Atlas '64 Rebuld

I located both of the bolts and nuts for the center stand. Evidently a PO had run a 5/16th bolt thru the bolts and nuts, thru the mtg. plates and secured this with nuts on both ends.
I don't know why. Andover was helpful also and said the same thing Slick, there is no factory thru bolt. They were able to supply me with the critical measurements of the rear wheel spacers and the spacer between the plates for the footpeg rod, which is;
3 5/16"X3/4"X15/32". Rear wheel spacers are: 5/8X 1 1/4X13/16. right side.
and 1X1X 9/16th left side. (Done by eye with a rule.)
 
btw the early Commando gearbox lower mtg. bolt is the same and does not require any washers or spacers.
 
Interesting there has been a discussion either on this forum or the NOC website about a securing bolt through the centre stand bolts securing up to the engine plates I understood it was a factory fitment, going further my '66 Atlas had the holes in the engine plates for the through bolts.
 
yeah possm, mine has the bolt holes in the engine plates also. For what it's worth, they look factory drilled. I am going back with the thru bolt. Just for peace of mind. It's easy enough for any future owner more of a stickler for details than I am to remove it.
 
After a few major setbacks, I finally am at the point to run the engine. I have the twin Amal setup and everything seems to be in order. Good compression, good spark, and fuel to the carbs. After a number of kicks it will pop and fire but not run. Set at full choke and 1/4 throttle. After a number of kicks (7 or 8) I pull a plug and find them dry. I had rebuilt the carbs and reset them back the way I found them. btw the bike was running before I rebuilt the engine. I could use some help on this. Thanks guys
 
possm said:
Plug leads round the wrong way?
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no, I think they're ok... when it fires it fires out the pipes. It just doesn't seem to be getting any fuel from the carbs into the engine. The float chamber is full and when I press the tickler, fuel bubbles up in the throats, so that's working ok. With full choke and 1/4 throttle and after 7 or 8 kicks I am stymied by the plugs being dry. ???
 
if it's got good vacuum through the intake and not drawing fuel, all l I can think of is some obstruction in the carb. If confident of all the timing/valve/ignition, I might use some starting fluid to see if it will catch and run a few revolutions, but if you have something major wrong that might be catastrophic, so I think I'd take carbs off, check for blockage, and also do a hand test on the vacuum at the intake if possible, trickier with a kick start. I'm just a home mechanic so take with a gulp of your favorite beverage. I use starting fluid on one of my bike's when it's sat a while and fuel has evaporated, the prime isn't working even though it's a brand new OEM petcock. Old bikes are fun.
 
Sorry, but somebody has to ask if you're operating the choke correctly? Slack wire/on, taut/off (if my memory serves me correctly)...
Also if encouraging fuel flow, I'd not open the throttle at all. If plugs are still dry, disassemble...
 
possm said:
Interesting there has been a discussion either on this forum or the NOC website about a securing bolt through the centre stand bolts securing up to the engine plates I understood it was a factory fitment, going further my '66 Atlas had the holes in the engine plates for the through bolts.
Click to expand...
There was an article in the NOC Roadholder a year or two ago. Apparently, the factory intentionally left out the bolts on many bikes. Mine did not come with them factory new. IIRC, the NOC article speculated someone found less vibration without the bolts, and the factory began leaving them out.

Slick
 
I can see the chokes sliding closed when I put the lever on full, so I think that's ok. I will try the hand over the intakes and see if I do have good vacuum. I have somebody who is helping me kick her over so that should make this test easier. When it does fire it only pops, not run.
 
What do you know of the magneto's history? Has it ever been rebuilt? I am supposing the bike ran before you started this rebuild, but it is possible the capacitor has failed in the interim.

Having spark when you ground a plug is not good enough. The spark should be blue-white, at least blue, and a blue-yellow spark is weak, a yellow spark most likely will not fire under compression.

I have shifted to ignition from carbs because an engine should run for 2-3 seconds on the priming dose. Your occasional pop suggests weak spark, not lack of fuel.

Slick
 
If you take the plug cap off the HT lead, or stick a metal rod in it, spark should reliably jump 1/4” from the end of the HT lead to the cylinder head.

Remove the spark plugs for this test. Earth the HT lead that you are not testing.

The simple and obvious test for whether you’ve timed it to spark at the top of the wrong stroke is to swap the leads over.
 
I've never had much luck with monoblocks. I re built an Atlas and had the same isuues with starting and running. I even got some brand new monoblocks but to no avail. I stripped them down, checked and re checked timing, checked manifold seal, nothing. In my frustration I fitted a Mikuni kit I had and it started first kick and ran beautifully. I've had exactly the same issue with the N15 I now have and resorted to a Mikuni and it runs like a clock, first kick starter. That's just my experience but I would never have twin monoblocks on any bike.
 
If you are running Monoblocs crack open the main jet cover on the off side carb and see if petrol leaks out. If it doe forget the choke, tickle until gas comes out of tickler, hold throttle about 1/3 open and try a couple of kicks. If no joy remove main jet and needle jet and look for blockage.
 
This gives me quite a few things to check. I'll try each one of them and see which gives the best results. I don't know the history on the magneto. I'll try all the suggestions and hope to reply with some good news. Thanks to all
 
First thing to check is always magneto. If it is original and has never had the condenser/capacitor replaced it is nearly certain to be bad. Usual give away is bad or no running when warmed up. Failure to run at all may simply mean condition is even worse. IMHO there is nothing wrong with Monoblocs for ordinary use. Far easier to work on than Concentrics which cost less to produce and have only marginal functional advantages for street use. The main issue with the twin Monobloc setup, unless you have the good fortune to have a handed set, is that it is a major PIA to get to the air screw for idle adjustment on the left carb, the one with the float chamber.
 
texasSlick said:
If in doubt about spark quality, get one of these in line spark testers: If you shop around, you can find one with a right angle plug cap, which is more convenient for our Nortons.


A good spark produces a bright orange flash in the tester. It tells you what is happening in the cylinder.

Slick
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You mentioned this to me before, Slick. I've been away from my project due to medical issues but am trying to get back in the swing of things. I'll get one of these in town and see what's going on.
 
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