A10 Engine Rebuild Checklist

[rowan.bradley]

Remove the old ball and spring from inside crankcase. You should be able to see/measure the plain bore of the hole containing ball and spring.
Open the small diameter to match that.
Use the A65 spring and 1/4 ball.

I still don't understand this process. How deep do I need to drill the hole? Presumably this affects the spring tension so this needs to be right. Or if I drill right through, what does the bottom of the spring rest against?

Can someone please explain exactly where the oilway goes behind this oil pump hole? It seems to go directly into the crankcase, perpendicular to the oil pump jointing surface. The surface of the existing ball seems to be about 17mm below the oil pump jointing surface, so there will be no shoulder for the new spring to rest against unless I restrict the drilling to less than say 15mm, or unless the drilling is a larger diameter than the existing hole which contains the existing ball and spring. I have not removed the plug yet so I don't know what this diameter is - can someone tell me this? Is 15mm deep enough to give the right amount of space for the spring? After this I guess there is a drilling straight from the bottom of the hole into which fits the PRV, intersecting with the oil groove around the timing side bearing bush, and meeting the hole beneath the oil pump at right angles. Is this correct?

I don't what to start drilling until I know exactly what I'm doing...

Thanks - Rowan

[chaterlea25]

Hi Rowan,
Sorry I should have measured and responded sooner
Ok
The hole from the delivery of the pump is opened up to 5/16in.
The depth to where it meets the grub screw that's fitted form the inside of the crankcase
is 0.8in. the pointy bit of the grub screw reduces this measurement to approx 0.78 at the centre of the hole
I remember the last one I looked at had the point of the screw flattened off
The hole from the pump meets another at right angles that feeds the main bush
No need to seat the ball on the new pump, seating it reduces the spring pressure per sq mm.
Just make sure the gasket does not interfere with the ball where it seats on the pump

John

[rowan.bradley]

Hi Rowan,
Sorry I should have measured and responded sooner
Ok
The hole from the delivery of the pump is opened up to 5/16in.
The depth to where it meets the grub screw that's fitted form the inside of the crankcase
is 0.8in. the pointy bit of the grub screw reduces this measurement to approx 0.78 at the centre of the hole
I remember the last one I looked at had the point of the screw flattened off
The hole from the pump meets another at right angles that feeds the main bush
No need to seat the ball on the new pump, seating it reduces the spring pressure per sq mm.
Just make sure the gasket does not interfere with the ball where it seats on the pump

John

Thanks for this info. So the spring rests on the end of the grub screw does it? I would not have thought that flattening the end of the screw would make any difference, because the spring must surely rest on the edge of the screw, not its middle?

Thanks - Rowan

[chaterlea25]

Hi Rowan,

because the spring must surely rest on the edge of the screw, not its middle?

Yes,
Maybe when the previous engine was converted there was a shortage of the correct length screws??
Its harder to measure to the semi pointed end though???

John

[rowan.bradley]

If I understand this correctly, the spring must be much longer after the conversion than before, because the ball (i.e. the front of the spring) is about 16mm higher up, but the back of the spring, where it rests against the grub screw, is in the same place. Is the spring supplied by SRM (part number 68.0353) the correct length for this installation (it is about 25mm long uncompressed)?

Thanks - Rowan

[chaterlea25]

Hi Rowan,
The SRM spring is the correct one,
Maybe your old spring has partially compressed?

John

[John Sander]

  ;)Thanks for this great information. It's going to help tremendously as I head down the path of rebuilding my (recently acquired)  1958 Golden Flash. Its a project for sure. It hasn't run in about 52 years, covered in dust and is in lots of pieces. All there I am reliably informed.

[Greybeard]

  ;)Thanks for this great information. It's going to help tremendously as I head down the path of rebuilding my (recently acquired)  1958 Golden Flash. Its a project for sure. It hasn't run in about 52 years, covered in dust and is in lots of pieces. All there I am reliably informed.

Hi John.  Please will you find 'Introductions' and give us a short intro post. More pictures of your project would be welcome and useful for reference.

If all the parts are present, restoring the bike will be far more enjoyable.

[berger]

did you find it in the stores at a cement factory

[Greybeard]

  ;)Thanks for this great information. It's going to help tremendously as I head down the path of rebuilding my (recently acquired)  1958 Golden Flash. Its a project for sure. It hasn't run in about 52 years, covered in dust and is in lots of pieces. All there I am reliably informed.

The bike in the shadows, on the right, looks like it may be a Honda CB750

[Swarfcut]

     Quite so, GB. Looks to be the open top crankcase version.

 Hi J.S. Get the vacco on it and send in a few pictures.  Congratulate yourself on a reasonable find. Looks to have been dry stored, which helps. Ask the vendor if the correct front wheel is available. Can't make up my mind whether the fork legs are clamp on or earlier screw in spindle or even Ariel type. Whatever, the front wheel is the single sided type, with the better brake, but not strictly correct for the model year. Frame and engine numbers can confirm model year for now.

  There must be a back story of how it came to be partially dismantled, even down to the missing lower fork yoke clamp bolts. Any papers or reg no? Keep us informed, I think it will be a journey of discovery.

   Get your cover story rehearsed for SWMBO, and arrange long term finance.......

 Welcome along.

 Swarfy.

[ianbsa]

Don't forget the sludge traps evil twin, the ..oil tank. It really does need more than a quick swill with paraffin. Years of crusty semi loose metallic sludge and worse will have tucked itself away in all those creases and internal seams, behind the pipes and corners ready to break loose when we least expect it.
I bung up the holes then fill it with a good degreaser, Jizer etc  and let it sit in a tub for the duration of the build with the occasional shake, prod, then take it to a garage forecourt. Wrap it in an old bed spread, sofa cover etc  then with a power wash blast the interior alternatively through the filler and drain holes to within an inch of its life, let it dry then ....repeat. Tedious in the extreme but it's the only way to take it back to factory new condition.

 

[muskrat]

G'day John. 
Let the fun begin.
Being a sandgroper there's a few members over there. Roughly where in that half of the country are you? Give us an intro here https://www.a7a10.net/forum/index.php?board=13.0
Cheers