This Place Rocks

New to the sight and just spent the last hour fishing around...I just got the '06 450F and took it for its maiden voyage on Saturday...Came across many of the main problems everyone else is having with jetting, etc. After reading everything I cannot wait to get at the carb and get out this weekend. One question I do have is can I put in the 48 pilot with out changing the Main? What is the number on stock main?

Thanks for all of the information everyone has contributed and I can't wait to become more involved here...... :thumbsup:

Stock main, 165. Go to a 48 pilot, 168 main, 68 starter, 40 leak and you'll be just about perfect...SC

I have looked in the Yamaha parts list. It seems like the stock starter jet is a #65 (3TJ-1494F-13-00). The parts list however doesn't show any other available sizes :thumbsup:

Anybody know what the part number is for a #68 starter jet :thumbsup:

Just get the 72 starter jet: :thumbsup:

Yamaha Part numbers are:


3TJ-1494F-13-00 .JET (#65) AP 1

3TJ-1494F-12-00 .JET (#62) AP 1

3TJ-1494F-14-00 .JET (#68) AP 1

3TJ-1494F-15-00 .JET (#70) AP 1

3TJ-1494F-16-00 .JET (#72) STD 1

3TJ-1494F-17-00 .JET (#75) AP 1

3TJ-1494F-20-00 .JET (#82) AP 1

3TJ-1494F-18-00 .JET (#78) AP 1

3TJ-1494F-19-00 .JET (#80) AP 1

Is the starter jet only for starting and idle?

what does the starter and leak jets do? I have a 04 WR450 with 168 main and 48 pilot runs awesome! But stock leak and starter jets. Will changing the stock leak/starter jets get me anything?

There is not a lot of info around on starter jets but a bigger starter jet will generally aid COLD weather starts, vv for HOT weather.

Check out the tech and jetting articles to find out how to set up your AP circuit.(Accelerator pump). From memory, there is also some good info on Leak jets there.

Generally speaking, the timing of the AP squirt, and duration, set the initial engine throttle response when the throttle is snapped open. More fuel = less bogging/hesitation.

The LEAK jet controls how much fuel is allowed to pass (leak) back into the float bowl. So, a bigger LEAK jet allows more fuel to recirculate back into the bowl, hence LESS fuel to the AP squirt and to the engine.

The stock Leak jet is #50 and is good for HOT and humid conditions when you dont want much AP squirt fuel.

Check out Clark4131 and Indys jetting guides for exact starting points. Most call for a #40 leak, very cold conditions require #0 Jet (a soldered up whatever).




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