Mods

[etuke]

I did the engine vent tube mod today and tried the O-ring mod but haven't run it yet.I was getting a bad hesitation if I tried to hit the throttle quickly,my 426 didn't have this.I was wonder if there were any other mods that is recommended I should do to my 07 yz450.I have looked through the stickies and these 2 stood out in my situation.I was wondering if the 06 CDI would have any benefits to the 07 as it does to the 08-09.

[slothman]

The hesitation can be a fuel problem. Inspect and clean the jets. Make sure it has fresh gas. Check the spark plug and make sure the air filter is clean. You need to do preventative maintainance BEFORE modding the bike ?

I did the engine vent tube mod today and tried the O-ring mod but haven't run it yet.I was getting a bad hesitation if I tried to hit the throttle quickly,my 426 didn't have this.I was wonder if there were any other mods that is recommended I should do to my 07 yz450.I have looked through the stickies and these 2 stood out in my situation.I was wondering if the 06 CDI would have any benefits to the 07 as it does to the 08-09.

[etuke]

O nly thing I haven't done is check the jets.will run her again and see if it improved before tearing into he carb.

[mikedabike]

My 07 runs perfectly fine without any carb mods other than fine tune the jetting.

[etuke]

its also still cold here so that's not helping any.

[slothman]

its also still cold here so that's not helping any.

colder air is going to change the air to fuel mixture of the bike. You need to compare your mods and your altitude with other members to see what jets you need to run. My bet is your pilot jet is clogged.

[luvnoldcars]

My bet is your pilot jet is clogged.

every time I have had a pilot jet get clogged the bike wouldn't idle without the choke on.

[slothman]

every time I have had a pilot jet get clogged the bike wouldn't idle without the choke on.

it really depends on how dirty the jet is. If it's only partially clogged, the bike will idle without the choke on, but it might have hesitation/bog just like the OP said.

The problem might also be the needle position. The needle controls fuel all the way up to 1/4 throttle.

Bottom line is, the OP needs to clean all of the jets, inspect the needle, and set the air screw.

[etuke]

I installed one of those easy adjusting fuel screws so I try to set it where it doesn't pop out the exhaust,last time I rode the bike it wasn't too bad but had a slight hesitation off idle if you hit the throttle quick to raise the front wheel.Durning the ride we stopped for a bit and when we started to go again I gave it a quick shot while rolling and it bogged bad enough that I though it was gona shut off,then picked up fine.It is possible the engine cooled enough to be considered a cold engine as like I said its colder here and we were stopped for awhile.I don't think my jets are clogged I think its more along the accelerator pump,roll on throttle is fine.When the weather warms and it still does it then I will tear into the carb,when I got the bike it was popping something bad.Put the fuel screw in and fresh gas and it ran a lot better,have since installed new plug and O-ring mod but haven't tried the bike.Was thinking of doing the chain slider mod also even though my swingarm isn't worn,was going to do the 1 with the foam under the slider to minimize the chain slap at low rpm.Also wondering if its necessary to install a small filter on the hose that I ran to the airbox for the vent tube.

[etuke]

The bog seems to be gone now,only had a short ride but it didn't bog once.Throttle response seems great,just don't know if it was the new plug or the O-ring mod.

[mikedabike]

I like a little popping. Every yz450 i have ridden that didnt pop a bit off throttle was too rich for me on the pilot.

[peaceofwork]

one thing at a time clears up a lot of mystery when playing carb games