[Cappy]

My 06 Iron Barrel (850 miles) has developed a clanking sound in addition to the usual noises.  Seems to be after it has been running for about 5 minutes.  I don't hear it at idle but it seems to start clanking (tapping) when I rev it a little, then stops again at idle.
I adjusted the valves ( a little on the tight side) and that doesn't seem to be the problem.
It's also not detonation or "ping".  I don't think it sounds like bottom end "thud".  In fifth gear, the noise stops when I'm slowing down  - off the throttle - at a little under 40 MPH (indicated).  It comes and goes when I dound shift through the gears to stop.

What else could be causing this sound?  Also, what would cause this "slapping" noise on a bike with 850 miles?  Wrist pin? 

I don't notice the sound at cruising speed but perhaps it's hidden by wind noise.  I may remove the head and take a look.  Can a rocker arm make that noise?

Any help is certainly appreciated.

[Vince]

     Before you start dis-assembling the engine you should check the stuff that is easier and less expensive to check. Check chains. A loose drive or primary chain can make a clank that sounds like an engine noise. A broken muffler mount, or a baffle broken loose inside the muffler can also be tricky. Check for anything loose or broken. Check that your push rods are straight. If they are not you will not be able to properly adjust them and they will make noise. Ana, of course, make sure there is oil in the engine.

[Chasfield]

I had piston slap before I changed the piston when I had the top end apart a couple of months ago. It was only apparent when the engine was cold and had something of the character of knocking two coconut half shells together.

My engine is now reasonably quiet when cold. I get a lot of push rod clatter when it is half warmed up, which quietens down somewhat once the push rods have caught up with the head and barrel in getting hot.

[mikail gransee]

If an engine is self destructing...one will have traces of "stuff" in the oil. Change the oil and filter. If it is just oil...good...if you cave odd creatures lurking in it...

[single]

One of my most indispensible tools is a stethoscope.You can most ly isolate where the sound you don't like is coming from,area wise.A long screwdriver will serve but a stethoscope for auto use is way better.I do not have experience with Enfield knocks or clatters other than what is normal,but what Vince says is good advise.Do everything you can to discover the cause short of tare down.Not to be in denial but rather not to do something that is not necessary.

[RBHoge]

I would check the valve adjustment first.  The next likely suspect would be the Primary chain.  Then again, a broken fender or chain guard stay (brace) is also a persistant source of clanging.  The fender stays are notorious for fatiguing and breaking. I have had both happen on "Old Bill". The fender stay went at about 1,000 miles.
Not to worry though,  CMW has a reasonably priced OEM replacement, and a set which are much more strongly made. Both items are quite reasonable.
Bob.

[MotoJ]

For days before my pedestrian slicer finally fell off and I ran over it I was convinced my motor was about to blow up at at certain RPMs. Once it was gone the motor sounded much better!

[barenekd]

The suggestions above are good, but one thing you don't want is the valves adjusted "Slightly Tight." This can burn your valves. Better a hair loose than tight.
But that won't be the cause of you clanking noise. Assuming your hearing is good enough to detect an engine noise as opposed to the front fender, my first guess would be the small end of the rod. Or as you said, piston slap. As you try to detect the spot, if it's coming from the bottom end, it's probably a main bearing. If you ultimately have to tear down the top end, pull the timing cover off and check the seal at the end of the crank. Very important to oil pressure and engine life.
Bare

[MotoJ]

It's probably something simple and non-motor related if you only have 850 miles clocked. These things shake off parts like a dog after a bath if you haven't gone over it with a wrench and some loctite. 'Course, you could have got a lemon, but it's unlikely.

[Monkee]

Have you found out the source of the slapping noise? I too noticed this on my C5 exact same conditions as yours at idle no noise. but when reving or at load you hear it. i suspect its the PAV valve? since i removed the hoses and blocked them off. I tightened the exhaust bolts and the slapping is still there

[Raymond]

Have you found out the source of the slapping noise?

Well, I hope so after thirteen and a half years.   

[allanfox]

Well, I hope so after thirteen and a half years.   

 

[AzCal Retred]

As others here say, carefully investigate the chassis for odd noise creation.

Piston slap usually lessens a bit as the engine heats up. The aluminium piston grows faster than the cylinder as it has less cooling ability. As it grows it "tightens up" and flops about less. A high silicon or forged piston does that less and resists becoming barrel-shaped more. Cheap insurance.

Valve train noise increases with temperature on these machines. The valves loosen up a bit as the engine gets hotter, a nice feature. Just like the RE engineers from the 1930's knew their business. Nothing is gained by running valves tight.

Valve train noise can come from the cam followers/lifters or the rockers. Look hard at both. Cam follower wear inside the timing chest is usually accompanied by cam nose wear. New parts fix this $$$. A worn lifter can cause erratic valve clearance.

Lifters rotate in operation. A "pocket" worn into the lifter face will change the valve clearance depending on where the pocket was when the clearance is set. Check clearances several times after setting, kicking thru 6-8 times between. If it doesn't change likely the lifters are OK.

The top end has to come off to replace the lifters/followers. A good time to fit a proper piston.

[Paul W]

My 350 Bullet has made some worrying mechanical noises over the 20,000 miles and six years I’ve owned it. The first thing I check is the exhaust system. My latest fix of what sounded to be an impending death rattle was to stretch out the diameter of the pipe where it slides into the head casting to make it a slightly better fit. A clue that is was the exhaust was popping back on the overrun. All sorted.

[Monkee]

As others here say, carefully investigate the chassis for odd noise creation.

Piston slap usually lessens a bit as the engine heats up. The aluminium piston grows faster than the cylinder as it has less cooling ability. As it grows it "tightens up" and flops about less. A high silicon or forged piston does that less and resists becoming barrel-shaped more. Cheap insurance.

Valve train noise increases with temperature on these machines. The valves loosen up a bit as the engine gets hotter, a nice feature. Just like the RE engineers from the 1930's knew their business. Nothing is gained by running valves tight.

Valve train noise can come from the cam followers/lifters or the rockers. Look hard at both. Cam follower wear inside the timing chest is usually accompanied by cam nose wear. New parts fix this $$$. A worn lifter can cause erratic valve clearance.

Lifters rotate in operation. A "pocket" worn into the lifter face will change the valve clearance depending on where the pocket was when the clearance is set. Check clearances several times after setting, kicking thru 6-8 times between. If it doesn't change likely the lifters are OK.

The top end has to come off to replace the lifters/followers. A good time to fit a proper piston.

Thanks! the sound im hearing isn't a ticking and its most prominent in the front part of the engine towards the left hand side. it kind of sounds like an exhaust leak. Do you have a link for the good pistons? i figure on the next major service i'll have to take thea rocker covers off and check the valves.

[AzCal Retred]

Hitchcock's has all the bits. They fit and are just a couple days away. The forged bits are in "accessories". I have one, it replaced an OEM unit that had "soft seized" on a gradual uphill on a coolish day. You don't have to think about the pistons personal comfort anymore with a forged unit.

OEM pistons are notoriously soft and have a dismaying variety of failure modes. The forged units bring the guts of the machine into the 21st century just like the modern machines. This particular piston is for the stock 6.5/1 CR as it retains the easy-going, easy-starting properties of the basic Bullet. There is a 8.5/1 version as well, but there are many practical reasons to stay with the stock CR. If you live in a summertime "hot" area (>105F/40C) maybe an alloy cylinder as well would be wise.


https://accessories.hitchcocksmotorcycles.com/23260?cont_shop=Shop-Engine-Upgrades&Model=500%20Bullet%20Indian%20Export%20Spec

PART No. 90204
PISTON COMPLETE, STANDARD, FORGED, 84mm (Omega/Accralite)
£160.00

Product Details
PISTON COMPLETE, STANDARD, FORGED, 84mm (Omega/Accralite)

This is an English made forged piston which is a straight replacement for the standard piston. Made by Omega, it gives a very strong and robust piston without changing the standard compression ratio of approximately 6.5:1 It is supplied with rings, gudgeon pin and circlips.
Size = 84mm (STD)

Suitable for all 500 Bullets from 1953 EXCEPT: Electra X and EFI models. See ''Fitting Guide'' for details.

[Esa]

Please note; a forged piston is not a straight replacement to standard piston, it always requires honing of cylinder to bigger clearance.

[Monkee]

Hitchcock's has all the bits. They fit and are just a couple days away. The forged bits are in "accessories". I have one, it replaced an OEM unit that had "soft seized" on a gradual uphill on a coolish day. You don't have to think about the pistons personal comfort anymore with a forged unit.

OEM pistons are notoriously soft and have a dismaying variety of failure modes. The forged units bring the guts of the machine into the 21st century just like the modern machines. This particular piston is for the stock 6.5/1 CR as it retains the easy-going, easy-starting properties of the basic Bullet. There is a 8.5/1 version as well, but there are many practical reasons to stay with the stock CR. If you live in a summertime "hot" area (>105F/40C) maybe an alloy cylinder as well would be wise.


https://accessories.hitchcocksmotorcycles.com/23260?cont_shop=Shop-Engine-Upgrades&Model=500%20Bullet%20Indian%20Export%20Spec

PART No. 90204
PISTON COMPLETE, STANDARD, FORGED, 84mm (Omega/Accralite)
£160.00

Product Details
PISTON COMPLETE, STANDARD, FORGED, 84mm (Omega/Accralite)

This is an English made forged piston which is a straight replacement for the standard piston. Made by Omega, it gives a very strong and robust piston without changing the standard compression ratio of approximately 6.5:1 It is supplied with rings, gudgeon pin and circlips.
Size = 84mm (STD)

Suitable for all 500 Bullets from 1953 EXCEPT: Electra X and EFI models. See ''Fitting Guide'' for details.

where i live the ambient temp ranges from 30c to 44c . The alloy cylinder and forged piston do sound like a good investment, though the ones you linked appear to be for the iron barrels?

[AzCal Retred]

Yuppers, Yron Barrle bits for the Yron Barrle section...

The newer machines (UCE & up) already have decent alloy barrels and high silicon(?) pistons. Good high viscosity oil (20W50) in the summer seems to be all they need.

The OEM IB pistons can shuck the top, drop a skirt or stick when they feel abused. A forged or modern high silicon piston can save a lot of grief. The alloy barrels are definitely noisier though.