Reduce engine braking on 2012 WR450

Thanks Cracker, I just found it in the service manual. Although I didn't realize 9-16 was the operating range. I'll check it out now.

 

 

Just checked my TPS reading. My D:01 reading is 11 with the throttle closed.

Edited by Spiritwalker2222

I don't think I explained the problem very well. I should have said that the bike is twitchy at low rpms when letting off the gas from 1/8 throttle to 0. The sustained engine braking is what I'm used too. It's just when I'm going thru technical sections it makes the bike jerky.

 

Anyways, I have a few things to try the next time I get out.

 

Thanks for everyone's help so far. I'll report back after I get to try out the new CO setting and different maps.

That's more of a flywheel problem. You need a heavier flywheel. But if that's the map your running, your going to have more bottom end twitchyness. Plug in my map and you'll see it helps a lot down low.

It's a four stroke so timing and compression are the ones that really control the breaking. You should feel the breaking with a high compression piston.

Yeah, it's kind of a big deal that doesn't seem like a big deal, cause if you don't do it, nothing blows up or fails.

 

Then once you do it, you do notice a subtle difference in throttle response, and a more consistant throttle control.

That's more of a flywheel problem. You need a heavier flywheel. But if that's the map your running, your going to have more bottom end twitchyness. Plug in my map and you'll see it helps a lot down low.

It's a four stroke so timing and compression are the ones that really control the breaking. You should feel the breaking with a high compression piston.

 

I would use your map before the flywheel weiight.

I don't like heavy flywheels personally. 

I've actually turned down CRF flywheels before.

I put them on, then take them off and go, 'holy crap, more snap!"

That's more of a flywheel problem. You need a heavier flywheel. But if that's the map your running, your going to have more bottom end twitchyness. Plug in my map and you'll see it helps a lot down low.

It's a four stroke so timing and compression are the ones that really control the breaking. You should feel the breaking with a high compression piston.

Vixjim, what are the numbers for your map?

Edited by Spiritwalker2222

I would try the map first too.

Vlxjim Map

Fuel    Timing
3 4 4     0 0 0
3 5 3   -2 -1 0
3 4 3   -2 -2 0


Vlxjim Map more bottom hit

Fuel    Timing
3 4 4    0 0 0
3 5 3   -1 0 0
3 4 3   -1 -1 0


Vlxjim Map leaner better mpg

Fuel     Timing
2 3 3     0 0 0
2 4 2    -2 -1 0
2 3 2    -2 -2 0

Edited by vlxjim

This must be what a dog feels like when he tries to read a newspaper.

This must be what a dog feels like when he tries to read a newspaper.

Before or after he does his business :devil:

Put an 08 YZ exhaust cam in it.   Runs way better in every other way too.

 

Or just tune your FI properly. It runs way better in every way, and you don't have to open the head to do it.

Uh oh.

Or just tune your FI properly. It runs way better in every way, and you don't have to open the head to do it.

 

You can't fix how the engine breaths with a map.

 

When the exhaust valve closes prematurely, it traps hot exhaust gas in the cylinder which then gets compressed for the rest of the exhaust stroke.  This creates strong engine braking.  Great for emissions (in cylinder EGR), but terrible for trail riding.

 

When the cylinder has trapped exhaust gasses in it, and it gets compressed, the engine runs hotter. 

 

When the cylinder has trapped exhaust gasses in it, it can't fill with a new charge and when it does that charge gets preheated.  And it won't burn nearly as well when it does burn.

 

All these things LIMIT how well the stock WR450F engine runs.  There is no way around the physics of it.   You can tune and map all you want, but that doesn't change that the exhaust cam really limits these engines.  And given that we have a thread asking how to increase low end response and another thread on how to decrease engine braking, both independently posted from anything I have done, I think its time people start considering cams.

 

Furthermore, there is no way, no how, that mapping the engine alone will ever yield the result that a simple exhaust cam swap and mapping will do.  The exhaust cam improves the low end lugging, decreases the engine braking, increases smoothness, increases throttle response and improves over rev all without touching the timing or fuel.

 

And you don't "open the head" to install a cam.   You take off the valve cover.  Its the same procedure as adjusting the valves, only you put in a new exhaust cam.   We all agree that adjusting the valves is a normal maintenance procedure, right ?  Its nothing more drastic than that.

You can't fix how the engine breaths with a map.

 

When the exhaust valve closes prematurely, it traps hot exhaust gas in the cylinder which then gets compressed for the rest of the exhaust stroke.  This creates strong engine braking.  Great for emissions (in cylinder EGR), but terrible for trail riding.

 

When the cylinder has trapped exhaust gasses in it, and it gets compressed, the engine runs hotter. 

 

When the cylinder has trapped exhaust gasses in it, it can't fill with a new charge and when it does that charge gets preheated.  And it won't burn nearly as well when it does burn.

 

All these things LIMIT how well the stock WR450F engine runs.  There is no way around the physics of it.   You can tune and map all you want, but that doesn't change that the exhaust cam really limits these engines.  And given that we have a thread asking how to increase low end response and another thread on how to decrease engine braking, both independently posted from anything I have done, I think its time people start considering cams.

 

Furthermore, there is no way, no how, that mapping the engine alone will ever yield the result that a simple exhaust cam swap and mapping will do.  The exhaust cam improves the low end lugging, decreases the engine braking, increases smoothness, increases throttle response and improves over rev all without touching the timing or fuel.

 

And you don't "open the head" to install a cam.   You take off the valve cover.  Its the same procedure as adjusting the valves, only you put in a new exhaust cam.   We all agree that adjusting the valves is a normal maintenance procedure, right ?  Its nothing more drastic than that.

 

Blah blah blah... you don't know what you're talking about, you have no frigging clue what FI mapping can or can't do as you've never done it, so shut up about it already. The exhaust cam is NOT a limiting factor on this bike. Who ever told you it is? Or did you just figure that out all on your lonesome? The cams were designed to run with the bike UNCORKED, not showroom stock. You fail to grasp that very basic concept, so every deduction you've made from there is based off a flawed premise. EPIC FAIL

 

Open the head = remove the cover. Swap out cams. All stuff you can severely damage your engine if you don't know what you're doing, or will have to pay a qualified mechanic to do it. Anyone can tune their FI in seconds with the GYTR tuner, without similar risks. Plus you MUST adjust the FI if you've made major changes to the intake & exhaust JUST LIKE A CARB'ED BIKE. But you remain steeped in denial about that.

 

Nobody should consider anything you've done, because you're a hack. You have no actual data to back up ANYTHING you've done, just opinions and feelings, which are WORTHLESS. Beyond worthless in your case, as you've proven time and time again you don't know how the FI works on this bike, you don't know how suspension works, and you try to mask riding issues with bike mods. A first year rider reengineering a bike because he knows better than Yamaha how to make it run right. :rolleyes:

 

FI mapping absolutely does everything you've listed there... which you would know if you've ever tried it. A whole bunch of us HAVE tried it, so we know exactly what it does and doesn't do. Yet here you are, with your all zeroes map telling us how it is? My the ego on you, thinking you have all the answers on something you clearly have ZERO experience with, and will sit and argue with people that have actually been there and done that.

Edited by GP1K

FI mapping won't increase valve overlap.  More overlap reduces dynamic compression.  Not saying that a different timing map would have no effect on compression braking, but I don't believe it would affect it to the same extent as a cam swap.  Much easier to load up a new map than to swap cams.  I'm interested in swapping cams to make more hp, don't really have an issue with engine braking.  My point is... well I don't really have a point.

I'm trying to stay out of this.

But the OP wants to get rid of the 0 - 1/8 throttle twitchiness. We'll guess what, that's what my map does. So let him try that first and see if it helps. It has helped quite a few here.

I've already stated that cams and compression are what controls engine breaking. But that's not what's happening here.

I've already stated that cams and compression are what controls engine breaking. But that's not what's happening here.

 

DOH !  <palm to forehead>  LOL !

The exhaust cam is NOT a limiting factor on this bike. Who ever told you it is?

  errr... less lift and duration than prior WRs ?  Ditto compared to YZs as well !  They call that DETUNING.  See my cam selection table !

 

 

 

The cams were designed to run with the bike UNCORKED, not showroom stock. You fail to grasp that very basic concept, so every deduction you've made from there is based off a flawed premise

  So they decreased the lift in 2007 why ?  The YZ, which runs the same aftermarket exhaust systems as the WR must have the wrong cams then because they retained the high lift.  The WR exhaust cam lost duration as well.   You need to go tell Yamaha !

 

 

 

Open the head = remove the cover. Swap out cams. All stuff you can severely damage your engine if you don't know what you're doing, or will have to pay a qualified mechanic to do it.

  Oh, no !  Not fear, uncertainty and doubt about adjusting the valves !!!   I guess we got a good indication of your mechanical skills.  Like going too far with mixtures and timing couldn't hurt anything !

 

 

 

Plus you MUST adjust the FI if you've made major changes to the intake & exhaust JUST LIKE A CARB'ED BIKE.

  My bike forgot to read that bible.   I'll slap it around and tell it to smarten up.  Or maybe the FI is pretty smart already ???  Hmmm.... 50 hours since I changed the exhaust, no hole in piston, no backfire, runs great, great power, great throttle response.... stupid bike !  I need a carburetor.  NOT !

Edited by MidlifeCrisisGuy

I've already stated that cams and compression are what controls engine breaking.

 

 

Not saying that a different timing map would have no effect on compression braking...

 

Maybe it would be safe to say that advancing timing won't decrease engine braking?  I don't know.  :excuseme:

There is nothing wrong with putting YZ cams in the new WR but people should know two things:

 

If you still have (which you should) the electric start it probably wont work starting the bike when cold due to the decompression pin. If you want to avoid this go with a aftermarket set of cams.

 

Second your bike will not,not fbike_zpsfb4e63d5.jpgit takes a bit more for that.

  errr... less lift and duration than prior WRs ?  Ditto compared to YZs as well !  They call that DETUNING.  See my cam selection table !

 

 

 

  So they decreased the lift in 2007 why ?  The YZ, which runs the same aftermarket exhaust systems as the WR must have the wrong cams then because they retained the high lift.  The WR exhaust cam lost duration as well.   You need to go tell Yamaha !

 

 

 

  My bike forgot to read that bible.   I'll slap it around and tell it to smarten up.  Or maybe the FI is pretty smart already ???  Hmmm.... 50 hours since I changed the exhaust, no hole in piston, no backfire, runs great, great power, great throttle response.... stupid bike !  I need a carburetor.  NOT !

 

I done with all this. 

 

First off its called Tuning. Cams, Heads, Bore and Stroke, Porting, Piston, Exhaust tuning, Fuel and Air Delivery and Timing.

 

What, your just going to go up the compression kick up the lift and duration as high as you can to go. Would that work for all situations? Of course not. Yamaha Has setup the WR to run in an all around off road condition. Yamaha change the heads the cams and the fuel system. Yet it is one of the best WR's made. The old WRs uncorked compared to the new WR's uncorked is night and day. So did Yamaha do the right thing with the WR. I think so.

 

Cams are a part of the tuning and that's just the way it is. Where the YZ was designed to be a hard hitting MX track bike. A bike that is rode just off the rev limiter all the time. The WR was not built to be rode like this. They have the YZ for that.

 

The WR was build from the factory to need the comp ECU and all the restrictions removed. That how they come in other places in the world.

The stock USA ECU cost $399 were the Comp ECU is less than $100. They want you to have it.

This is were you come in with your stock map. Yamaha made the Comp ECU's stock base map so that if you unplugged the muffler that the bike would run well. 

But Yamaha also knew that even with this setup and the new FI that you could adjust the map for different riding conditions. So they give you a list of other maps to use with the programer. 

Which change the bikes behavior in so many ways. 

You would not know this because you have not tried it WHY?

 

OH I know its because when you rip out all of you electrical to save weight you loss the ability to flash the ECU on the bike. I know this as I tried to help you back then.

 

I'm 100% sure that the cam made the bike just the way you wanted it to be. Its just to bad you never got to see or will see the way a map changes the bike. 

Edited by vlxjim

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