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Please read for important Fitment for 1999?2000 Models:
The 1999?2000 models originally used a 36mm carburetor. The original carburetor, typically marked ?TMX? on the side, has an approximately 44mm outside diameter at the intake connection.
This aftermarket carburetor measures approximately 46mm outside diameter, so on 1999?2000 models the OEM rubber intake boot will need to be carefully heated and softened to allow it to stretch over the carburetor.
From 2001 onward, these models used a 38mm carburetor. Please note that aftermarket 36mm and 38mm carburetors can both measure approximately 46mm on the outside at the connection point.
Carburetor size (36mm, 38mm, etc.) refers to the inside bore diameter, not the outside diameter of the carburetor. The outside diameter should be used when checking boot/manifold fitment.
38mm Performance Flat Slide Carburetor – Custom Tuned + Jet Kit
Performance 38mm long-body flat slide carburetor for select Yamaha YZ125 and YZ250 2-stroke motorcycles.
Each carburetor is completely disassembled, inspected, reassembled and personally set up before shipping. A baseline jetting configuration is installed, and additional main and pilot jets are included for fine-tuning.
INSTALLED BASELINE JETTING
Main Jet: 170
Pilot Jet: 50
Needle: DDJ
Slide: #7 Cutaway
EXTRA JETS INCLUDED
Main Jets: 165, 172, 175, 178
Pilot Jets: 45, 48
The additional jets provide several tuning options for different engines, exhaust systems, intake setups, elevations and temperatures.
CUSTOM JETTING AVAILABLE
Let me know which motorcycle and year you are purchasing this carburetor for and I can install a more appropriate starting jetting setup before shipping instead of the standard baseline.
Typical starting setups:
Yamaha YZ125:
172 Main / 48 Pilot
Yamaha YZ250:
175 Main / 45 Pilot
These settings are intended as starting points for tuning. Final jetting may vary depending on motorcycle year, engine modifications, exhaust, airbox/filter setup, elevation, temperature and fuel/premix ratio.
If no motorcycle information is provided, the carburetor will ship with the standard:
170 Main / 50 Pilot / DDJ Needle / #7 Slide
YAMAHA YZ125 FITMENTYZ125 – 1990s Models
Many 1990s YZ125 models used large-bore performance carburetors, making this 38mm long-body mechanical flat slide a possible performance replacement or conversion.
Yamaha changed carburetor configurations throughout YZ125 production, so the dimensions of the original carburetor should be compared with the measurements listed below.
Depending on the exact year and current setup, installation may require adjustment of the:
Intake/manifold boot
Airbox boot
Throttle cable
YZ125 – 1999–2004
These are particularly good applications for a 38mm mechanical performance carburetor.
The YZ125 used 38mm-class carburetion during this period. Carburetor details and jetting varied by year, so dimensions should still be verified before ordering.
For a YZ125 application, a typical starting jetting setup is:
172 Main / 48 Pilot
If you provide your YZ125 year and basic engine setup when ordering, I can install this starting jetting before shipping.
YZ125 – 2005–2021
Later YZ125 models continued to use 38mm-class carburetion, but the original carburetor design differs from earlier configurations.
This carburetor can be considered a mechanical performance conversion for these applications. Intake boot, airbox boot and throttle cable fitment should be verified before installation.
YAMAHA YZ250 FITMENTYZ250 – 1990s Models
Many YZ250 models from this period used large-bore performance carburetion, making this 38mm carburetor a possible performance replacement or conversion.
Because the original carburetor configuration varied by year, dimensions should be verified before ordering.
YZ250 – 2000–2004
These models are good candidates for the traditional 38mm long-body mechanical flat slide configuration.
The physical dimensions of your original carburetor should still be compared with the measurements below before ordering.
YZ250 – 2005–Present
Later YZ250 models continued with high-performance 38mm-class carburetion, although the original carburetor configuration differs from some earlier models.
This carburetor may be used as a mechanical performance conversion, but fitment should be verified rather than assumed to be a direct OEM-style replacement.
Depending on the year, installation may require adjustment of the intake boot, airbox boot or throttle cable.
For a YZ250 application, a typical starting jetting setup is:
175 Main / 45 Pilot
If you provide your YZ250 year and basic engine setup when ordering, I can install this starting jetting before shipping.
CARBURETOR DIMENSIONS
IMPORTANT – PLEASE VERIFY FITMENT
This is an aftermarket performance carburetor and is not represented as an OEM carburetor.
Yamaha used several different carburetor configurations throughout YZ125 and YZ250 production. Some applications are close to the dimensions of this carburetor, while others should be considered performance conversions.
Please compare these dimensions with your existing carburetor before ordering:
Depending on the motorcycle and year, installation may require adjustment of the intake boot, airbox boot, throttle cable or other components.
TUNING INFORMATION
Standard installed baseline:
170 Main / 50 Pilot / DDJ Needle / #7 Slide
Suggested YZ125 starting setup:
172 Main / 48 Pilot
Suggested YZ250 starting setup:
175 Main / 45 Pilot
Tell me your motorcycle model and year when ordering and I can install the appropriate starting jetting before shipping.
Jetting is always considered a starting point. Final tuning will depend on:
The included additional jets provide several options for dialing in the carburetor for your particular setup.
WHAT\'S INCLUDED
38mm Performance Long-Body Flat Slide Carburetor
Installed Main & Pilot Jets
DDJ Needle
#7 Slide
165, 172, 175 & 178 Extra Main Jets
45 & 48 Extra Pilot Jets
Model-specific starting jetting available upon request
READY FOR YOUR APPLICATION
Every carburetor is completely disassembled, inspected, reassembled and personally set up before shipping.
Let me know whether you\'re installing it on a Yamaha YZ125 or YZ250, along with the year of your motorcycle, and I can install the appropriate starting jetting before it ships.
Carefully inspected, personally set up and shipped fast.
