RT1 project

Along with redoing my SR500 this year I want to do a complete project. I went through my Yamaha projects and picked the '70 RT1 to move on to finish work. I bought the bare frame in September of 2014, and have been collecting parts for it since then, putting it into a loose mock-up.

The engine I'm using is from the last year of the original RT series, the '73 RT3. '70 and '71 were piston port, and '72 and '73 are reed valve engines. I bought the engine on ebay, and don't know it's history, but it looks like a good one.

You can tell by the case screws that it's likely never been split before. The engine was also fairly clean, but doesn't look like it was cleaned, so all points to the engine being a low mileage cream puff, at least as 44 year old two strokes go.

The bore was clean and damage free. At first I thought the 75 marking on the piston meant it was the 3rd oversize, but once apart and I measured it, I found it is still the standard bore. Piston to cylinder clearance measured in the .004" to .005" range. You could re-ring it and it would run, but if it didn't piston slap right away, it soon would, so will need to be bored oversize.

The rod big end measured to be in great shape, so a crank rebuild won't be needed.

Digging a little deeper, dirty as you'd expect here. At this point I could just replace the crank seals, but I think splitting the cases and making sure everything is clean and right is the best way to go.

Here is the bottom end disassembled.


There really isn't too much to these engines if you stay organized.

Here are the cases with the bearings removed and the initial clean-up done. Next will be the final cleaning, deciding what finish to do on the cases, and then installing the new bearings.


2017 Indiana events and places

 Here is an early 2017 Indiana events and places list. I'll be adding more as dates are announced.

World of Wheels - February 10-12 - Indiana State Fairgrounds

Indiana Motorcycle Expo - February 17-19 - Indiana State Fairgrounds

Vintage Motorcycle Swap Meet - March 5 - Boone County Fairgrounds

AMA Supercross - March 18 - Indianapolis

Grand Prix of Indianapolis - May 12-13 - Indianapolis Motor Speedway

Midwest Vintage Motocross - Wabash Cannonball MX - May 20-21

Indy 500 - May 15-28 - Indianapolis Motor Speedway

The Reunion motorcycle show (formerly Indy Rockers Reunion) - Indianapolis - June 10

SVRA Brickyard Vintage Racing Invitational - June 16-18 - Indianapolis Motor Speedway

Vintage Motor Bike Show - Portland - July 20-23

Brickyard 400 - Indianapolis Motor Speedway - July 21-23

Tippecanoe Steam and Gas Power Show - West Lafayette - July 29

 Mid-America Speedway - AMA Vintage National - August 4-5 - Indianapolis

 Indy British Motor Days - Zionsville - August 12

Motorcycles on Meridian - August 26 - Indianapolis

AMA Pro Motocross - August 26 - Crawfordsville

James Dean Festival & Run - Fairmount - September 21-24

Newport Antique Auto Hill Climb - Newport - September 29-October 1

Grand National Cross County Ironman - Crawfordsville - October 28-29

Pleasure Riders Motorcycle Club - hillclimb - Cayuga

Wildcat Creek Motocross - Rossville

Putnam Park Road Course - Mount Meridian

Lucas Oil Raceway - Indianapolis

Muncie Dragway - Albany

Bunker Hill Dragstrip 

Lawrenceburg Motorcycle Speedway - Lawrenceburg

Indianapolis Motor Speedway Hall of Fame Museum - Indianapolis

The Studebaker National Museum  - South Bend

National Automotive and Truck Museum of the United States - Auburn

Auburn Cord Duesenberg Museum - Auburn

Ropkey Armor Museum - Crawfordsville

Indiana Transportation Museum - Noblesville

Grissom Air Museum - Peru

Kerstings Cycle Center and Museum - North Judson

Elwood Haynes Museum - Kokomo

Kokomo Automotive Museum - Kokomo