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Author Topic: Yam RD "Blue Dream"- Ride,Maintain,Tune  (Read 35810 times)

Offline Ryan Stecken

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Yam RD "Blue Dream"- Ride,Maintain,Tune
« on: Jun 18, 2015, 06:18:22 »
Hey guys!

It took my 1 year of hard work to restore my RD 250 built 1979.Now iŽm in the middle of riding and maintaining it.This project had a steep learning curve and i will keep the curve steep :-)

The bike is now stock 250 besides a slight overbore.Carbs and intake fully stock.Pretty much any seal or gasket was replaced.
Carbs were meticulously cleaned.
She rides great,pulls like a diesel truck but I miss some kind of an "edge"  8)

For the next months i plan this:

Keep stock 28MM Carbs
-carb mod: R5 emulsion tube exchange
Y boot plus K+N air filter

For the winter i plan on doing this:

-350 conversion
Cylinders and heads already sit on my shelf
oil pump cog, primary cog and 350 clutch basket still need to get bought by me

-mild porting

-chambers-probably the ones off the LC,1WWT or 31K exhaust


this is how she looks/runs now:


Offline Ryan Stecken

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #1 on: Jun 18, 2015, 06:21:43 »
for the carb mod:

i need to replace the stock emulsion tubes with the ones off the Yamaha R5.left you can see the stock emulsion tube,right the one of the R5.
these are pics of a RD tuning website.

to make it work properly i need to drill out 2MM of the air vent of the carb,blue arrow in third pic.

Offline Ryan Stecken

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #2 on: Jun 18, 2015, 06:24:05 »
carb mod2:Y boot with K+N air filter

do you guys prefer K+N or Uni for this mod?heard that the Uni hates getting in touch with gasoline....

Offline teazer

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #3 on: Jun 18, 2015, 12:50:56 »
Q:  Why?

It's part of the so called Dave F carb mod and makes no sense.  R5 was piston ported and needed to be leaned out at small to mid throttle openings - much more than an RD with reed valves.

The whole change is designed to change teh amount of fuel at different throttle openings and loads.  Does your engine need those changes and is that teh best way to do it?

On the 400, Yamaha changed to a taller spray nozzle to richen up high RPM fueling and it's a 284 series IIRC. That changes teh fuel slope.  ON a stock bike with stock exhaust, try it on a dyno and if necessary change jets but don't just follow the crowd.

Offline Ryan Stecken

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #4 on: Jun 18, 2015, 13:00:57 »
hey teazer!thanks for chiming in!

so you mean the r5 emulsion mod is not useful performance wise?

i want to make the Y boot mod not only performance wise,of course i will need to rejet but the stock intake box with the rubber boots hinder any work on the carbs.

if i stick to stock carb emulsion tubes and y boot plus rejetting,will this increase performance?

Offline jpmobius

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #5 on: Jun 18, 2015, 18:25:59 »
I'm in the Teazer camp on the emulsion tube swap.  You should be able to have it running fine with the stock ones, adjusting jets and needle height to accommodate the air cleaner.  Good additional power can be had with some good pipes and cylinder head mods without compromising reliability.  I would tune the carbs as needed to suite the air cleaner and leave it at that until you convert to the bigger bore. 
Mobius


On a long enough timeline, the survival rate for everyone drops to zero.

1973 RD350 Yamaha build  http://www.dotheton.com/forum/index.php?topic=66498.0

Offline Ryan Stecken

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #6 on: Jun 19, 2015, 05:52:58 »
I'm in the Teazer camp on the emulsion tube swap.  You should be able to have it running fine with the stock ones, adjusting jets and needle height to accommodate the air cleaner.  Good additional power can be had with some good pipes and cylinder head mods without compromising reliability.  I would tune the carbs as needed to suite the air cleaner and leave it at that until you convert to the bigger bore.

hey mobius!
the r5 emulsion mod was anyways not really my pair of shoes,drilling around on the stock carbs is in my view not the way to go.
sorry for asking again but would you recommend the y boot plus k+n filter as a first mod?
i will need to rejet so i would buy 2 sizes bigger and 2 sizes smaller than my stock 115 mains.i would start rich then work my way down.
will i need the rejet the idle jets too?


my 350 haeds already seem to be modified.i will send pics this evening!

thanks in advance!!

Offline Tune-A-Fish©

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #7 on: Jun 19, 2015, 08:46:23 »
Not sure where you will buy the Y-Boot and filter, but HVC is $24 apart from K$N and UNI so no cost issue on either at $100><

The K$N is probably better up front and yes the UNI will become a wet sock if you clean it in gasoline. I have a minute of experiance with both and can say for sure that if you clean them often the UNI will out perform the K$N due to the fact you will begin to see the cotton break down and holes will form as it does, if you ever use air on a K$N you have blown fibers away that used to filter air, in saying that you also will ingest fibers with dirt on them over time... the UNI however will only take a cleaning for so long and the thing just starts to come apart at the seams (with warning). I would go to a track day and without asking any questions at first look and see what is being ran by the privateers... no sponsor for filters will show you what the guys who pay to play run.

IMO... Nothing is better than foam and oil  :o

Link to an awesome shop for parts: if you haven't been already  8)
http://www.hvccycle.net/y-boot-air-filter-k-n/
"I didn't come here and I ain't leavin"  Willie Nelson

"love hard, live fast, die fun" Kacey Musgraves

"Like a Wreckin Ball!" Eric Church

Offline DesertKZ

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #8 on: Jun 19, 2015, 12:19:14 »
I run the Uni's on my GT750, they just like right on a 2-stroke for some reason.
'79 CX500C Resto
'75 GT750 Smoker
'08 ZX14

Offline jpmobius

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #9 on: Jun 19, 2015, 18:07:37 »
I've been using K&Ns.  I like this conical one better than the straight - much easier to install and remove.  Part # RC-2600 for the stock y-boot on the RDs.  A section cut from a common size food can makes a perfect coupler.
Mobius


On a long enough timeline, the survival rate for everyone drops to zero.

1973 RD350 Yamaha build  http://www.dotheton.com/forum/index.php?topic=66498.0