Author Topic: help... gx440 carb selection  (Read 5076 times)

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Offline Tyler Steinmetz

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help... gx440 carb selection
« on: June 24, 2014, 09:24:21 pm »
hey guys, ive been building a gx 440, its cammed with a fully built valve train, and a arc rod(stock length), and its port and polished, ive tried running the HR tillotson carb, but i keep blowing out diaphragms it seems, ive tried running mikuni slide carbs, and nothing seems to work... what are you guys running? or can  get my HR built up from someone to make it work.. id love to use that HR but its no good if it wont hold up. and help is appreciated. Thanks in advance
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Tyler Steinmetz

Offline veedubmikey

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Re: help... gx440 carb selection
« Reply #1 on: June 24, 2014, 11:18:55 pm »
I run this carb, it has a 200 main jet, have not touched it, out of the box and it works great, same engine you have.
   
http://www.ebay.com/itm/Mikuni-VM-Series-Round-Slide-Carburetor-with-32mm-Bore-32-mm-VM32-33-42-6010-/261344510696?pt=Motorcycles_Parts_Accessories&hash=item3cd958c2e8&vxp=mtr
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Offline Cromwell C4

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Re: help... gx440 carb selection
« Reply #2 on: June 24, 2014, 11:41:36 pm »
The HR carb should work well for your engine if it is built correctly. The diaphragms often go bad but i've ever seen one blow out. Most guys run the Tillotson HR carb or the Mikuni BN38mm. Both have their advantages/disadvantages and depending on venturi and throttle bore size, each will work better on different tracks. I several Tillotson and Mikuni race ready carbs here, or I can build your HR carb specifically for your engine. PM me for more info.
Tyler Cromwell - Cromwell Racing Engines - Specializing in Briggs Vanguard and Kohler Command V-twin engines, and Honda/Clone singles from mild to wild! Built to win, Engineered to last.

-Cromwell Racing engines and parts are home to numerous national championship titles and fastest qualifying times.

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Offline Tyler Steinmetz

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Re: help... gx440 carb selection
« Reply #3 on: June 25, 2014, 12:05:37 am »
Well I pn you, and I'd love to stic with the hr if possible, but I got the intakes for both setups
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#601 Superstock WI 3rd place 2012
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Offline Gui961

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« Reply #4 on: June 25, 2014, 12:34:15 pm »
find a nice keihin FCR carburator around 39mm or 40mm you can get them cheap on ebay.  they are found on dirt bike 250 or 450 from the early 2000 to present . its super easy to tune will work fine even if everything is wrong and its the best carb ever made for racing.. after that they switched to FI
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