Topic: Harley XR750

[Bob3050]

I have made a little more progress on the XR. The top end is together and some of the smaller items have been dealt with. I'm hoping that someone reading this post knows all there is to know about old Harley magnetos.I took mine completely apart and cleaned it all. After reassembly it works fine on the bench. The thing that I don't know about is the key lock in the side of the case. I didn't have a key for it so I went to the local lock shop and they were able to fix me right up. With the new key the lock operates just fine,but I can't see any connection between the lock and the mag. I'm posting a couple of pictures of the opening in the mag case and all the pieces that came out of it. I must be missing some part or parts but I can't find any pictures of the locking mechanism in either my Clymer manual or my friend's genuine Harley book. As it stands now when the lock pieces I have are installed the key will turn a half circle as it should but there is no connection to the primary circuit that I believe that it needs. There is a primary kill button wire that comes from the other side of the case and that will go to a switch on the bars, but I sure would like to be able to use the lock. Anybody have any ideas because I'm stumped at this point.
Bob

[Bob3050]

Sorry about that but my picture of the lock pieces didn't get posted so here it is again.
Bob

[scottly]

As it stands now when the lock pieces I have are installed the key will turn a half circle as it should but there is no connection to the primary circuit that I believe that it needs. There is a primary kill button wire that comes from the other side of the case and that will go to a switch on the bars, but I sure would like to be able to use the lock. Anybody have any ideas because I'm stumped at this point.
Bob

I don't know about Harley mags, but the one on my old BSA had a single wire that was grounded to kill the motor, and open to run? Does the switch have continuity when turned to off? The kill button wire may be connected internally to the wire that goes to the switch, so if either one is grounded, the bike won't run.

[Bob3050]

As it stands now when the lock pieces I have are installed the key will turn a half circle as it should but there is no connection to the primary circuit that I believe that it needs. There is a primary kill button wire that comes from the other side of the case and that will go to a switch on the bars, but I sure would like to be able to use the lock. Anybody have any ideas because I'm stumped at this point.
Bob

I don't know about Harley mags, but the one on my old BSA had a single wire that was grounded to kill the motor, and open to run? Does the switch have continuity when turned to off? The kill button wire may be connected internally to the wire that goes to the switch, so if either one is grounded, the bike won't run.

No, there are no internal connections of any kind.  What really gets me is that I can't find any mention of this lock in any manual or any of the sportster suppliers. It is an original magneto made by Fairbanks-Morse and I've seen other sporties with this same set-up. My best hope is that somebody out there is familiar with how this thing works.
Bob

[scottly]

Just about every magneto I've ever seen grounds the "coil" side of the points to shut the motor off. With the switch assembled, measure the resistance from the kill button wire to ground, both with the key switch in the off and on positions. The points must be open for this test.

[Bob3050]

OK, I finally got my head out of my rear and solved the problem I've had with the magneto lock switch. The switch is located in the side of the case by means of a bakelite block. In that block is a threaded hole with a detent ball and spring held in by an allen set screw. It looked very correct but that is not the way it's supposed to be. I guess because the key was gone that someone substituted the set screw for the proper round head 10-32 screw. Under that round head screw is supposed to be a wire that connects to the points kill wire connection. So in the off position the wire is grounded through the detent spring and ball to a roll pin in the switch detent socket. In the on position there is no roll pin. The yellow wire in the picture is the one I added and now it works like it should.
Bob

[Bob3050]

I'm getting closer to firing up this machine . I've gotten a lot of the small things done and out of the way but the last big obstacle I ran into is the rear pipe. I'm having to remake it because of a lack of clearance after I put the drive chain on. I can't use the sportster pipe mount on the rear pipe like I thought I could, so I'm going to go to the original style competition mount. that uses a simple strap from the top shock mount to a clamp on the pipe.It should be a fairly easy job,I hope.
Bob 

[Bob3050]

I re-made the rear pipe today and now all I need to do is make up a couple of spacers for the mount. Once I get that done and wire up the new kill button I just got and I will be ready to light this baby up, I think.
Bob

[Powderman]

If you make that strap a bit longer and slide the clamp back to the axle the shock and strap will be at the same angle and painted properly will minimize the look of the strap.

[Terry in Australia]

Looks great Bob, fire it up! Cheers, Terry.

[Bob3050]

Well it fires up and actually runs very well. It's hard to kick start but I'm figuring out the ceremony I have to go through to light it up. right now I'm having the best success with kicking it once or twice with the choke on and it may start. When it doesn't start after choking I turn the mag off and kick it through with the throttle wide open then turn on the mag and kick it with just a small amount of throttle opening and it may start. If it doesn't start I start the whole procedure again. It really is fun to ride but it"s geared a little too high. It has a 24 tooth counter sprocket now but I have a 20 tooth I'm going to try. I now need to paint the tank and seat/rear fender and get someone to make me a set of stainless steel pipes to replace the nasty ones that I made. My pipes should make a good pattern for the new ones.
Bob

[Powderman]

You do know the secret of starting one of these motors is to make sure it's on a compression stroke with the pedal engaged high and put all your weight into one stroke down. Worked for me all the time, never could understand those that said Harleys are hard to start. After my brother and I would wash our bikes at the car wash I would go sit on the curb when we were ready to leave. He would ask why I was sitting down. I would say I was going to rest and watch him try and start his wet Triumph. After about 5 minutes of kicking and swearing his would fire. I would go over to mine, kick it through till it's on the compression, give it 2 big squirts of fuel with the throttle and one kick VAROOOOM. Pissed him off every time.

[MoMo]

 I agree with Powderman that the bracket should match the angle of the shock.  Looking good Bob...Larry

[seanbarney41]

That looks like its gonna be more fun than a barrel full of monkeys

[754]

I could be wrong, but I think XLR pipes is what you need, if you can find them,
Looking good..

[Bob3050]

Even though my Harley is not quite finished (needs pipes and paint) I took it to a local car show over the weekend. They had an American M/C class that had probably ten or so dressers and choppers in it. I didn't do any good but my buddy's '41 Indian Junior Scout (500cc) took the trophy. They also had an Asian/ European class that got no entries. I should have taken my CB500 and gotten a sure win.
Bob

[Bob3050]

My new stainless steel exhaust system arrived today(some assembly required).
Bob

[754]

You know if we have a SOHC 4 reunion in Calif., we expect both your bikes to be there..

[Bob3050]

You know if we have a SOHC 4 reunion in Calif., we expect both your bikes to be there..

That sounds great. If it is going to happen just let me know where and when.
Bob

[scottly]

 

[Bob3050]

So the tank and seat/tail needed paint. I started by stripping the tank of the stripe that it had down the center. Then I gave it a skim coat of bondo to catch as many of the little flaws that I could. I used a single stage paint with a white sealer/primer for the finish.I now need to get the orange peel color sanded and cleared up. Luckily I have a friend who is well experienced with this and is going to give me a hand with it. Here are some pictures as it stands now.
Bob

[Bob3050]

My buddy and I color sanded my tank and seat with 1500 and 2000 grit and then buffed to get the orange peel out as best as we could. Then I took them to the guy who striped my CB500 and had him do a white pinstripe on all the edges. I'm really happy with the results, so here are a couple of pictures.
Bob

[BPellerine]

looks nice!

[754]

 X 10

[mrbreeze]

Every time I see that tank it reminds me of Steve Mcqueens XR that was in Corbin's bike collection in Hollister. The color scheme and the hi pipes just do it for me! Are you gonna clear coat that Bob or leave it as is? To me....either way is cool