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jams33

2015 wr 450 on/off throttle off idle

28 posts in this topic

Hi all, had my WR for a couple of weeks now. Have found that just off idle the throttle is like a light switch. Really bugs me as I'm used to smooth off idle and really can't get to grips with it. Is there a way to smooth this out? It's an EU model.

Cheers

James

Edited by jams33

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Use the clutch...

 

Any time you are down into idle territory you should have the clutch in. Modulate it as the RPMs rise to give the desired power output.

Edited by woods-rider

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Use the clutch...

 

Any time you are down into idle territory you should have the clutch in. Modulate it as the RPMs rise to give the desired power output.

 And what do you do when it does this at 4 or 5 k?

 

I had the same issue, I reduced my ignition timing for the bottom left of the map to -3. Bike isn't as peppy, but I can still get the front end up with 1/4 throttle.

 

This is the map I currently have with a Co of -12. Bike is stock, with GYTR ecu of course, and opended up the airbox and exhuast. Still have hot start issue tho.

 1 1 1    0  1 3

 0 1 1   -1  0 1

-1 0 1   -3 -1 0

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You need to take it to the dealer to modify your FI and IGN map below 4k, so using the GYTR tool is not the answer.

 

That's the issue: ultra lean at idle to rich at 1/5 throttle, when the TPS changes the maps.

 

You can also adjust the TPS resistance up around .65 ohms to help the transition issues you are having

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I had found that upping the idle speed helped a bit, still not great but better. But it's idling annoyingly fast now. Off to dealer I think. Will try the TPS thing first though.

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Yeah it's not mapping problem, its before the mapping kicks in.it's nice and smooth up in the revs, just awful off idle, so bad I'm knackered after riding it a mile in technical stuff.

Edited by jams33

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Switch to a 12 tooth sprocket so you aren't trying to ride at such low RPM in technical sections.  We've put 12 tooth sprocket on 3 WR450Fs and 1 YZ450F and every rider has said its a huge improvement.  Cost: $20 and 20 minutes.

 

Swap in a YZ exhaust cam.  WR exhaust cams are extremely restrictive.   When you shut the throttle off, its like having an exhaust brake.  You won't believe how much better your engine will pull and how much better the low end is with a YZ exhaust cam.  Cost: $150 and about 4 hours to install, depending on how handy you are.

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Putting on a smaller front sprocket will make the problem worse, not better.

 

The problem IS mapping.

 

You have an ultra lean condition at idle jumping to a rich condition at 1/5 throttle.

 

As mentioned before, if you raise the resistance of the TPS to about .66, you will reduce the problem, but if you have the dealer change the idle map to be +2 richer, it will dissapear.

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Putting on a smaller front sprocket will make the problem worse, not better.
  No it doesn't.  Most of the people are complaining about the throttle response at crawling speeds.   When you gear the bike down, the engine runs faster for a given speed and its no longer an on/off throttle response that the rider wants.   And when the engine is running faster the flywheel is more effective, smoothing things out.

 

Unless you've tried it, you can't know.  Like I said, we've done this on 3 WRs and 1 YZ and every rider has said its better for the technical terrain we ride. 

 

The problem IS mapping.
  Mapping contributes to the problem.   The real problem is the restrictive exhaust , which acts like an engine brake the moment you close the throttle.   When you close the throttle, all fuel injection ceases, so the exhaust brake effect is going to be there no matter what map you use.   The only thing the map does is somewhat smooth out the response when the throttle is turned back on.  That is only half the solution, if that.

 

You have an ultra lean condition at idle jumping to a rich condition at 1/5 throttle.

 

As mentioned before, if you raise the resistance of the TPS to about .66, you will reduce the problem, but if you have the dealer change the idle map to be +2 richer, it will dissapear.

 

These things improve it somewhat, but it doesn't disappear.   FWIW, the 2015 YZ250FX has this problem 4x what the WR450F has.   It also has a severe amount of engine braking.   Once again, Yamaha stuffed a really stupid WR exhaust cam into that engine, just like on the WR450F.   Changing the cam to the YZ version should fix the problem and make it an all round better engine, just like the WR450F.

 

FYI, just so there is no miss understanding, there is no idle *map*.  There is an idle mixture adjustment that is set with the FI tool.  Its parameter C1.  You use the same tool to read the TPS setting.

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I don't think my bike ever ran ultra lean at idle with the comp ECU.  I never had the glowing header.  I'm at -8 CO.  I have a one finger easy clutch lever and my finger is on it all the time.  I just work the clutch when I'm going slow.  The transition doesn't bother me.

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  No it doesn't.  Most of the people are complaining about the throttle response at crawling speeds.   When you gear the bike down, the engine runs faster for a given speed and its no longer an on/off throttle response that the rider wants.   And when the engine is running faster the flywheel is more effective, smoothing things out.

 

Unless you've tried it, you can't know.  Like I said, we've done this on 3 WRs and 1 YZ and every rider has said its better for the technical terrain we ride. 

 

 

 

  Mapping contributes to the problem.   The real problem is the restrictive exhaust , which acts like an engine brake the moment you close the throttle.   When you close the throttle, all fuel injection ceases, so the exhaust brake effect is going to be there no matter what map you use.   The only thing the map does is somewhat smooth out the response when the throttle is turned back on.  That is only half the solution, if that.

 

 

 

 

These things improve it somewhat, but it doesn't disappear.   FWIW, the 2015 YZ250FX has this problem 4x what the WR450F has.   It also has a severe amount of engine braking.   Once again, Yamaha stuffed a really stupid WR exhaust cam into that engine, just like on the WR450F.   Changing the cam to the YZ version should fix the problem and make it an all round better engine, just like the WR450F.

 

FYI, just so there is no miss understanding, there is no idle *map*.  There is an idle mixture adjustment that is set with the FI tool.  Its parameter C1.  You use the same tool to read the TPS setting.

 

 

 

 

The WR ECU has a three-axis continously variable FI and IGNITION mapping system.

Edited by KRANNIE

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Tps adjustment solved it. Running 13-47 sprockets. Might go up to 50 on the back as it produces a load of slap at low revs.

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  No it doesn't.  Most of the people are complaining about the throttle response at crawling speeds.   When you gear the bike down, the engine runs faster for a given speed and its no longer an on/off throttle response that the rider wants.   And when the engine is running faster the flywheel is more effective, smoothing things out.

 

Unless you've tried it, you can't know.  Like I said, we've done this on 3 WRs and 1 YZ and every rider has said its better for the technical terrain we ride. 

 

 

 

  Mapping contributes to the problem.   The real problem is the restrictive exhaust , which acts like an engine brake the moment you close the throttle.   When you close the throttle, all fuel injection ceases, so the exhaust brake effect is going to be there no matter what map you use.   The only thing the map does is somewhat smooth out the response when the throttle is turned back on.  That is only half the solution, if that.

 

 

 

 

These things improve it somewhat, but it doesn't disappear.   FWIW, the 2015 YZ250FX has this problem 4x what the WR450F has.   It also has a severe amount of engine braking.   Once again, Yamaha stuffed a really stupid WR exhaust cam into that engine, just like on the WR450F.   Changing the cam to the YZ version should fix the problem and make it an all round better engine, just like the WR450F.

 

FYI, just so there is no miss understanding, there is no idle *map*.  There is an idle mixture adjustment that is set with the FI tool.  Its parameter C1.  You use the same tool to read the TPS setting.

 

 

You need to think about that statement......

 

 

Utter nonsense.

 

Gearing a bike down increases throttle response per throttle amount turned.

 

No way gearing it down can smooth out throttle transition, as it is now jumpier then before.

 

If you gear it down, it will climb the rpms faster....exactly what you don't want.

 

If you are having to run the bike at 6k rpm to make it smooth, the tuning is waaaaaay off....

 

I have ridden all years WR's from 12-15 / 53-46

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I changed my c1 variable to +8 and it helped my hot start issue and gives it the proper fuel at idle. -8 os extremely lean for having exhaust and intake on a bike setup to pass California emissions.

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If you install the comp ECU you're no longer setup to pass CA emissions.  I've never had an AFR meter on it so I don't really know the ratio.  I'm assuming that the guys setting it to +12 are rich at idle, maybe in the 13:1 area.  That seems to work well for racing on carb'd bikes.  I don't think you need to tune a fuel injected bike like that.  The carb has to draw fuel from the bowl or some kind of accelerator pump circuit but it gets pumped in with a fuel infected bike.  That's how I see it as a layman.  I could be totally wrong.

Edited by chu

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You need to think about that statement......

 

 

Utter nonsense.

 

Gearing a bike down increases throttle response per throttle amount turned.

 

No way gearing it down can smooth out throttle transition, as it is now jumpier then before.

 

If you gear it down, it will climb the rpms faster....exactly what you don't want.

 

If you are having to run the bike at 6k rpm to make it smooth, the tuning is waaaaaay off....

 

I have ridden all years WR's from 12-15 / 53-46

 

 

I guess that the 4 of fuel injected Yamaha 450F riders that I ride with are wrong then.  Our brains must be fooling us.

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Wouldn't first gear on a YZ be almost like second on a WR though?

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Wouldn't first gear on a YZ be almost like second on a WR though?

 

I ride with a mix of FI WRs and YZs.  Every one of the riders has liked going to the 12 tooth sprocket for technical terrain.

 

Yesterday a YZ450F rider with the 12 tooth sprocket had trouble with stalling, but turning up the idle speed seemed to solve that. 

 

A 2015 YZ450F running a 12 tooth sprocket with the idle set a bit slow is the same speed as my WR with a 12 tooth sprocket with the idle set correctly.  Bumping the idle speed on the YZ makes it faster.  Running a 52 tooth rear sprocket on the YZ would get it down to the right speed.  

 

FWIW, the 2015 YZ450F seems like a great tight woods bike.  He and I are riding with 300cc 2 strokes and having no trouble keeping up.

 

We ride tight woods trails in foothills and mountains.  Unmaintained, except once in a while someone will bring a chain saw and cut the most terrible logs.  The grades are steep, often with no run up.  The trail can be anything from dry to snot.  Imagine if you went out into a mountain forest and bushwacked a trail up and down various ridges and valleys and then rode it until it was worn in.  That is what we ride.

 

Good throttle response is critical in these conditions.  The Yamaha FI 450Fs are proving to be excellent mounts for this type of riding, provided they are set up right.

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