A10 Cam Followers - Removal/Refitting

[ghl]

I have an 1963 A10 GF that was rebuilt about 3 years ago and I've always had a bit of a question in my mind as to mixture settings with modern fuel etc. Well, after a nice run-in of just short of 1000 miles, thought everything was going well and running lovely - until it nipped up on me (primary drive side) - this always seems the weaker side.

I've now removed the head and barrels and think I've almost got away with it. The barrels could do with re-honing but apart from that, they look OK. I will definitely replace the rings and probably the pistons to be on the safe side (in case they were stressed).
I decided that it would be best to remove the cam followers before taking the barrel to the local (well respected) Engineering Works to have them re-honed.

Question is, how do they come out - there are 2 flat blade grub screws on the sides, which I have removed, but without risking damage, can't find anywhere that details how to remove the followers - or refit them afterwards for that matter.

Has anyone any suggestions/experience of how to handle these please?

[idie]

There should be another grub screw, under this will be a small ball bearing which sits in a groove in the pin. Once the ball is out the pin should knock out releasing the other two followers.

[ghl]

Many thanks and sorry for the noob type questions...
Just found a spares catalogue I got from my Dad (00-5086) - scan of page attached, it shows the extra screw on the top of the base flange, with the ball bearing (parts 10167-0276 and 40101-4676 respectively) this looks perfect - thanks for the pointer.

Once I have removed the outer screws, should the outer followers gently drift out (or rather a firm push due to them being a lubricated snug fit) and then once I remove the other screw and ball bearing, the pin should come out and the inner 2 followers should then gently drift out too?
Do you know if the pin you mention is the one under the flange (inside the engine) and referred to as pin/peg (part 11167-0331)?

OR do I need to remove all 3 screws (and the ball bearing) before anything will shift?

Thanks so far, you've been a great help.

[DAVE BRADY]

Hi,

The pin is the one under the flange.  The cam followers should slide up and down with no resistance other than from the stickyness of any oil present.  Once the screws are removed they should just about fall out under their own weight.  So no drifting but perhaps a gentle push.  Note their position and put them back the same way.  Perhaps a bit pedantic but they do bed in.  On reassembly use bit of grease.  This will hold them all up out of the way when sitting the barrels back on.   Squirt plenty of oil down from the top once the barrels are back on.
Check the con rods.  The primary/lefthand one should have a small drilling from the shell to the side just above the big end journal.  The hole should face the flywheel and make sure it is not blocked.  The hole is there to help to even the oil supply to that journal and by directing it on to the flywheel it creates an splash feed up the left hand bore to improve the lubrication of the piston.

Dave.

[ghl]

Many thanks to you both. Found the top screw (thought it was just a bit of rough cast originally). 2 of the followers are nice and free - as you said, glide up and down with an oil resistance. However the other 2 (actually from the right hand side 'good' cylinder) are stuck - think I pushed them up originally. Going to take to the engineering works 'as is' for the moment and see if they can free them (and the central retaining screw) for me - also get some advice on the bore condition.

[ghl]

OK, just an update. The cam followers were indeed just caught on a slight lip and were freed off with a gentle 'nudge' at the reboring guys (they just used a valve from possibly a wagon engine as a drift and tapped with the palm of their hand). I just didn't want to damage it at all. It's the first time I've really touched an engine in over 30 years as the bike had been stood that long between my fathers garage and mine - so just building up the confidence and knowledge again really.

They said that they don't normally remove the cam followers unless needed - re-hone sorted the bores, so fortunate with that. The cam followers now glide under their own weight on the oil and feel nice.

Not sure if I can see the hole in the left hand side con rod with it in situ but will have a check and if I can, make sure a, that it has been reassembled correctly previously and b, that it's not blocked.

Thanks for the advice - no doubt with will be back with other questions (on new topic threads, as appropriate)!!

[idie]

The hole in the drive side rod is very small and faces the flywheel. BSA added this to direct some oil onto the drive side cylinder bore as they had instances of seizures on that side.

[ghl]

So am I correct that even at TDC I wouldn't be able to see it without splitting the con rod. The guy who rebuilt the engine 3 years ago regularly works on British bikes and has an A10 of his own - plus his father is still involved who's worked on them for more years than even he cares to remember so I'm fairly confident that it'll be right - but always worth a double check if it's in bits - just depends if it'd mean splitting the bottom end.

[DAVE BRADY]

Hi,

You may be able to just see it but you may have to turn slightly away from TDC so that the fly wheel does not get in the way.  A small inspection mirror will be beneficial.  It may be difficult to see if it is not blocked as pumping oil through the crank is not really possible with the bottom end assembled.
If you cannot see the hole it may be worth speaking to the person who built the engine to get confirmation that the correct rod was fitted, the right way round and that it was checked to see oil coming out of it.

Dave.

[ghl]

Thanks for the info Dave. Had a look on the con rod and could see on the left hand one that there was a small hole on it - but think I got the wrong place. It was at the base of the rod but above where the shells sit (more on the rod itself, more than the side face of where the shells sit) - this was different to that of the right hand rod though as it didn't have this extra hole. It was facing inwards though towards the flywheel.

It was only now that I have thought of this fact (typical), so the head and everything is already back on and have moved onto carburation. Think all will be OK!

[idie]

The hole should be on the left hand con rod facing the flywheel to squirt oil onto the bore.

[ghl]

Yep, the hole I found is on the correct rod and the correct side, just wasn't sure if it was the hole you were both describing. If possible can you take a look at the attached picture please and see if it's the one you were meaning (circled in red)

[DAVE BRADY]

Hi,

Yes, that is the correct one.

Dave.

[ghl]

Thanks to both of you for the info - fortunately all installed correctly - I couldn't check that it wasn't blocked when in situ but the guys who rebuilt the engine are known for being mechanically very good so am confident that it would have been checked when fully stripped down.
Thanks again. Geoff