Tappety noise from engine

Previously wrote:

Read RH 296, pushrod location, sounds unlikely but it also happened to me.

Hi Robert, I've just joined the club and my first Roadholder was 297 so can't comment on any article in 296.

I've had a bit of an event that meant me havingthe Head and Barrelsoff again so all possible causes of the "clack" are being looked at.

OK on trying to find where the "Tappety" noise was coming from I was using a stethoscope but could not pinpoint it's source as it seemed to sound the same no matter where I listened. During the process I noticed the R/H exhaust had started to smoke and blipping the throttle pointed to things not quite right.Head came off and revealed pistons that were sloppy in the bores and a fair way out of servicable tolerences, how I built it up like this I'll never know my head must have been elsewhere.Anyway a +20 rebore with new style Hepolites have cured the clatter and I'm now 150 miles into the running in process.Currently running a new single MK1 concentric with 106/250 Jets and a No 3 slide with the needle on the top groove, Bike fires up easy and once warm ticks over nice and even but plugs still look a wee bit rich, another wee thing is that it occasionally cuts out as I come to a stop is it worth going for a bigger cut away on the slide? Pilot screw was set using a colourtune plug but could the setting of this be responsible for the cutting out?

Previously wrote:

Hi Mac. Not sure where you're looking or what you're looking for but Norvil list small end bushes (not bearings) as P/N 012100 for £7.54 ea. +VAT for all twins. RGM list itfor a Dommie asP/N T2160 for £6.90 +VAT. Haven't found it on Andover Norton's site yet.

Cheers, Lionel

Thanks Lionel

Sorry I've not replied sooner, as you can probably see it wasn't the small ends after all, just sloppy pistons, I gave up measuring the gap when it went out of tolerance, sounds a lot better now.

Mac.

Previously wrote:

Donald, ifyou are the Willy on accessnorton, looks like you sorted theproblem? Good one!

So how much clearance was there? Actually, I run a 3.5 slide on my single Mk2 Amal, that is on a 850 MkIII. Bennie.

Hi Bennie

Yes I'm the Willy Mac on the Access Norton site, the 3.5 slide might be the way to go, I'm still running in just now so I'm thinking a tad rich might be better than a tad weak?

Cheers

Mac

Previously wrote:

Glad you got it sorted. Did you just replace the pistons and rings in worn bores so it was basically worn bores? It's made me wonder about my noises now! Best of luck with the running in. Hi Keith, if you read my post again you'll see it had a +20 rebore with new pistons and rings.

The difference in noise levels is like chalk and cheese!

Hi Keith

The engine was built up initially in 1987 and I ran it about for most of that year, but the oil return pipe fractured while on a bit of a fast run and lost all the oil.

The engine was stripped down and the crank rebuilt and balanced with two crank webs and standard secondhand rods.

I can't remember why I never re-bored it then, probably because it seemed to run ok, so when it went together again this time I never thought about checking the wear in the bores or on the pistons.

The rebuilt engine had good compression and ran with no signs of burning oil for 200 miles just the clackety noise, it was while I was trying to find where the noise was coming from that it started to smoke from the R/H pot, so that was when it came apart again and I found the bores and Pistons out of serviceable limits.

A Schoolboy error on my part for not being more thorough but it has given me more experience with the insides of the beast so all is not lost, just got to hope for some decent weather to get more miles on it now.

I'm not running it rich on purpose it's just turned out that way from scratch. If you see my post about Amal Cutaway size you'll see I'm in the process of trying to get it just right.