Boyesen Accelerator Pump Cover?

James, Thanks............ :)

JD,

is the leak jet the same as the started jet? i cant find leak jet anywhere in my shop manual or anywhere in the actual yamaha parts catalog. if the started jet is the jet that you are talking about then how do i drop 20 when stock is 72 and the lowest that yamaha has is 62? thanks in advance for the help.

Starter jets and leak jets are different! :)

Here are the Yamaha part numbers the leak jet goes in the bottom of the float bowl! :)

LEAK JET Yamaha part numbers:

4JT-1494F-03-00 .JET (#40) AP 1

4JT-1494F-07-00 .JET (#50) AP 1

4JT-1494F-11-00 .JET (#60) AP 1

4JT-1494F-15-00 .JET (#70) STD 1

i cant find it in my manual. or in the parts catalog. and im afraid if i go to my local yami dealer and tell them what i need they are going to get lost when they cant find it in the computer. i just need to tell them the part #?

JD, I'm curious if you did any tests of the Boyesen cover vs stock regarding fill quantity and reservoir recycling time? Repeated rapid throttle opening can deplete the fuel in the AP reservoir quickly causing the engine to stumble. I believe the Boyesen addresses this problem by increasing reservoir capacity, which would provide better response in situations requiring several quick throttle twists, such as hill climbing. Boyesen produces quality products and I've never known them to market something simply to separate customers from their money.

JD, I'm curious if you did any tests of the Boyesen cover vs stock regarding fill quantity and reservoir recycling time? Repeated rapid throttle opening can deplete the fuel in the AP reservoir quickly causing the engine to stumble. I believe the Boyesen addresses this problem by increasing reservoir capacity, which would provide better response in situations requiring several quick throttle twists, such as hill climbing. Boyesen produces quality products and I've never known them to market something simply to separate customers from their money.

i have the #40 lj and i occasionally experience exactly what you describe (at least it feels that way to me) when i'm in technical sections on and off the throttle every now and again it will just quit. not often but enough. i'm gonna try the boyesen cover with the #40 lj and see what happens,it should be here fri. :) i also agree that boyesen is a reputable company and i'm sure a little engineering went into this product :)

i cant find it in my manual. or in the parts catalog. and im afraid if i go to my local yami dealer and tell them what i need they are going to get lost when they cant find it in the computer. i just need to tell them the part #?

Yeah just give them the part number. :) Dealers know so little about bikes! :)

Bump.....I'd like to see JD's answer to my previous question on this.

what about the leak jet on a 98 YZ400F? what do you change it to to help get rid of the bog. my bike had it bad and pops constantly while decelerating.

anyone have this problem on the 400?

the 98-99 doesn't have a removable leak jet

Here are the Yamaha part numbers the leak jet goes in the bottom of the float bowl! :)

ok, where on the bottom of the float bowl. be a little more specific please. i spent probably 20mins, at least, going over my entire carb looking for it. thanks in advance for the help.

come on. someone please help me out with locating the leak jet. i need to get my bike back together and tuned before this weekend. thanks in advance.

its inside the float bowl not the carb. when the bowl is off look down into it;brass thingy with a screwdriver slot :)

i see no leak jet. there is no little brass thing with a screwdriver slot. they're on the '00 carb's right?

ok, so i looked over the float bowl before i put it all back together but i could not find it for the life of me. im planning on going riding sunday so if i could find out what the problem is it would really help me so that i can tune it with the leak jet in while riding. thanks again for any and all help and sorry for so many questions.

Garrett

beats me,maybe the 00 doesn't have it? mine was visable right away :)

maybe JD can chime in and help me out on this one. so if mine doesnt have a leak jet then can i buy a float bowl from a '01 carb and put it on my bike or will it not work? thanks again for the help.

Just got my new Transworld Motocross mag. today and they think this cover is priceless. If you haven't got one yet good luck getting one once word spreads!

what does that have to do with this topic?

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