HELP!!! I broke it!!! Won't start. Warning LONG!!!

[Gordon in nc]

I'm going to give in and ask.....just to many "other" won't start threads to search through.

As Pink would say "I'm a hazard to myself....don't let me get me...I'm my worst enemy"

Back ground: 1975 XS650B. I've had it a little over a month and within that time, woke it up from a LONG sleep. I've been going through the bike and trying to get in road worthy. Just a couple of weeks ago the bike ran for the first time since 1985. I've put a little over 50 trouble free miles, never getting far away from the shop and taking it easy with it.

No problems until a couple of days ago. I just got back from a short run and the bike was running fine. BUT (here I go) I decided to strobe check the timing again to see if it was still in spec. It was off just a little so I re-adjusted it. Right side first, then left. I'm feeling pretty good about that task by now. While I'm doing it.....I get to thinking about the advance. There hasn't been a problem with it but I read a lot about lubing the advance rod. This bike sat unused for a LONG time and everything else was gummed up and stuck....so I figure, what the heck I'll pull it out and that will be one more thing I won't have to worry about.

I did the research...printed out some posts (5twins) that explain how to do it. No problem. First I rechecked ( I had already done it because Barb told me to) the weights movment (with the points held open) and they seemed to be free. But I was bound and determined to pull that rod out to see what it looked like if nothing else. Well....the only thing I DIDN'T do following 5twins instructions was to pull the locating pin out of the advance side. I gave it a little tug and it didn't move so I figured the heck with it I'll leave it in and it'll be indexed correctly when I put it back. Good thing is....the rod was free but pretty dry. I felt good about getting some moly in there and also the points cam had a bit of surface rust and I cleaned that up too. Slid the cleaned and lubed rod back through the cam......slid the knotched spacer on.....tightened the nut (w/a drop of blue) lined up the two scribed lines on the advancer and attached the weights. I figured I would need to re-adjust the points gap because of the cam cleaning...and I did. Job's done.....let's fire it up and see how it goes. That was two days ago.....the bike wouldn't start then and still won't start.

All I get is a slight chuffing through the carbs when I'm trying to start it.

Here's what I've done up to now.

Swapped the weights around and got a backfire......figure I'd put them back where they were.

Checked the cam chain adjustment (twice)

Checked the valves (twice) (this was a puzzler and might be a clue? Exhaust were tight and inlet were real loose...it's been run a little over 50 miles since I adjusted them the first time)

Checked the points gap (twice)

Static timed it (twice)

Checked spark to the plugs (yes)

Checked for compression (yes...finger over the plug hole....it's the same as before, when it ran.)

New plugs

Gas is getting to the cylinders

Some how........something has changed. My guess is timing but, HOW. If I line up the two scribed lines on the advancer....the locating pin is a 12 oclock. If I go around and look at the points cam....I can barley see the notch behind the nut but it's at 12 oclock too.

It was running fine/starting with the first touch of the started button before I took the advance rod out.

Timing chains......grrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr

I did get a pretty good backfire when I swapped the advance weights around...but that was only after it didn't start.

It's got to be something simple...might not be simple to fix but I'm not giving up.

Searching for answers and needed to vent.....thanks in advance.....Gordon in NC

 

[fredintoon]

Hi Gordon,
from what you say, my best guess is that you somehow, despite your best efforts, managed to get your sparks 360º out of phase.
It's an easy thing to check, swap the plug wires over so that each wire and coil is firing the other sparkplug.
If it starts like that, then you know.

 

[pamcopete]

Gordon in NC,

Yes, I would agree with fredintoon. You were careful to line up the scribe marks when you reassembled the advance rod, but maybe the scribe lines were out 180 when you took it apart and the PO swapped the plug wires to get it going. Now it's your turn!

 

[TwoManyXS1Bs]

Hey, Gordon. Rust on the points cam isn't good, it'll chew-up the points followers. Besides, they DO wear down, can affect ability to properly time within adjustable region. New ones are available:

http://www.mikesxs.net/product/14-0656.html

 

[Gordon in nc]

Thanks for the help fellows......as soon as I read these replies I went back out to the bike.....pulled the tank and swapped the wires (Orange/Grey) to the points and gave it a try. No start but some impressive FLAMES out of the mufflers.....so I swapped the wires back around.

I'm 99.9% sure I looked at the scribe marks before I pulled the rod.....and left the engine alone while I had the rod out.....figured then even I couldn't mess that up.

Two many....the rust was just a light coating of surface rust.....cleaned off easily with 600 grit and left no pitting.

I've done something wrong but I'm out of ideas.

I forgot to say that my points are in good shape (no visable pitting) and I made sure they were free of any grease or oil.

I've been working on it off and on since the problem reared it's UGLY head and started from scratch setting up the timing again. Cam chain, valves, points gap, static timing (this time I know the light comes ON when the points open....not goes OFF like it does on my Brits)

I'm still reading posts and trying to find where somebody had a problem like mine.

Gordon in NC

 

[Gordon in nc]

Come on fellows.....I know you have other ideas????????

After doing some more reading I re-checked the cam/points/advancer alignment. Put the engine a TDC (at the rotor) and both locating pins are in the same position and are at 12 or 6 oclock.

I always go back to the last thing I did when I mess something up...and oh yea, I have messed a thing ot two up....I've been riding/wrenching motorcycles (mostly BSAs) since 1968.

It was running, I decided to strobe time it again and adjusted it a little. When I finished strobing it, it started with one push of the button (that part is going to spoil me).

THEN (dumb arse, don't try to fix something that ain't broke!)I got the idea in my head to clean and lube the advance rod.....oh yea, I just HAD to see what that looked like. Pulled it out.....not 100% sure I left the scribed lines together but never moved the engine and never removed the locating pin on the advancer side. Cleaned and lube the rod.....put it back in with the scribed lines alined......and tighten it down.

Sorry that I'm going over this again but I'm trying to figure out what I did wrong.

I have......spark, fuel and compression. The bike won't start.

I have backed up and set the bike's timing just like I would after a rebuild. Cam chain tension, valves, points gap and static time. THREE times now....at least it's getting a LOT easier now.

I have swapped the points wires and all I get is a wicked backfire out of the mufflers and some pretty cool flames.

What am I going to do next?

I'm going to switch out all the bits that deal with spark. I understand that all my parts could be 40 years old. So let's get new coils, condensor, plug wires w/caps and points. That's a $100 that I feel is not wasted one way or the other and at least I'll know they're not the problem.

Spark weak under compression? Why now? Not sure what a "good" spark looks like with the XS but my BSA would run all day with what I'm seeing with it out of the head.

I'll take any and ALL suggestions/advise you have to offer and will update this by the middle of the week.

I'm pretty much out of ideas.

Thanks for letting me cry on your shoulders

Gordon in NC

1975 XS650B That sounded GREAT when it was running
and a few BSA unit singles.....that are SO much easier to understand

 

[TwoManyXS1Bs]

Come on fellows.....I know you have other ideas????????

I have swapped the points wires and all I get is a wicked backfire out of the mufflers and some pretty cool flames.

Hey, Gordon. Just thinkin' out loud here. That particular scenario is interesting.

Now, when the points wires are swapped, the plugs will fire 360° out, during the valve "overlap" phase. The intake valve should be opening at about 35° BTDC. If your idle ignition timing is correct, around 15° BTDC, the intake valve would be quite a ways off the seat, and you should get backfire outta the carbs too.

If not, perhaps the plugs are firing BEFORE the intake valves start to open, forcing all the backfire out the still-open exhaust valves. This makes me think that your ignition timing is too advanced, by at least 20°.

The slotted disc that the advance weight ears fit into isn't known to be symetrical about the index pin slot. If your original/good/running configuration was set with that advancer slotted disc upside-down ( 180° out), then later reinstalled correctly, it very likely will shift your ignition timing.

Well, that's all I got. I'd triple-check the static timing, both idle position and advanced position. The older manuals have a short blurb on wedging sticks or whatever to hold the weights fully outward for static checking the 'advanced' timing...

 

[pamcopete]

OK. Here's a new thought. Do you have vacuum barbs on your carbs? If so, are they plugged with caps? If not, the engine will not start because the mixture would be too lean with the barbs open.

 

[Gordon in nc]

TwoMany......I never removed the locating pin in the rod for the advance side so wouldn't that have made me put it back like it was? If the disk had the scribe mark on just one face (that's a question) ....I'd be pretty sure I put the same side out.

The idea of something going bad just sitting there is far fetched......but it woul be my luck.

Pamcopete, it's a stock B with no barbs. After I finished strobing it I started it....one push of the button. After that the only thing that was messed with were the points (held open with thin carboard, the bob weights removed and the rod removed and put back in place. That's it.....

Do any of the sensors stop the bike from starting......like the ones connected to the warning lights on the dash?

Grasping at straws here in NC. Gordon

 

[5twins]

Have you tried cleaning the points faces? It's very easy to contaminate them with an oily feeler gauge or even the oil on your fingers. Then they don't fire right or at all. You're probably familiar with the cleaning procedure - 1/4" wide strips of white business card sprayed with electrical contact cleaner and dragged between the points faces.

 

[retiredgentleman]

If you have 40 year old ignition components, they should automatically be thrown out, as they are well past there "best before date". They can no longer be trusted.

I would not be buying OEM equivalent replacement ignition coils. They only provide 11K to 12K high voltage. I recommend you buy a single dual output coil that puts out at least 30K volts. If you want to stay with points you can do that, along as you keep the coil primary around 4 ohms or higher. In fact, you would be much better off with a Pamco, unless you enjoy fidling with points.

I have had experience using points with a 30K dual output coil. If you want details, just ask.

These engines run really well if they have a good healthy blue spark, but don't run well with wimpy yellow sparks.

 

[Gordon in nc]

Have you tried cleaning the points faces? QUOTE]

Yes sir, they were spotless and couldn't be that old because they seem to be in good shape.....no visible pitting at all. Which also leads me to believe the condensor is okay too.

BUT......just for shits and giggles when I got home from work tonight I cleaned them again and checked the static timing..... again.

I have been thinking about what TooMany wrote about being to advanced.....so for the heck of it....I marked where the points were set....and after checking the point gaps one more time I started moving the points a few degrees and then checking where the timing mark was hitting the case. I'd mark that spot and then check that the left side was keeping up with it...and it was pretty close every time (pun intended). I moved it in both directions and once I was sure the left was close to the right I'd try starting it.

No joy....you know that if it was a timing issue.....and if swapping out the plug wires didn't do it....I would have hit it close enough moving the plate around to make it run...maybe not run good but it should have run. I tried at least 3 positions on either side of the correct timing.....nothing but some slight popping in the exhaust.

I'm 90% sure it's not a timing issue. The main reason is because of the fact that i left the locating pin in the advance rod in place and heck if I had moved it....reversing the wires/plug or points would have solved that mess up. Static timing is pretty easy and not something you'd not figure out sooner or later. Once I found out that the light comes on with the XS instead of goes off (when the points open) it was a snap. I'm 99.9% sure it's timed close enough it should at least run.

I'm backing away from it and by the middle of the week I'll have some new bits to install and we'll see how that goes.

Retired.....I don't have a problem with points. My main ride is a 1967 BSA B44VR which now has a Velorex chair attached to it. I taken it on several longish (well over 1000 miles round trip) trips the past few years and with points.....I can change them on the side of the road if I need to. The other thing I like about points is that you can have a flat battery and they still work. BUT......I have bikes with EI on them too....most of the time I do that when I'm building one because unlike the XS.....new auto advance units for a BSA aren't that easy to find....and when you do find one they aren't cheap. I use Boyers...have for years on some of my bikes.

I knew that I needed to change out all the stock/old components but I didn't want to sink a lot of money into this bike until I knew a little more about it and if I was going to have to go into the engine.......it was all an unknown and I was just going on what I had been told.

For the time being....I'll stick with points.

Thanks for all the help......updates near the end of the week......Gordon

1975 XS650B that ran for a few days
and a few BSA unit singles......one carb, one piston, one set of points, one set of valves, one spark plug, one coil,..........more is not always better.

 

[5twins]

Have you tried setting the tank on Reserve? Sometimes, you are running out of fuel the last time you used the bike but don't realize it. The next time you go to start it, it won't, because it's out of gas.

 

[pamcopete]

Gordon in NC,

When you removed the advancer to clean / lube it, did you also remove the locating pin for the advancer? If so, did you replace it? Is it possible that it just fell out, unnoticed?

5twins has a good suggestion as well. I did that once. Spent the whole afternoon screwing with the points. I was just out of gas.

 

[Gordon in nc]

Gordon in NC,

When you removed the advancer to clean / lube it, did you also remove the locating pin for the advancer? If so, did you replace it? Is it possible that it just fell out, unnoticed?

5twins has a good suggestion as well. I did that once. Spent the whole afternoon screwing with the points. I was just out of gas.

Pamcopete......the locating pin stayed in the rod the whole time. I tried to pull it out and it didn't move easily.....so I left it alone. I can see that both locating notches are still pointing in the same direction. And......if I line up the stator on TDC the notches are either pointing (together) at 6 oclock or 12 oclock. BUT.......right now I can not 100% swear that the pin is still in there without pulling the disc back off. But the pin didn't move easily and as far as I know it never moved and I'm pretty sure, since this was my first time that I watched the disc go over the pin.

That will give me something to do tomorrow after work.......since I'm waiting on parts and it's worth the effort to make sure the pin is still in there.

5twins.....yes, today I thought about the gas and used the reserve. I also tried primeing (sp?)the plug with a little gas. Yesterday....or was it Saturday??? The plugs were wet with gas when I pulled them. Fresh gas....heck, it's only been running a week.

I also use gas lines (Dennis Kirk) I can see through......and can tell there is fuel making it to the carbs.

Yep...... I'm stumped

Gordon in NC

 

[pamcopete]

Gordon in NC,

The only sure way to check for gas is to drain the carb bowls and with the drain plug removed, turn on the gas and see if you are getting flow out the drains.

The pin I am referring to is the third pin that locates the advance plate.

 

[Gordon in nc]

Gordon in NC,

The only sure way to check for gas is to drain the carb bowls and with the drain plug removed, turn on the gas and see if you are getting flow out the drains.

The pin I am referring to is the third pin that locates the advance plate.

Good point on the gas flow. I will check that tonight just to be sure.... but when you've been trying to start the bike.....and it doesn't, when you pull the plugs and they're wet with gas....it's a good guess there is gas flowing.

Okay, I see the pin you're talking about but following 5twin's instrutions....I never removed the advancer and I'm thinking that I would have had to undo the flanged nut to get to the pin you're talking about????? That's a question.

Thanks for the help....I'll check for gas flow tonight.

Gordon

 

[retiredgentleman]

I'm betting you need a new strong ignition coil and new spark plug leads.

 

[Barb]

Deep breath, Gordon,

Lessee---it sounds like you are being entirely too logical.....so I'm just gonna throw a couple of obvious ideas out there, and you can chuckle and make "Chick" jokes. OK? Once. Then all is fair.....

So. First, have you stuck a meter on the battery? I know the electric leg works, but have you tried kicking it? The starter has quite a draw on these bikes.

Second, and this is really obvious (except I've done it more than once), when static-checking the timing, you have the bob-weights held in by a clamp, right? OK, then the only other obvious thing I can think of might be something like really worn and weak advance springs? Do both bob-weights stop on the tabs at the same time when you manually advance the timing? Did you drop a bit of oil on the bob-weight shafts so the weights swing freely? (Grasping at straws...)

Oh! Long shot, but with the gas tank off anyway, are the coils hot after turning on the ignition key and leaving it for a few seconds? You know about that one, I know....

This is a tough one, Guys. Mainly because Gordon is (quietly and without fuss) a bit of an engine guru on Brit bikes. I'd feel perfectly fine taking any BSA he ever built and riding cross-country......and I've been telling him how neat and cool the XS is, and now it's grinning at him and being stubborn. I'm gonna pop the covers on my bench engine and take a look, just to try to see if there is something we may have overlooked or taken for granted. It's such a simple engine.....this is frustrating!

 

[Gordon in nc]

I'm betting you need a new strong ignition coil and new spark plug leads.

I've got my fingers crossed that you're right. New bits should get here tomorrow and we'll see.

I'll be damned if I can figure out what happened. At first I would have sworn it was a timing issue but with all the setting/checking I feel pretty sure it's timed corretly.

In the best of worlds I would just swap out one thing at a time, then try it so I'd know what was bad.....but the hell with it. I'm pulling all the old stuff out and replacing it....well, everything to do with spark. I'll deal with charging later.....(fingers crossed) I haven't seen a problem there yet.

I need to pick up that projet bike that's for sale here in NC so next time I want to see what something looks like....I can go into that engine first.

Thanks again for all the help......and the shoulder to cry on.

Gordon in NC