The CRF250L Owners thread

Hey Spud, now that's something I could use.

Hook me up with a bike and one of those and I'll answer any questions anyone has...

So have I taken up a page yet....

I know on vehicles with aftermarket exhaust, they have produts to fool the computer that the o2 sensor is still there. probably not enough of a demand for bikes yet, but they may interchange considering an o2 sensor has no idea whether its a car or bike

Honda's PGM-FI doesn't use OBD codes like the car world like you would expect, but a more Honda style. You can pull codes if needed through the RED DLC plug on the bike, by jumping the Brown and Green wires together or purchase Honda special tool "SCS connector". Make the connection and then turn the main switch on and count the MIL blinks.

The flywheel has notched or raised sections on the flywheel to determine crank position and thus injector or ignition timing.

From what I'm reading this system is like the old first efi system on ford f series pickups. No map just a sensor for speed density. Based off the o2, and speed/rpms. This system sucked. Very dependent on throttle body cleanliness. When the butterfly plate got dirty the system would rev up everytime you pushed in the clutch. It didnt take long for it to get dirty either. It did fuel good though, and the rev up didnt cause any driveability problems though. There were alot of guys doing a swap to newer map systems from newer trucks. It was very hard to program a new ecu override to add more power. It was done, but very expensive. Thus the swap that people were doing. To be clear, the system I speak of also had an iats and tps. This was obd1. I believe that your verbiage of sensor acronyms applys to or should apply to both bike and car.

As part of what I wrote to mental above, the bikes will contain the same stuff as the cars but are dependent on open or closed loop. The parts may be smaller and values different, but essentially the same parts.

This confirms my suspicion of obd1 type system. Thats how you got codes off of them. Call them obd or not its the same principle.

Here is a small discussion on what the HRC race ecu does. I believe we might be able to open source tune this bike :) I'm assuming some of you smarter people can hack this ECU?

http://www.cbr250.net/forum/cbr250-performance/3328-hrc-cbr-has-map-adjustable-ecu.html

wouldnt it just be easier, or at least about the same amount of money in the end to just put a bigger jug on it, or overbore to get the added power. You know nrfd. You get more gain for the same money.

I know your post count is set to 100 so look on page 26. Not one post from you. Your just trying to catch up.

Whats sad is that I'm posting on a forum for a bike I dont even have and dont know if I would buy The reason for this is I have nmd (no money disorder)

I was given a 2 week "vacation"... Thats why...

If you don't want me to post let me know. I have no problem helping people out or sayin screw ya all!!!

It's your choice...

Maybe this will help. Here's some background...

4 level neck fusion, 3 level lower back fusion, every disc degenerated, 4 are bulging, 2 heart stents, a heart arthmia, 3 episodes of acute brain trama, 20+ concussions, a brain tumor and more...

I'm screwed up in the head and admit it.
Sometimes I'm an idiot other times a savant, Probably both soon...

The injector only needs to squirt every other revolution. It needs a cam sensor or fancy programing do do this.

This system is very close to a pre 0BD2 system but not as advanced. It is very simular to Dodges system they used on early 4 cylinder MPI cars.

If you change things like intake, exhaust, or bore size, you have to change the amount of fuel going into the motor.
Most FI mixture corrections do not add a lot of power, but give better response, less surging, eliminate backfires, make the motor run cooler, but do not add a lot of power.

Some systems like what is on Harley's are set really lean (no cats to clean things up) and you can not do much without having problems.
Bikes with cats seem to be able to run richer and deal with some changes ok, my TU250 does.

And I do not think any system on bikes is anything like anything ever used on a car, cars were always wideband systems I think, even the early ones, while there are no wideband systems on bikes that I know of.

The systems in use on bikes are simple carb replacement systems using maps to set the mixture, with very limited input from the oxy sensor.

Sure, but I would like an open source ECU and a big bore.

Even some systems on cars would pulse the injectors with a closed intake valve, the mixture just hangs around before being sucked in.
Some bikes must do that as there are no cam position sensors and there is nothing to tell between TDC on the power stroke or the exhaust stroke.

Any thumper without a cam position sensor would HAVE to do this.

The computer can be programed to sense when the combustion stroke happens by monitering the increase in crankshaft speed. With the proper software it is possible to fire the injector at the corect time with only a crank sensor. Some cars do this when the cam sensor fails so they cam still run in limp in mode...

There's only one O2 sensor, and thus at the exhaust port.
The title is a little confusing where it's placed, though ...



L

If I change the gear ratio from 14/40 to 13/43 will this give me better performance off the line?