2012 450 Tight Woods Stalling

[SparksXR426]

Hi Guys

Havent been on here for a bit and I did a search but havent found much of interest so here goes. Ride mostly tight trails and singletrack though the terrain varies up here from dense forest to near desert. Have a GYTR flywheel weight and generally run the "woods" map found in the sticky or a "soft hit" map that adds a little fuel and takes a little timing away just off idle. Problem I have is every once in a while in the first gear stop and go stuff the bike stalls and its not very predictable when. If your blipping the throttle and working the clutch it just pops and quits,usually on top of a damn log. Not new to riding mx 450s in the bush and my 08 was a great bike for it. This bike is better in most ways but the cough and die thing gets on a guys nerves, if your revs are up its fine but just off idle on small throttle openings its not predictable. About 12 hrs on the bike now and it happened 3-4 times on the last 2hr ride. Tried turning the idle up a bit and it helps but doesnt cure it, anybody else had any luck with fixing or improving that? Thanks

[Quernix]

I am not so happy with the power delivery at smaller loads and in slow situations. We have had the YZ on the dyno and checked the mixture of the smooth/broad map vs. the Standard Map. My Tuner said the mixture didn't change much with different maps. All maps where borderline rich off the bottom. In his opinion this could could cause to the jerky power delivery and the unstable engine run just off idle.

I am not liking how much clutch I have to use in 2nd gear corners to keep the bike alive. I have a GYTR flywheel on the way and will probably try the GET ECU. Turning the idle up will not really help since the first and second gear are too long for what you are looking for.

We also have reduced the intake diameter slightly. It helped with bottom power i.e. staying in 3rd gear longer, but made the second gear problems worse...

Did the flywheel help at all?

[supermega1]

2012 WR? Or 2012 YZ? Seeing as you said MX 450's I am assuming YZ,

What do you have done to it? Comp ECU, Exhaust ETC?

The comp ECU made a huge difference on my '12 WR at low speeds. This is my first bike so the majority of my time is spent at low speeds going through the single track in the desert and had some issues until I switched the ecu. I run the woods map currently cause of the softer hit for my newbie skills. I generally don't have to much of a problem and can pretty much come to a complete stop before it stalls.

Also what elevation are you at? If your at a higher altitude that map might be to lean at those low speeds.

Edited May 11, 2012 by supermega1

[SparksXR426]

I am not so happy with the power delivery at smaller loads and in slow situations. We have had the YZ on the dyno and checked the mixture of the smooth/broad map vs. the Standard Map. My Tuner said the mixture didn't change much with different maps. All maps where borderline rich off the bottom. In his opinion this could could cause to the jerky power delivery and the unstable engine run just off idle.

I am not liking how much clutch I have to use in 2nd gear corners to keep the bike alive. I have a GYTR flywheel on the way and will probably try the GET ECU. Turning the idle up will not really help since the first and second gear are too long for what you are looking for.

We also have reduced the intake diameter slightly. It helped with bottom power i.e. staying in 3rd gear longer, but made the second gear problems worse...

Did the flywheel help at all?

Yes, the flywheel was worthwhile for power delivery. I ran one on my 08 as well and there's really no downside to installing one. I cant say the power delivery is bad on this motor just that odd tendacy to cough and die. I would almost say its something to do more with the way the idle is set up than anything to do with the mapping? If nothing else a guy could try leaning/riching the low rpm settings and see if that helps. Like I say, its not a huge problem, just an annoyance.

2012 WR? Or 2012 YZ? Seeing as you said MX 450's I am assuming YZ,

What do you have done to it? Comp ECU, Exhaust ETC?

The comp ECU made a huge difference on my '12 WR at low speeds. This is my first bike so the majority of my time is spent at low speeds going through the single track in the desert and had some issues until I switched the ecu. I run the woods map currently cause of the softer hit for my newbie skills. I generally don't have to much of a problem and can pretty much come to a complete stop before it stalls.

Also what elevation are you at? If your at a higher altitude that map might be to lean at those low speeds.

Its just a stock YZ motor outside of the flywheel weight and an 2011 stock muffler. Under load at almost any rpm its not a problem just when you close the throttle and open it quickly, something close to a "blip". If you happen to be rolling fast enough you can bump start it but since its at basically crawl speed when it happens that doesnt always work. I ride mostly sea level to say 2000 ft. Guess I'll play with the fuel settings at low rpm and see what happens. Thanks.

[supermega1]

You might also try raising the idle rpm on it a little bit. A little increase in that might help enough to keep it from stalling.

[texboy]

I have had the same thing happen to me in a cross country race. I have the milder woods setting and also have rekluse clutch. It happens when I chop the throttle in a tight snady turn. It pops and dies. I am going to turn the idle up some and see how that works. Since it pops does that mean it is lean?

[grayracer513]

I have had the same thing happen to me in a cross country race. I have the milder woods setting and also have rekluse clutch. It happens when I chop the throttle in a tight snady turn. It pops and dies. I am going to turn the idle up some and see how that works. Since it pops does that mean it is lean?

My comments are in regard to this particular situation, but the second part may bear on FI YZ's with normal clutches as well.

When I installed my Rekluse Z-Start Pro, I used the recommended base setting of a medium engagement RPM and the faster of two engagement rates. I found the bike tended to do as you say, mostly in second or higher, but even in 1st, and that it would not allow second gear starts without using the lever. I changed it to the slower engagement rate at the same RPM (medium/slow Rekluse calls it) and cured the entire problem. Might fiddle with the clutch.

That said, another thing comes to mind. One of the main causes of stalls that occur when chopping the throttle quickly from a low speed load is a rich mixture. This causes the engine to drop to idle so quickly that it drops right past it and quits. Just as excessively rich mixtures cause the idle to hang, a mix toward the leaner side of normal eases the engine back to idle a little more reliably than a richer one does. I mention that because from what I've seen, the air/fuel ratio on the EFI YZ's is a bit on the fat side below 3500, and apparently, the tuner doesn't affect that too much. Could be a worthwhile area to investigate.

[Joe846]

Not exactly the answer you're probably looking for, but having a 12 450 the conclusion I've come to is: pick your favorite gearing, your favorite map across the board for the type of riding you do, and then carry speed/momentum at slow speeds, or be gentle with the throttle.

Carrying momentum, has made stalling a fairly small issues on my bike, and when I'm worried about lack of momentum or tough conditions I either work the clutch, or avoid big pull/chops on the throttle at all costs. At very low rpms/tight tree/slow rocks, you need to adjust to the bikes needs in the case of the YZ450, no vice a versa. Trust that the torque is going to carry you over, or use the clutch to force it. The suspension is so good and the bike rolls over obstacles so well when you take a little weight off the front that I roll much more than I thought I'd be able to. Then, when it's tight and I have to keep the front loaded in repeated turns, I just cover the clutch and remain aware of not chopping the throttle.

I haven't tried it yet, but based on my bike, something like a slow pull throttle from G2 might be the ticket once you decide on the map you want. Like someone else mentioned, the bike just does not like too much throttle/fuel in the low rpms, and DEFINITELY not in the wrong gear. That's no matter what the Power Tuner setting, and that's doesn't even really play into it as most of us richen the map at 1/4 throttle to smooth things out, making it even more rich.

I know that's all super basic feedback, but "keep it simple" and all. Hope that helps!

Edited May 26, 2012 by Joe846

[upnorthbacon]

I just put the G2 throttle on mine with the 400 (Throttle tamer) cam and it's better. I installed it merely to stop from whiskey throttling it since it's so damn responsive! Between the throttle and tuner (broad powerband map) I'm absolutely happy with the power and I can lug down super low without stalling. If I'm going slower than walking speed I'll ride the clutch to get through obstacles.

[SparksXR426]

Just thought Id update this one. My setup is: 2012 YZ450, stock 2011 muffler, GYTR flywheel weight and a 51 tooth rear, running different maps depending on the terrain. Ive really struggled with this bike randomly flaming out at small throttle openings at low rpm. So much so that you never want to drop the revs too much for fear of stalling. Raising the idle helped marginally and map changes really did nothing to help this. The power DELIVERY was never an issue, just the stalling. My 08 was light-years better in this regard. Sent my throttle body to Wade Wilcox at Injectioneering a couple weeks back and just put my first normal ride on it today. I have to say that was the best money Ive spent on this bike. I ran the stock map just to give me a baseline even though I should have put the woods map in it for the terrain but it ran so well I never even considered changing it. Awsome. Bike also starts WAY easier and doesnt seem to flatten off in the upper revs as much as before either. If I rode only MX I dont know how much value this mod would have but for me this is a big deal. Ive really wondered how consistently tuned these bikes are from the factory and if some are better/worse than others from the factory, doesnt really matter though, mines finally running like i think it should. ?

Edited August 20, 2012 by SparksXR426

[eazrider]

What he said. everyone that uses a FI YZ450 off road should send their throttle body off to Injectioneering. You will be a happy camper, both with the respnse, and, rideability....

[Crusty Cy]

I too have struggled with many of the same issues - I have a 2011 YZ450F and it works great for trail riding and MX; not so well in tight woods and hare scrambles due to inconsistent starting and the occasional pop and stall. Set up as follows: woods or less hit mapping, 50 or 51 rear sprocket, G2 300 throttle cam, and FMF 4.1 RCT with insert. It is very frustrating, as the potential is off the charts. At times, I wish I had kept my KTM 300, but could not come to grips with the below average suspension (even though reworked). I may try the Injectioneering mod, as the positives of the YZ far outweigh the negatives.

[SparksXR426]

I too have struggled with many of the same issues - I have a 2011 YZ450F and it works great for trail riding and MX; not so well in tight woods and hare scrambles due to inconsistent starting and the occasional pop and stall. Set up as follows: woods or less hit mapping, 50 or 51 rear sprocket, G2 300 throttle cam, and FMF 4.1 RCT with insert. It is very frustrating, as the potential is off the charts. At times, I wish I had kept my KTM 300, but could not come to grips with the below average suspension (even though reworked). I may try the Injectioneering mod, as the positives of the YZ far outweigh the negatives.

I haven't put enough time on to really test the mod yet, I need to ride a few locations with different maps etc. but I have to say that I'm excited so far. The bike is otherwise great but it doesn't matter if you gain a few seconds in some sections and then throw it away with a stall. Until yesterday I've seriously wondered if I took a bit of a step back with the new bike after my 08 which was a great woods bike. I don't wonder anymore.

Well, except maybe for those rad shrouds, seems like I hit every third tree with them. Weird.