1980 Yamaha RC100

[Romero Llamas]

Here is a 1980 Yamaha RC100 that I am working on. Paint will be 90 % original. I had to sand and repaint the chipped and surface rust areas. Got in cheap, and almost complete, so I figured lets try it out.

[sam bennett]

Awesome Romero! How were you able to identify the year of the chassis?

[Romero Llamas]

Awesome Romero! How were you able to identify the year of the chassis?

Hi Sam,

I well Scott Wigginton is the Yamaha expert. He was a few yamahas of almost all early years. There are certain changes year to year that help narrow down the year. Mine actually has an earlier gas tank for now. The shape changed in 1980. There are differences in brake systems used, tanks, geometry, bumpers and wheels. These wheels are the type that came out in 1980. Moving upward into the 1980s a few changes where made in wheel types, brakes, tank graphics, etc.

Attached is a photo of Scott's amazing 1980 Yamaha RC100SE. Also a few period ads.

[Romero Llamas]

Awesome Romero! How were you able to identify the year of the chassis?

Hi Sam,

I well Scott Wigginton is the Yamaha expert. He was a few yamahas of almost all early years. There are certain changes year to year that help narrow down the year. Mine actually has an earlier gas tank for now. The shape changed in 1980. There are differences in brake systems used, tanks, geometry, bumpers and wheels. These wheels are the type that came out in 1980. Moving upward into the 1980s a few changes where made in wheel types, brakes, tank graphics, etc.

Attached is a photo of Scott's amazing 1980 Yamaha RC100SE. Also a few period ads.

Made some time to work on tank graphics last night. Only 99 more details to go.

[Jim Waltz]

Nice project.

Glad to see that members are populating this page on the forum.

[Romero Llamas]

A few update photos.

[Romero Llamas]

Sent a good amount of time trying to mount 6 inch wide rear Dunlops on the factory 8 inch wide wheels. Then tired to mount 6.5 inch wide Dunlops. Even after using jelly, soap, half a can of WD40, straps and 50 psi, break down, start over 6 times, the 6.5 wide tires would not pop. If I relaxed tire to 20 psi it would pull away from the wide rim. 

So I went with the 7.10 wide Dunlops, many say these are too much tire, too much rear grip etc. But they did mount finally. I had to make a tire wrap out of an old bucket and triple strap them, lots of jelly on the beads  and soap.

Might look for a pair of somewhat period correct 25mm metric rear wheels in 6.5 to 7 inch width to mount the 6.5 wide Dunlops as a back up.   PM we with anything that might fit.

Getting closer.

[Romero Llamas]

Here are what my 1980 RC100 rear wheels / Hubs look like. They are 8 inches wide total, 7.5 inner lip to lip. The wheel halves also have a black center wheel spacer that holds an O ring on each side. If anyone has any rears like this let me know. Or some metric wheels 6 to 7 inches wide that would fit these rear hubs.

[Romero Llamas]

Well after being in the basement all winter the RC100 emerged to the garage the Tuesday before New Castle event.  Still had many details to resolve and assemble deep into Wednesday night at midnight. Painted the pipe in the rain, had to ask someone how to assemble a DXL at 11pm, made a throttle sleeve stop out of a pen cap at 1130pm. At the track Don Axle helped me with set up and 1st start up  and determine I needed a carb return spring that Comet had in stock trackside. I was able to work though various issues such as an ill fitting DXL gasket emptying clutch fluid, and fouling plug on slow exit parade lap. THe Mychron was giving me first normal 250 to 350 degree temps then also warning flashes and temps of 1400 to 1600 degrees. I decided to ignore this data. On the parade lap for heat 2 the pen cap gave way and I drove the 6 laps with my left hand operating the throttle with my right , Ran a mid 1:12 lap that way. In Heat 3 I was still off the pace with clutch gremlins and motor did not pull as well as before,   running a 1:10.90 lap. I think I could have ran a 1:08 with all going well.  A top ten lap for the class would have been 1:05 ish in yamaha piston port. ( I ran in 1980 to 1987 to stay out of the way, I did run one heat in the back of piston port unscored).  It seems to run well and handle like a go kart, it seemed to have good ba1ance and turn in. I was able to assemble the kart with 98 % OEM yamaha parts.