Complete Head Overhaul plus New Piston Liner etc

[philipx2000]

Just thought I would post a few pics of work done so far,these are a few pictures showing older piston which was previously fitted and the original liner and original piston that will be fitted making the bike totally original build

Armstrong 500ec Canadian version Electric Start







Any questions on the build ask me
Ex REME VM

[Wirralman]

Great work, keep the pictures coming
Eric

[Minter]

Brilliant! keen to know the history of the piston - not seen one that shape in a rotax before..

Gary

[philipx2000]

The Piston and as you see has a shorter skirt which is the incorrect piston, some one who overhauled this engine previously who shall remain nameless could not find the correct Piston in Canada and I am sure he never looked at a few of the UK sites which have numerous parts available for this type of bike, needless to say by comparison to the original it has no oil squirt lubrication holes in it and due to the shorter travel of sweep has caused more ovality in the liner once measured in three planes in each direction, I overhauled the rest of the bike completely last year and as the engine managed to run reasonably well I resisted the overhaul but should have at least checked, nevertheless I am now on it and glad of the find
The piston I think is a cut away racing type after market piston but had less compression than the specs state so i am now placing a new liner std with a 88.97 piston original from the MOD Uk giving the original sweep of 500cc making the bike as original as I can make it
SO far Bike has run 896 KM, its a Canadian version with electric start but manufactured in Bolton near Wigan in Lancashire it came it boxes when I received it and I am not the owner
it is a good friend of mine that lives in Winnipeg Manitoba, I am doing the work but thought I would place this for all to see on what not to do as far as after market pistons which are incorrect any comments welcome
Picture below is the new piston correct one

[philipx2000]

Just another addition to problems found the top camshaft toothed wheel was very sloppy on removal and had about a 1 degree movement in ether direction advancing the crankshaft timing or retarding it thus causing also difficulty in running smoothly once running ,this cam wheel should be an interference fit and is a common problem on this engine consequently new one on order ( Noticed that the alignment mark was slightly out when placing a straight edge against the timing marks on the crankshaft and cam wheel)

[Drifter]

You do realize this is like mechanical porn to minter. :lol:

I wish I had the skills to rebuild engines like that.....

Thanks

[Minter]

You do realize this is like mechanical porn to minter. :lol:

I wish I had the skills to rebuild engines like that.....

Thanks

I wish i could cook! Beans on toast is my speciality!

The cam pulley is best lock tighted as well as the bolt that holds it on.. Ive stripped a few that just pull straight off..

[philipx2000]

yes that is good advice to loctite the top pulley this I had already done with a loctite 249
which is all I had available from my dwindling stock but I suppose any after market thread locker or shaft locker will do the job
and yes this engine is actually the second time I have done anything with them since 1992
and in the Army all available special tools were then no problem plus its amazing how much I had forgotten to reply in the forum apologies, the engine now runs fantastic with optimal compression and kick starts first time but alas I never had a problem with the starter last year until the owner brought the bike back to me after the head gasket had blown and I overhauled the top end completely
consequently sprag clutch was found to be worn I have not had the time to remove the clutch cover again to inspect the drive gears but hope they are not to worn and pitted
either way parts ordered through Forces Motorcycles, Staffs, and excellent quality parts arrived but delays due to postal problems so my other plans had to be put on hold
Litchfield Solihaul sent me the generator puller for the gen and also gear pullers for future projects and also had a great parts selection and special tools
they came in excellent time 5 days from ordering so well pleased.
Be warned I made the mistake of not checking that item properly before replacing clutch cover and now paying the penalty of another 2 hour job "ah well" at least caught it now.
Anyway engine runs great so I will upload a video next week after the sprag clutch is changed and show you the finished job also pictures of rebuild.
Original AMAL carb ordered also from Litchfield for a very reasonable price.

[philipx2000]

You do realize this is like mechanical porn to minter. :lol:

I wish I had the skills to rebuild engines like that.....

Thanks

its not rocket science really many Canadians over here with no mechanical background in engineering or mechanics change head gaskets outside in -40 degrees conditions so if they can do it so can you any way thanks for the compliment.
8 months of winter this last winter so suffering from Cabin Fever Lol