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#35 leak jet fitted to my WRF and still bogging... where now?

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Oh no... it's another bogging thread! :smirk:

As the title says... I've fitted the smallest leak jet Yamaha sell and my 09 WR still has a slight bog right off the bottom. It sent me over the bars last night when I was trying to lift the front over a log!

What's the next step? Do I have to shell out a load of money on a Quickshot thing or is there any more tuning I can do to the stock setup? Will adjusting the needle clip make any difference.

The AP timing seems good, the fuel squirt doesn't hit the slide at all. I've not timed the squirt with the #35 jet but with the #40 it was around .5 sec.

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Have you changed the AP spring to a stiffer one, or done the 'O' ring on the AP mechanism.

Rather than get 10 suggestions on what to do....post up what you have done so far

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.post up what you have done so far

I have... that's it :smirk:

I thought the o-ring mod was to change the timing. How would this affect the amount of fuel going in?

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Check the AP timing screw gap.

It needs to be .010 or so. You might need to install both o-rings (if you're using a JD Kit).

Or, skip the o-ring and wire it, just make sure ledge isn't in continual contact with the arm.

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The way the AP works is the rod that pushes down on the diaphragm follows the throttle cam but not a lot of pressure is asserted. With the o-ring on there more pressure is asserted down on to the diaphragm therefore a stronger squirt is forced out. The AP isn't the only thing that can cause a bog, it all depends exactly where in the throttle position the bog is.

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Thanks for link, that's a good read.

So the o-ring mod will effectively increase the duration of the fuel squirt by causing a stronger force through the rod, and not change the timing?

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Thanks for link, that's a good read.

So the o-ring mod will effectively increase the duration of the fuel squirt by causing a stronger force through the rod, and not change the timing?

It causes the squirt to start sooner and be more forceful (it does diminish the duration but that is not the goal).

Think of a childs squirt gun. The tykes weak fingers can squeeze the trigger but not that hard, too much give in his tiny muscles. Take an adult hand with stronger muscles (like adding an oring) and the squirt from the gun is sooner, stronger and actually is a shorter duration.

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Check the AP timing screw gap.

It needs to be .010 or so. You might need to install both o-rings (if you're using a JD Kit).

Or, skip the o-ring and wire it, just make sure ledge isn't in continual contact with the arm.

That is not correct.

Initial timing adjustment is dependant on slide position. There are two methods to do it.

The first (and best) is to slide a ,8mm drill blank under th slide. You may have to lower the idle speed to ensure the slide 'clamps' the blank. Then adjust the timing screw to just barely remove the free play.

The second and less accurate method is similar to what you describe. You have to lower the slide all the way down until it bottoms in the carb body. Then adjust the timing screw to to remove all but .010" freeplay.

The second method looks at the slide all the way down and that is not a critical location compared to having the slide at a certain point in its travel. When adjusted via the first method, rarely is there any further adjustment needed. The second method gets you in the ballpark and is rarely spot on first test.

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To the OP. you used you eye to adjust things and trust me, unless you digitally time the squirt, just youtr reaction time with a stop watch can make or lose .5 sec.

Restore the AP timing to stock (I trust you know exactly how much and which direction you turned the screw). You are going to find the 35 LJ is way too rich, a most, a 40 is all you need and even then, that is very rich unless you do super tight slow single track.

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No, I am too damn grumpy....:smirk:

Fixed......:smirk:

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