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Hugh Bog after JD Jet Kit

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Just tested my bike after making some Mods. Mods include Megabomb Header, HotCams Stage 1, Disconnected neutral wire, & JD Jetting Kit. The bike is nice and crisp on the stand (After warmed up real good). The problem is when I'm riding the bike. When in 2nd gear running just above idle (say 5 mph) I hit the throttle hard and it will absolutely kill the bike. It seems as if maybe it hit takes off for just a VERY SPLIT SECOND and then it boggs and coast to a stop. The best I can tell this is about 1/8 throttle. I played around with the Fuel Screw and this made no difference. Once I get it pass this bog it seems to real good? I went with all the JD Jetting recommendations on the carb. Everything is stock jetting except JD Recommendation. When checking my AP squirt duration, it seemed awfully short to me? I hard a real hard time timing it with a stop watch (As fast as I could hit the start/stop botton). This was about 1/2 second.

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.5 a second is key.

Try going it with a video camera and counting the frames per second, (about 30 FPS) So 15 frames = .5 second...

Also, a bog isn't directly linked with just your AP, try raising the clip up one, or going in with the fuel screw, or a combination of both.

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Raising the clip will lean it out more correct? I did try the feul screw in and out (no help).

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Just tested my bike after making some Mods. Mods include Megabomb Header, HotCams Stage 1, Disconnected neutral wire, & JD Jetting Kit. The bike is nice and crisp on the stand (After warmed up real good). The problem is when I'm riding the bike. When in 2nd gear running just above idle (say 5 mph) I hit the throttle hard and it will absolutely kill the bike. It seems as if maybe it hit takes off for just a VERY SPLIT SECOND and then it boggs and coast to a stop. The best I can tell this is about 1/8 throttle. I played around with the Fuel Screw and this made no difference. Once I get it pass this bog it seems to real good? I went with all the JD Jetting recommendations on the carb. Everything is stock jetting except JD Recommendation. When checking my AP squirt duration, it seemed awfully short to me? I hard a real hard time timing it with a stop watch (As fast as I could hit the start/stop botton). This was about 1/2 second.

What I've found is that 3/4 ths of a second is just about perfect for the AP duration. I don't know which leak jet you are using, but you should be somewhere in the 40 to 50 range. The smaller the leak jet, the longer the AP squirt duration is. Do you still have the stock AP cover, or do you have a Boyesen cover? That can change things if you do. The proper AP duration, making sure the AP doesn't squirt on the slide, right needle & clip position, pilot jet, and fuel screw setting all interact with each other to give you crisp low end acceleration with no bog.

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AP Timing Gap: 2.60

Needle: Red 5 slot from top

Main Jet: 185

Fuel Screw: 1 3/4

Squirt Duration: 1/2 second

Squirt length: about 3'

Leak Jet: Whatever stock is

Pump Cover: Boysen

Squirt does not hit slider

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AP Timing Gap: 2.60

Needle: Red 5 slot from top

Main Jet: 185

Fuel Screw: 1 3/4

Squirt Duration: 1/2 second

Squirt length: about 3'

Leak Jet: Whatever stock is

Pump Cover: Boysen

Squirt does not hit slider

I've always found the JD instructions to be too rich unless really cold.

With your engine mods I suggest you go down on both PJ and MJ.

On my 05 with just a pipe , i ran 178MJ when 90+ and 182 MJ when below 50deg. Red needle 3rd

40PJ.

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Go back to all stock jetting and pump cover. Do the AP O ring mod. That should work real well.

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AP Timing Gap: 2.60

Needle: Red 5 slot from top

Main Jet: 185

Fuel Screw: 1 3/4

Squirt Duration: 1/2 second

Squirt length: about 3'

Leak Jet: Whatever stock is

Pump Cover: Boysen

Squirt does not hit slider

Sounds a little rich to me, maybe try a 182, or maybe a 180 for the main.

You need to get the AP duration somewhere around 3/4 to 1 sec, but no more than that. Remove the leak jet & find out what it is. Get the next size or 2 smaller (smaller numbers = smaller hole). Install the next smaller one than what you have now & time it. Trying to do it with a watch is pretty much impossible. The video camera trick is pretty good. You do need to know the frame rate of the camera (in frames per second), as they can be different between brands. You can get the video going, then whack the throttle a few times. Stop the video & rewind it, then go frame by frame, and count the frames.

The thing about the AP is if it goes for too long, or not long enough you'll get a bog, but for different reasons. That's why you have to do this. It's not really hard, but it is worth is once the carb works right.

Don't worry about how the bike runs on the stand also. If the AP is set right, the bike will ride good, but it may still bog on the stand with no load on it. Once you get the Ap in the 3/4 to 1 sec range, put it back on the bike & ride it. You'll know once it's right.

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Whats your altitude? My instructions says anything above 6000ft use the red needle. Also it says the red needle may be desired for hot humid weather. For example above 80f with high humidity. Maybe that has something to do with your issues.

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Whats your altitude? My instructions says anything above 6000ft use the red needle. Also it says the red needle may be desired for hot humid weather. For example above 80f with high humidity. Maybe that has something to do with your issues.

Elevation is about 1100' I went with red needle because Missouri is hot & Humid. However that is during the summer. Last night when I tested bike it was 50 and humid. Maybe I should go with the blue needle until it starts warming up?

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Elevation is about 1100' I went with red needle because Missouri is hot & Humid. However that is during the summer. Last night when I tested bike it was 50 and humid. Maybe I should go with the blue needle until it starts warming up?

Hell it wouldn't hurt to try the blue needle on the 5th groove.Put the #185 MJ in which is for sea level to 4000ft elevation.Turn your fuel screw clockwise until its lightly seated, then turn it back out 1 3/4 turns.The fuel screw may need to be adjusted to get a smooth idle and crisp response. Use the stock pilot jet.

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I duno, try using a 182 main and going to clip 4...

I think this will be my first move? Maybe a 180 main jet

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Is the bike bogging when you go to WOT, or just wick to about 1/2 throttle?

Always work one step at a time.

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Is the bike bogging when you go to WOT, or just wick to about 1/2 throttle?

Always work one step at a time.

From about 1/8 throttle I whack it WOT and it will go for a very very split second then boggs to a complete stop.

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From about 1/8 throttle I whack it WOT and it will go for a very very split second then boggs to a complete stop.

I work for the local Yamaha shop as a mechanic. Try these settings for starters. 175 MJ, 45 Pilot, 100 pilot air jet, #50 Leak jet, and the blue needle at #4. With the exception of the blue needle ('cause we use the Yamaha needle) this is how we jet an 06 so they run good out here in Cali. Give it a shot.

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Won't be able to try anything until next week. St Louis Supercross is this Saturday.

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Have had a chance to tune on the bogging issue. First I changed the main jet to a 180 (Was 185) and raised clip 1 notch (was on 5 notch). Double checked the fuel screw and these changes made obsolutely no difference. So second change was pretty drastic, I move the clip all the way to bottom notch (Raising the needle) and this still made no difference. So tonight when I got home I changed from the red needle to the blue needle and still no difference. So apparently the needle is not the problem? None of these changes hurt or helped the at all. I done some reading in the manual last night and noticed that there is a Throttle Position Sensor. When I pulled the Carb off to do the JD Jetting install Idid remove this from the carb. Did not notice what position it was in when I removed it. I did not even realize (Nor did JD direction mention it) that it was adjustable until I re-installed it. So is this something that could be causing problem? I have ordered several jet (PJ 45 & 48, MJ 182, & LJ 70, 60, & 50). Tonight when testing the Blue needle I have noticed that the huge bog is from 1/4 to 3/4 throttle. If I'm barely idling along in 1st gear and barely burp (from 1/8 to 1/4) the throttle the bike jump (no bog). But if I twist it on up to 3/4 throttle (hard) it kills the engine.

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I have ordered several jet (PJ 45 & 48, MJ 182, & LJ 70, 60, & 50). Tonight when testing the Blue needle I have noticed that the huge bog is from 1/4 to 3/4 throttle. If I'm barely idling along in 1st gear and barely burp (from 1/8 to 1/4) the throttle the bike jump (no bog). But if I twist it on up to 3/4 throttle (hard) it kills the engine.

So it sounds like your 45 pilot jet and 60 or 50 leak jet are a good next experiment! I think you're narrowing it down..

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