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Author Topic: Yamaha rd350 Road Racer Liquid Cooled!!  (Read 43352 times)

Offline teazer

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Re: Yamaha rd350 road racer
« Reply #30 on: Jun 27, 2016, 13:19:52 »
Match that new rotor with almost any modern 2 piston sliding caliper and the thing will stand on its nose.

DYNA S is cheaper and allows you to keep the stock lights and charging system.

Motoplat/FEMSA/Hitachi/PVL/ etc is best for track but no charging circuits.

Powerdynamo is a great compromise for the street but not cheap either.

How will the bike be used?  Street/touring/track days?  May help to decide on ignition to suit.

Offline jpmobius

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Re: Yamaha rd350 road racer
« Reply #31 on: Jun 27, 2016, 23:31:34 »
I'll second the PowerDynamo system as a good choice.  Personally, I like a Banshee system better, but it is a real PITA to implement as you need to build a Frankenstein crank to accept the permanent magnet stator and the ignition trigger does not fit inside a stock Rd case cover.  The PowerDynamo system is nearly identical but is a much bigger hassle to adjust the ignition timing.  It is fine once you do set it, and the charging/power supply is huge improvement over the old RD system.  It is a bit pricey, but you do get a lot of hardware and can easily run with no battery as the charging system and ignition system are completely independent.
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 davedogg

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Re: Yamaha rd350 road racer
« Reply #32 on: Jun 27, 2016, 23:37:07 »
There's nothing wrong with points. Save the money and put it towards something else. BTW I have stock shocks in decent shape for cheap.

Offline jpmobius

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Re: Yamaha rd350 road racer
« Reply #33 on: Jun 27, 2016, 23:59:07 »
Agreed.  My driver RD is 100% stock.  Points and charging.  Coils are replica original - the OEM ones are crap and were when new.  Runs like a top, but the charging system is anemic (even when tuned to perfection). The rotors are doomed to failure if you lean on the motor and are now getting scarce (ish), which is the best (IMHO) reason for swapping out to a more modern system.  Points are GREAT  on a mostly stock engine if you replace the coils and are ok with the normal tune up regimen.   
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 Shoeman

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    • My old RD tuning pages from the 90's
Re: Yamaha rd350 road racer
« Reply #34 on: Jun 28, 2016, 07:12:28 »
And I'll add that IMHO there is no real need to update to alloy rims.  Put the money into shocks and upgraded swingarm bushings along with the tapered steering head bearings you already mentioned.   Everybody's input on points and coils is dead on for a streeter.  Some mild porting and head work along with the pipes you have will wake it right up for not much money, even with the stock carbs.
 
I like cilp-ons, clubman's and superbike bars depending on the bike.  And rear-sets.

Offline teazer

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Re: Yamaha rd350 road racer
« Reply #35 on: Jun 28, 2016, 12:17:08 »
And there are other opinions...  I wouldn't leave points on anything more than lawn equipment.  Maybe I'm just lazy and like the convenience of ignitions that are stone axe reliable and don't wear and change timing.  I love to build and ride bikes, I just hate to do maintenance.

Alloy rims are nice but the difference is small on a street bike, agreed but they do look good when the cash is available for an upgrade at some future date.

Offline Hurco550

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Re: Yamaha rd350 road racer
« Reply #36 on: Jun 28, 2016, 12:42:53 »
All good points to be taken into consideration. I really appreciate the feedback guys! The direction in my mind for this is to be in spirit close to a street legal race bike, but that said, I'm far from a purist, and I'm not the kind of guy that will spend 200 bucks for a period correct bolt or something silly like that. I also don't want to tune it past the ledge of reliability. I would like to come as close as I can to building the motor right the first time as far as porting ect, though I know a two smoke just lives for the day it gets to finally grenade on you lol. 

For now, I think a good point was made on the wheels, but, I may possibly have a set coming to me for little to no coin, in which case I'll lace them.

The ignition is still something I'd like to do, as I don't enjoy fussing with points, that said, money will be spent on the crank and pistons first and I can always do that later on when funds build back up.

I'm not building this thinking that it will be a low budget thing and I know I'll have to spend some cash to make it right, but, I don't have a pile right now, so it will have to be done in stages.

I've been reading up on squish dimensions lately. I'm a welder and machinist by trade, so I'm planning on trying to tackle that on my own.

I have my eye on a crank, I'm trying to decide which banshee pistons to order, and sort the reeds. There are a number of piston options out there and I'm trying to decide where to go out which would best suit this build

Again, thanks for you input so far, I really appreciate the wealth of knowledge that has presented itself here already!
"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 Hurco550

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Re: Yamaha rd350 road racer
« Reply #37 on: Jun 28, 2016, 12:49:53 »
There's nothing wrong with points. Save the money and put it towards something else. BTW I have stock shocks in decent shape for cheap.
Pm sent
"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 TranceMachineVienna

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Re: Yamaha rd350 road racer
« Reply #38 on: Jun 28, 2016, 12:52:35 »

I've been reading up on squish dimensions lately. I'm a welder and machinist by trade, so I'm planning on trying to tackle that on my own.

I have my eye on a crank, I'm trying to decide which banshee pistons to order, and sort the reeds. There are a number of piston options out there and I'm trying to decide where to go out which would best suit this build

Again, thanks for you input so far, I really appreciate the wealth of knowledge that has presented itself here already!

with the support of a good friend i managed to modify the squish on my RD and it makes a good difference to the performance before.
I used 350 LC pistons (i have reed valves), converted my stock RD carbs back to R5 specs (needles and needle jets),running 185´s mains with KN filter and DG pipes,it runs dang fine, just explored how easily those smokers wheel...its a blast ;-)

Online farmer92

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Re: Yamaha rd350 road racer
« Reply #39 on: Jun 28, 2016, 13:51:54 »


I've been reading up on squish dimensions lately. I'm a welder and machinist by trade, so I'm planning on trying to tackle that on my own.
Toroidal chambers too?