Help bring an old flat track racebike back to life!

...Soooooo, my question is, is there a way to check the displacement without taking the head off? I understand the principle of cc'ing a motor. The stroke would be known, so by knowing the amount of liquid used, the bore could be calculated. EXCEPT, I would need to know something about the volume of the combustion chamber, piston top shape, etc.

Any ideas?

You could try to flashlight into the sparkplug hole, and see if the pistons show a small flat ridge that Jay760 mentioned in this other thread.

http://www.xs650.com/threads/how-to-tell-if-i-have-a-750-kit.42213/

It's only about 0.100" wide.
 
YIPPEE!!! After about nine months of work, I finally got Prom Queen licensed in California as a 1971 Yamaha! Not bad, when you consider that the only Yamaha part is the engine. Now, when the weather cools a little, I hope to get the carbs sorted out and do some riding.

I had to get a CHP inspection, so had fitted turn signals. But I had them on a separate wiring harness to make them easily removable. I also had the plate frame under the seat for the inspection. Now it is where it should be.
2020-08-07 12.49.28.jpg
 
Oooh this one needs on the calendar for 2021. I’m gonna nominate it over on the calendar thread. I totally forgot about this one!! If you would like to be considered go over there and accept the nomination.


THANKS SO MUCH FOR YOUR SUPPORT!! That is very kind of you, but I was actually honored to have Prom Queen featured in last year's calendar.

It has been so gratifying to being Prom Queen back to life through the help of all those on this forum. Thanks again!!
 
YIPPEE!!! After about nine months of work, I finally got Prom Queen licensed in California as a 1971 Yamaha! Not bad, when you consider that the only Yamaha part is the engine. Now, when the weather cools a little, I hope to get the carbs sorted out and do some riding.

I had to get a CHP inspection, so had fitted turn signals. But I had them on a separate wiring harness to make them easily removable. I also had the plate frame under the seat for the inspection. Now it is where it should be. View attachment 174735

well done! I aim to have a framer registered on the road here in CA sometime in the next couple years as well. would love to hear about your process @ DMV!
 
Pretty awesome!

question - did chp ask for the signals?? They became law in 73.

I’ve jumped their hoops more times than I care for, just always good to know what they may hold you to.

I’ve run a few by with no signals without any issues.
 
Odd. I did a long reply on the process, but somehow it didn't post. I was wanting to get it licensed as a 71 Yamaha and not a 2020 custom. I made two wiring harnesses, one main and one just for the turn signals. As a 71, if it had been registered without turn signals, I wouldn't need them, but the bike was a racer from new and never registered, so I didn't want to take a chance.

I had front and rear brake lights working, hi-low headlight, a little electronic horn from a bicycle, etc. CHP don't come out for inspections like they used to, so I had to schedule an appointment about six months out.

Oddly, once I had the appointment scheduled, they gave me a temporary plate. I guess they know how messed up they are. When I finally had inspection, the cop was totally disinterested in motorcycles and didn't check anything except the numbers on the engine and frame. That could vary a lot depending on the person inspecting. This guy was just bored. Then, DMV wanted confirmation from New Mexico that the bike had never been in their system. Finally, CMV here gave up on that and issued a plate!

If one of you wants to borrow my turn signal setup for licensing, just let me know. I made it intentionally as a standalone system. Just mount the signals and supply power to the system and you are ready to go. Flasher and switch are in the harness. I just mounted the switch on the bars with zipties.

If any of you have any more specific questions, shoot me an email at duczupa@gmail.com or call me at 760-285-2220. It was a lot of work, but I got exactly what I wanted.

Turn signals .jpg
 
Hi guys!

I have some great news! The American Motorcycle Association magazine is doing a very nice article on Prom Queen! I believe it will be the March, 2021 issue.

There are some incredible photos, as well as a fascinating history of the old gal from her start in Alamogordo, New Mexico all the way to crusing the streets of Palm Springs, CA.

Again, THANKS SO MUCH for all the help in getting that old warrior up and running again.

All the best, David
 
That is wonderful news David - you have done a superb job on her and she certainly deserves to be on the road again.

Well done - and please keep us posted!

Pete

PS - we like photos and a video of that old gal blorting up and down the road would be super!
 
Thanks a lot! This has been a wonderful journey between getting her running and finding out her history.

I think I have posted these, but until I get new videos, give these a try:

I will post outtakes on the photos as soon as the magazine is released.

The bike is running now, but not running right. I am starting to work on that again. When I rode it for the photo shoot, the bike cleared its throat once and really sounded strong as well as pulling pretty hard. It starts fairly easily, but I know the carbs need work and these carbs are new to me. I will get it sorted, though, even if I have to seek professional help!
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The American Motorcycle Association magazine

This is great news David, as a life member ('72') of the AMA, I will look forward to reading about your wonderful restoration. Maybe it'll be
the center spread, although they usually leave it to their Hall of Fame Museum bikes. It's not in the Feb. edition but the center spead
has a beautiful rendering of the Hurricane.
 

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WOW! just read through this whole thread. It don't get much cooler than that. What a wonderful machine with amazing history you have @Apexdc. Thanks for keeping it around and bringing it back to life! Congratulations on your AMA magazine feature. It's bikes like this that always make me wonder what's still out there secreted away and forgotten about that are waiting to be rediscovered.
 
@Apexdc

Love the video and the story of the bike besides the awesome period paint job and wonderful charming exhaust sound!
For the exhaust system the regulation entities would flog you over here in europe hehe.
In my opinion you won't need professional help, why don't you ease your life a hint with buying or borrowing a wideband O2 sensor?
All you would basically have to do weld the binge into the header as recommendef, adjust correct and "even" timing and then check the lambda values.
For brisk acceleration etc you might still have to play with mixture tube Styles (depending on what design is in there; bleeder or else) but you would ease your life considerable and the learned lessons prove very valuable.

Kind regards
Christian
 
WOW! just read through this whole thread. It don't get much cooler than that. What a wonderful machine with amazing history you have @Apexdc. Thanks for keeping it around and bringing it back to life! Congratulations on your AMA magazine feature. It's bikes like this that always make me wonder what's still out there secreted away and forgotten about that are waiting to be rediscovered.
Even though I just got the bike plated and have not ridden it much, I have had SO MUCH FUN with the journey. Sorting out all the things that are in this thread with all the members here was just great. Learning the history of the bike was another great journey.
 
@Apexdc

Love the video and the story of the bike besides the awesome period paint job and wonderful charming exhaust sound!
For the exhaust system the regulation entities would flog you over here in europe hehe.
In my opinion you won't need professional help, why don't you ease your life a hint with buying or borrowing a wideband O2 sensor?
All you would basically have to do weld the binge into the header as recommendef, adjust correct and "even" timing and then check the lambda values.
For brisk acceleration etc you might still have to play with mixture tube Styles (depending on what design is in there; bleeder or else) but you would ease your life considerable and the learned lessons prove very valuable.

Kind regards
Christian
Thanks for the suggestion, Christian. Our weather is now getting pretty nice, so I think I am going to take another run at the carbs. I actually think it won't be too tough to get it running well. It is largely just learning the quirks of these carbs. I am glad you enjoyed the story of the bike. The AMA article just came out, so I will try to post it in the coming days.
 
I really like the right hand shifter mod. I did that on all my flat trackers in the 70’s when I use to flat track. I quit in 1981.
The bike had some very nice machine work done on it. The way the right hand shifter was incorporated into the right case cover was really well done. I have converted it back to the left for the street, but I could take the entire bike back to being a proper flat tracker in a couple of hours. The engine is as gnarly as ever. I just put some small baffles in the TT pipes to make my neighbors a little happier!
 
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