Just had my 55 B31 delivered and it's not running right. It seems difficult to start and will only run on at least half choke. It has been standing for a while I think and it may have wet sumping as well. I have just done 10 miles on it and I assume any oil might have returned to the oil tank.
Any ideas please
David
Wet sumping is quite common. Basic solution is to ride it regularly. For now I would drain the sump (should be 200mls or so - more than that is excessive). You can put an automatic valve in line to minimise it if you only ride once in a blue moon (I put one in my previous B33 without issues) didn't use one on my BB GS engine nor on current ABSAF DBD type.
Depending on your carb (should be a Monobloc) the most likely problem is blocked pilot jet.
I would strip and clean the carb and flush the petrol tank out making sure you have effective filtration.
If that does not work - back to basics, correct plug and cap, correct ignition timing and carb jets.
Good luck and please keep us posted on progress.
Thank you for the advice. To be honest it was my own stupid fault. I actually tried running it on full choke. I am not used to all these levers and when I bought the bike I was told the choke was off pushed forward when in fact it was on. It runs great when it runs, however it's awful to start. I don't know if it's me doing something wrong or there is a fault. I have just changed the plug and had a nice run out but after leaving it for 20 minutes i couldn't start it. I am a bit disheartened at the moment as I paid a lot of money for the bike but I am sure I will get there.
Things to determine:
Choke lever usually pull wire tight = choke on
To confirm look inside carb inlet and open throttle wide and when choke is on you will see the choke slide in the way that will lift with choke off.
Is your advance retard tight (early bikes) or loose on full advance (later machines, GS types and better IMO).
Usual starting is to switch on fuel, tickle carb briefly until it bubbles out a little. 1/2 choke.
Use valve decomp to turn the engine over gently to prime.
Half retard the ignition
Rotate engine to compression, nudge over compression gently.
Set throttle to just off the stop and give full swing on kickstart (stand on side - not sit on as it might damage c stand.
Hot is same but no choke.
Good cold but hot starting is usually a weak mag issue (windings/capacitor etc. Too big a subject for here now
Neil, Is Choke on a typo? Mine are all pull wire tight choke off.
DGB, If you are new to all this, you are on a steep learning curve, but it will get better with practice.
It's not uncommon for these old bikes to be difficult to start, and a lot of it is down to starting technique.
Follow Neil's advice, and if it doesn't start, then perhaps alter the advance, or throttle opening, maybe try it with a closed throttle? Try it with either less tickling or more tickling.
An easy way to check if fuel is getting through is to examine the spark plug. Is it wet or dry? If it's wet, maybe you are tickling it too much or using too much choke. If it's dry, maybe more tickling or choke and try to start it with the throttle closed, to draw more mixture in. Hopefully, you will discover the technique your bike needs to start it.
Otherwise, it's diagnostics. Pilot jet blocked? Magneto breakdown etc. A simple test would be to invest in a neon spark plug tester. It's not a full test, but it will tell you if there is no spark.
Let us know how you get on.
Yes, sorry, thank you for pointing that out (looking inside the carb is still a good idea!( choke is on when cable loose, my brain had moved onto advance retard lever. I type too slowly on my phone.
Agree it is trial and error to see what works best.
I can usually start a B31/3 or ZB34 without the valve lifter but a 10:1 CR Goldie is strictly by the book!