Which carburetor to buy?

[RB55]

Top quality: Mikuni vm18 carburetor. It's very expensive ($75 or so) but you get what you pay for...a extremely well-made Japanese performance carburetor. Otherwise I'd buy a CNS or stick to tuning the HT. Mine gave me a lot of issues until i re-jetted from 0.70mm to 0.60mm with a mini drill bit and some solder. Heat up the solder with a torch until it drips down into the hole. While the solder is still liquid, insert the drill bit and move it up and down. As the solder cools, remove it. This almost completely eliminated the 4 stroking and bogging I experienced on my bike. Yes, it still has minor issues, but after all, its a 70$ hunk of Chinese metal, what do you expect...

 

[LewieBike]

The NT carb seems to be the one everyone gets the best performance out of for the least amount of extra cash spent . I instead ordered a Yamaha PW 50 carb not unlike this one except for the choke cable and airbox..

Yamaha Zinger PW50 Carb-Cables_Airbox

 

[Txsandman]

Top quality: Mikuni vm18 carburetor. It's very expensive ($75 or so) but you get what you pay for...a extremely well-made Japanese performance carburetor. Otherwise I'd buy a CNS or stick to tuning the HT. Mine gave me a lot of issues until i re-jetted from 0.70mm to 0.60mm with a mini drill bit and some solder. Heat up the solder with a torch until it drips down into the hole. While the solder is still liquid, insert the drill bit and move it up and down. As the solder cools, remove it. This almost completely eliminated the 4 stroking and bogging I experienced on my bike. Yes, it still has minor issues, but after all, its a 70$ hunk of Chinese metal, what do you expect...

Does the mikuni require any modifications to hook up?

 

[Street Ryderz]

Does the mikuni require any modifications to hook up?

It requires a 23mm o.d. on the intake to just bolt on.

 

[Member 30059]

Yikes not a CNS. Dellorto sha 15/15 for basic builds, or a vm18 for mild-mid performance build. Those are the only way to go

 

[Txsandman]

The carbs usually come with a 70 jet. You'll need to go smaller. Here's a link for a 5 pack 65 thru 70. I'd order a pack of 65-70 and a pack of 60 to 65. Keep reducing the size until it just stops 4 stroking. It helps if you drill another small hole in the emulsion tube in the carburetor also. It helps the fuel atomize better. There's a description on how to do that on the forum just use the search.

Fine Tuning Jets - High 60s | Bicycle Motor Works

5mm Fine Tuning Jet Set fits stock "NT" Carburetors, SHA 15/15 Carburetors and many others! Your set will include one of each of the following sizes. .66, .67, .68, .69, .70

bicyclemotorworks.com

so when the bike starts 4stroking at about 55% throttle, i thought i should add that it doesnt seem to bog down. Do you still think i need to re-jet in the .65-.70 range? JW because in the past ive had bikes bog down at a certain point in the throttle range.

 

[GreasyChris]

so when the bike starts 4stroking at about 55% throttle, i thought i should add that it doesnt seem to bog down. Do you still think i need to re-jet in the .65-.70 range? JW because in the past ive had bikes bog down at a certain point in the throttle range.

if it is 4 stroking then it is running rich, just keep decreasing jet size until the 4 stroking stops. the nt carb is the easiest to tune and without any modifications probably works the best. i use a 21mm oko carb on my first bike and a 24mm oko carb on my second build. they are both about have the price of the mikuni and work great but youll need an intake with a 32mm inlet to attach the carb to or make your own adapter to attach the carb.

 

[Txsandman]

if it is 4 stroking then it is running rich, just keep decreasing jet size until the 4 stroking stops. the nt carb is the easiest to tune and without any modifications probably works the best. i use a 21mm oko carb on my first bike and a 24mm oko carb on my second build. they are both about have the price of the mikuni and work great but youll need an intake with a 32mm inlet to attach the carb to or make your own adapter to attach the carb.

Ok thanks for the useful information.

 

[Mad Willy]

VM18 or NT. 21mm carbs are a pain to tune, but doable if yer a fiddler.