Dunstall Commando starting issues

Hi, this bike is a genuine factory Dunstall Sleeper with 810cc 10:1 comp. Mk4 cam and 32mm carbs( new) it now runs a recent single dual feed coil (Boyer) Now then it is a reluctant starter, in that, it always starts on one cylinder and after starting (many kicks) it continues to run on one cylinder for 30 seconds or so, then picks up and is absolutely fine, ticks over like a bloodhound lapping milk, and starts very easily,I was thinking pilot jet blockage but this completely disappears after 30 seconds and all works perfectly..any ideas?

which cylinder is firing... is it always the same one?
swap plugs after checking gaps, swap leads & caps is a simple start point.
On points or EI??
Certainly could be a jet blockage especially if fuel has been left to "fester" in them for a long period
Start with the simple checks first before jumping in

Had a problem with a float needle in one carb on a Triumph leaking just enough over night to flood one cylinder. It would clear up in a few ( 30 ) seconds after a cold start and not be a problem the rest of the day.

bonnietiler said:

Hi, this bike is a genuine factory Dunstall Sleeper with 810cc 10:1 comp. Mk4 cam and 32mm carbs( new) it now runs a recent single dual feed coil (Boyer) Now then it is a reluctant starter, in that, it always starts on one cylinder and after starting (many kicks) it continues to run on one cylinder for 30 seconds or so, then picks up and is absolutely fine, ticks over like a bloodhound lapping milk, and starts very easily,I was thinking pilot jet blockage but this completely disappears after 30 seconds and all works perfectly..any ideas?

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Duff Suppressor cap, spark plug HT wire, start witj yhe easier things first.

I have fixed it!!! Starts every time now...well maybe every second time from cold....after re-reading Mr Dunstalls starting instructions, he clearly states Flood the carbs using ticklers, this I did, then open the throttle a little, this I didnt do, so trying again, I opened the throttle and ....nothing...so I opened the throttle a weeny little less, so that it was ..b.a.r.e.l.y open and it fired up straight away...hmmm, I waited until the following day when the motor was stone cold again. bike started 1st time, the lesson is, when someone as famous as Paul Dunstall hand writes you instructions of exactly HOW to start his overtuned Big Valved 810cc machine...do exactly what he says!!!

bonnietiler said:

I have fixed it!!! Starts every time now...well maybe every second time from cold....after re-reading Mr Dunstalls starting instructions, he clearly states Flood the carbs using ticklers, this I did, then open the throttle a little, this I didnt do, so trying again, I opened the throttle and ....nothing...so I opened the throttle a weeny little less, so that it was ..b.a.r.e.l.y open and it fired up straight away...hmmm, I waited until the following day when the motor was stone cold again. bike started 1st time, the lesson is, when someone as famous as Paul Dunstall hand writes you instructions of exactly HOW to start his overtuned Big Valved 810cc machine...do exactly what he says!!!

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Yay ! Yay ! Yay !

When all else fails, and you are out of options, read the instructions!

Slick

texasSlick said:

When all else fails, and you are out of options, read the instructions!

Slick

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In the IT world this was called an "RTFM" issue.

Read The F'n Manual.

In fairness the manual doesn't help on this particular machine, the single sheet of worn and grubby paper with hand written starting instructions in Paul's own fair hand, is the way forward, he built the bike and clearly.....
Is the expert

In the middle ages when scores of monks were copying manuscripts, the final line written in the manuscript was, "If the book is worn and in poor condition begin a new book." Or words to that effect. Aside from photocopying Dunstall's page I would find a museum-quality plastic sleeve and enshrine that page forever. Would the National Trust keep adequate care of it?

Tornado said:

In the IT world this was called an "RTFM" issue.

Read The F'n Manual.

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Read the Fuckin' manual. Or rewrite it.

Great job figuring it out.

As an added take away for garden variety bikes, similar procedure, if cold, tickled, rolled through once key off, stop just past TDC, be ready for a slight throttle roll on (closed to 1/8) and begin the kick while cracking/rolling on (only to 1/8!)
And whatever the variables, the engine usially finds a mixture offered that it likes.

JMWO

Every twin I've owned with a tickler button I have given a bit of throttle as I kick it over
On a big single I keep the throttle shut IE I have it shut or half a turn in on the throttle slide idle adjustment screw
I don't really see why a dunstall would be any different
Can someone explain?

Throttle cracked open or not -- the debate rages on.

In my experience it varies from bike to bike. From dead cold, tickled, spark retarded, choke on full, my Matchless single will pop only once on the first or second kick. It will continue to do that until and unless I give is a handful of throttle. Then it bursts to life with a roar and will idle down as though it's been doing that all day. The Atlas, on the other hand, tickled and choked, starts on the second kick at idle and will die unless given some throttle. After about 30-45 seconds it will idle down. The e-start Commando, of course requires no kick but does require tickling and choking and the clutch lever pulled in. Then I must warm up my right thumb by blowing on it forcefully before pressing the start button.

In years past, when I worked at the Norton shop I had to start many Commandos per day. Real men kicked threir bikes to life, not unlike dead mules. Most of them required the 1/8 throttle roll on as you kicked. If they didn't start after about three kicks, it was time to start looking for a problem. Was it still breathing?

Thomasa said:

In my experience it varies from bike to bike.

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True this. And I had a profound revelation after installing an e-start on my bike - it wants a crack of the throttle when hot.