Hi. Iv'e recently bought a 1962 D7 from a deceased friends estate. The bike is in very good condition but reluctant to start. It will only run for 4 or 5 seconds & then die. My freind was having the same problem in his ownership & had the Carb cleaned ultrasonically. He fitted a Viton tipped float needle as well.
375/31 carburettor. Slight play in the body only.
Main jet 140. Pilot 25. (Needle jet 105. Burlen state 1005 for a D7 ) Needle 5 groove. on No2 from top
3.1/2 cutaway.
Spark plug new NGK B6HS 19 thou gap. Points (15 thou) and condenser new. The Plug cap is new as well
Starting technique. Check C/Case is clear of fuel Flood the carb & kick. It will not start with the choke on.
I have had the bike running once for about 10 Minutes but it wasn't happy at the Pilot/ Throttle C/away stage
Any advice appreciated
Not owning a Bantam, but have the crank seals dried out due to lack of use. I know this gives problems on 2 strokes.
Try reducing the points gap - see service bulletin below.
Hi
I don't know how to eliminate the seals as a possible cause
I will try retarding the ignition & see if it helps with the starting
Hi. Sorry for the late reply Caring duties stopped play
First of all I decided to check the ignition timing.
I set up a dial gauge in the plug hole and located TDC Then turned engine back 80 thou. Then forward to 62.5 thou BTDC
I have a buzzer connected via a battery to check the point's opening (Bike ignition off)
When the points opened the Buzzer continued to sound
I disconnected the coil wire and the buzzer stopped working when the points were open
I touched the coil wire to the points the buzzer sounded again with the points open. Earthing out.
Is this a coil fault? If it is how come I get sparks at the plug when kicked over.
Can someone get me on the right track. Thanks
Try disconnecting the condenser, that maybe leaking to earth which will give you a weak spark and keep the buzzer sounding.
Hi.
Its ok with just the condenser connected. the buzzer stops when points open.
Do you know anything about the primary winding being in parallel to the points so earths out.
Is the D7 model with a battery affected. or is that the earlier models
Thanks
Worn crank seals cause very difficult starting and poor running.
The carb could have been ultrasonically cleaned but could still have a blockage. Is the needle seated correctly? Is fuel definitely getting into the carb? The needle in the slide can become displaced and this will allow the bike to start but not rev. It does sound like your friend had problems for some time with it.
Hi,
Is your D7 running the magneto type coil (in with the generator) or a separate coil under the seat?
Do you have a good strong, blue spark?
The D7 is pretty tolerant ie it will usually run even if things are not perfect (at least mine does!). If the spark is weak check that the plug cap doesn't have any suppression, copper HT leads also seem to suit Bantams better than carbon.
It sounds like fuel starvation though. The settings on your carb seem fine but it is worth double checking the internal passageways in the carb body (I soak mine in vinegar overnight, others boil there's for ten/fifteen minutes or so in a washing powder solution!). Can you borrow a good carb from someone else and swap it out just to see if that's the problem? (Try a post on the Bantam club site to find someone near you).
It's also worth trying with the air filter removed, especially if it's not the original sort.
Hope you get it sorted.