A65 Engine Set Up

[Rob Neal]

My A65 Lightning fires up from cold, comes off choke quickly and idles nicely and will rev up cleanly when blipping the throttle.  Once out on the road the engine does not seem to want to pull under load.  The best way to describe it is as if it is trying pull away in too high a gear.  The 'box selects correctly (on main stand with wheel free to rotate), new Wassell electronic ign system incl coil, leads and plugs.  Timing set statically to the A mark on the rotor with the piston at 34 degrees or 7.7343mm BTDC.  Checked using dial gauge through the plug hole and a timing disc with both readings corresponding. Valve clearances correct (new valves & seats), new liners and pistons (std bore) and new complete clutch assembly.  New carbs (u/sonically cleaned and blown through on the airline umpteen times). They have the blanking plug mod allowing the pilot screw bore to be blown through and checked as clear. Pilot screws set to 1 1/2 turns out, slides lift together and clear the bores, choke slides working correctly. In line fuel filters on each carb feed, new petrol tank and fresh petrol as well as new fuel taps.  Feels like a fueling issue to me and thought the tank vent may be blocked but have same problem when running the bike with the filler cap open. There's a new cam in there and the bottom end was built up by T&L Engineering with a re-conditioned crank. Fresh battery (Motobatt) and the circuit is charging reading 14.5 VDC across the terminals with the motor running.  As you can imagine I've run out of ideas as well as patience! My wallet's a little empty too!  Does anyone have any idea as to what I've missed or what could be causing the problems?  I would really like to get the bike running and get some miles on it this summer.  .

[DAVE BRADY]

Hi,

How many miles since rebuild?  A tight engine can feel like this.
What year is your A65?

Dave.

[Rob Neal]

Hi Dave.  I've only managed 4 miles over several 'trips'!! Bike is a bit of a bitsa.  Left the factoru=y in 1962 as a Star (according to g to frame and engine numbers).  By the time I got it a twin carb head and TLS front end with rev counter had been fitted. 

[Dibble]

Hi Rob probably a million miles away but is it at all possible it may be the clutch is slipping under load? Sorry if you've already thought of that. You mentioned blanking plug mod on carb how is this done?
Dave.

[DAVE BRADY]

Hi,

As you have done such a low mileage it is possible that the engine is tight. It is important not to load or labour the engine with such low mileage.  Try taking the plugs out and with the ignition off kick the engine over to see how much effort it needs.  If it does feel tight then perhaps consider running the engine at a fast tick over, to keep the oil pressure/flow up, with the occasional blip of the throttle.  Do this several times throughout a day but do not let the engine get too hot.
Next time on the road, with slightly fast tick over set, keep the engine revving a bit.  As you have a tacho. use that to monitor engine speed.  The engine should not be laboured so keep the revs up and speed down.  Avoid using top gear when in a 30 mph.

Dave.

[DAVE BRADY]

Hi,

Just a thought, usually the rotor marks that are used are the 'wedge' shaped bosses with a line through them.  The line corresponds with the keyway in the crank and, within manufacturers tolerances, the correct static timing position.
So what 'A' mark' are you using?

Dave.

[neil1964]

Brakes binding?
Do both wheels spin freely?

[Gup holland]

Got also a bitsa, 62 engine. There is a diference between the early crank and late crank. My engine had a late crank in it.
Now rebuild with an early (narrow) crank, discovered that the keyway is some degrees off,
So if you strobe the timing it isn't correct.
The rotor has a slightly diverent position. I have also the late cover on it for strobe timing. So have to make new timing marks. Check your timing by mesuring pistons before tdc. And then look at rotor marks.
I'm not been ready to do this on my engine (so i could be wrong)
Early engines had no strobe timing marks, i believe. I also doesn't have a plug hole.

[Gup holland]

Read your story twice about the timing it should be right, sorry for the confussion.
Anyone info about the keyway position?

Gr gup

[Rob Neal]

Thanks for the input everyone, much appreciated.   I hadn't thought about the engine being tight.  It seems fairly free on the kick start but I'll certainly run the engine up as suggested to see if this helps.  The symptoms aren't typical of a slipping clutch where I would expected the engine to rev without much drive.  Instead it just fluffs/bogs down and dies.  The bike rolls OK in gear with the clutch pulled in which would seem to rule out an excessively dragging clutch.  But I'm desperate enough to grab all straws so will check this again.  The ignition marks I refer to are those on the rotor and static plate provided with the electronic ignition kit.  Ignition timing set up as previously described aligning the rotor mark with the 'A' mark on the stair plate.Picture attached.