Engine has a 'blip' feeling on deceleration

[Lord Percy]

Triumph Tiger 900 (1999 model).

I've noticed my bike feels like it's making a very tiny and cyclic 'blip' on the engine when decelerating from high-ish speed.

It's roughly 2 blips per second, and is always well timed, but only happens noticeably at higher speed and decelerating, e.g. if I let off the throttle at 60mph I'll feel it.

I suspect it's a fuel injection thing, and an engine pressure thing.

Any thoughts/knowledge appreciated.

[Nobby the Bastard]

Does it just pop the exhuast on the overrun? All triumph triples do that...
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Pete.]

Could be a small exhaust leak up at the headers allowing air into the system. It will combust any un-burnt fuel on the overrun.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[stinkwheel]

How's the throttle cable tension? I remember them having a little electronic cam-wheel type arrangement to set the tension, maybe it's fiddling with the throttle?
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Lord Percy]

[Lord Percy]

[Lord Percy]

[Nobby the Bastard]

If it's surging (bike accelerating or amount of retardation reduces) it's not the same.

The exhaust poping is just a noise and they all do it, by design. Cause it sounds cool.

You may be describing 'hunting' which is what a lot of modern engines do to reduce emisions. Basically it's changing the mixture trying to find one that is cleaner.

Maybe a oxygen sensor? Have you stuck it on on a OBD reader?
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Lord Percy]

It isn't the exhaust at all and it isn't hunting, I think maybe I've not been clear in the way I described it.

During deceleration from higher speed, totally off the throttle, there is a cyclic 'blip' which feels almost like I'm tapping the throttle, but nowhere near the level of oomph that happens when actually tapping the throttle.

The best I can find from elsewhere to describe it is this forum post, but it's for a carb bike so I don't know if the exact situation is the same.

In my case, the 'blip' feeling is so slight that it might not even be a problem. The bike runs very well indeed so I won't go playing around with things unless this is a sign of worse things to come.

[Nobby the Bastard]

My 1050 goes pop, pop, pop on the overrun. They all do. If there's no lurch or apparent change in retardation I suspect thats what it is.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Lord Percy]

Yeah there's nothing severe happening, so perhaps this is natural.

I'll have a nose around the exhaust and throttle anyway but if it's a known thing on these bikes then I can rest easy a bit.

[Nobby the Bastard]

Like I say, I wouldn't consider a blip as such. Just a noise from the exhaust.

Think it terms of a rally car...

27 seconds in...

https://www.youtube.com/watch?v=ipkwVJt66_Q

Obviously no where near as loud...
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Lord Percy]

Oh no I'm not describing backfire at all.

Like I said, it feels like blipping the throttle, i.e. a physical jerking sensation.

But nowhere near as large as actually blipping the throttle. It's almost unnoticeable unless you focus on it. And only happens on deceleration, hand off the throttle.