Rebuilt RD needs choke on to pull load

[4schizzle]

Just fired my RD 350 after rebuild.  New seals, bored, new pistons, and rebuilt carbs.  The bike started first kick almost.  Runs and idles.  However it will not pull load without choke on.  I was told i could have switched the float bowls.  Is this something? 
Thanks

[m in sc]

well, if it only works w the choke on, then the bowls are correct. yes you can swap them but it will make the choke NOT work.

sounds like you just have a lean condition. probably in the needle if it weill idle w/out choke when its warm.  .02

[4schizzle]

How are the bowls different?  The clip is in the middle, 150 main jet and 27.5 pilot jet i believe is what i used in the rebuild kit.   

[4schizzle]

stock pipes and pod uni air filters. 

[m in sc]

one has the bottom drilled for the feed the choke. the other is blanked.

ok, theres quite a few issues we need to go over though.

1: if you used the needles in the rebuild kit, take them out, they are incorrect. use the stock ones. k&l kit or keyester? wrong profile.  the 'yl1' needles they  use are patterned after UK 350-b ones and poorly so.


2: you can not run just one size up from mains with uni filters. that's way, way too lean. On a stock rd with unis, your main jet will be in the 190-230 range. I'm not kidding. I know it sounds ridiculous but trust me on this one. run ti for any length of time and you will absolutely hole a piston.  remember, the 75s used a ballfed air filter and  smaller main, but an unbaffled rd element puts stock jetting at 140 mains.  running unis are fine but you have to jet it up. a lot.   

3: IF you are not going to run the stock airbox, then see above. IF you have the stock airbox an the bike is stock otherwise, you can get away with 150 mains. mods are going to make a difference as well. 

[4schizzle]

one has the bottom drilled for the feed the choke. the other is blanked.

ok, theres quite a few issues we need to go over though.

1: if you used the needles in the rebuild kit, take them out, they are incorrect. use the stock ones. k&l kit or keyester? wrong profile.  the 'yl1' needles they  use are patterned after UK 350-b ones and poorly so.


2: you can not run just one size up from mains with uni filters. that's way, way too lean. On a stock rd with unis, your main jet will be in the 190-230 range. I'm not kidding. I know it sounds ridiculous but trust me on this one. run ti for any length of time and you will absolutely hole a piston.  remember, the 75s used a ballfed air filter and  smaller main, but an unbaffled rd element puts stock jetting at 140 mains.  running unis are fine but you have to jet it up. a lot.   

3: IF you are not going to run the stock airbox, then see above. IF you have the stock airbox an the bike is stock otherwise, you can get away with 150 mains. mods are going to make a difference as well.

I used the Yamaha RD350 Carb Repair Kit by K&L from economy cycle.  I still have the stock needles i took out of the carbs.  It is supposed to be going to Jemco at the end of the month for expansion chambers.  How does a 200 main sound?  Do the pilot jets also need to be larger?  If so any suggestions.  I do not have an airbox and not planning on running one.  Also deleted the oil injection.  Premix. 



Thanks,

[m in sc]

put the needles from the stock carbs back in, and  200 is a good starting point. also might want to up the pilot to a 27.5 or a 30.

[4schizzle]

Also right now just running it with stock pipes and unbaffled mufflers.  Got a cheap set to start it up because i am putting expansion chambers on it. 

[4schizzle]

I have 27.5 in it now, but will order 30's.  If there is an issue with my stock needles.  Rocky Mountain ATV has Yamaha OEM needles: Part# 360-14116-04-00.  Is this the needle to order? 

Thanks

[4schizzle]

Mikuni Neddle, 5L1 13-5L1 is this the right needle?

[m in sc]

i think so. I don't have stock carbs on anything except the r5 and the ds7 anymore.  but i know rocky mountain did sell them. before you go through all that, why not to the dave f mod. drill the airjet out to 2.00 mm, get the different jet tubes and 5dp7 needles. common old school mod, will work really well w your setup. john does sell the kit to do this as well. I know, more money, but at the end of the day, this is really worth while. 


https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/fuel-and-airintake/carburetor-rebuild-kits-parts-related/popular-carb-mod-kit-for-rds/

[4schizzle]

I think that is what i will do.  I will order the dave f mod.  What get drilled out the airjet?  Do you just need to drill it out bigger with the drill bit included?   

[m in sc]

yes, theres directions. it the one at the 6 o clock position looking at the bellmouth.

[4schizzle]

Thanks for info. Will order and update. This forum has a lot of knowledge and has been a great help!

[4schizzle]

I did the Dave f carb mod. 200 main jet, 27.5 pilot jet, clip 3rd, drilled air jet, air screw 1 turn out, and used old needle with new velocity jet/tube.  Hard to start and still only will pull a gear with choke on. Have spark cause I checked it because it was so hard to start. Any ideas? Thanks again

I still don't have the chambers yet. Using stock pipes baffles removed with pod filters.






quote author=m in sc link=topic=5374.msg45542#msg45542 date=1678136421]
i think so. I don't have stock carbs on anything except the r5 and the ds7 anymore.  but i know rocky mountain did sell them. before you go through all that, why not to the dave f mod. drill the airjet out to 2.00 mm, get the different jet tubes and 5dp7 needles. common old school mod, will work really well w your setup. john does sell the kit to do this as well. I know, more money, but at the end of the day, this is really worth while. 


https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/fuel-and-airintake/carburetor-rebuild-kits-parts-related/popular-carb-mod-kit-for-rds/
[/quote]