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Yz144 Bud Racing head?

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I was wondering if it is worth getting one of the Bud head and insert for my 05 yz144? Costs about $250, help keep it cooler and changes power delivery. I am most interested in it because I want more bottom end for the technical trails I ride.

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Posted (edited)

FMF doesn't offer a Gnarly option for the YZ125.

 

You can also re-cut the original head, decreasing the squish band height 

I did on my track ridden YZ125 and it made it run even crisper on the bottom

(stock was 1.37mm, currently at 1.05mm)

 

About the only thing you can do for best bottom end is keeping the engine fresh (piston, ring, reeds, packing)

and fine tuning the jetting on the pilot and needle circuits. Adding a flywheel weight makes the engine more tractable but

there is not much that externally easily 'bolts-on' (reeds, pipe, silencer etc.) that will improve the low end on a small bore 125/144.

 

Edited by mlatour
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The four-stroke guys use octane booster. Significant power ganes but it's illegal for racing. Some 2-stroke oils have octane booster. Try a different oil. I won't go into brands of oil here as it always sparks a huge debate.

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2 minutes ago, arthur6 said:

The four-stroke guys use octane booster. Significant power ganes but it's illegal for racing. Some 2-stroke oils have octane booster. Try a different oil. I won't go into brands of oil here as it always sparks a huge debate.

Octane does not add power.

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My advice, for what it's worth, is if you dont want this to turn into a money pit with very little low end gain (it is a small bore after all) I'd do this...

Check your compression psi on a fresh set of rings and piston. If it's not too high I would then get the head milled to correct squish. This will gain you bottom end. Make sure your jetting is properly done after that. Run premium gas to prevent detonation and pinging.

After that you might want to consider a gearing change to add more torque to each gear.

Id also consider a flywheel weight but im not familiar with what works well on a small bore for trails and woods riding. I want to guess 6oz from my experience with one on a 250 .

Also, Ive read a million times that stock pipe works best with 144's.

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If it was my money i would look into modding my 05 like a yz125x that's sold in Japan. 

I would go after the 125x cdi box for the different mapping. With that i would also look at how the 125x power valve governor was setup. More shims and a stiffer spring will make the power valve open slower giving better bottom end. 

The power valve governor is inside the right clutch cover it's what controls the opening and closing of the power valve rod.

This give you better results than just a head mod. Yes there's such a bike the yz125x is sold in Japan only. To get a 125x cdi go through webike Japan. They are awesome and fast.

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You want more grunt out in the woods toss a 52 tooth rear sprocket on with a Maxxis IT rear tire and hang on!

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13 hours ago, arthur6 said:

The four-stroke guys use octane booster. Significant power ganes but it's illegal for racing. Some 2-stroke oils have octane booster. Try a different oil. I won't go into brands of oil here as it always sparks a huge debate.

I think you are confusing oxygenated race fuel which can make more power to "octane boosters" or high octane fuel.

Otherwise no, if the engine doesn't require it, simply raising the octane count will not add power by itself.

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How can you have a 144 without a modified cylinder head?

What type of 144 kit do you have?

What is your squish clearance?

The Buds Head looks nice! but the difference in performance will be small if your cylinder head has already been modified.

You can advance the ignition timing over stock for more midrange hit but you better have a good understanding of your cylinder head dimensions and jetting. or risk detonation and possibly require race gas to tame the detonation.

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Check your squish dimension and CC your head combustion chamber and post up the info.

Did your 144 conversion not give you a significant increase in Bottom End Power?

If you have the money then buy the Bud head and post a picture of the combustion chamber

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Posted (edited)
On 6/22/2018 at 9:56 PM, mlatour said:

I think you are confusing oxygenated race fuel which can make more power to "octane boosters" or high octane fuel.

Otherwise no, if the engine doesn't require it, simply raising the octane count will not add power by itself.

Id like to think so... but my experience is that 99.99% of the population has been tricked into thinking octane makes gasoline produce more power.

The fact is that nearly 100% of the automobiles on the roads do not need anything more than regular

Edited by YZ144FirstTimer

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Here's some info from the bud catalouge for the head/domes.....guessing the interesting  bit is -10.80 and the +0.30 for the 125 and +0.30 for the 144 squish/compression numbers ?

IMG_6111.PNG

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