Most likely an engine mounting bolt.At worst,it could be a cracked frame at a mounting.Just have a good look around all the bolts first.Then we explore other possibilities

 

Sounds like one (or both) of the carb slides are sticking a little and when you suddenly shut the throttle it is being held momentarily before the power of the spring forces it to close.
The click is when it hits the bottom of its travel.

Mark

 

With the engine not running, I hear my carb slides bottoming.
Better than them sticking open.

 

Hard to guess without hearing it, or maybe more detailed description? Is it a faint click or a loud one? Any idea whereabouts its coming from? Carb springs can get a bit tangled or improperly seated, and make a clicking sound - but would surely do this without the engine running? Air getting into the exhaust usually causes a bang or pop, but maybe it can also sound like a click? Typically happens when shutting off suddenly.

Otherwise, I guess its a case of figuring out what changes from being under load to not being under load, eg: the final drive, primary drive, or as Rambo suggests, engine movement?

 

A click, like one would normally think of it, is probaby pretty hard to hear when the bike is at speed and you decelerate.

When you decelerate the forks compress. So try holding the front brake and rocking the bike to simulate the forward thrust. Could be something inside the fork, maybe something is hitting the fender when they compress like the brake hose, maybe the caliper is loose and the forward thrust in concert with some drag from the pads makes it shift forward, etc.. Fender might have a broken brace and decel causes it to bang, although I'm doubtful about that happening only on decel.

Another possibility is your chain or maybe chains is better. When you decel you change the load on the chains so that the bottom strand is now tight and the slack moves to the top. The chain wants to fly upward due to inertia as it runs up and over the rear sprockets for both the primary and drive chains. So, the chain may be hitting inside the primary and I would expect that to sound like a click since the alum being hit makes a very sharp, but short sound. Or the rear chain might be hitting the chainguard. I would expect either of those to be loud enough to be heard at speed.

When you decel, you also remove load from the rear shocks, so a loose shock might make a clicking noise as you unload it. You might be able to test for that by bouncing up and down on the bike to see if you hear anything.

How about your handlebars. They are rubber mounted and if the iso mounts are loose, when you decel your weight on the bars pushes them forward. Try using fingertip light grip on the bars (that's what you should be doing all the time anyway) and see if it does it. Or when you test the front end in step 1 above, you'll be pushing on the bars and might repeat the noise then.

Last possibility I could imagine is just something loose enough to swing with changing momentum. Could be a floppy throttle cable or any cable that is long and not properly supported or tied to the bike. Could be your keys swinging when you decel. Are you one of those guys with a wad of keys or key fob hanging off your bike key?

I would try to make it "click" while riding at different speeds. See if it does it when going very slow. Or try backing off the throttle slowly and gentley to see if that makes it click with less perceived volume or not at all. If you can drill down to some of the variables that alter or eliminate the click, then you'll be able to narrow down what is actually making the noise.

Good luck and don't forget to report back so we all get a little smarter.

regards,
Rob

 

Top engine mount on the cylinder head loose make a good noise.I did have a loud noise sometime back when the primary tensioner rod snapped.On deceleration it got very noisy as the primary chain hit anything it could now reach.Plenty of ideas here so who wins ?

 

Maybe we should start a pool, Rambo. Winner gets a free round trip ticket to Cairo.

Do the Triumphs vibrate badly when the top mount is loose.? My BSA was missing the top mount, which is really just a brace, when I got it and it shook like a gravel sifter. I made a brace and that turned it into an electric motor. Amazing difference.

regards,
Rob

 

Yes Rob,it is noticeable if the top flat bar is very loose.Happened once on my T120r but I use better locking nuts now.Always worth checking under there when going over the fixings.My BSA is smoother than the Triumph until it gets around 4000 rpm then the handlegrips buzz too much

 

This could be a lot of things.We don't even know what area it's coming from.
It could be the rear chain catching on the uppermost primary cover to engine mount bolt if the bolt is installed wrong way around (the head of the bolt should be toward the chain).It usually catches under load when the rear suspension compresses.It goes away with zero load.
It could be flogged out rubbers in the clutch cush-drive (metal to metal contact on backlash,backing off).
It could be a worn primary chain tensioner,more highly loaded on deceleration.

 

Snakeoil: That would that be Cairo, NY, wouldn't it?

The "village idiot" has been there once.........: Jim

 

Well, I've been to Cairo, NY. No pyramids. No terrorists, either.

regards,
Rob

 

I would get a click like you describe when the primary chain is too loose. When you take the load off the chain, it flops and rubs on a stator stud.

 

just one click? multiple clicks could be a slack primary chain

 

Thanks you all for the responses!
It's a single click, and I was nervous that it was the primary chain. I've been unable to recreate it with the bike stationary. At first I thought it might be the kickstand clacking against the exhaust or something. I pulled off the center stand awhile back, so it's not that. I've also checked all the fasteners. It's hilarious how quickly they loosen up.
.
I thought it could be the slides snapping shut, but it seems a little loud for that. I can hear the click with a full helmet in the wind on the freeway. The sound is right, but the volume is impressive.
.
I'll check the chainguard just in case, but I don't think that's it. I checked the chain tension, and it seems good, but the inertia of the chain itself is a good idea. I'll see about that.
My bars are rubber mounted and I just replaced the rubber.
The forks are due for an oil change. Sound seems to be coming from the engine somewhere.
.
I'll update when/if I can solve the problem.

I think you all have to chip in $ to the pool if we're sending the winner to cairo. I'm spending my extra money on loctite.

 

One click makes me think something is loose, like the the engine. But you have checked that. Do you have the original air filters or have you put pre-OIF pod type filters? I'm asking because I'm looking for things that might hit a piece of sheet metal and make a noise but only once.

How about your seat? Any chance that it is moving forward when you decel and hitting something? When it slides back it just comes to rest against the pins, but going forward it hits something. Be careful but try standing on the pegs and see if it still makes the noise. Could be your weight is bring it forward with enough inertial to make a noise.

Same could be doing on with your tank. Is the center bolt tight and is the rubber horseshoe between it and the frame? I'm thinking that the gas sloshing might be making it move and it is banging on something.

Don't discount the noise a cable can make. If you have mid-cable adjusters, they might be floppiung forward and hitting the tank or something else and making this noise. Check your throttle cables to see if the adjusters can bang into anything.

This would drive me nuts until I found it. I had a rattle on a bike and I could find nothing loose. I finally found it one day be reaching under the tank while riding. It was a mid-cable adjuster that at the right revs or road vibes would hammer on the bottom of the tank. Repositioning and a zip tie solved it.

regards,
Rob

 

I'm rebuilding the engine, and when I opened up the primary side and looked at the shifter assembly it occurred to me that maybe the click was the shifter. Shifting up would lift the arm that accommodates the clutch assembly. Is it possible that the shifter has enough play in it that this rotates back down and clicks on the stop?

 

Don't have a pair of shears in the toolkit do you?

davy