and compensate before the mismatch happens, thus preventing or reducing it.

 mitt

[flynbulldog]

Retro, why would you want to put a bigger rear tire on it? You want it to turn-in slower?

[yotogi]

A slipper is mechanical and only works after the fact that there was a serious mismatch in drivetrain speeds.  An ECU could predict the event and compensate before the mismatch happens, thus preventing or reducing it.

While I understand what you are saying, you still haven't convinced me that if you were to downshift when your bike was previously near the redline that the ECU would be able to do anything to prevent wheel lock. At that point, it would need to rev the engine past the redline to match speed I would think, something that would be bad. In this situation, a slipper would just not transfer power to the wheel. Am I somehow having a misunderstanding about how TC systems on bikes function?

[mitt]

While I understand what you are saying, you still haven't convinced me that if you were to downshift when your bike was previously near the redline that the ECU would be able to do anything to prevent wheel lock. At that point, it would need to rev the engine past the redline to match speed I would think, something that would be bad. In this situation, a slipper would just not transfer power to the wheel. Am I somehow having a misunderstanding about how TC systems on bikes function?

True, if you were at redline, the engine can't rev up anymore, and a slipper is probably the best bet. 

But, like the link Spidey added, some ECU's can reduce engine braking by allowing "leaks" into the cylinder chamber, which could also work, and which we will probably see more of incorporated into TC/ECU's for the street.

mitt