timing on my 1959 super rocket

[ducati2242]

before your rebuild you had it running ok . I only ask as a10 and a7 have different timing marks for the valve timing but cogs are the same . I believe . Sounds like valve timing is out to me .

[JulianS]

The early long stroke A7 used different timing pinions to the later models.

The short stroke A7 (engines prefixed AA7 BA7 and CA7) and the A10 used common pinions with the same timing marks.

One of the most common causes of failure to start after a rebuild is timing on the wrong cylinder as Dave mentions. Sometimes a kickback is caused by the excess mixture in cylinder firing on the exhaust stroke or in the silencer when ignition is 180 degrees out.

[mashermick]

 hi all , just looked at another forum that says compression tests are better done with the throttle wide open ! I didnt know that. tested again and getting about 120 psi per cylinder  .going to try and start it again ,going to try and rig up a starter roller on my brake tester as my knee dont like kicking over !

[mashermick]

ok ,checked ignition timing again ,5/16 btdc ,checked valve clearance at fireing stroke both 12 thou ,plugs out seems like a spark occaisionaly ,hard to see !   took of new carb looks ok new gaskets ,, just wont start ,not even a kick back, gona thke mag off and test !

[Saltydog42]

Just timed my S/R at 3/8 BTDC then checked by disc, came out at 34 degrees.

[idie]

New spark plugs do not have glazing on the porcelain. If you flood the carbs to start and it doesn't, the porcelain will saturate and short the plugs. Try new unused plugs if you haven't already.

[Saltydog42]

Sometimes its the simple things that can screw you up.

Does the Mag have an ATD fitted , if so did you jam it fully advanced before timing the ignition.

If its manual, try about half retarded as fully retarded throws the internal timing of the mag out so the it is difficult to get a spark at kick over speeds.

Keep at it you will get there

[mashermick]

ok ,removed outer and inner timing cases to check pinion marks ,all on dots an dashes , re assembled .took mag off ,built test rig ,sparks like a good one ,re fitted mag ,checked timing again,points just opening at 5/16 BTDC on fireing stroke ,checked new monoblock again ,all seems ok but the B.....D wont start although did get 2 kicks ! did what i would never do gave it a shot of easy st art ,still no go .im a single man and this is my first twin ,should have kept my B33

[DAVE BRADY]

Where do you live?  After the lock down see if someone can call by and help.

Dave.

[idie]

Have you tried swapping the HT leads over.

[chaz]

ok ,removed outer and inner timing cases to check pinion marks ,all on dots an dashes , re assembled .took mag off ,built test rig ,sparks like a good one ,re fitted mag ,checked timing again,points just opening at 5/16 BTDC on fireing stroke ,checked new monoblock again ,all seems ok but the B.....D wont start although did get 2 kicks ! did what i would never do gave it a shot of easy st art ,still no go .im a single man and this is my first twin ,should have kept my B33

are you sure they are the right marks? could be one revolution out. Ive had it before. re check valve clearances after.

[JulianS]

First thing is to try swapping the HT from one cylinder to the other, quite common to get them the wrong way around.

I see you say you set the valve clearances on the firing stroke -one exhaust valve clearance should be set when the other is fully open and the same for the inlets. That way the cearance is set when the follower is on the cam base circle not on the quieting ram.

The twin timing marks only line up one way. If they line up they are correct.

[mashermick]

   yes ,have re set tappets on the heel as suggested ,both sides valves op/close on the right stroke so should be ok on marksi, both valves closed as piston going up. going to check timing with a degree disk,seems 34 degrees is recomended by many on here ,thanks for all your replies