Trying to get the rebuilt A65 to run properly I'm checking the ignition timing yet again. Setting the firing point I'm using a timing disc (34 degrees BTDC) and cross checking this by measuring the position of the piston. For this I have a DTI and adaptor fitted via the threaded spark plug hole.The equivalent piston position should be 7,7343mm BTDC (seems a bit precise but anyways..). However the plug is angled relative to the cylinder axis centre line. So that I can adjust the DTI reading to place the piston in the correct position does anyone know what the angle of the plug relative the cylinder bore is? I can then use simple trigonometry to work out the numbers. Thanks. Rob
Had the same problem on an A10 recently. I ended up measuring the angle with a gauge off the top fin. I can't find where I wrote it down as there's a chance its the same. I spent some time comparing the piston measurement with the timing disc and was surprised to find i could get a more accurate reading off the DTI/plug gauge than the disc.
Hi,
To overcome the angle issue I use a hex key that cannot got through the plug hole but can be held upright and by rotating the wheel I find TCD with the final position being at the end of an up stroke to eliminate any backlash.
Using a thick feeler gauge laid flat on the top fin I mark the TDC position on the hex key (made easier if coated with felt tip). Now measure the BTDC position above the TDC mark and away from the plug hole scribe or mark with a junior hacksaw blade.
Put the hex key back in the plug hole and turn the engine backwards until the BTDC mark is below the feeler gauge. Then carefully bring the piston up until until the feeler gauge and the mark on the hex key line up.
Another thing to remember is that if you have the head off or before you fit it, measure the BTDC position and set the static timing.
Dave.
Thanks for the input. Timing now set to 7,734mm BTD using the 'dipstick' method and checked at 34 degrees BTD with a timing disc. Still won't run so just to check with those who know. A good spark on both sides from the new electronic ignition set up and new spark plugs. Good compression L&R both at 137psi. Valve timing checked (several times) to timing marks on gears. Problem noted, plenty of suction found when blanking right carb inlet with my hand but hardly anything on the LH side. Strange with such good compression. Cover off shows valves operating with no obvious problems noted. But it must be the valve timing mustn't it noting lack of suction on LH carb? I set valve timing with pistons at TDC. Timing set with LH piston at the correct position BTDC (rather than the right). No rags or debris in the carb or cylinder head inlets. So why doesn't it run? New Wassell carbs thoroughly cleaned out with carb files, carb cleaner, U/S bath (many times). Good fuel flow from tank (Cleaned and new filters), carbs flood ok when tickled, floats set to correct height (2mm below face) using modern black floats with the bendable tang. Got spark, air, fuel, compression....won't go. Aaagh! I've had it apart and back together again so many times it's driving me nuts. Any thoughts?? (apart from a lighted match into the tank which has crossed my mind!!). BTW rebuilt head (no cracks), new valves, seats, guides, springs (T&L Engineering), Valve clearances ok (8 thou inlet, 10 exhaust) new pistons, rings with new sleeves matching pistons (Again T&L). In desperation. Rob
If you have electronic ignition I assume the mechanical advance/retard unit has been removed.So proper ignition advance is provided from the electronic ignition.
The timing has been set with some indicator light?
I got my A50 back in 2019, with covid and other problems, the restoration has taken a while. It is fitted with the Micro system. I marked the ignition plate on removal but with time and cleaning the marking has been lost.
I down loaded the instruction sheet from the web site and re set.
was it clockwise or anti? pos earth changed to neg will that change,? a custom loom? all factors to consider.
finally , this weekend I found a small window of time to have a go at starting it. As the fuel has been sat for a few months, the battery is still holding charge.
a squirt of easy start, kick and a single bang. then nothing
left a while ,same routine and then a single bang.
then a longer squirt and its running until it runs out of easy start.
fuel coming through and it keeps running, revs a bit high but happy days.
all I can add, is re check fitting details, make sure its running and set up the right way CW or ACW as specified. I set TDC with a depth gauge, valve clearances set. No disc and no setting plug.
make sure its on the correct cylinder.
Hi,
Good point about direction of rotation. The rotor for the timing goes anti-clockwise so it is the left hand hole to line up on.
As the EI fires both plugs at the same time it, doesn't matter what cylinder is used.
I always use the right side as I can set the rotor and adjust the stator all on one side.
Dave.
I have double checked that I have the angle of rotation correct and have set it to the 'A' or anticlockwise mark as per the instructions. All of the original ignition set up, including the mechanical advance/retard has been removed and replaced by the electronic kit. Fairly confident the ignition is OK now so will move on to the valve timing. Will remove the timing side case (yet again!) and check the alignment of the timing gears. A thought though, does anyone know if there's any info about that shows when the inlet/exhaust valves begin to move relative to crank rotation? I'm thinking that this would act as a check against the timing gear markings to see if they are indeed correct.
Hi,
Can you post an image of the timing gears as they are?
I think page B29 of the workshop manual has an illustration.
Dave.
Could this be some help
Why i am seeing different no about the 34 degree crank angle btdc,
7.7343mm or 7.216mm ???
Am i missing something or what????workshop manual 00-4177
Gup
The dimension 0.3045 inches is consistent between the two documents however with the metric conversion, there is an error. 25.4 mm/in x 0.3045in=7.7343mm which is the value given in the complete table. The document showing only the 34 degrees value has the metric conversion error.
Jim
Thanks Jim that makes all clear,
I had a bad grade in school about calculations :D :D
Greets gup.
Thanks for the replies. Gup, the valve timing info sheets look really useful, thanks. Rob
I'll send a picture of the valve timing gears set up as soon as I get the timing cover off. Currently have a house to-do list I need to get cleared before I can get back in the garage. Only fair as I did promise to do these jobs in exchange for being allowed to buy another bike last week! (1976 Suzuki GT750 since you ask! I know, it ain't British, sorry). Rob
Measurements to four decimal places are ludicrous on engines built 60 years ago by unskilled assemblers, and that have been "rebuilt" X number of times, had parts swapped around, and run on vastly different fuel to when it was built.
A stick down the plug 'ole, done properly, is more than adequate for these basic engines.
Not to say that accuracy isn't desirable, just that the "tolerances" are too wide for four decimal places to make much difference.
Is that a Kettle you've just bought? I had one many years ago. Quite liked it but the handling was odd. A65 was way better but the kettle engine and brakes were very good. It was so smooth it actually needed a gear indicator. It handled quite well 2 up but had a weave at speed one up.
Re-piston position - I'm using old ally knitting needles with notches filed on. They are about 3/32 and go near as damn it vertical which avoids the whole angle plus piston dome correction since anything angled is moving across the dome.
Snuck into the garage this morning, don't tell! Picture of the ignition timing marks set at 34 degrees/7,7343mm BTD. The other pictures show the valve timing marks. Tried to highlight these to show up better. Marks looks to be in the same positions as those shown in the Haynes manual diagram. It would be easier if BSA had the marks align in a straight line and so remove any ambiguity with the set up. Just my view! Does anything look outrageously out of whack do you think?
Hi,
BSA could have done better with these marks but yours do look right. Although I have Boyer and Pazon fitted, I would say that your Vape looks right for the anti-clockwise seat up.
Dave.
The same diagram is in the BSA Workshop Manual page B33. Looks like Haynes copied it and replaced the pencils in the original with arrows, still it confirms Haynes got the details right.
Thanks everyone for taking the time to respond. I'll now check the valve opening/closing position relative to the crank position in degrees btdc. Will let you know when(if) I get it fired up correctly!
Can you revert to points to de-bug it and get it running then swap back to electronic?
This is a very common issue on old Land Rovers when owner swap out the mechanical dizzy for an electronic one and get all sorts of issues but never think to swap back and see what difference that makes.
When I had my A65 I fitted a Lucas RITA system, made a huge improvement, but the RITA was very tough and had a simple static set up that was within a few deg.
The bike came with an old electronic ignition fitted so I don't have any of the original mechanical system to hand. I fitted a brand new ignition and have also tried a second system which the supplier kindly lent me to try out. I have nice sparks from both set ups so hopefully all is well here. I'm now looking at valve timing. Both cylinders give 140psi readings on the compression test which is good and I've confirmed earlier with club members that I have the valve timing marks set up correctly. Covering the RH carb with my hand shows good vacuum being generated but the left one has hardly anything. Valves must be seating correctly otherwise the left to right compression readings would, logically, differ significantly.So valve timing? I'm trying to check the point at which the valves open in terms of degrees of engine rotation as per the manual specs. I have a 68-103 cam fitted which is in good condition with new bearings installed and end float set by T&L engineering. I'm measuring the beginning of the valve lift with a gauge resting on the top of the valve spring. As soon as the gauge reads movement I check the timing disk. Is this method correct as I cannot get anywhere near the figures (ATDC, BBTD etc) quoted for valve openings in the workshop manual. The timing disk has been set using a dial gauge to find TDC so confident this is correct. Any thoughts?
Do you have any theory as to how the valve timing could be wrong? If the camshaft and gear are the correct A65 parts there's not much left. I can only think one of the Woodruff keys is missing in the camshaft or crank gear, perhaps fell out as the gear went on and now its out of place.
I would do a basic visual check with a pencil in a plug hole to get TDC then rotate with a spanner on the crank and watching the valves and timing trigger. You can easily see which cylinder is on what stroke.
Is it possible to cross 2 push-rods? Its so long since I built an A65 I cant remember. Unlike an A10 you can see the push rods are all seated and go to the correct rockers.
I have checked the pushed rods and am sure they are correct, shorter ones at the back opening the inlet and the longer ones opening the exhaust. I even considered the rocker arms but these will only fit one way round and they are seated ok. I will take a look at the woodruff keys. I'm sure they were in place when I fitted the gears but as you say, there's not much else that can be wrong! Thanks for your time on this. Rob