Leak Jet?

[sausage boy]

can anyone tell me what the leak jet is for? i have read threads where people have blocked it with solder.

[Indy_WR450]

The leak jet allows some of the AC pump squirt volume to leak back into the float bowl. #40 leak jet seems to work best for WR450. I use the "zero" leak jet for winter riding.

[sausage boy]

The leak jet allows some of the AC pump squirt volume to leak back into the float bowl. #40 leak jet seems to work best for WR450. I use the "zero" leak jet for winter riding.

thanks indi,

i have just changed the leak jet to a 40, i haven't had chance to try it yet, do you think it will help reduce the dreaded Bog?

[Indy_WR450]

The treaded bog is caused by many possible issues you just have to find out what is causing it:

Too early an AC pump squirt timing.

To little/too much AC pump squirt volume

Too rich/lean a pilot circuit.

Keep playing with the carb and eliminate the dreaded bog!

[sausage boy]

The treaded bog is caused by many possible issues you just have to find out what is causing it:

Too early an AC pump squirt timing.

To little/too much AC pump squirt volume

Too rich/lean a pilot circuit.

Keep playing with the carb and eliminate the dreaded bog! ?

i'm running red #3 160 main i dropped the pilot jet to a 42 and the leak jet to a 40, i think i have eliminated the breaded dog i just have to check the plug, the altitude i ride is 8,000' -11,000' so i'm running pretty weak now, how much power do you lose at those altitude? i also installed a "power now" not sure what it did for the bike ? i know it erased $100 from my bank

thanks

[Indy_WR450]

At 10,000. feet you lose approx 20% of the HP at seal level. That is why a 250 four stroke is so weak at high altitude. The 450 should feel more like a 350 at those altitudes. Your jetting looks good to me. I run a 45 pilot at 10,000. feet but each carb jets a little different.

[sausage boy]

At 10,000. feet you lose approx 20% of the HP at seal level. That is why a 250 four stroke is so weak at high altitude. The 450 should feel more like a 350 at those altitudes. Your jetting looks good to me. I run a 45 pilot at 10,000. feet but each carb jets a little different.

thanks Indy

[chipwich]

Guys, I dropped into my local Yamaha dealer and tried to purchase a #40 leak jet, but he couldn't find the part listed. Does anyone have the part number and an online source? I'm going with a bunch of guys to Ouray Col. in Aug, and want to make some jetting changes for altitude. I thought while I have the carb off, I'd try the leak jet swap. Any help with this would be much appreciated.

[SpeedBlitz]

chipwich, check the Jetting D-Base. The part numbers for all jets are listed there on page 4 or 5 of the database.

https://www.thumpertalk.com/forum/showthread.php?t=230021&page=4&pp=10&highlight=part+numbers