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Discussion Starter · #1 ·
Hi, Iam a Triumph Newbie who needs some help ferreting out a nasty noise. When I accelerate in gears 2,3,4 from a low RPM range, I hear a rattling that sounds as if it is coming from the left to bottom side of the engine. The rattling begins as I near 2600 to 3000 rpms and subsides soon after. I do not hear the sound when I run consecutively through the gears in quick succession. The condition only seems to show itself when I am accelerating coming out of an underpowered situation ie riding at a lower RPM at lower speed than than the gear might dictate, but not aggregiously low. I can recreate the sound in 2,3,4th gears by slowing to below 3000 RPMS and then rolling moderately hard on the throttle. Any ideas in simple terms (as this is the first bike I have had in years and my nearest service dealer is 3 hours away) would be greatly appreciated.
 

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Heh Grinnin. Welcome.

I think I get the same thing so I will be interested in the results. I figured it was just a low rev vibe that resonates through the fairing being to close to or perhaps touching the engine in some parts. Perhaps a minor engine mount issue. Like you only notice when bike is under heavy load at low revs.

Been meaning to have a look but keep forgetting. My bike is performing faultlessly and the vibe has been there for yonks (that's oz for a very long time) and lots and lots of miles. So I'm not to concerned.
 
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Discussion Starter · #4 ·
Galesa,

Hate to say Iam glad to hear you have the same issue, but always nice to have company. How long has your bike done this? Mine seemed to just start, Was curious as to whether weather might have had something to do with it as our weather is just getting cold - never noticed it in the warmer season. As is true with you, the bikke performs flawlessly elsewise - the noise just freaks me a bit.
 
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Discussion Starter · #6 ·
Stlakid,

Iam using super unleaded from the same station Ive always purchased from. Why would this just show up now?
 
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Discussion Starter · #7 ·
Pre-Ignition - Pre-ignition is when the intake charge is ignited too early.The combustion pressure exerts large forces on the upward traveling piston and can destroy the engine. On the other hand, detonation can occur at any point during the combustion process. It is basically a violent and uncontrolled explosion in the combustion chamber. Although folks commonly refer to combustion as an "explosion" it is actually more appropriately termed a "controlled burn". Explosions in the combustion chamber are undesireable, and the violent release of energy can also destroy an engine. Pre-ignition can sometimes lead to detonation because the premature burn is simultaneously compressed. Pre-ignition and detonation are both bad news. Detonation is usually caused by a *lean* A/F mix. (vacuum leaks) or improper jetting. Also by low octane fuel,overadvanced timing, lugging of engine, and of course excessive carbon in the combustion chamber. A rich mixture can lead to detonation due to excessive carbon build-up in the combustion chamber decreasing its volume and raising the compression excessively. -from www.totalmotorcycle.com/dictionary.

My question is this, the noise Iam hearing sounds like a metallic rattling not like backfire or pinging or any kind of explosion. Does this still sound like detonation?
 

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Recently My 02 RS has been pinging like never before too.I realized I was lugging it too much ,(great amount of torque)just drop a gear and enjoy,
but in cold weather I been getting huge 12 gauge Backfires ,Whats with that?
 

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I am using super unleaded from the same station Ive always purchased from. Why would this just show up now?
Basically you're loading the engine to hard. I can pull away cleanly from 1500rpm and up, but you can't be as low as say 2000rpm and just whack the throttle open and not excessively load the engine. Either drop a gear and 'gas it' or 'ease' into the throttle at low rpm's to avoid the condition. A little lighter touch on the throttle may be all you need to do. I can run my bike on 87 octane without getting it to ping as long as I take it easy on the launches and don't load the motor. Just part of the learning curve with these bikes since the torque is very addictive.

The manual recommends 89 octane minimum here in the states. And my bike actually runs the best on 89, but I can MAKE it ping on the premium 91 octane fuel too.

[ This message was edited by: Stlakid on 2006-11-13 23:44 ]
 

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Quite a coincidence but my 2000 ST started having this rattle during a long trip to the Snowy Mountains last weekend. The weather was hot and the noise was noticeable under load and uphill. It did not sound loud enough to be a slipping chain and I could not detect an increase in revs, however having 53,000 Kms on the original front sprocket I checked it and found it to be well worn with bent teeth . Anyway the bike is in for a service tomorrow and will be fitted with a new chain, sprockets, plugs etc. I will also ask that they check timing and compression.
Will get back to you and let you know if the problem has been fixed and what was causing it.
Cheers Gavin.
 

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Mine too on an '03 I started to notice the same loud rattle at 3000 RPM when lugging under load in the last 5K miles (it currently has ~28K).
I think I am using 87 octane - will try 89 and atttempt not to lug so much.

I switched to the 18 tooth front sprocket and it seems worse? I would think that should make it less, but does not seem to be so.

Glad to hear it it is user error not engine melt down.
 

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This is an easy noise to replicate. It simply comes from lugging the motor. I have done this with my 99 Sprint on many occassions when I get lazy or my attention drifts and I suddenly find myself a gear higher than I should be. Usually it happens when accelerating of a corner and is simple to stop or avoid. A quick downshift to the correct gear will stop the noise. Several people mentioned that it does not occur at 3000 rpm and above. That is the same rpm that mine stops as well.
 

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Stlakid is absolutely spot on. One surefire death to an engine is to lug it and death won't take long. You are hammering the bearings to pieces with lugging. These aren't Harley engines and the higher you go the better they like it.

It's called having a high BMEP. Or Break Mean Effective Pressure. At low rpm and a wide throttle opening a lot of F/A mix is being drawn into the cylinder. Very dense and a lot of pressure. With lower octane gas a hot spot (spark plug electrode, piece of carbon, valve edge) can cause (as you are finding out) this F/A mix to detonate uncontrollably at the wrong time causing a hammering in the combustion chamber. This hammers the piston top, wrist pin, rod, crankshaft bearings, melts rings, and the valves don't like it much either. There isn't much meat between the valve tracts and these areas can and do crack. In other words, detonation has, can and will turn a fine engine into instant junk. And don't be fooled, pinging is detonation too.

IF you use a lower grade fuel, as Stlakid said you have to be gentle, but even with hi-grade you just can't whack the throttle at low rpm pulling a load either.

These are hi-performance highly tuned engines running a lot of static compression. You hurt them riding like they were a tractor.

Don
 

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Funny thing is that I have had my bike since new (June 2000) been up the same road a few times in previous years and not had the rattle untill now. I always run 98 Octane BP or Mobil if possible, ride quite fast (enjoyed the twisties and the powers worked a treat) and the bike has clocked up 53,000km.
So either I have changed my riding style or the bike has changed. Should find out about the bike when I get it back from its service tomorrow. And as for my riding style, quite possible it has changed as I have mainly been riding my 05 ST for the last 12 months with an 18 tooth front sprocket.
Another thought is that I had to buy my fuel in country towns and may have been given ***** petrol. :)
 

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One thing it aint with my bike is pre ignition, pinging or knocking!

I use 98 Ron (BP ultimate) all the time.

Grinnin: Can't remember exactly when I first noticed it but I think I should say that I am pretty sure its some kind of frame/chassis/engine/fairing resonance rather than anything in the engine.
 

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I had a similar sound and found that the bolt to the exhaust headers were loose. I tightened them up and it never made the noise again.
 
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Discussion Starter · #20 ·
I certainly appreciate the replies and info guys. Been keeping the rpms up and slipped a litttle octane boost in for the short term. I sure do love this beast and want to keep her around for a long time.
 
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