efi idle adjustment- found some interesting things that may help

Decided to not race today and continue working on the 290. Getting a higher idle has been discussed a couple times so I dug in to see what we can do. First the choke knob is the idle adjustment. Turn it in lowers idle. Out raises. When you pull the choke out, this raises idle and works as a enrichener. But...not really. Since our bikes are efi we can physically manipulate air or throttle position. That is what we are doing with the choke and idle. Fuel is predetermined by setting in the ecu. If you notice, if you turn idle up (turn choke knob out) and pull outward on the choke knob- the pull or distance it moves is shorter than if you pulled knob at low idle setting. I took the idle knob out and when you turn it outward, you are 'opening' up a bypass circuit. The hot start is inline with this circuit, but has much larger effct. If you push hot start while bike is running you should notice idle rise. If it doesn't- there is an issue with the fuel/air mixture. Could be lean or rich. So.. to the point- idle cqn be raised past the 2400rpm setting by 2 methods. Adding tension to the hot start will allow idle to rise. I also tried a copper washer shimming the idle. I am notnsure which is better but both work. I felt better with the hot start tension. The copper washer shim wasn't as adjustable. Basically just opened choke port. Lastly, fuel/ air ratio has a major effect. If you modify the bike- pipe, high flow filter without screen, etc or even oxygenatedn fuel- it will change the air/fuel ratio. The bike cannot adjust to physical changes to the bike. Only to temperature and elevation. This is where a fuel controller will fix issues. Even a controller like the fmf or wiseco units may be all you need. The stock map is good..for a stock bike. Once a change is made past the oem fuel/ air ratio parameters- performance will suffer. I mentioned in another post I had a trick I was testing. I wanted to prove it before trying-it works! A 9 volt battery. By hooking a 9v battery to the power plug, this keeps the electronics charged. It is a common trick by quad guys for gncc starts. A 12v battery can also be used. I simply use a kill button and wired positive through it to battery plug. When starting bike, just press button, it send juice to epectronics and in one swift kick the bike will fire to life guaranteed. Isf in gear and you habe clutch drag this will really help. Not all kicks are equal with battery less efi. A slow or half kick will give a low voltage sine wave that will jot be enough to fire the iniector. Dobeck performance has a great video on utube demonstrating on a crf450. Fast full kick is necessary to give full power. With the battery we are supplying power that would be made in that kick- so we are just ading the electronics and priming pump. Hope this helps!

I have been using the rich plug for my full exhaust. I still think it runs lean though. You are correct it is optimal to be spot on for the ignition. You will make more power and with programmers like the power commander and the yoshimura pim2 you can adjust the throttle position sensor which can add another 2-4 hp in most cases from what I have heard. Man I'd love to get a big bore sleeve I'm too broke though.

I think whatever feels best. You can tune on a dyno or o2 sensor,but it really comes down to if you like it. The big bore is cool,but I still do like a 250f. Im 33 and 200lbs. If I was young and able to rip around at 12k rpm it would be different.

ac, you are a trip. Thanks so much for all of your help on here.

Andy

So im gonna try this...thanks AC! Im not so used to my 10, and its starting to get colder. This will be awesome for hare scrambles!

The 9 volt battery does work. The hot start or choke adjust does too. If you look at what injectioneering was doing to the throttle body for the crf and yzf- they straightened butterfly, added or reshaped hole in butterfly to bring air in on starting and low throttle situations. Also, a taper bore is a nice touch on the inlet side. If you look at butterfly valve and you have odd gaps around butterfly to valve- that isn't good. We want the air to be controlled and metered through the valve. Through the inlet you can also see how hot start and choke come into the circuit. I made a rubber fitting to get the injector to spray more downward. Didnt notice an improvement with it. At some point I plan on trying a ktm throttle body from a 12 or 13 and adapting it. Our throtle bodies are good, but the one ktm uses is better. I am not sure if the rmz pcv will be adaptable though. I was also looking at if e-start was feasable. The kicker gear can turn feely with kicker in place. Kicker engages oposite of gear rotation also, there is an idler gear. I am thinking a starter motor could be adapted to the back of the kicker gear or the idler. Kinda like a ktm or a crf450x. At this point I don't have a need for electric srart, but it woukd be a fun project. The crf x starter look like it could be used or the ktm 450 starter. A bracket from the clutch cover would have to n e made to support the starter. All theory so far lol. Just trying to think for the people that want electric start

I have been using the rich plug for my full exhaust. I still think it runs lean though. You are correct it is optimal to be spot on for the ignition. You will make more power and with programmers like the power commander and the yoshimura pim2 you can adjust the throttle position sensor which can add another 2-4 hp in most cases from what I have heard. Man I'd love to get a big bore sleeve I'm too broke though.

can the TPS also be adjusted with a Vortex box? 2-4 HP is huge.

Good info!  

 

I run a Dobeck Gen4AFR+ on my 450.  It's crazy to see how lean the bike was running with the lean coupler and a FMF exhaust.  AFR was up to 16 when letting off the throttle!

Good info!  

 

I run a Dobeck Gen4AFR+ on my 450.  It's crazy to see how lean the bike was running with the lean coupler and a FMF exhaust.  AFR was up to 16 when letting off the throttle!

Its good to see afr. I wish it was easier to compare bike to bike. It would help us all a lot. Seems like fuel, mods, etc from one bike to another can make a big change. I ran oit of u4 today and put some pump gas in. It was feeling different, so I unplugged the grey coupler..snap came back. So the oxygenated fuel needed richer mapping compared to the pump gas. I anticipated this. I mapped on the rich side with rich coupler. I knew I could always go leaner with the plugs. This has helped me tune greatly-- by using the couplers as reference. The couplers didn make as big of difference until I got the big bore. Efen with a high compression piston- the difference was vague.

can the TPS also be adjusted with a Vortex box? 2-4 HP is huge.

Not sure about that particular programmer. I believe that they vary from manufacturer to manufacturer which settings you can and cannot adjust. It's possible that if you can't adjust the throttle positions sensor alone, the parameters may be factored in somewhere else in a certain map. Big gains are up for grabs there. That is word on the street.

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