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Author Topic: Yamaha rd350 Road Racer Liquid Cooled!!  (Read 42084 times)

Online Hurco550

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Re: Yamaha rd350 road racer
« Reply #50 on: Jul 05, 2016, 18:21:44 »


BTW I have stock shocks in decent shape for cheap.

Shocks came in, good nick as described! Thanks man!
"If you just picked up a drug habbit instead of a kawasaki triple at least you could get high while you waste money"
~ bradj
1988 tw200, the swamp donkey: http://www.dotheton.com/forum/index.php?topic=75455.0
2006 Suzuki DR650 Adventure monowheel trailer build: http://www.dotheton.com/forum/index.php?topic=75033.0
1976 BMW R90/6 farkilitious: http://www.dotheton.com/forum/index.php?topic=74349.msg882477#msg882477
1975 RD350 Road Racer: http://www.dotheton.com/forum/index.php?topic=70652.msg833688#msg833688
1976 GT250 Rebuild: http://www.dotheton.com/forum/index.php?topic=64973.new#new
Full Custom Pit Bike: http://www.dotheton.com/forum/index.php?topic=66954.new#new
1971 Yamaha 90cc twin HS1: http://www.dotheton.com/forum/index.php?topic=70498.0
"much ingenuity with a little money is more profitable and amusing than much money without ingenuity" - Arnold Bennet

Offline davedogg

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Re: Yamaha rd350 road racer
« Reply #51 on: Jul 06, 2016, 13:50:46 »
No problem.  Good idea with the grease.  Let's see some smoke!

Online Hurco550

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Re: Yamaha rd350 road racer
« Reply #52 on: Jul 07, 2016, 17:12:50 »
Not much to update really, besides  receiving fork seals and neck bearings in the mail. Von yinzer left a pile of xs650 parts in my garage, and as a rent payment, I'll be rebuilding my front end with his  34mm tubes in place of the crusty ones currently on the Rd chassis.



 
I dig the fairing, but it looks pretty good with the r5 body works on it too.


Still trying to get the specs I need to build the motor I want. Trying to explain it is harder. Basically, it will be a street bike, but a toy. I don't expect this to be my daily rider, but I want to be able to do an hour or so ride when I can to a vintage bike night or the Sunday ride to the twistys ect. I just know (er have heard) that these motors have plenty of power to unlock, but I don't want it to be completely useless on the street. It may see a track now and again, for fun, not competition, and a track only bike is not the end goal. I want a zippy bike to go have the kinda fun you can have on a two stroke ripping around the roads, but I don't want to be so close to the edge that I can't ride it and i don't want to only make power over 10k rpm. I think that is possible on this bike, and I appreciate you guys that have already helped me in trying to know what to do to obtain it. Will be slow going for the next couple weeks, as I'm taking a vacation for a few weeks to the hot, sweaty dirty south, but I still have this project on the front of my mind. Headed to mid Ohio tomorrow as well to see what kind of goodies I can drag home as well.

"If you just picked up a drug habbit instead of a kawasaki triple at least you could get high while you waste money"
~ bradj
1988 tw200, the swamp donkey: http://www.dotheton.com/forum/index.php?topic=75455.0
2006 Suzuki DR650 Adventure monowheel trailer build: http://www.dotheton.com/forum/index.php?topic=75033.0
1976 BMW R90/6 farkilitious: http://www.dotheton.com/forum/index.php?topic=74349.msg882477#msg882477
1975 RD350 Road Racer: http://www.dotheton.com/forum/index.php?topic=70652.msg833688#msg833688
1976 GT250 Rebuild: http://www.dotheton.com/forum/index.php?topic=64973.new#new
Full Custom Pit Bike: http://www.dotheton.com/forum/index.php?topic=66954.new#new
1971 Yamaha 90cc twin HS1: http://www.dotheton.com/forum/index.php?topic=70498.0
"much ingenuity with a little money is more profitable and amusing than much money without ingenuity" - Arnold Bennet

Offline julian.allard66

  • Posts: 279
Re: Yamaha rd350 road racer
« Reply #53 on: Jul 07, 2016, 17:37:28 »
Sounds like you want a road tune for it, start by getting the squish right and then change the ports if you feel the need, on UK pump petrol 0.9 mm used to be the right squish, but it'd probably need to be more than that on modern US fuel as it has a high ethanol content

Offline Redbird

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Re: Yamaha rd350 road racer
« Reply #54 on: Jul 07, 2016, 17:53:29 »
Subscribed.

I've got odd and end spare parts from my DS7 build. Holler if you need anything ;)
When you are Dead, you don't know that you are Dead. It is difficult only for Others.

It is the same when you are Stupid.

Offline teazer

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Re: Yamaha rd350 road racer
« Reply #55 on: Jul 07, 2016, 19:18:41 »
Ports on those motors are relatively mild in terms of port timing and width and there is a lot of room to improve things without going stark raving mad.  You don't want a race tune with powerband from 9,000 to 10,500 and nothing either side.  You can go beyond a mild tune though as long as you keep the end objective in mind.

What's up with that pipe?  It looks as if it is very low compared to most RD pipes.  It could just be a badly shaped header pipe.

Offline davedogg

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Re: Yamaha rd350 road racer
« Reply #56 on: Jul 07, 2016, 23:32:33 »
My RD's are very reliable and enjoyable. Stock is fun. I've taken my modified 350 and stock 400 on 100 + trips. But there are simple add ons to unleash some power. My experienced tuner just rode my bike the other week and was impressed (so I know I did things right)  This may be overkill but here are some performance mods I did to get you started:

2 into 1 K&N Y boot (more air) ~$90
Dave F/ Dale A carb mod (more air needs more gas) I'm not an expert. I just know it works.
RZ/Banshee crossover manifold and tube (erases flat spot around 5k) ~$50
YZ125 Reeds petals (consensus for better low end torque) ~$40
Heads squished and o-ring (better compression = more power) look up Scott Clough Racing ~$190
Good set of pipes. DG's are ok. I would get SpecII ~$500-700

Using both Wiseco (forged) and ProX (cast) pistons I like the ProX more. I'm sure there is more but this is all I can think of off the top of my head.

Online Hurco550

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Re: Yamaha rd350 road racer
« Reply #57 on: Jul 08, 2016, 20:20:38 »
Subscribed.

I've got odd and end spare parts from my DS7 build. Holler if you need anything ;)
Thanks a million man, I may hit you up sometime

What's up with that pipe?  It looks as if it is very low compared to most RD pipes.  It could just be a badly shaped header pipe.

I have no idea. I thought that they seem like they hang awfully low as well. I was thinking it could be something about flow with a less sharp bend. I would shorten them, but besides the basics of how chambers work, I don't know how the changes will effect (for better or worse) performance by shortening the head pipes.
My RD's are very reliable and enjoyable. Stock is fun. I've taken my modified 350 and stock 400 on 100 + trips. But there are simple add ons to unleash some power. My experienced tuner just rode my bike the other week and was impressed (so I know I did things right)  This may be overkill but here are some performance mods I did to get you started:

2 into 1 K&N Y boot (more air) ~$90
Dave F/ Dale A carb mod (more air needs more gas) I'm not an expert. I just know it works.
RZ/Banshee crossover manifold and tube (erases flat spot around 5k) ~$50
YZ125 Reeds petals (consensus for better low end torque) ~$40
Heads squished and o-ring (better compression = more power) look up Scott Clough Racing ~$190
Good set of pipes. DG's are ok. I would get SpecII ~$500-700

Using both Wiseco (forged) and ProX (cast) pistons I like the ProX more. I'm sure there is more but this is all I can think of off the top of my head.
I should change the title of this thread, the frame is rd350, but the motor I'm using will be the piston port r5 motor. Thanks for all the great info though!
"If you just picked up a drug habbit instead of a kawasaki triple at least you could get high while you waste money"
~ bradj
1988 tw200, the swamp donkey: http://www.dotheton.com/forum/index.php?topic=75455.0
2006 Suzuki DR650 Adventure monowheel trailer build: http://www.dotheton.com/forum/index.php?topic=75033.0
1976 BMW R90/6 farkilitious: http://www.dotheton.com/forum/index.php?topic=74349.msg882477#msg882477
1975 RD350 Road Racer: http://www.dotheton.com/forum/index.php?topic=70652.msg833688#msg833688
1976 GT250 Rebuild: http://www.dotheton.com/forum/index.php?topic=64973.new#new
Full Custom Pit Bike: http://www.dotheton.com/forum/index.php?topic=66954.new#new
1971 Yamaha 90cc twin HS1: http://www.dotheton.com/forum/index.php?topic=70498.0
"much ingenuity with a little money is more profitable and amusing than much money without ingenuity" - Arnold Bennet

Online Hurco550

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Re: Yamaha rd350 road racer
« Reply #58 on: Jul 08, 2016, 20:29:09 »
Also, even though I know aluminum rims aren't a need, I picked these up at Mid Ohio for a song. Both 18's, rear is an akront and the front is a tasakaga. Got both for $20 bucks, so I couldn't pass em up, not for cool old high shoulder hoops



« Last Edit: Jul 17, 2016, 18:54:44 by hurco550 »
"If you just picked up a drug habbit instead of a kawasaki triple at least you could get high while you waste money"
~ bradj
1988 tw200, the swamp donkey: http://www.dotheton.com/forum/index.php?topic=75455.0
2006 Suzuki DR650 Adventure monowheel trailer build: http://www.dotheton.com/forum/index.php?topic=75033.0
1976 BMW R90/6 farkilitious: http://www.dotheton.com/forum/index.php?topic=74349.msg882477#msg882477
1975 RD350 Road Racer: http://www.dotheton.com/forum/index.php?topic=70652.msg833688#msg833688
1976 GT250 Rebuild: http://www.dotheton.com/forum/index.php?topic=64973.new#new
Full Custom Pit Bike: http://www.dotheton.com/forum/index.php?topic=66954.new#new
1971 Yamaha 90cc twin HS1: http://www.dotheton.com/forum/index.php?topic=70498.0
"much ingenuity with a little money is more profitable and amusing than much money without ingenuity" - Arnold Bennet

Offline teazer

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Re: Yamaha rd350 road racer
« Reply #59 on: Jul 08, 2016, 21:20:36 »
Pipe lengths are critical on expansion chambers but until we look at the dimensions of that set of pipe, I wouldn't worry too much.  If necessary a new set of header could be bent up or those could be changed to suit.  It was just odd that they seemed so low.  Are the fitted to the barrel correctly or were they just a loose fit?

Those hoops will not work at all, but I will allow you to send them to me to spare you the embarrassment.....  Great find Slip a spare spoke into each and see if the are close to the right angle for a disk hub or drum hub.  Would be awesome if they are one of each.

And R5 carbs are the so called Dave F mod.  That's what he basically changed RD carbs to (more or less).  Y boot is good mod though.