ANOTHER YAMAHA PROJECT

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 Well I picked up another project bike.It's a Yamaha RD 200.Low miles bike with 2K miles.I know I don't need any more projects but it is a good one and does not need much work.My first bike was a Yamaha 200.These bikes are a lot of fun with 250 like performance.Because they share the same basic frame as an RD125 and are just over 250 LBS !! They have an excellent power to weight ratio.They are pretty quick for a little 200 but run out of steam on top.But with a feather weight driver these have been able to get to 85-90 MPH.Not bad for a 200 ? I will detail it, tune it.Drive it.And then gradual mods, put some chambers on it,And then weld up the cylinders and put some RD 350 LC reeds and carbs on it, do some porting mods,that should help get more air in her on top.Goal is to have a little 200 that will crack 100 MPH.That might be fun ? I might change the appearance a bit and put it on a diet too.As they say taking off weight is like adding on HP ?

[sf]

Great looking little machine. I have a R5 that needs some detail and performance.

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My brother Duane's first bike was an R5.They are good bikes too.

[tzrcarbonn]

Bonne année acceleration, same chassis than my bigbear 1966, i had in 1967,

keep the passion,

tzrcarbonn

[autofobe]

Hey tzrcarbonn,Sorry but it's not the same chassis as a 1966 Yamaha 250 bigbear.I have one here.My first real bike was a 1966 Yamaha yds3 250 Catalina (the low pipe not the big bear).
The bike in the pic has the same frame as a 1967 Yamaha 180 bonanza.Very similar to the Yamaha ta 125 race frame.Just so you know.


Brad

[tzrcarbonn]

Bonne année Brad, yes you are right, and there was the 305 cc, with low pipe, named : cross country
i have done 90 mph with the bigbear, in 1967, two days, after buying it, 29 april 1967 in Montréal.
at the price of 700 dollards, with 1000 miles on it.
tzrcarbonn

on that summer 1967, i ride 10 000 miles on it in 5 months.

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TZcarbonn Big bear was a cool bike.10,000 miles in 5 months is a LOT of riding.Yes the frame on the RD 200 is similar to the TA 125 race bike.And a lot of the body parts for the TA 125 can be applied to it.To make a cafe racer.The RD 200 was a good light weight, good handling package.The front drum brake is huge the same as a 350
so it has excellent stopping power.These bikes were over shadowed by the RD 250.Because most people bought the
RD 250 instead.0-60 MPH these bikes were real quick.Planning on taking off some weight and adding some HP.If I can get it to cruise comfortably at 70 MPH and hit 100 MPH.It should be fun.I know of several folks that have built them that way.

[tzrcarbonn]

Hi, it is a new generation of motor, i think that the motor casings can be dismantle up and down,

not like the big bear that dismantle side way. a real problem for the mecanician,

in those time i fill the tank with 90 cents, and ride all the 1967 summer without any helmet.

tzrcarbonn

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The engine cases split side ways !! They didn't change to the split from top to bottom on the RD 200'S from those years.

[tzrcarbonn]

Hi, you know what i would do, the first thing,  block the carburators intakes, block the exhaust muffler,

and inject high pressure in the spark plug hole, and check the pressure at the other plug,

to have an idea of the leak at the midle crank shaft seal, since you need an assortiment

of pullers to dismantle the casings.

tz

[autofobe]

The cranks on those early yamahas all had lab seals that rarely leaked in the centre.(unlike dumb Kawasaki)
Most of these bikes after sitting for years could be run as is with no issues.
Worst case,the outer seals might need replacing which could be pulled with a wood screw and replaced without
opening up the engine.


Brad

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Yes the cranks on the RD125 and RD200 are pretty reliable.The RD125 can spin reliably well past the red line.The RD200 crank also.But to spin them really high the electric start set up puts a heavy load on the crank.And some folks remove and replace it.Not in the present plans.But if I planned to do any sustained high RPM racing with the RD 200.I would do that, along with balancing the crank and rods and weld the crank pins.Yes it is nice that the Yamaha cranks have lab seals.Here is a picture of one of several RD350LC cranks built in our shop.This one was blueprinted and the crank pins were welded.At sustained high RPM the crank pins can drift if they are not welded.Measuring the lab seal clearance in this picture.asuring the clearance on the lab seals in the picture during the assembly process.

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Well going to continue with progress on the RD 200 project.Now that spring has arrived.Slowly but surely.I recently got a different tank and seat for it, to give it a more modern look.Going to prep and paint them since we now have a whole lot of body panels to do.Thanks to all the fine folks that sent us their stuff to do.I am planning to port the cylinders, weld up the cylinders for larger reed cages and carbs.I have some chambers that I plan to use on the bike too.Taking off weight and adding on HP is part of the plan.It would be nice to have a light weight combo with the power of a larger displacement bike.The cool thing about this bike is that it uses
a similar frame as the 125 road racers.Much of that stuff can be applied to it.These things handle like the 125 road racers when built similarly.We'll see what happens ?

[brewguy]

Keith this is Daves (norm) brother Doug.

I saw this local Kijiji post and thought of you.


www.kijiji.ca/v-motorcycle-parts-accessories/barrie/1975-yamaha-rd125-twin/1441451080?enableSearchNavigationFlag=true

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Hi Doug, That RD125 looks like it is in good condition.The RD200 uses the same frame.I have a spare RD 200 parts bike for the project.
Looking forward to seeing you and Dave join us for our annual bike ride to the vintage bike show in Ormstown.We had a blast last year!!