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Author Topic: Yam RD "Blue Dream"- Ride,Maintain,Tune  (Read 47110 times)

Offline crazypj

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #250 on: Jul 19, 2016, 23:53:12 »
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?

 I haven't read through every post but I did look at all the pictures  8)

 Not only is it NOT a performance tweak it will make bike run very rich at certain throttle openings. and richen u top end  (probably why it worked with some expansion chambers?)
The reed valve makes motor work mote like a fourstroke as far as airflow is concerned
Pretty sure you would have a ton of people with VM30's on their CB350's who would 'take the stock RD ones off your hands  ;)

You know when a clutch gets down to the EOL and slips a little, builds up some glaze and then the lever get the jitters... With that perch and lever setup you can quick adjust for hot and cold running so you are in the meat all the time like a hydro :o

 I thought that was stock for a brand new Barnett clutch set  ;D
 The stock Yamaha reed blocks are pretty horrible -BUT- they can be modified to work at least as well as the Boysen's that used to be sold
Back in the day Micron made the best exhaust for the RD250 they probably sold the design though?
air cooled TZ pipes can be fitted to 400 but I don't remember seeing them on 250
 Did you check oil pump plunger diameter and stroke length?
It's such a long time since I've done one I forget if they have different diameters for 350 and 400?
To get studs out of crankcase you have to heat the case around stud as Yamaha loctite them in. Probably need around 350f to loosen them off (and they are styill tight)
Locking two nuts together rarely works I had to buy a Snap-On CG500 stud remover and then get metric collets to go in it (they do a metric version nowadays  ::) )
you shim plunger to get correct stroke length which gives correct oil delivery
 You shouldn't have to 'clutch it' to get front wheel up the opposite is usually the case with 350/400 (and even the 250 if on stock gearing)
 just roll it on in third until you hit about 5k  shift to second and open it up. It helps if you push the forks a little and open up as they rebound. Should be able to get to balance point then run through the gears as XB said way earlier (not that I would advocate running around on one wheel  ;) )
 
« Last Edit: Jul 20, 2016, 01:05:52 by crazypj »
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Offline TranceMachineVienna

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #251 on: Aug 02, 2016, 14:36:22 »
long time no hear.

pretty much rode the ish out of my RD, I got ride of the right cylinder head leak ( new original gasket, so no fancy tricks whatsoever)
here are some pics of my last rideout in austria i wanted to share with you guys  :)


Offline TranceMachineVienna

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #252 on: Aug 07, 2016, 10:27:39 »
Hey guys just ran into an offer..
A guy wants to sell me his genuine mikuni 34's he used to run on his rd400...
What you guys say...are these worth the hassle?how will they affect drivability?
Thanks in advance!

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Offline julian.allard66

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #253 on: Aug 07, 2016, 13:15:32 »
You'll lose mid range and gain top end.

Offline der_nanno

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #254 on: Aug 23, 2016, 07:27:12 »
We'd have to do a lot of port-work and the gains would be... limited. Especially considering your style of riding, I would advice against it. Go for some 30ies or 32s and we'll do a mild port-job in Winter, if you want.

Cheers,
Greg
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Offline TranceMachineVienna

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #255 on: Aug 23, 2016, 07:45:12 »
We'd have to do a lot of port-work and the gains would be... limited. Especially considering your style of riding, I would advice against it. Go for some 30ies or 32s and we'll do a mild port-job in Winter, if you want.

Cheers,
Greg

I didnt go for the 34Žs for exactly the reasons you listed above (thanks mobius for your insight).
Sounds good man, lets see what the XS will need in winter time + money wise....my motorcycle projects are slowly eating up my ressources ;-)

Offline teazer

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #256 on: Aug 23, 2016, 12:34:00 »
My RZ350 has stock 26mm carbs and makes about 60HP.  No need for bigger carbs on a street motor.

Next time you have the heads off, look and see if you can machine the barrels to get rid of that step and allow you to use a 400 head gasket, but check compression when you do that and set squish while you are at it.  That would eliminate the split level effect that Mobius was describing.

Offline julian.allard66

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #257 on: Aug 23, 2016, 16:35:49 »
I agree with Teazer, my tuned 350 YPVS did about 135 mph and had the stock carbs and airbox, you only need 34s if you're going for a full F2 tune.

Offline TranceMachineVienna

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #258 on: Aug 24, 2016, 04:38:09 »
My RZ350 has stock 26mm carbs and makes about 60HP.  No need for bigger carbs on a street motor.

Next time you have the heads off, look and see if you can machine the barrels to get rid of that step and allow you to use a 400 head gasket, but check compression when you do that and set squish while you are at it.  That would eliminate the split level effect that Mobius was describing.

Will do!

My aim was anyways to work on the sealing problem in winter, possibly using the O Ring method Mobius advises me of.
Somehow I did manage to seal the right cylinder (new gasket,properly torqued).

The stock 250 had the 400 gasket design, never ran into any sealing problems back then.
I also will need to go back to the stock exhausts for MOT, so it will be rejetting time, and see how she does with the stock baseball bats (of course I will switch back the time when I get MOT  :))

I guess this is one the most asked questions in 2 stroke tuning but is there a way to gain low and middle range power?
All tuning seem to be up really high but losing down low power...not quite useable if you are a street rider.

Offline jpmobius

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Re: Yam RD "Blue Dream"- Ride,Maintain,Tune
« Reply #259 on: Aug 24, 2016, 12:09:35 »
I guess this is one the most asked questions in 2 stroke tuning but is there a way to gain low and middle range power?
All tuning seem to be up really high but losing down low power...not quite useable if you are a street rider.
Well, yes and no.  Very difficult to get more power across the rev range.  Without valves, 2 strokes rely principally on sonic wave activity to move things in and out of the engine.  So if you design for max power, you want to have that happen as often as possible and focus on max rpm.  Or you can design for more friendly to drive lower rpm and/or broader rev range, but if the power happens less often due to low revs or is compromised by not designing for a target speed you have - well - less power!  The solution is to design mechanical valves to add control to how things move in and out and a good example are the reed valves on the intake side of engine you have.  They are of tremendous benefit for driveability but can be an obstruction if max power at max rpm is the goal.  The predecessor of the reed valved RD's was a nearly identical bike without them.  Every bit as powerful as an Rd, but harder and slower to ride.  You can also place valves in the exhaust like the successor YPVS liquid cooled bikes but obviously if this is the intent you'd be better off starting with that to begin with!  So for the most part you will have to make a trade off.  The guys that designed your engine had the goal of making it as powerful as possible within some parameters.  Keeping it quiet and driveable high on the list.  You can make it faster and louder pretty easily, but faster than that will result in either swapping low and mid range optimization for higher rpm optimization to take advantage of the increase in power pulses per minute or adding mechanical complexity and the associated weight.  High speed and complexity yield a shorter lifespan and lower reliability.  And for what it's worth, there is a usability factor that will eventually come into play.  I have a pretty seriously hot rodded RD myself.  Runs great.  Totally awesome to ride around on - for about half an hour.  It's no good for around town - I live in Florida and it is too hot to ride it in city traffic for long as it gets hot.  Out of town it's great, but rather a lot of work to drive as it drives really fast a lot more comfortably than just driving "normally".  I can blast around for about half an hour before I get tired, and start worrying about losing concentration or meeting new policemen, plus it's loud as hell.  So most of the time I drive my stock bike.  Not exactly blindingly fast, but always super fun and I can thrash it for hours (until I get tired of putting gas in it!).
Mobius


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