Setting AP Timing

I have an 07 250 and I have read about people setting the ap timing screw but I am not exactly aure how to do it. I have a 45 leak 45 pilot and 175 main and it runs pretty good but there is still slight hesitation. can any recommend how to set the ap timing screw?

We did the oring mod and it made a good improvement. There is a great instruction booklet on here somewhere!

I have an 07 250 and I have read about people setting the ap timing screw but I am not exactly aure how to do it. I have a 45 leak 45 pilot and 175 main and it runs pretty good but there is still slight hesitation. can any recommend how to set the ap timing screw?

I just set mine a few nights ago. I set mine to squirt a bit earlier than stock setting.

Remove the subframe and airbox (leave the mufflers in place). Take the tank off, but set it sideways on the frame, and hook up the fuel line, so the bowl will stay full of fuel. Put engine at TDC so fuel will stay on top of the valves, and you can suck it out with some tubing and a syringe later. Take off the black plastic throttle wheel cover on the carb. Twist the throttle and look in the back of the carb. Good lighting is key. The squirt will probably miss the slide. Turn in the timing screw a little at a time, and wack the throttle, until the stream just nicks the bottom of the slide. **Note: turning the screw IN, on the 07-08 carbs, makes the squirt earlier, while backing it out, delays it. This is opposite of the '06 and earlier carbs.** Keep some q-tips handy to dry off the slide when it gets wet. Turn the screw back out a bit, and recheck, until the stream just misses the slide. Have someone (or something) hold the throttle wide open, and you can see all the fuel you just squirted, sitting on top of the intake valves. I used about 16" of tubing hooked to a large syringe, ran it down on top of the valves, and sucked the fuel out to prevent a massive flooded condition.

That is how I set mine, and ended up with about one full turn in from stock, and it made a difference over the stock setting. Previously, I had the R&D power pump turned all the way in, and JD jet kit, with still some bog off of low rpm. The new AP timing helped, and now I really have to try to make it bog when idling along, which isn't a condition I ever really see when riding anyway. I would say I have the bog fixed on mine. I am finally satisfied.

Also, I would go back to the #42 pilot if I were you. You may also try a #40 or even a #35 leak if you still bog after setting the AP timing. I tried a #45 leak and had way more bog than with the R&D power pump, turned all the way in.

We did the oring mod and it made a good improvement. There is a great instruction booklet on here somewhere!

You don't need to, and can't, o-ring the '07-'08 carbs. They have a push linkage, instead of the follow type linkage.

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