Throttle lag

[cobraman]

Greetings! I now own a 2007 WR450 and starting to ride again. On my first official day of ride number 1...I already crashed. Nobody told me that even in 3rd gear and a handful of throttle, I would see the sky and you can imagen what happen from there. ? OOpps.

Anyhow, a question to all. From an idle position, when you hit the gas hard the enging wants to die..or if it's warmed up there's just to much lag between gas and power.

Any thoughts?

Thanks in advance for your help

[fishpost19]

Two words:

"Accelerator Pump"

[timoyz1]

New bike or used? If it's new then yes, your AP timing is off or blocked all together. If its used and had any gas left in it, or rode alot and dirt has made it up into your carb and just needs some cleaning. Heavily suggest a jet kit and a Merge APS, and if you have to pull the carb off, grease your suspension, mine was very dry.

[w00dsRider]

New bike or used? If it's new then yes, your AP timing is off or blocked all together. If its used and had any gas left in it, or rode alot and dirt has made it up into your carb and just needs some cleaning. Heavily suggest a jet kit and a Merge APS, and if you have to pull the carb off, grease your suspension, mine was very dry.

Can't say it enough... Grease that suspension! Yamaha factory treats grease like it's gold.

[cobraman]

It's a brand new bike. Only have about 3 hours on it so far. Thanks to all that have responded so far.

[timoyz1]

New bikes can have crap in the carb too. Have you done the mods? Snorkle, throttle stop screw, and exhaust baffle will do wonders alone.

[face_plant]

i was told at the last yamaha class that idle to 3k if you snap it it will die

it is normal. same thing for the yfz450

[WR450SM]

i was told at the last yamaha class that idle to 3k if you snap it it will die

it is normal. same thing for the yfz450

That is a load of crap. It may be normal for off the showroom floor bikes to do this, but that doesn't mean the owners should not tune them for the conditions that they actually ride in. The AP can be tuned to give unbelievable response, and not stall when throttle is applied quickly from 3k or even idle.

[William1]

Get yourself a #40 leak jet from the YZ parts bin, and also O-Ring the AP linkage

[hoople]

does anyone have a pic of the o-ring mod?

[w00dsRider]

does anyone have a pic of the o-ring mod?

Here's some pics of it done on a KTM and it doesn't look much different.

https://www.thumpertalk.com/forum/showthread.php?t=626571&highlight=o-ring+mod

[timoyz1]

I spent the $20 and got the Merge APS. I had the carb off and apart and figured money well spent instead of a o-ring that could break and get stuck somewhere at the wrong time and place.

[William1]

https://www.thumpertalk.com/forum/showthread.php?t=624773

[Rick1141]

http://www.yamaha-motor.com/sport/products/modelscitemdetail/5/210/1222/5389/2007/1/6228/0/1/detail.aspx