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General => Douglas Motorcycles - General Discussion => Topic started by: williamjoynes on 28 Jul 2013 at 14:58

Title: Problem with t35 timing issue
Post by: williamjoynes on 28 Jul 2013 at 14:58
Hello
I was wondering if anybody can help i am restoring a 1947 t35 350 twin and all i have left to complete it is timing the engine however it is not firing up there is not a very good spark could this be the issue?

many thanks
William joynes
Title: Re: Problem with t35 timing issue
Post by: eddie on 28 Jul 2013 at 17:46
William,
             Your magneto should be timed at 36 degrees before TDC, fully advanced. Unlike most other bikes, Mark series machines are set up with tight wire advance, so without the cable connected, the magneto will be fully retarded. If your bike has a weak spark, it is probably due to a faulty condenser in the magneto armature. You could try wiring a distributor condenser between the cutout wire and earth to see if this improves the spark, but this is only likely to provide a temporary remedy.
  Regards,
                Eddie.
Title: Re: Problem with t35 timing issue
Post by: aggettd on 08 Aug 2013 at 19:28
My manual for the T35 shows ignition timing to be set at 10 degrees BTDC at full retard. Eddie's note was for full advance. Also the breaker gap should be .012" at full open. The manual also indicates that full advanced ignition should be 43 degrees BTDC and that the breaker gap should be .004" when the pistons are at TDC. Whether 36 or 43 degrees, that small difference shouldn't make a huge deal for starting, but may be important for power and economy. The magneto fires each cylinder independently (ie. there is no lost spark) so you must be sure that the magneto is firing the correct cylinder in order for the timing to be on. I know that there is some dissension on this forum, but my T35 works immensely better on Iridium plugs, however, they do require a good strong spark, so if your magneto is a bit weak, they may not help. Finally, I have found the T35 to be very sensitive to stale petrol. To be sure, use fresh fuel. Good luck.