WR400F Stuttering when I accelerate?

[Ozzy_Kabuto]

So I bought a WR400F cause Im a yamaha fanboy and I wanted something different from a DRZ like all my mates have.

Everything seems fine except for the speedo not working (If anyone knows a digital one I can get please let me know), Until I accelerate...its only when I accelerate, its been getting worse I think.

When ever I take it from half throttle or less to wide open (slow or fast) the bike almost stutters of coughs before finally getting the revs up then all of a sudden it's just peak power and goes like a lubed up rocket (Smooth). Even sometimes when Im dropping gears and I revmatch the bike will just cut out like its not getting enough air or not enough fuel? Happened a few times now, mainly when I blip the throttle quickly instead of a smooth flick.

Anyone have answers on how to get that smooth action the entire way? oh and BTW (I know absolutely nothing about Bikes and carbys)

[Ozzy_Kabuto]

Also, YES I have googled and looked, but its all a bunch of mumbo jumbo to me that I don't understand. Or its never a straight answer.

[FORMA MOTO]

Your description is to vauge to be able to pin point your problem, that, and you have not told us what state of tune your bike is in (intake, exhaust, jetting, etc).

 

It sounds like a very dirty air cleaner, or a main jet that is too big, or a bike that is still stock/corked up.

[twerth]

Maybe a bad accelerator pump?

[ridesanoldbike]

As far as a speedo, I have the trail tech vapor on mine. Works great and I like having a coolant temp gauge and tach as well. Not too pricey either.

[Ozzy_Kabuto]

15 hours ago, twerth said:

Maybe a bad accelerator pump?

Got no idea what this is...

19 hours ago, Krannie McKranface said:

Your description is to vauge to be able to pin point your problem, that, and you have not told us what state of tune your bike is in (intake, exhaust , jetting, etc).

 

It sounds like a very dirty air cleaner, or a main jet that is too big, or a bike that is still stock/corked up.

It has an exhaust on it, Staintune or something like that, Intake got no clue, jetting got no clue. I know F*** all about bikes.

[Ozzy_Kabuto]

2 hours ago, ridesanoldbike said:

As far as a speedo, I have the trail tech vapor on mine. Works great and I like having a coolant temp gauge and tach as well. Not too pricey either.

yeah saw these, was kind keen but didn't know if it would work on the wr400

[twerth]

3 hours ago, Ozzy_Kabuto said:

Got no idea what this is...

The accelerator pump is a little valve on the carb that gives your engine a shot of fuel straight down the intake when you open the throttle. These often fail or need adjustment. If yours isn't working right, you could be getting a lean mixture when you crank the throttle. Might be the cause of the issue you're having.

[Ozzy_Kabuto]

16 hours ago, twerth said:

The accelerator pump is a little valve on the carb that gives your engine a shot of fuel straight down the intake when you open the throttle. These often fail or need adjustment. If yours isn't working right, you could be getting a lean mixture when you crank the throttle. Might be the cause of the issue you're having.

ahh, I will need to have a look at that. This bike seems it may be injecting lean yet exhaust is rich ? According to my friends behind me.