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The 2-Stroke Garage => Turning Wrenches => Topic started by: motodreams on June 17, 2019, 07:52:31 PM

Title: RD350 28mm carbs on RD350LC
Post by: motodreams on June 17, 2019, 07:52:31 PM
Hi All,

After having difficulty finding hte stock 26mm LC carbs I am going with the AC 28mm which are much more readily available.

Curious on a starting point for jetting.  The RZ and LC run well over 200 jets without the PJ.  The AC carbs are 140 mains stock.  Both engines are the same displacement. 

Is there a reason for this large gap in jetting?  Both are Mikuni carbs.

Trying to figure out the 'why' on this one.

Thanks!
Title: Re: RD350 28mm carbs on RD350LC
Post by: m in sc on June 17, 2019, 08:27:50 PM
lc and ac rd will jet close.(IVE USED 28MM AC CARBS ON AN LC W CHAMBERS, VERY CLOSE JETTING TO AN ACRD WITH CHAMBERS.) however, the jet tubes and everything else are completely different between the stock carbs, so toss those stock numbers out unless you plan on being bone stock otherwise.  how will the lc be set up? intake, pipes, porting, etc.

forget about the rz too.
Title: Re: RD350 28mm carbs on RD350LC
Post by: pdxjim on June 17, 2019, 08:55:53 PM
Just a reminder, if you don't have the Mikunis already,  PWK28s are on sale at Bike Bandit for $119 each.
Title: Re: RD350 28mm carbs on RD350LC
Post by: lawnboy on June 17, 2019, 09:04:03 PM
man would love one to replace the oko i've been fighting on my kitted lambretta but site says "sold out"
Title: Re: RD350 28mm carbs on RD350LC
Post by: pdxjim on June 17, 2019, 09:49:49 PM
https://www.bikebandit.com/oem-parts/detail/kawasaki/15003-1643/b778173 

Works for me!
Title: Re: RD350 28mm carbs on RD350LC
Post by: lawnboy on June 17, 2019, 10:59:56 PM
sweet! i've got 65 bandit bucks i've been sittin on
thanks for the link jim
Title: Re: RD350 28mm carbs on RD350LC
Post by: motodreams on June 18, 2019, 02:05:44 AM
This is helpful and explains a whole lot.

I'm running stock chambers (early CDN RZ) with pod filters at 3000ft elevation.  Should I try a 150 in there to start or is that still too small?

With the differing jet tubes this is essentially allowing more fuel to flow with a smaller jet?  Is that the correct theory?

Quote from: m in sc on June 17, 2019, 08:27:50 PM
lc and ac rd will jet close.(IVE USED 28MM AC CARBS ON AN LC W CHAMBERS, VERY CLOSE JETTING TO AN ACRD WITH CHAMBERS.) however, the jet tubes and everything else are completely different between the stock carbs, so toss those stock numbers out unless you plan on being bone stock otherwise.  how will the lc be set up? intake, pipes, porting, etc.

forget about the rz too.
Title: Re: RD350 28mm carbs on RD350LC
Post by: quocle603 on June 18, 2019, 06:09:50 AM
Always buy a number of jets within a range and start at your highest and work your way down.
Title: Re: RD350 28mm carbs on RD350LC
Post by: m in sc on June 18, 2019, 06:52:44 AM
if you have stock aircooled 350 carbs and pods and chambers, you need to start jetting at 250-260 mains, 30 pilots. the lack of airbox makes the biggest difference.  yeah, that big of a jump, im not kidding. then work up or down from there.  :twocents:

Quote from: motodreams on June 18, 2019, 02:05:44 AM
This is helpful and explains a whole lot.

I'm running stock chambers (early CDN RZ) with pod filters at 3000ft elevation.  Should I try a 150 in there to start or is that still too small?

With the differing jet tubes this is essentially allowing more fuel to flow with a smaller jet?  Is that the correct theory?

Quote from: m in sc on June 17, 2019, 08:27:50 PM
lc and ac rd will jet close.(IVE USED 28MM AC CARBS ON AN LC W CHAMBERS, VERY CLOSE JETTING TO AN ACRD WITH CHAMBERS.) however, the jet tubes and everything else are completely different between the stock carbs, so toss those stock numbers out unless you plan on being bone stock otherwise.  how will the lc be set up? intake, pipes, porting, etc.

forget about the rz too.
Title: Re: RD350 28mm carbs on RD350LC
Post by: motodreams on June 18, 2019, 09:07:40 AM
Thanks M!  Much appreciated.  I will start there. 

That is also close to where I would expect the stocker 26mm carbs to jet as well.