manual for my WR250F says idle (when bike is warm I assume) is between 1900 and 2100 RPM. I have the power commander ECU and the corresponding unit I can plug into the bike to load and safe engine maps and monitor RPMs and temperatures and also pressure in the cylinder. I can't set it exactly at 2000 RPM like my OCD brain tells me to, so I have an option of it fluctuating (due to upgraded exhaust with less restricted air flow I assume) between 1900 and 2000, or 2000 and 2100 on average, though on the bit slower setting it hits 2000 half the time, 2050 about 10% of the time, and rest around 1950, occasionally dipping to 1900.
is this fine? am I totally overthinking this? or is it better to be at the low or high end of the idle RPM range?
btw I assume bike is fully warmed up with I can 1) have it idling for 5-10 minutes, 2) the cooling fan comes on and stays on, and 3) I can cook bacon on the titanium exhaust pipe
Also, how to best get a feel for the idle speed on my son's carbonated bike with no tools to measure it...
thanks!
AP
Re: Dirt bike idle speed question
Posted: Sun Jan 03, 2021 2:29 pm
by armedpolak
Oh look I found an app to acoustically measure RPM
dammitgriff wrote: ↑Sun Jan 03, 2021 3:01 pm
Shut up and ride the damn thing, already.
Lmao!
I take my son and my dog for a walk in a park close by in the evenings. it has grass with small hills/bumps and gravel trails. it's totally empty after 9pm and yet the lights stay on till 11pm. so I walk the dog while sipping on scotch from my yeti cup LOL while he rides and the dog runs free.
my bike on the other hand needs one more modification: I need to install the stock sprocket; previous owner installed a +2 or +3 on in the rear. it's too torque'y for me however after reprogramming the ECU to stock map it certainly feels like the bike is much less homicidal toward me besides I haven't found a place to ride yet that is not a paid track, nor do I have a way to transport it yet. will get a hitch or a trailer soon. for now I took it for a spin around my neighborhood a few times to test the changes reprogramming the ECU did... so far so good...
Re: Dirt bike idle speed question
Posted: Sun Jan 03, 2021 3:10 pm
by armedpolak
I also installed an ATV thumb throttle with a limiter for him. I could not find a twist one with a limiter so I put one for an ATV and reduced the engine to maybe 10-15% power. initially when he first rode it the throttle was too much for him and he crashed into bushed a few times. we had a talk about target fixation and throttle control, but I immediately got different parts and 3 days later he was practicing in the backyard for few days. now he rides in the park at night.
here's Nick 2nd time on a bike once I put thumb throttle with limiter (btw he now has full dirt bike gear and he wears it every time!):
Re: Dirt bike idle speed question
Posted: Sun Jan 03, 2021 3:25 pm
by armedpolak
so I was able to confirm ECU reading on Yamaha and set my son’s bike idle rpm properly using the iPhone app mine is nearly at 2000 and my sons at 1500 according to the manuals!
however after reprogramming the ECU to stock map it certainly feels like the bike is much less homicidal toward me 
besides I haven't found a place to ride yet that is not a paid track, nor do I have a way to transport it yet. will get a hitch or a trailer soon. for now I took it for a spin around my neighborhood a few times to test the changes reprogramming the ECU did... so far so good...
