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Discussion Starter · #1 ·
Hi guys,

took the cafe racer to brands the weekend (great weekend), and noticed a very pronounced "shudder" from the transmission, it feels like the gearbox, as load comes on when moving off or accelerating from slow speeds, the whole bike shakes, if I ease the power off slightly then re apply it smooths off. has anyone had this ?, its in for 1st service on sat so will see what the dealer has to say.
 

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I wonder whether it could be the clutch? The other thought I had, is the chain in-line or could the chain be too tight?

Regards.
 

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Gearbox Judder

Hi Busaguy,The judder you are asking about sounds just like the thing that i get.I have always said in the 2 years that i have had my TNT that it is the only niggly thing that i can fault the bike for.I have always thought that it is to do with the driveline.Since i fitted a 3 tooth larger rear sprocket and keep the chain tension fairly taught i think it is better,but i wonder if the main problem is the running of the engine,ie has the hesitation and spitting back got anything to do with it,in other words is there a roughness in the power delivery that could cause it?
I hardly notice it when i am on my own because the TNT is almost impossible to ride steadily! But when i have the missus on the back then i notice it more because i am not accelerating quite as hard and pulling higher gears in towns etc.
Lets hope that someone knows the answer eh!
Zebo.
 

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Discussion Starter · #4 ·
hey Zebo, you hit the nail on the head, I was 2 up this weekend with luggage and thats when I noticed it was there and long rides send your hands too sleep from the vides through the bars (190 miles to brands from my home)
 

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Hi

But why is the extra weight causing the shudder. Perhaps the extra weight on the rear, is somehow throwing the swinging arm off centre, or the chain, for some reason, is tightening?
 

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Discussion Starter · #6 ·
It is strange, I checked the chain tension with my mate and missus on the bike and is fine, it is far more severe in second gear, when the "shudder starts I just ease of the power and it clears, it feels like something loose or not fitting correctly in the gearbox
 

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I'm firing on three
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Hi guys, I think the problem you are describing is mapping, there is a weird flat spot in the map when accelerating at low revs particularly under load (almost feels like it’s running on 2 cylinders), It was made a lot better on my 05 bike when I fitted the PC III but not erased……...the Benelli no 2 cylinder (middle one) runs hotter than 1&3 so the fuelling needs adjusting via the ECU software to compensate.
 

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I think vtxbrit is on the right path here, and when we add a couple of items to the sceme, I think we have pretty much covered it.

The Benelli triple behaves more like a twin than an i4 on low revs, which means that trying to run the engine with heavier throttle under 4k rpm will result to a 'protest' of a sort, the engine will shudder, cough and yank the chain in pulses, until the revs rise well above 3k rpm, or you let down the throttle.
Add to that a sligtly too loose or too tight chain, and the 'funny spot' in the ecu around 4 to 5k rpm, where the throttle body keeps opening and closing the other valve with light throttle. This is most likely to occur in slow traffic, when you have to ride slowly behind the tin cocoons blocking the road ahead. Open up the throttle a bit, so that the revs rise above 5,000 rpm, and you'll get a smooth run. Tuneboy might improve things a bit, too, but it won't remove the shudder on the below 4,000 rpm. That's just the nature of the triple beast.
 

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Shudder

Triumph have managed to perfect it.So lets hope that Benelli get up to speed with it soon Heh! I have always had a Triumph triple in my collection since 1995 and they have all been fine.I thought that they used a similar injection system as well.
Zebo.
 
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