1966AJS 250 CSR WEAK SPARK

bag-o-nails · Post by **bag-o-nails** » Fri Jun 29, 2007 3:42 pm

Hello MY Long suffering Commrads

this Fault will not go away [ Intermittent starting]
this is what i have done so far
replaced battery, points,condenser, feed cable low tension cir,
coil HT lead/cap spark plug BP 7ES Cleaned tightened earth points
re-placed ign s/w checked ign timing checked valve clearence
still it has a weak spark

carb running rich
stripped and cleaned replaced pilot jet, all washers, replaced float/needle and all gaskets and jet block washer, main jet neddle
set to bottom notch
the compression tested at 8.5
the bike is a recent purchase it was a non runner so i dont know the history what do think!! other than getting it too John Bolton
or setting it on fire and claiming the insurance!!!
many thanks for your wisdom
cheers phill

Biscuit · Post by **Biscuit** » Fri Jun 29, 2007 4:38 pm

Have you tried a new/different coil, doesn't appear on you list.

itma · Post by **itma** » Fri Jun 29, 2007 5:41 pm

has it got an epoxy coated frame? it can be a bugger to get a decent earth through this vile stuff.
also not sure a P plug is a good idea

Biscuit · Post by **Biscuit** » Fri Jun 29, 2007 6:13 pm

The NGK equivalent for the FE80 is a B7ES, not sure what difference the projected insulation would have on the 'P' plug.

itma · Post by **itma** » Fri Jun 29, 2007 7:18 pm

I used to find use of these resulted in carb problems on Triumphs, they did,`t like them, Wasn`t recommended use back then, don`t know why.

lawrence · Post by **lawrence** » Fri Jun 29, 2007 11:12 pm

John Bolton is a first class mechanic/engineer/technician/chap and would surely sort the bike for you. But.......... if you let someone else do it, the bike becomes less yours. You will part with a wad of cash but have no satisfaction of a problem solved.

It sounds as if you have a good idea of the electrical system. Persevere and when it is ok you will get more pleasure from the bike.

My motto is always do it yourself where possible (then if stuck get Alan to do it )

Biscuit · Post by **Biscuit** » Fri Jun 29, 2007 11:57 pm

Watch it Lawrence he's a bit close!

bag-o-nails · Post by **bag-o-nails** » Sat Jun 30, 2007 8:53 am

Thanks for your thoughts
i did change the coil, the manual says the unit number for the carb
is amal 389/82 However the number on the carb is 466 but the jets
are the right numbers i replaced them after a trip to surrey cycles
cheers
Phill Still no improvement weak spark sooty plug

itma · Post by **itma** » Sat Jun 30, 2007 10:52 am

On the basis its the really silly things that give the most grief, try switching over the wires on the coil and see what happens........

bag-o-nails · Post by **bag-o-nails** » Sat Jun 30, 2007 11:25 am

hmm! is there not a danger of reversing polarity and demagnatising the alternator
or cause a short in the s/w?