Difficult to start at my wits end

[BSA500]

I just wish he lived next door

[CheeserBeezer]

This has been my bike for 30years plus so no change or stopping of cam/idle gears I will check every thing just for sanity and due process but as Andrew says I probably swop back to my mag and send back his for him to check again for sanity and good pratice

I suggest you don't fit yours until i've checked the one that comes back.

[BSA500]

OK I will pop yours off and I will sort out checking the rest of the engine including the primary chain that is as tight as a violin string

[muskrat]

  Sheared keys  on crank and cam are rare but not unknown.
Swarfy.

G'day 500.
I was thinking the same. I know sometimes when putting on the cam pinion the key can slip out the back.
Cheers

[KiwiGF]

Is it a monobloc carb? When I first got my bike running after a rebuild it started and stopped a few secs later, turned out the vent in the float bowl (aka tickler) was blocked, resulting in a low level of fuel in the float bowl (found after I used cling film and rubber band to observe the carb filling up, or not in my case  ).

Basically it ran until all fuel lying around in the carb from using the tickler was used up. What fooled me was that the carb bowl was not full but fuel was running out of the inlet, which makes you think the bowl MUST be full, but fuel was actually coming up through the main jet under pressure from the fuel tank (I think).

The other cause of the same issue can be a missing spacer on the float “pin” allowing the float to hit the side cover.

[BSA500]

All things to check thanks

[Sakura]

Sticking inlet valve(s)?

[tomkilde]

Is the clutch loose or oily?  If it's slipping, the force applied to the kickstarter will not be fully transferred to the crank.

[RichardL]

"... use a degree dick under the cush nut and strobe light."

Confessing that I am just starting to read through this thread. I know Aussies use a lot of odd expressions to represent otherwise boring words, so, not sure if this is one of those cases. I'll say this, I'm not putting mine under the cush nut.

Richard L.

Richard L.

[muskrat]

G'day Richard.
  One finger typing at 4am with a sticky keyboard
All the Richards I know are called Dick. Put a Richard under the cush nut 
Cheers

[BSA500]

Right checked over the rest of the engine. Timing gears all matched up all valves working a ok, carb working as it should no obvious problems. All looks normal just need to confirm a nag is OK and work from there.plugs new leads new cap non supressed

[RichardL]

Oh God, I hate to mention this because it's so likely not happening that it will make me seem rude for even mentioning it. I've combed over this thread pretty extensively now and have come to the conclusion you are extremely familiar with your bike. So familiar, that I can imagine the possibility of an opening for overlooking something because you are so familiar with where everything goes that you might miss something that appears in the right place, but isn't. Is this starting to sound like one of those online stories where it takes forever for them to get to the point? If so, you can take that as indication of how uncomfortable I am to mention this possibility, which, as far as I can tell, has not been mentioned in this thread.

Here goes: Have you carefully checked that your plug wires are not reversed? There was a mag replaced and the engine was retimed. Maybe, in the past, you've always timed on the nearside cylinder but forgot and timed on the offside. If you were used to, for example, the bottom pickup going to the offside, now it would have to go to the nearside.  Did you check the plug wires by verifying against the position of the brass on the slip ring as the pistons approach TDC?

OK, that's all. Please don't travel to Chicago just to kick the crap out of me.

Richard L.

[CheeserBeezer]

I'm fairly convinced it's a mag problem. The mag I lent is on its way back and I'm going to try it on a bike of mine. Any mag I send back to BSA500 will have been tested on one of my own bikes first. I keep a record of all mags leaving the workshop and the 'lent' mag was removed from one of my bikes about twelve months ago and it was working fine so I assumed it was OK. The only way of eliminating the mag from the issue is by getting it, or another, running on a bike. Sometimes, even though they test out OK on the bench, they don't work quite right on a bike. It's difficult to replicate running conditions in the workshop.

[KiwiGF]

Oh God, I hate to mention this because it's so likely not happening that it will make me seem rude for even mentioning it. I've combed over this thread pretty extensively now and have come to the conclusion you are extremely familiar with your bike. So familiar, that I can imagine the possibility of an opening for overlooking something because you are so familiar with where everything goes that you might miss something that appears in the right place, but isn't. Is this starting to sound like one of those online stories where it takes forever for them to get to the point? If so, you can take that as indication of how uncomfortable I am to mention this possibility, which, as far as I can tell, has not been mentioned in this thread.

Here goes: Have you carefully checked that your plug wires are not reversed? There was a mag replaced and the engine was retimed. Maybe, in the past, you've always timed on the nearside cylinder but forgot and timed on the offside. If you were used to, for example, the bottom pickup going to the offside, now it would have to go to the nearside.  Did you check the plug wires by verifying against the position of the brass on the slip ring as the pistons approach TDS?

OK, that's all. Please don't travel to Chicago just to kick the crap out of me.

Richard L.

Don’t worry I was thinking along similar lines, mainly cos I just fitted a new piston to my B44….and it wouldn’t start 

After checking all the obvious (but not as it turns out), giving up, then going back to it I finally  noticed the slide sticking up a few mm, due to the cable in a slightly changed position. That’s a first for me! Being a bike that needs zero throttle to start that was enough to stop it starting. Most likely a mate would have noticed straight away.

If anyone had asked I would have said it can’t be the carb I hadn’t done anything to it.

[BSA500]

It's OK I am the master of the lead stopping game in the world of 50:50 odds of getting it wrong I managed it 100% of the time,its the first thing I check