71 R5 Project - Build

[71R5JPAR]

Hi All,

New member here. Recently acquired an original 1971 Yamaha R5 that I plan to build. Bike has a tad over 10,000 miles and is in running condition. Photos below make it look to be a little better condition than it actually is. The closer you look the more corrosion and misc dents you can find. I've wanted an RD350 for a long time and when I saw this pop up on Marketplace I knew I had to go and get it. Never knew about the R5 until I saw this bike and started to do research. Story I got from the owner is that this bike was purchased new and ran for 3 years by the original owner. I still have the original license plate with 71, 72, and 73 registration tags. It was then put in the original owners basement for likely 40 years. It was then purchased as part of an estate sale (with the house). That second owner sold it to the owner I purchased it from. So I'm the 4th owner.

Sorry to any of the purest here, but this bike wasn't in good enough condition for me nor does a stock RD/R5 speak to me, so I'll be slowly turning this into a custom build.

My Plans:
Suspension Swap (modern setup)
Swingarm Swap
Disc Brake Conversion
17" wheels - hoping for 150 in the rear
Electron Ignition
Engine Refresh w/mild porting
Pipes
Lectron Carbs

Here is a photo of when I first picked it up.

[71R5JPAR]

Stripped it Down

Sourced a Duke 390 front end and converted with All Balls Racing conversion.

Now I need to find a swing arm. I'd really like to run the duke/rc390 rims so I'll need to keep this in mind when sourcing a swing arm.

Anyone have any suggestions on a swing arm? At this point I don't mind keeping twin rear shocks or converting to a mono-shock.

[m in sc]

I cant see any of the images. 

[71R5JPAR]

I cant see any of the images. 

They are attached.

[SoCal250]

I cant see any of the images. 

They are attached.

Something strange is going on with those pics. The files are not viewable, they are only downloadable. And when I download them some cause an issue with my photo viewer app causing it to hang/crash.

EDIT:
Figured it out. Your images were way too big (4032x3024). I downloaded them, resized them, and edited your posts. Should work OK now.
In the future you should resize your image files before posting so they fit on a typical screen. I used 25% for your images (to 1008x756), but you could even go with 20%.

[rearwheelslider]

I am not a purist, by any means. And it seems like a cool concept. But its just sad seeing another unmolested classic reduced to a half modern bike. I am not hating, just thinking out loud. Look forward to seeing the progress!

[m in sc]

there they are. cool and all.... but i have beta envy. swingarms going to be tricky and (obviously) the ktm one wont work, so hoping you have the ability to do lathe work, going to be necessary to get the ktm wheel in there on any swingarm you wind up using.

[71R5JPAR]

there they are. cool and all.... but i have beta envy. swingarms going to be tricky and (obviously) the ktm one wont work, so hoping you have the ability to do lathe work, going to be necessary to get the ktm wheel in there on any swingarm you wind up using.

The Beta is a hoot to ride! I have it plated for both trail and road. Kind of needed in my area as bikes aren't allowed on all trail sections so you have to hit the black top to bypass those sections sometimes.

Yeah I was able to get measurements on the duke swingarm. 235mm width at the pivot so it's too wide. I'm still looking around. Might do a slightly extended tracdynamics or metmachex. Cost of both of those are sky high though when comparing against a conversion swingarm purchased off of eBay. Still hunting around.

[71R5JPAR]

I am not a purist, by any means. And it seems like a cool concept. But its just sad seeing another unmolested classic reduced to a half modern bike. I am not hating, just thinking out loud. Look forward to seeing the progress!

Understood. I thought hard and long before deciding to make it a custom. When I first saw the pictures I thought for sure it was too nice to play with. After getting it home and giving it a good look over I changed directions.

[AAAltered]

You're in the right place!  Excellent bones to start with.  I bought mine as a basement queen, where it had sat for 30 years, according to its license plate.

Here's mine, as bought and current state.

[71R5JPAR]

You're in the right place!  Excellent bones to start with.  I bought mine as a basement queen, where it had sat for 30 years, according to its license plate.

Here's mine, as bought and current state.

Where did you find the tank emblems?


What swingarm are you running?

Nice bike!

[rearwheelslider]

On a side note, youre so lucky to be able to have that Beta and have it registered with a plate. I live in commiefornia and we cant buy a new two stroke and get it even registered to ride anywhere public trails(no OHV sticker), let alone a plate. Insanity.

[AAAltered]

Badges:  I got a repop screw on set years ago, and was also gifted a NOS set.  I don't recall what's on there right now.  You'll see repops from time to time on EBay.  IMO hold out for screw on ones rather than stickers.

Swinger: is a vintage DG RD400.  That's 2" over stock for a 350.  Can only run stock size tires.  Had "fender extenders" machined by a good guy on this site.  Bike is NOT prone to wheelies unless you try.

[71R5JPAR]

Very little progress lately.

Took a gamble and ordered a 2012 Ninja ex250 swingarm. It would need to be milled slightly narrower on the pivot width. The more I look at it though, the less enthusiastic I'm about converting to monoshock.

Can anyone provide be feedback on current tracdynamic swingarms? I'd like to run twin shocks but still convert to disc rear. Thinking of also using either the Duke 390 wheels or the new gen ninja 250 wheels. Ninja is a little narrower as it fits a 140 rear.

[SoCal250]

Have you considered MotoLanna? Some members here have used them.
MotoLanna SuperTuff swingarm
MotoLanna SuperLite swingarm

https://www.2strokeworld.net/forum/index.php?topic=415.msg2782#msg2782
https://www.2strokeworld.net/forum/index.php?topic=4211.msg36419#msg36419