Will not Start

Information relating to the Matchless G11 or AJS Model 30 600cc twin
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Will not Start

Postby freddie 136 » Wed Oct 07, 2009 4:43 pm

Hello again,I have a 1958 G11 600 twin, some of you kind people will remember that i had problems with my engine back in June after i had had a re bore and new pistons,rings, bearings etc, well after it almost nipped up i had the barrels bored out to [6 though] as suggested by itma, it has done 800 Miles now and still running at about 40/45 MPH last week i did another 45 miles no problem, went to start it up on Monday and it would not start, after one or two tentative tries it started running but very uneven, i thought the timing might have slipped so have had the timing cover off points looked o.k.,gap at 12 though, took timing sprocket off got off side piston at TDC straight after inlet vale closed then with a mark on a piece of rod 3/8" higher than the TDC mark put bike in gear and turned back wheel in a backward rotation till the high mark was in same position as the lower mark, [as per Hand Book]checked points and just as they were about to open with fiber block on bottom cam put it all back together again checking nothing had moved. I also took the carb off [ this is a new carb not dona 1000 miles yet] and dismantled it, taking it completely to pieces and blowing every thing clear with my small compressor and air line, there was i think a bit of dirt in the pilot jet but all are clear now, put all the bike back to gether and it still will not start . I have since had the mag off and dismantled it,the pick ups are new replaced with good brushes, to be honest i think the chap who had the bike before me had the mag redone,as it seems very clean in side, there is a spark at each plug.When i try to start the bike with air leaver closed,and approx 1/3rd retard, with petrol in the carb, the bike will not start, but i am getting loud bangs coming through the silencer more so if i open the throttle more. I have checked for air leaks at the carb and exhaust and round the cylinders but can't find any. I have now run out of ideas, all the valves appear to be operating as they should, does any one have any suggestions please.

Edited by - freddie 136 on 07 Oct 2009 4:46:24 PM

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Will not Start

Postby moley » Wed Oct 07, 2009 4:52 pm

Plug leads on the wrong way around ?

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Will not Start

Postby freddie 136 » Wed Oct 07, 2009 7:00 pm

Hi, thanks for the reply, the rear lead from the mag goes to the off side plug [R/H side of bike] i think this is as it should be but please correct me if i am wrong, thans once again, Fred

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Will not Start

Postby moley » Wed Oct 07, 2009 7:25 pm

that is correct but it dies depend on where the points are when you time it. Try it !


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Will not Start

Postby freddie 136 » Wed Oct 07, 2009 7:31 pm

Hi, thanks again,i will change the leads over in the morning and let you know,thanks. Fred.

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Will not Start

Postby Don Madden » Wed Oct 07, 2009 7:49 pm

Remove the rear pickup & look inside using a mirror. Turn the engine until the brass segment can be seen. That is the plug that will be fired. Now check to see which side is on the firing stroke. It will be the one with both valves closed or you can hold your thumb on the plug holes to see which is compressing.

Cheers, Don.

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Will not Start

Postby laxy » Wed Oct 07, 2009 11:01 pm

hi freddie, when you set the ignition timing was the advance/retard lever at the handle bar in the fully advanced position?
loud banging in the silencer is classic sympton of timing the wrong cylinder and swapping the plug leads over will correct this but if the bike has been running ok and you havent swapped the ht leads over then you can rule that out.(unless some wag has been playing silly bu**ers).another thing, wet sumping makes starting difficult if not impossible on twins.how long has the bike been stood prior to you attempting to start it.try draining oil from sump and putting it back in the tank.unleaded petrol has a shelf life of about three weeks before it goes stale,although my single will start and run happily on petrol thats been in the tank for a year my twin refuses to fire up on petrol more than 5- 6 weeks old.on the petrol theme,check and clean filter in petrol tap if fitted
Im on dangerous ground here but winter is nigh and you should be thinking of changing to straight 40 (gulp! wot have I said?)

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Will not Start

Postby wilko » Wed Oct 07, 2009 11:48 pm

My 650 twin and a friends 500 twin REFUSE to start without copius tickling until it's dribbling everywhere with at least half throttle. Try it! Also we have to repeatably replace plugs when too flooded.

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Will not Start

Postby smsxr05 » Thu Oct 08, 2009 9:56 am

Open the choke and leave it open. To start the bike flood the carb, slight advance on the lever, just crack the throttle and kick.
Sonof.

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Will not Start

Postby freddie 136 » Thu Oct 08, 2009 2:59 pm

Hello again,thanks to every one for there help.

Don. yes the Brass segment is in position[viewed through a mirror] when piston is in timing position via the Hand Book, and HT Lead is to R/H plug.Bike still will not start.

laxy. Bike has a valve fitted to stop wet sumping, and have tried changing petrol in carb, as above bike still will not start.

Wilko, Tried over flooding carb, and Air and A/R levers in many positions, still will not start.

I have also set timing again today three times, [1] in correct position via info on this web site. [2]with cam in mag to far retarded, and [3] with cam in mag to far advanced, still will not start. The only thing i can think of that has not already been suggested is that the spark from the mag is not strong enough to ignite the petrol, or mag is not firing when plugs are in the cylinders and under compression, the plugs are in good condition, the HT Leads have been changed and all three carbon brushes in the mag are good,as i have already said i have checked the mag and it looks almost new inside but that does not mean it's working o.k. does it. Can a test be carried out [not by me] that will ascertain what the output is and that the condenser is o.k.thanks for your help, Fred.

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