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The 2-Stroke Garage => Turning Wrenches => Topic started by: rodneya on May 15, 2019, 01:31:24 AM

Title: RD400 carbs for a 350
Post by: rodneya on May 15, 2019, 01:31:24 AM
Are there any issues running Rd499 VM28 carbs on a 350 better or worse than stock?
What do you do with the pipes that went from the float bowl to the airbox when running pods?
Title: Re: RD400 carbs for a 350
Post by: Yamaha 179 on May 15, 2019, 05:40:01 AM
I run a four or five inch piece of fuel line up from the fitting up to the area between the pods.  Use a firm hose that needs no support and you'll be fine.  If I remember correctly, dangerous assumption, it is to equalize the air pressure in the float bowl with the atmosphere.
Lyn Garland
Title: Re: RD400 carbs for a 350
Post by: SUPERTUNE on May 15, 2019, 08:10:28 AM
Carbs are both 28mm's, so not a big difference other than things like site plug for syncing carbs and a ball in the airjet system.
You can plug them if doing a Primary needle jet conversion...(known as the Dave F mod)
If running crossover/boost bottle system and pipes this would be the mod you would do.
If staying on the stock beed NJ system do as Lyn said!
Chuck
Title: Re: RD400 carbs for a 350
Post by: rodneya on May 15, 2019, 11:31:44 AM
Can i use the 350 throttle cable?
Title: Re: RD400 carbs for a 350
Post by: m in sc on May 15, 2019, 11:36:52 AM
only if its a cable for a 350 low top carb. :twocents:
Title: Re: RD400 carbs for a 350
Post by: rodneya on May 15, 2019, 01:33:22 PM
Thanks  for the info
Title: Re: RD400 carbs for a 350
Post by: rodneya on May 17, 2019, 10:16:51 AM
Quote from: SUPERTUNE on May 15, 2019, 08:10:28 AM
Carbs are both 28mm's, so not a big difference other than things like site plug for syncing carbs and a ball in the airjet system.
You can plug them if doing a Primary needle jet conversion...(known as the Dave F mod)
If running crossover/boost bottle system and pipes this would be the mod you would do.
If staying on the stock beed NJ system do as Lyn said!
Chuck

The bike I am working on will have a Vape CDI ignition from Economy, VForce 3 reeds, porting (unknown, it was a race bike is the 70's, then sat in boxes for 30 years), pods and chambers.
Am I better off with the Dave F mod or going to a larger carb or flat slide?
Title: Re: RD400 carbs for a 350
Post by: SUPERTUNE on May 17, 2019, 06:20:18 PM
I would say yes, do the primary jet mod with a crossover/boost bottle setup.
Chuck
Title: Re: RD400 carbs for a 350
Post by: rodneya on May 21, 2019, 10:32:35 AM
Pretty sweet deal. Picked the carbs up and they look to be in pretty good shape and the  Dave F mod is already done. They even have 2.o air jets installed.
Not bad for 100 Canadian