Does this CD 150 look normal?

[Jeffds1360]

A picture of my choke fully open.

Is that little tension spring, and the rest of it, in the right configuration?

It needs choke in the cold at start but it  runs so rich that I have to push choke in within 5 seconds to 1/4 or it 'hunts' and dies. I loose throttle affect at 1/2 choke as well so I need to blip for about a minute. 

Any clues as to what might be worn please?

[johny]

all looks ok to me but does sound like my Vitesse which doesnt need much choke to start but yes a higher tickover. To achieve this Ive got that choke operated throttle screw wound out quite far but am very careful to only partially pull out the dash choke lever (depending on the ambient temperature) so as not to rev too high before the oil gets round. Like this it starts without the mixture being too rich but has high enough tick over to keep going and drive off...

[Jeffds1360]

Cheers Johny. I'll try some delicate adjustments. 

[PeteH]

Can I just ask?. Is the Dashpot/oil at the correct level?. It sounds as if the Vaccum might be lifting the Needle too high at low revs?. The vaccum is greatest at low rev`s. It`s actually a bloody long time since I worked on a Live one so it`s a bit of a shot in the Dark?.

Pete

[Jeffds1360]

Good thinking Pete, I checked a week or so back but believe I may have wear there and loose more oil than I should. Must get thicker

[johny]

The oil should only slow the movement of the piston not change its actual final position for a given vacuum although, of course, without oil it will tend to jump around more. Also the vacuum applied to the diaphragm is greatest when the butterfly is fully opened and shouldnt be confused with the vacuum for the distributor retard or brake servo which are tapped off in different places.

Yes have a play with the choke throttle setting Jeff. Unlike the description in the manual, with choke off I have my cam very close to the throttle screw and as I dont drive in really cold conditions only have to give 1/3 to 1/2 choke for perfect starting... 

[Jeffds1360]

Speaking of distributer vacuum, I have sucked on that tube, probably up to 20" and I cannot see a flicker of movement on the distributor plate!..... another problem for another day!

Also cannot get revs below 1000 with both screws right off. Timing is good as is mixture...???

Lockdown time CAN be useful 

Had to buy more swarfega

 

[johny]

hmmm it should rotate quite easily with a bit of vacuum. Could you suck in air? If not does the backplate move by hand?

For the high tick over it sounds like air is getting in somewhere. Either the carb pistons arent returning to the base or theres a leak...  

[Jeffds1360]

It's all new again to me Johny ( well 50 years ago I played about with spits and a vit.) so I'm on a big learning curve..... which bit of the distributor plate is meant to move? No air sucked, just no visible movement. Timing does move with revs nicely though, so something is working.

Piston drops solidly. Maybe an air leak but where? Maybe need new spindles. 

Too cold in garage. Too wet outside. Start again tomorrow.  Thanks a lot.

[johny]

the whole plate in the dizzy with the points or electric ign sensor on should move clockwise when you push on them.

A worn spindle will let in excess air and you can feel for any play by rocking the ends where they exit the carb body... 

[Pete Lewis]

couple pf ideas 

the fast uncontrolled tickover  could be a rebuild has put the throttle plates in bach to front 

take the carb off with idle screws out there should be no daylight through the throat 

the plates do have a chamfered edge and are easy to fit back to front

the dashpot has no effect on idle it just slws piston lift for your accelerator pump flat spot eliminator 

dizzy  do check any top plate  screws are not toooo   Looong    often replacements go through far enough to jam the moving top plate against the fixed bottom plate 

if there was a leak you would not get any suck on the tube .  

 

[Jeffds1360]

Thanks Pete, I take it that the throttle plate is the butterfly valve ?

My mechanical advance is working BTW.

I'm investigating some iffy 'creaks and clonks' from the rear o/s suspension this morning

I'll check dizzy plate for movement too.

Carb off later if that is what I need to do to check it out

Cheers

Edited to say

Been and checked the dizzy plate. It moves about 2-3 mm outside edge in an anti clockwise motion ie  stretching the spring going into the vacuum unit. I have sucked and sucked, probably getting 20 inches of mercury vacuum but no movement at all. Tube is clear as I can blow through it  Carb vacuum works as a vac gauge reads zero at tickover but runs up to 20 on blipping throttle. Ho hum. bloody drivers door catch giving me grief again!! So much for my creaks and groand

[johny]

The dizzy plate should move clockwise as the spring is pulled by the vacuum diaphragm rod. You might need to detach the spring and spray the plate with WD...

[Jeffds1360]

Aaaah! Right. Vacuum advance is stuck then.

Surely the mechanical advance, which works (according to my tachoscope) moves the same plate? Why can't I move it then?

I'll try again when my fingers warm up...... weird,  probably just me???

Startedit and took it out the garage but it was raining so straight back in!

[Pete Lewis]

if you disconnect the vacuum rod does the thing actually move if out and free ???

then you know all that sucking is not  .....wasted  

Pete

 

[Pete Lewis]

no the centrifugal advances the cam on its spindle  the vac unit advances the points plate 

do check the points/condenser screws are nice and short if someone fitted worn out /stripped points screw its often far too long 

 

Pete

[Jeffds1360]

I'll have to work out how to do that, after I warm up and have some dinner. 

No cause of creaking found, door latch sorted. Found 2 tyres are 9 year old and 2 are 4 year old ...more expense! Any recommend "low mileage, long lasting " tyres?

Cheers lads. Get back later.

[Pete Lewis]

ignore the long lasting 

age will kill them well before they wear out 

Pete

[Jeffds1360]

well the plate does move , probably about 6-9 mm on outer edge but boy has it left imprints in my finger and thumb tips!!! Using the condenser and points pivot for leverage it moves smoothly but takes some rotating!!!! Surely the vacuum cannot exert that much force on to it???

That little spring cannot exert enough force to rotate the plate that I have 'inherited'??? 

How free should it be?

I know I know.... it is like teaching a blind man, who is partially deaf to write the alphabet in a straight line

 

Edited..... went out and pushed it a bit harder.... BANG..... something went 'crack' and the spring came off

Back out to remove points and plate. 50 years since I did this last.

[Jeffds1360]

Sorry to harp on !! ........... right, getting somewhere. There was a length of wire, one end earthed to the little Philips screw set in the notch for the cap clip. which was jammed between the plates. It seemed to be heading for the low tension connection???

With the vacuum spring off, the plate moves freely. Mind that spring is a tough little thing!  When I hook it back on it is a hard push to mover the plate!

I'm going to read up about the wiring and then try some suction etc. ATB

Edited to say :- it was the (original?) earth wire for the base plate! Single thin wire with cotton black cover. Base plate will not jiggle off but I've cleaned it up and will now ponder how to re-connect an earth via the riveted flat connection .... any hints?

P.S. the (brass?) base plate swivel point is only a few mm high. Is this right?

[johny]

Not sure exactly which dizzy youve got but theyre all pretty similar. The moving part of the backplate is usually 'crimped' to a fixed base so that it can rotate round a centre bush supported by a brass guide point. The fixed plate is then located in the dizzy case with screws but to ensure a good earth of the moving plate a wire is attached with a very short screw (so as not to go right through and jam on the fixed plate) and runs to the case where its fixed with another screw. This must be used whether you have points or electronic ignition.

My free online workshop manual has great photos of the individual components and the complete assembled item so its very useful.... 

[Jeffds1360]

That is great johny. where can I find your online manual?

I'm starting another post about my contract breaker plates

[Pete Lewis]

not jonny's but Steves online has been on here for years 

http://vitessesteve.co.uk/Servicemanuals

Pete

 

[johny]

Yes cant claim that one! Its not perfect but still a big help....

[Pete Lewis]

well youres seem invisible  ha !!

Pete