Help with the XS650B air boxes

[5twins]

Yes Barb, where you been girl?

 

[Gordon in nc]

Hi Guys,

Well, Gordon, you've done a beautiful job so far, and you *totally* understated the amount of primer on the poor thing!

Sorry---I should have remembered about the 180-out timing thing....

Guys, don't mention the SR500 around Gordon! He is World-Class crazy for Brit singles, and if he get's his claws into an SR500, it's all over.....

Gee. My first post since 2012. My, how time does fly.....

Barb

Barb, I'm still not sure what I was doing wrong with the static timing. If the guy's story was to be believed (and I do believe him) the bike ran when the father in law passed away. So all I was doing was checking the timing....thinking I wouldn't have to set it. I used my meter on ohms.....just like I do on my BSA's.....that didn't work so I switched to ye ole bulb with two wires.....same results. 180 out. So the hell with it, I got down and used a feeler gauge and watched/felt when the points opened and it was pretty much spot on. That one still has me puzzled. This is the newest bike I've worked on...there's something different about it.....but I don't know what it is yet. I'll get the strobe on it this week (if the petcocks don't still leak) and check it again before I run it much longer.

Now.....I've owned a few twins.....1974 Norton 850, 1969 BSA A50, 1960's Baby Super Hawk and a 1960's Super Hawk....oh and I had one Harley years ago. For the life of me I STILL don't know why a bike has to have two or more of everything ........you know my main ride is a 1967 B44 Victor Roadster and even though I've loved my twins......I'll go to the grave with my singles.

Hugs......GG

 

[5twins]

Are the Brit bikes positive ground? Maybe that's what's throwing things off. On the Yamaha, when the points open, the little light will come on. I know, you would expect it to go out when they open, but it doesn't. It's out until they open. I use one all the time and it works fine. I don't do the ohm meter method because it requires unplugging the points wires up at the condensers to work, don't know why. That means pulling the tank to access those connections. The bulb works just fine so that's what I use, followed by a real timing light of course, once it's running.

And for gapping points, I don't get a feeler gauge anywhere near them any more, I use a dwell meter. I know what a good points gap looks like so I set them by eye, then start it up and use the dwell meter.

 

[retiredgentleman]

Are the Brit bikes positive ground? Maybe that's what's throwing things off. On the Yamaha, when the points open, the little light will come on. I know, you would expect it to go out when they open, but it doesn't. It's out until they open. I use one all the time and it works fine. I don't do the ohm meter method because it requires unplugging the points wires up at the condensers to work, don't know why. That means pulling the tank to access those connections. The bulb works just fine so that's what I use, followed by a real timing light of course, once it's running.

And for gapping points, I don't get a feeler gauge anywhere near them any more, I use a dwell meter. I know what a good points gap looks like so I set them by eye, then start it up and use the dwell meter.

Yes 5T, if the bulb is connected across the points, and the points are closed during the dwell, then the bulb cannot light as you cannot have voltage across a short circuit. When the points open, you then have the voltage from the coil that will light the bulb.

Its just Ohm's Law in a series circuit. When the points are closed, all of the 12 volts is dropped across the ignition coil. When the points are open, 99% of the 12 volts is dropped across the bulb.

 

[Gordon in nc]

5twins.....YES!!!!!!! All my BSA unit singles are positive ground. That has to be it.....95% of all the bikes I've ridden and worked on since 1968 had points so I thought I was schooled on them.

My main ride is a 1967 BSA B44 Victor Roadster with a 1972 Velorex sidecar attached. I take it on a 1500 mile round trip to Northern PA in the fall just to do a 200 mile loop with some friends (we call it the One State Mountain Ride) ....there's no way I would leave home without feeling comfortable with a points ignition.

BUT......that said, this strange puppy sure had me scratching my head and I finally gave up and did it an old fashion way.

My 93 year old dad was a mechanic on the real "Dam Busters" during WW2 and he taught me what I know about wrenching. He could make anything go.....and almost NEVER threw something away....some how, some way he'd make it work.

+ earth.......yea........that has to be it.

Thanks again for the help..........Gordon in NC

 

[Gordon in nc]

<snip> you *totally* understated the amount of primer on the poor thing! <snip> Barb

Hey lady you saw the ad for the poor thing. You really couldn't tell that much about the bike with those photos. I was floored when I actually saw it. BUT.....I could tell there was a bike under there that needed some love, so I ended up bringing it home anyway.

I'm a sucker for a mess somebody else has given up on.

Hugs from me in NC.......Gordon