BSA A7 engine rebuild

[bsaa7]

I know everyone enjoys pictures of dirty,oily engine rebuild pics so here we are. Background the bike was due a rebuild after covering 15,000 miles in 3 years but it decided when this was to happen by stripping the magneto fibre gear....



Dropped this inside while checking for sparks at the roadside





Stripped gear



Hmmm scorched pistons



And one crankshaft shim



More to follow as I go through the engine

[doogalman]

Proper engine, the fabbled fibre gears still doing what they allways did. I had an A7 some years ago but now have my 650 Triton and Norton fastback for tinkering.

[Elderly]

I had a plunger A7 in the 60s - I paid £4.00 for it

[bsaa7]

I've owned this bike 25 years and this is the first time I have stripped the gear(but not the first time I have rebuilt her )

[sjwb]

My God, that brings back memories!
Instant cure for the fibre gear - use a steel one.
She has been running a little weak, burning oil and the valves are badly pocketed. All easily fixed though.
One word of advice and critical to any BSA twin. Remove the crankshaft big end journal taper plugs and thoroughly clean the sludge trap.
Good luck.

[bsaa7]

sjwb said:

One word of advice and critical to any BSA twin. Remove the crankshaft big end journal taper plugs and thoroughly clean the sludge trap.
Good luck.

Yep done that every time the bottom end is opened up. These bikes do run for many miles without attention if you set them up right I rarely adjust valve clearances etc as they don't change.

[bsaa7]

More pics...

[Russwhitehouse]

Brings back memories of my A10.(notice I didn't say happy memories) great old bones to work on though. As said previously, if set up right they will plod on for miles and miles. Great sound as well. Not as crisp as Triumphs, but a more " thuddy" sound. Love the old beezas, magic stuff. Hope to see photos of the finished job. All the best with it.

[Hooli]

Lovely

Reminds me of rebuilding my T140, not to dissimilar inside.

[bsaa7]

Shes finished now but some more rebuild pics before the reveal