Mikuni 24mm Yamaha TTR125 PreJetted Carburetor w/ Blue Billet Cap

Additional Information

Fitment Information

• Description says "Includes tuning jets for future performance modifications". Cool. Can you specify these? I often go from sea level to about 6-7000 ft, and need to jet accordingly.

  Our TT-R125 carb kit comes with with a 150 main jet installed. This is perfect for stock bikes ridden from sea level to about 3500 feet. We also supply as 145 main to cover riding to about 5000 feet as well as a 140 main jet which will cover operations to about 7500 feet.
  I have attached a link to installation manual for your kit. This will prove helpful to you:
  http://www.vintagebikebuilder.com/tt-r125-mikuni-carb-carb-convesion.html
  

  Answer by: rick c (Admin) on Jan 29, 2020 11:33:00 AM

• Do I need to buy a new throttle assembly or swap anything out?

  I would depend on the year of your bike. This kit is designed to fit all models of the TT-R125 including the basic early model (kickstart only), the E model (electric start), the L model (larger front wheel and disc brake) and LE model (larger front wheel, disc brake and electric start).
  Our kits are designed to use a single, stock cable from the 2000-2007 models. If you have a later model, your dual cables will not fit and you’ll need to obtain a stock cable from a 2000-2007 model. These cables are available from a Yamaha dealer or you can often find good new and used cables on eBay.
  We have learned from several customers using post-2008 models, that the pull side of the throttle can be used and some even say the pull cable can also be used. We don't know this for a fact, but it seems that you can use a 2007 cable with a later model throttle, just by using only the pull side.
  I have attached a link to assembly instructions from for our kit:
  http://www.vintagebikebuilder.com/tt-r125-mikuni-carb-carb-convesion.html
  

  Answer by: rick c (Admin) on Nov 25, 2019 3:26:00 PM

• I'm the third owner of ttr1125 last owner said he did the big borer on the bike. I do not know which one the 24mm or 26mm
  Thank you for your time.

  You would need extensive headwork to benefit from the VM26. We almost always recommend the 24, over the 26.

  Answer by: Web Support (Admin) on Jan 4, 2021 10:47:00 AM

• is this a bolt on swap or do i need to use a aftermarket air filter?

  This is a bolt-on swap and no aftermarket filter is used. We sell a bunch of these and our customers love them!
  Below is a link to the instructions I've put together. At the moment, it's on my personal website and I haven't yet uploaded them to our Niche website. These will give you an idea of how easy the installation is.
  http://www.vintagebikebuilder.com/tt-r125-carb-carb-convesion.html
  
  

  Answer by: rick c (Admin) on Jan 11, 2019 10:10:00 AM

• I’m having trouble getting this jetted properly to run at 10,000ft elevation. I have open air box, aftermarket exhaust. Any suggestions on the jetting?
  

  As you go higher, you need to limit the fuel going into the carb. This is called "leaning the mixture." Our TTR kit comes with a 150 main jet. The main jet effects the top 25 percent of your RPM range. At 10,000 feet, you will probably need a 135-137 main jet. After you install the new main, you'll need to install a new plug and then run a test. This is outlined in a MIkuni Tuning and Jetting manual I have attached below.
  You will also want to lean the mid-range. You can do this by raising the clip on the jet needle one notch. This will drop the needle deeper into the needle jet and limit fuel. Again, you will need to install a new plug and run another plug test. These tests will let you know if you running either too rich or lean. It will also indicate if you need to drop the needle further. The pilot jet primarily controls the mixture at idle. You should probably drop this jet down to a 30 or so. But, you will also need to adjust your air/fuel mixture screw after you do this. I am going to forward two important links that will help you with jetting. Both are from my website. The first is an installation guide for the TT-R125 carb kit we sell. This will have a section on adjusting your air/fuel mixture screw. You can also read this over to see if you made any mistakes during installation:
  http://www.vintagebikebuilder.com/tt-r125-mikuni-carb-carb-convesion.html
  The other link is for a Mikuni tuning and jetting manual I put together. You should pay special attention to the section labeled "Tuning and Jetting." But, if you take an hour or so and read the sections before that, it will give you an excellent understanding of how the Mikuni works and what parts of the carb affect different areas of the RPM band.
  http://www.vintagebikebuilder.com/mikuni-tuning-and-jetting-guide.html
  Note: But sure you use new plugs when testing.
  Here are links for the jets you will need:
  http://www.nichecycle.com/ncs/categories/carburetor/mikuni-parts-by-category/jettting-tuning/genuine-mikuni-main-jets/vm4-042-vm4-042-main-jet-by-mikuni.html
  http://www.nichecycle.com/ncs/categories/carburetor/mikuni-parts-by-category/jettting-tuning/pilot-jets/vm22-210-vm22-210-pilot-jet-by-mikuni.html
  
  

  Answer by: rick c (Admin) on Jan 10, 2020 12:25:00 PM