Help bring an old flat track racebike back to life!

Welcome to the forum, David. Now, that's a downright cool period survivor. Definitely worth dusting off.

Unless there was some mix/match of engine components going on there, it looks like the engine is likely a later-half '71 XS1B. Earlier engines had plastic buttons in the head fins, 4-bolt camchain tensioners, gusset reinforcements behind the left-rear cylinder stud. Yours has the later type "B" XS2 tensioner, no reinforcing gussets. Engine serial number could confirm.

Go thru these threads and imbedded links for discerning info on the front motor mount.

http://www.xs650.com/threads/engine-interchange.50643/

http://www.xs650.com/threads/xs1-engine-mounts.47629/
 
If your engine is of the later XS1B variety, your kickstart needs just the single small 1mm thick thrustwasher (part #20). The axial roller bearing (part #9) was dropped early on, along with some changes to the kickstart shaft. Dry assemble the rightside cover, and push/pull on the kickstart shaft. Should be less than 1mm endplay. Early kickstart levers don't swing out as far as later levers, which needed to clear changes to the brake lever. Check out the tech section for the kickstarter thread.

More kickstart info:

70-10-02_P300-01_FramePegsBrakeKickstartChanges.jpg


Warning, the parts pic shows the shim (#20) and circlip (#21) in reversed order.

70-72-KickStarter01.jpg

70-72-KickStarter02.jpg
 
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Your drum brake front wheel is throwing me, and deserves more research. Your '76 pic shows it to be a 36 spoke wheel, with an overdrilled 72-hole drum. Honda CB-450 front wheels were 40 spoke. Later '80s CM-450e front wheels looked identical, but were 36-spoke, as shown here.

CB450-FrontWheel.jpg


Your twin-leading-shoe brake plate shows protruding anchor posts, which I don't recall ever seeing before...:shrug:
 
Wow again, I just can't stop looking at it!!!!!!! I bet the carbs are tuned for those black megaphones, you should consider keeping them on.

Lights......small LED turn signals, rear signals mounted at top shock bolts, tail light and plate mounted at left rear axle. Yeah, small Bates style head light, LED.

That thing is hardly even Yamaha, built to compete with those HD's that owned the sport at the time.

Scott
 
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Kickstarter: Wow, 2M, what a ton of great info. Cleared up my kickstart question. I still have a blanking plug in the side of the case that I need to get out before I can do a test fit. Great info on the engine type also. My S/N is 023368, FYI.

Brakes, I thought the front drum was from a Superhawk, but might have been a CB450. It is 36 holes for sure. Just counted it twice. Your photo sure looks a lot like it. Just talked to Buchanan about stringing up a Borrani 19 WM3 to the brake. Rear is a WM3 x 18 Borrani.

On lights, I will use a very small Bates style headlight, chrome. I think it is about 4.5". Really simple. I will just rig turn signals to get it registered and then take them off. Taillight is small simple round. Looks like a marker light on a thirties Ford. No billet stuff anywhere. Probably a little more chrome finish that I would do on a new build today. Like I feel the headlight housing should be chrome.

I'm not sure where I am on jetting for the carbs. The area where the bike lived was around 4500' elevation and I'm almost sea level, so I roughed out the change on an altitude adjustment chart I found and then bought one above and one below. I thought that should get it running. But I sure like the look of the megs. Not sure how to baffle them a bit. Who knows, it might not be obnoxious if I don't ride like a jerk. My Duc has race pipes and I can manage to keep it calm in town.

I just can't tell you how much I appreciate all the help and enthusiasm all of you are showing. I know the Duc like the back of my hand, even adjusted my own valves, which is a big deal on them. But this is all new to me, so I'm learning a lot. Oh, this all started by me mentioning to my buddy that I wanted to do a project around an XS650. Then, he said he had an old one he might sell me.

And here we are!

THANKS!
 
That is a beautiful bike! Looking at your pics makes me feel the same way as when watching "On any Sunday" :) Sadly, I was only a snotty kid in the mid 70-s....
 
Wow David - she’s a pretty one and historically significant too! The answers to all of your questions are here on this forum - and don’t forget that we love pictures!

Looks like you’ve got yourself a ballgame there and thank you for leaving her as she was created back in the day.

Keep on keepin’ on!

Pete
 
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When I first started looking at the bike, I was thinking about having Trackmaster make a new swing arm so I could run a wider tire. My mindset before seeing the bike was I wanted to build a street tracker, so that was where I was coming from. Then, after looking at the bike a bit and really thinking it over, I realized it would criminal to change it, skinny tires and all.

Regarding "On Any Sunday", in this odd world, Roger Riddell, who was Bruce Brown's partner in "Endless Summer" also worked with him in doing "On Any Sunday". Roger is my closest friend, best man at my wedding and main motorcycle buddy. This is the text from the Sports Illustrated article with McQueen on the cover. https://www.si.com/vault/1971/08/23/612102/harvey-on-the-lam

Roger and McQueen became close friends during the filming of On Any Sunday. McQueen had already passed away when Roger and I met, but Roger has some pretty good stories about him.

I have attached some pix on the crank end cover after the alternator was removed. I could send accurate dimentions, but fabrication on a new one will have to be based on how much was taken off the side cover.

Also, this afternoon was spent making some new rivets for the front brake linkage. I will be taking it to the plater this week, but needed to be sure I could fit it back together. The rivets are stepped in that one side of the linkage has a smaller hole than the other. I dimpled the end so I can reinstall them with a chain press. I cut them out of 6mm stainless bolts.

I have told the plater not to make them perfect. The original Honda pieces were incredibly rough.

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Another machinist? Fantastic!
Well, then, allow me to put a bee in your bonnet.
Food for thought.

....or a hot poker in the eye.

Thinkin' on your charging system challenge.
Myself, I don't particularly care for large/heavy alternators.
And tend to lean towards stealth.
There's still some room in that left cover.
Modern rare earth magnets, in thin discs, are cheaply abundant.
Large gauge winding wire, the same.
It only takes about 25-30 watts to power the conventional points ignition.
Using only modern LEDs for lighting would add another 20-30 watts.
So, only need a 50-60 watt PMA system to meet demands.
A budget PMA rectifier/regulator would not be overtaxed by this.

Google: "Disc alternator".

DiscAlternator.jpg



My dear 'ol dad made a few of these back in the early '60s, for a special project. Finished size was about the size of a nickle.

Could punch apart an old, bad rotor. Repurpose its tapered core as a mount base for a thin aluminum disc, containing an array of thin magnets...

Pics from gggGary's album:
full

full

rotor-001.12424

rotor-002.12425
 
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I'm open to giving the disk alternator a try, but electical systems are not by strong point. I think if you can give me enough detail in design, I can figure out a way to make it. As I mentioned, I will need turnsignals temporarily but won't keep them. To give me a bit of a head start, I bought the main wiring harness for a 71. I realize it will not be plug and play, but thought it might help keep me organized. I'll do my own connectors, fusing, etc.
 
Col bike with an interesting race history. My girlfriend and I saw it at the Quail show. She really liked the funky paint scheme.

The Pikes Peak configuration front hub appears to be from an early ('68 or '69) Honda CB350 or CL350. These had "fake" extra spoke holes and are readily available on eBay. The CB/CL350 brake drum is 180mm in diameter and can be made to work fairly well for a 350lb bike. The Honda CB77 and CB450 hubs have 200mm diameter brake drums and are probably the best bang for the buck when it comes to a 2LS front drum brake.

If you are planning to run total loss ignition, use an ignition system that retains the mechanical advance (e.g., stock points, Dyna, etc.) as these systems are not voltage sensitive. Anything with an electronic advance will likely die if the battery drops to less than 12-volts. You might find you can get sufficient range running a Shorai lithium-iron battery if you conserve other electrical draws with LED bulbs. Remember vintage bikes are not required to have daytime running headlights, but it's a good idea to have a headlight that works in case you are pulled over by 5-0.

If you can't get sufficient range with a total loss system, consider installing a Powerdynamo/MZB system. They're not cheap, but reliability is great, and they can be set up to run without a battery (substituting a large capacitor). Not having to mess with a battery is a really good feature on a bike that is ridden on a limited basis.
 
Glad to hear you saw the bike at the Quail. That is such a great show!

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The brake measures 200mm inside the drum. It was supposed to be a CB77 or CB450 when I bought it on eBay.

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I have a Shorai that is the highest capacity in a size similar to stock. I bandsawed the top off the old battery and siliconed it to to the Shorai. I thought I would do a quick connection to hook up another battery, leaving the first in place. The leads would be light as the loads are peanuts. Put the second in a backpack. Run LED's on head and stop lights, then hook the second when the first is dead.

Looks like a nice setup with the Powerdynamo and it sure looks a lot better than original. But I'm crazy enough to be intrigued by the disk alternator concept. I'm just not sure I can pull it off. I'm going to have to do a total rewire on the bike and I might have my hands full there. I have a Shorai in my Duc and I can leave it for months and the charge never changes. But it is an old school electrical systym that has no small loads when ignition is off. The 650 should be the same, I think.

My thought is to get it running on total loss, then ride it for a while. If I really like it and want more freedom, then I'll add an alternator of some sort.
 
That's a CB77 hub as it has 36 spoke holes. The CB450 hubs have 40 spoke holes. The design is a pretty good copy of a Fontana 2LS brake and should work well for your application.

RaceTech can set up the Ceriani's for your weight, with better valving for street riding. I had them go through the Ceriani that's going on my Rickman Mk3. The service wasn't prohibitively expensive.
 
That is good to confirm on the hub. Good to hear on Race Tech doing Ceriani's. They put Gold Valves in my Duc forks. They are not far from me. I need to confirm my front axle is 15mm. I think it is. If not the bearing is about 42mm, so I should be able to get a match.

They are also truing up drum brakes. Vintagebrake.com also sets up those brakes. They will also install any sort of new shoes based on intended use.
 
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