BoGGG when whipping throttle

I bought a bone stock 2006 crf450x a month ago.

I need revving to be more responsive.

The powers there and when it revs its revs good... but when i whip the throttle it boggs a bit before it revs.

I just bought the JD Jetting Kit. ( Installing this weekend)

I need to adjust air screw. (this weekend)

what else can i do to make my 450 rev quick and not bog.. need this thing to rev like my yamaha raptor 700 that i had.

Are you talking about when it is sitting on the stand and you go from idle to wfo as fast as you can? If so how often do you ride your bike while it sits on the stand... never. Although I am a stickler for a proper running bike but there should not be a lot of merit put into the stand test. I would start with checking the AP timing and make it squirt earlier. If that doesn't solve it a smaller leak jet and larger pilot jet should solve the problem.

not on the stand. actual riding. bogs a bit before a jump when i twist the throttle to get the nose up.

You need to install a smaller leak jet (50 or 55) and the Merge Racing AP spring. After you install the AP spring, you need to adjust the timing of the squirt and there are lots of posts in this forum for how to do so--it's easy. These will address the bog issue. I didn't use the JD kit so I'm not sure if it comes with the leak jet or not.

The remainder of the jetting changes (larger main, different needle, and fuel screw adjustment) will make the bike run noticeably stronger--look out!--and cooler.

You're going to be well pleased when you're done.

Do exactly what Nathan said and you will be satisfied.

In 2008 the factory improved the Accelerator pump linkage, just like what the merge racing spring upgrade does, on all X's.

not on the stand. actual riding. bogs a bit before a jump when i twist the throttle to get the nose up.

Not sure where you are in California, but I have an 06 and it is dialed in.....for now. You can see my settings in the stickies jetting data base. AP pump is a must before the bogg will go away.

dolfinfan- so is the ap pump your talking about... thats just the spring right....how about the diaphram? ... another kit by crfsonly site has a diaphragm, plunger rod, spring and o-rings,--Honda Accelerator Pump Diaphragm Kit 16021MENA01...which is better the merge spring or this kit from crfsonly?... sounds like all i need is the spring

Edited by zj4041
dolfinfan- so is the ap pump your talking about... thats just the spring right....how about the diaphram? ... another kit by crfsonly site has a diaphragm, plunger rod, spring and o-rings,--Honda Accelerator Pump Diaphragm Kit 16021MENA01...which is better the merge spring or this kit from crfsonly?... sounds like all i need is the spring

Replace all the moving parts in the apump system :

Diaphram, Spring, orings, plunger.

http://www.crfsonly.com/catalog/product_info.php/cPath/138_147/products_id/3932

The spring being refered to as a upgrade is not the diaphram spring, it is the 'detent spring', also known as the 'linkage return spring'.

Part # 66

http://www.sudco.com/fcrmx.html

http://www.mergeracing.com/products/AcceleratorPumpSpring.php

thanks for clearing that up..( i ordered the merge aps-accelerator pump spring)... now how critical is the pump diaphram kit for the throttle response... sounds like it has a larger diaphram which is what the aps is intended for right?

thanks for clearing that up..( i ordered the merge aps-accelerator pump spring)... now how critical is the pump diaphram kit for the throttle response... sounds like it has a larger diaphram which is what the aps is intended for right?

The Pump diaphragm kit is to replace damaged or worn diaphragm and spring. It is not an upgrade.

well mine is an 2006 the description for the "Honda Accelerator Pump Diaphragm Kit" states "updated '08 version for better off-idle performance" ( not sure whats different but some how the 2008 has a better diaphram kit. Does anyone know what is the advantage to this?

http://www.crfsonly.com/catalog/product_info.php/cPath/138_147/products_id/3932

From the description its mentioning a new cover but from the pic it just looks like the standard rebuild kit for any AP. Now if your parts are old or worn, do what Krannie said and replace it all. If your stuff if good then maybe all you need to do is shave down the stud on your stock AP diaphram to allow it more room to move. Also as Krannie said, you should do the Merge racing AP pump spring. That is what eliminates the need for the O-Ring mod.

Its in the TT Store http://shop.thumpertalk.com/product_p/merge_00-018.htm

or at the Merge site http://www.mergeracing.com/products/AcceleratorPumpSpring.php

response from crf only is....It has the improved diaphragm for longer pump squirt and has the '08 pump cover

... buttt i have to remove the check valve in the float bowl to use the new cover. Otherwise I can use my own current cover.. .. (removing the check valve doesnt sound like a great idea...iduno any ideas? )...

The '08 and later carb has a different pump design and linkage.

It is just barely different.

You can put the '08 diaphragm on if you like, but you do have to remove the check ball inside the pump cavity.

I'm using OEM '05 Honda parts and I can't keep the front end on the ground without serious throttle modulation (in other words, the apump is working very well).

You don't have to grind down rivets in any case. The picture might show an old pre '05 CRF450R type diaphragm with the tall rivet. That tall rivet diphram is not longer used. The first few years of the R had the short throw apump diaphram, which made every bike bog to the point of guys getting hurt on the track...

How do i check and adjust my timing... any body got any good tutorials on this... couldnt find anything worthwhile myself.

Does this mean if you have a 2008 crf450x you don't have to mess with the apump?

Does this mean if you have a 2008 crf450x you don't have to mess with the apump?

YES, accept for leak jet size, and apump linkage adjustment. The pump and linkage upgrades are built in now.

I got a jd kit for my cut airbox and ti4 procircuit pipe but it didn't come with a leak jet what leak jet do you recommend? I'm at sea level if it matters. Or if you don't know can point me at the right direction. Thanks in advance for quick replays

50 leak

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now