Boondocker turbo tuning..having bog issues

Are you running an AFR gauge? What is the AFR when the bike begins to bog in boost? Two people I know are running the 13 KX450 turbo and you need a minimum of 8-9#'s of boost for the bike to start running right. A common problem I hear of is that people attempt to run too low PSI and the bike starts to run like crap.

And from what I've seen Boondockers numbers on the bike are too lean. It seems like a lot of fuel needs to be added across most of the TPS/RPM ranges. Call Boondocker for updated numbers.

I think it's important to realize that the minimum
boost is set by the spring on the actuator. That is about 8psi. Asking for less than 8 just doesn't work.

Hey C-man i was wondering if you had any luck figuring out your bog problem i just put a bd turbo on my 13 yz450f and am having the same issues really bogging at low/high rpm and using alot of fuel ....i have tried new numbees from boondockers but they havent worked was wondering if it was just a controller issues for you or some other problem thanx.

Boondocker tuning

Here's a few hints that may help. The single cylinder turbos are *very* sensitive to backpressure, especially before boost comes on, and each motor tunes differently so one person's settings may not work for someone else's with the same bike.

Air filter:
First, make sure the airfilter isn't plugged with snow, even a light dusting of snow on it can make a big difference, so keep an eye on it esp. when in deep snow.

RPM fuel settings
The 2 rpm screens are used for off-boost tuning (rpm adjustment only), and are usually used to subtract fuel before boost.

Xtra Screen
Another way to accomplish removing fuel is using the Xtra settings by adjusting the RPM window and PSI settings (Both must be turned ON, fuel adjustment is made whenever rpm is within rpm settings AND boost is below PSI setting which can allow fuel adjustment to be made before boost). Example: RPM LO: 3500, HI: 8000 (just needs to be high enough to make sure boost is on), PSI < 3 (usually 2-4psi is high enough to overcome backpressure rich spot), fuel -5 (don't remove more than about -8 or you will start to be too lean during deceleration which can cause popping). Some of the latest programming has 3 separate fuel adjustments (LO, MD, HI) depending on TPS position for better control (LO can be 0 to -3, this helps avoid decel issue, MD/HI can be -5 to -8). Note: In the Stats screen, there is an 'x' in upper right corner that displays whenever Xtra fuel adjustment is being made - very useful during captures (see below).

PSI screens
The psi settings are for when on boost, fuel is added at specified rpm/tps values in proportion to fuel number multiplied by boost (0 boost or 0 fuel means no additional fuel will be added than just stock fuel). Note: some of the rpm and psi fuel settings overlap so you need to be aware of what the boost is doing to know what adjustments are being made.

Button Mode (in Xtra Menu)
Put button in CAP (capture) mode and be ready to press and release it during the bog or area to be tuned (when button is RELEASED, 10 captures will occur on Stats screen) - this will help give an idea of rpms, tps, boost that is occurring. Up/Down arrows scroll through captures. Note: **Captured data will be lost if engine is shut off! **

The TUN (tune) mode can be used to subtract or add fuel whenever button is pressed (note: same fuel number will be used if using Xtra feature, recommend turning Xtra settings OFF if doing this) - may have to use large numbers (+-10 or more) to feel a difference but can help determine if you need to go rich or lean in a certain spot.

Air/Fuel Gauge
Of course, an Air/Fuel gauge will help a lot (may not be accurate at low rpms due to air re-entering exhaust pipe, and especially if hitting the rev limiter!). If you really want to tune, there is a special version of programming available to show A/F number in Stats screen (great for captures), but box will need to be sent in - and you won't have temp in Stats since temp wire is re-used to connect to A/F gauge.

Tuning requires good concentration (and lots of patience), I try to find an easy open slope where I can focus on listening to the motor instead of worrying about riding. Focus on one certain rpm/tps range and try to change just one thing at a time - sometimes it helps to keep making an adjustment in one area until you notice a difference in order to know if you're going in the right direction or adjusting in the right area.

Thanx fastgas for the writeup that helped explain the bd controller alot better .. im just going to explain my situation ..im starting to think maybe i have an issue with the bike its self. I bought the bike brand new with the turbo already installed and it was never ridden. I was on the phone with boondockers all day today trying new settings , but the bike always seems to bog and have terrible throttle response with the afr reading between 10 and 12 and i have burnt two full tanks of gas riding for 40 minutes trying to tune this thing the only time i can get th e bike to run good with minimal, bog and good throttle respose the afr is reading between 12.5 to 14.5 which is not good . Im not sure if because its a new bike it is using all that fuel for break in or wat, but im not sure wat to do or where to start or if the tuning just needs to be adjusted that drastically . Any input or advice would be appreciated thankyou.

Are you sure the sensor is good on the afr... if using lead gas it can kill the sensor... when mine starts to go on my Nytro I get incorrect lean readings... for ubstance i would spike into the 15s and 16s but i was really in the 12s amd 13s then I started dumping fuel in and it helped bring down the afrs but went I switched out the sensor I was running super rich... just a thought before you go crazy...

seitz9 said:

Thanx fastgas for the writeup that helped explain the bd controller alot better .. im just going to explain my situation ..im starting to think maybe i have an issue with the bike its self. I bought the bike brand new with the turbo already installed and it was never ridden. I was on the phone with boondockers all day today trying new settings , but the bike always seems to bog and have terrible throttle response with the afr reading between 10 and 12 and i have burnt two full tanks of gas riding for 40 minutes trying to tune this thing the only time i can get th e bike to run good with minimal, bog and good throttle respose the afr is reading between 12.5 to 14.5 which is not good . Im not sure if because its a new bike it is using all that fuel for break in or wat, but im not sure wat to do or where to start or if the tuning just needs to be adjusted that drastically . Any input or advice would be appreciated thankyou.

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The yz450 is usually one of the easier bikes to tune and they generally have better throttle response since the exhaust is closer to the turbo. I don't pay much attention to A/F number until the engine is on boost (lot of times it's jumping around or inaccurate, and since motor isn't under full load, shouldn't hurt if it's a little lean anyway), so that doesn't sound out of line (I've seen numbers up to 16:1 at times), unless that's what you're seeing after steady full boost is reached (for at least a few seconds or more). I'd keep going that direction to see if the bog condition gets better. Also, to overcome initial backpressure, some people run their wastegate actuator loose (partially open), which can help, but not recommended (over time it will break due to fatigue). Since it's a new install, check everything over carefully (turbo spinning up ok?, any boost leaks on intake, good spark plug gapped a little tighter, etc). Keep at it, once you figure it out, it will be worth it!

I would call Kelly at KMS. I fought my 13 kx450 turbo for a couple of months and could never get rid of the bog. After doing the KMS BD upgrade it all came together! If you go to the KMS web sight there is a great explanation of why your kit isn't working right. I took mine out for the first full day test run on sunday and the bike ran flawlessly! I pulled a few hills that amazed me! My only issue that day was the air forks bleeding off, once that is fixed this thing will be unstoppable! Good luck!

We just had our first baby two days ago, so my first awesome ride was probably my last for a while as well!
Glad You got it running! Was it Allen's tune?