LCGB Forums

Hi
I have a 1959 Li 150 series 2 6v. D.C. all as original. It had been in the back of a garage for 40 years , last used 1973.
I got it 2 years ago rode it for about 200 miles but had leaking fuel problems with the original Delorto MA19 bs5 carb.
As Stickys manual i upgraded to a MA19 bs7 carb,
I fitted new rings and have just done 500 miles running in ( its been very slow going )
From cold it starts 2nd or 3rd kick now and runs smoothly up to about half throtle after 8 miles it starts to hesitate pops and misfires.
Have fitted new atomiser needle and jets ,have tried from 78-88 main jet with no effect.plug colour is too light.
Have fitted new regulator,coil, points,HT lead cap and plug.
I did a 15 mile run today 30-35 mph. after 8 miles it started to hesitate , the problem is worse when it gets hot
Is it electrical or fuel problem ?

Help appreciated regards phil

If the plug colour is too light, I would start with fuel.

Is there any muck in the petrol tank ?
Is the filter inside the tank blocked ?
Is the fuel flow adequate ?
Do you have an in-line fuel filter that might be restricting the flow ?
Is the fuel line too close to something hot, causing the fuel to vaporise upstream of the carb ?

For carb settings and electrical issues, you'll need to wait for a grown up to respond.

I might be barking completely up the wrong tree as I am thinking back donkeys years now but have you changed the condenser?

Rich'

Thanks Torquewrench and Rich.
Dont think there is problem with fuel from tank to carb, fast flow tap fitted had carb off many times to check and all clean.

Will change condenser next

I also agree with the condenser, also light plug colour can possibly be caused by over advanced ignition or overheating caused by insufficient cooling of combustion chamber

Hi Phil. I had this years ago when I got a S2 with it's original 6v points; I never seemed to get more than 5-8 miles before loosing power and eventual engine cut out. I chased the fuel issue with new tap, new tank, in-line filter plus repeated cleaning and fiddling with the carb. I then went down the ignition route with new points and condenser but still no joy. In the end I went over to 12v electronic ignition and it seemed to solve the problem. Might be worth trying a different, proven, stator.

Tony

Have changed condenser.
Did 15 mile run this morning with no problems.
Will check timing next.

Thankyou all for your advice, brilliant forum.

phil

don't forget with modern fuels being crap that the ignition timing in the manual is too advanced. 23 degrees is way too much, try 19 degrees and see if it helps

Checked timing and it was 15 degrees,there is no arrow or timing marks,i think it must have been guess work,
stater was fixed in centre of slots,now set at 19 degrees.
Just had it dyno'd and it was too rich so back to 78 main jet.

Now running smooth problem solved i hope.

thanks again phil.