Thanks a lot guys.Saturday I have a little more time to spend with my tr1 and I will find the better solution (changing the 6w with 21w or search for another relay).the tr1 I have was of my friend's father. It was hidden in the open air for more than ten years and then in a garage for another ten years... not used for all the time.it has only 8400 miles but I worked many hours to bring it back to life

yesterday I pushed the starter for the first time after all those years....five times and the engine runs perfectly. I can't believe at my eyes.now I have to solve this little problem,install the new speedometer with km/h scale because the original one was in miles, and then go out for a ride.I'm very excited and I hope that all the things works without surprise
So....Thank you again guys for the help.