Rattle

[Greybeard]

Following the recent work I did on my '55 Plunger engine it was fairly quiet. Since doing a few long runs the engine has developed a rattle. I have recently adjusted all the tappets to 8 thou, which has not made a difference. I'm not sure the sound is tappets but I'm wondering, on a standard engine with an iron head, careful rider, how close can I set tappets? . I'm even thinking about setting them with no clearance as a test to see what difference that makes. Obviously, I would not leave the tappets like that.

I'm going to take the sump plate off to see if metal is found there. 

[Butch (cb)]

I think I've got them out at 12 thou on my s/arm.

But then i'm more used to riding Moto Guzzis.

[Greybeard]

Musky once suggested that I could get away with setting tappets closer than BSA advised but I cannot remember, (or find on the forum) his recommendation.

[bikerbob]

I have just rebuilt my 1956 SA  A7 engine and I have a noise that sounds like tappets but with a stethascope it is coming from the timing case exactly where the 3 rifles logo is. I have a toothed belt drive so that eliminates dynamo chain noise, and the belt is not too tight. My thinking is and I maybe wrong but I think maybe either the idler pinion bush 67-686 or the idler pinion spindle bush 67-286 or both have worn slightly and are allowing the the timing gears to chatter causing the noise, it will have to wait till the winter lay up as I have other jobs to do at the moment.  Before you start altering tappet settings maybe check with a stethascope or a screwdriver to your ear and find out where the rattle is coming from.

[muskrat]

G'day GB.
I agree with Bob, a stethoscope to locate the "rattle". As for tappets you can warm the engine up to operating temp then set them to two thou", I wouldn't go any closer.
Cheers

[Greybeard]

Thanks guys, I'll let you know what comes next.

[duTch]

 When you start to have a 'hum' with it you should maybe concerned...

[RichardL]

I had a spontaneous and mysterious rattle a little while back at the start of this riding season. It turned out I was so anxious to get out that I forgot to buckle one of the straps to the pouch above my front mudguard. The unfastened buckle was clattering against the mudguard. It took a bit of riding time to figure out because it was out of view.

Richard L.

[Greybeard]

When you start to have a 'hum' with it you should maybe concerned...

You too

[Greybeard]

Right. Got a chance to dive into the shed this morning. Getting at the tappets is a fiddle on my bike. I have to undo four nuts to remove the saddle before I can remove the tank. Last time I removed the tank I'd just filled it to the brim. The machine was up on the hoist so lifting the tank down without doing any damage required all of my strength! Not too bad today, tank was only half full.

Anyway, today I found three tappets were at 10thou but the drive-side intake had a tight 20thou.  Last time I set the clearances I'd just fitted lash caps to the inlet valves. I put a blob of grease inside so they did not start off dry. I guess I had not managed to squish excess grease out when I checked the gap. Doh!

I've set all tappets today to a tight 8 thou.

I put the bike back together and went for a spin. The engine still seems quite noisy. After all the trouble I've had this summer I'm probably being paranoid.

I used a screwdriver against my lughole as a listening device. It seems to me the focus of most noise is around the camshaft bush. Would you expect this sportier cam to be louder than the standard one?

[Topdad]

Hi BB ,I've got the spitfire cam in my A10 and haven't noticed any increase in noise but maybe thats due to my Goldie "silencer" 

[muskrat]

G'day GB.
The only difference a cam might make is the "click, clack" of timing gear backlash. Usually only heard when turning the motor over with plugs out by hand.
 "It seems to me the focus of most noise is around the camshaft bush"
That's where you'll hear it, at a slow idle 10 per second could sound like a rattle. Were the cam bush's changed with the new cam?
While we're in that region. Hows the dynamo and chain?
Cheers

[berger]

quicky, stripped my engine put followers in order of how they came out , somehow put them back in different places. when pushing bike in gear to get oil round heard the clicking. had to strip the engine again straight away because of those crap piston rings, carefully studied cam bits and put them where I thought they had been origionaly and no clicky. edit, don't ask me why because I still don't know why

[Greybeard]

Were the cam bush's changed with the new cam?

Nope

While we're in that region. Hows the dynamo and chain?

Dynamo has a belt

[Greybeard]

...stripped my engine put followers in order of how they came out , somehow put them back in different places...

New camshaft and followers