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Discussion Starter · #1 ·
Hello,

my 2006 TNT 1130 Sport is suffering the fact, that the exhaust gas pressure closes the flap at high speeds.

My dealer tells me that he can do some small changes to the flap to prevent this to happen. Additionally he would apply a stronger spring.
What kind of modifications do you know?


I have 2 issues with this.
1. The solenoid is already quite weak and it is connected to the to bowden cables via a swing.

2. I have read on the solenoid that the Power consumption is 100W which means at 12V that 8,3 Amps of current flow through this thing. I consider a consumer of 8,3Amps at low refs for a high potential to drain the battery. Recently I came after a decent tour back home and stopped the engine 200m in front of my garage because I met a friend. After 5 minute chat I tried to restart the engine and the battery was flat. Finally I pushed the bike into the garage. Since I charged the battery and disconnected the solenoid I have not experienced this again.

Disconnecting the solenoid is great for sound and performance (no swith at 4000RPM, smoother acceleration from 2000RPM. The only thing it is too loud with the HPE muffler fitted.

I would like to discuss my assessment, some solutions / experience with you.

I am thinking about to exchange the solenoid with a DC or stepper linear motor which will be stronger and consume only power when is moves. Those motors are being used for door locks and front light adjusters, Any experience?


Best regards

Mark
 

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Hello to all they are Italian, I see that there are many gets passionate you of this bike ! I have mounted exaust a complete Hpe and have removed is the flap of the airbox that the throttling in plastic, but I have noticed a bug between the 4000 rpm and the 4500 rpm, who of you has removed the flap and the plastic has noticed this problem? Thanks and excused my English
 

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I used to have the same problem with my 2001 GSXR1000. I just removed the cable, solenoid and lock the valve open, it sounded wonderful at high revs.
 

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When i got my tnt from Phantoms in Barton the bike had about 20hrs of dyno work on it to sort out the flat spots and the lack of power well they took off the head to have a look in there but they found the restricted exhaust headers so they were ripped out!!!!!! then the exhaust exup valve was also taken out, as why the hell do u need 1 of them on a triple with 1131cc!!!!!! they put it all back together with a few other small mods, and back on the dyno and 127.5 ponnies at the back wheel popped out for me to abuse......
Drop the guys a message at the shop a line to find out what they did....
www.phantommotorcycles.co.uk
fatnfast
 

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Discussion Starter · #5 ·
Hello,

I hope you did not have to pay for the 20 hours on the dyno.

The flaps are just for noise reduction. Nothing to do with power. Otherwise it would not make any sense to move the flaps at a definit RPM of 4000 from full close to full open.

In Germany they follow 2 mods.

1. Just take out the exhaust flap but leave the mechanics to suggest to the friendly policemen that everything is fine.

2. They bend the flap into a position that the dynamic load does not close the flap as heavy as original. Tis works fine - I did it on mine. Some also report that they are using additionally a stronger spring. (Spring is useless - the flap is not in a good position originally and the gas forces are too big. Additionally the solenoid will not be able to operate with a higher spring load.)


I have added a switch in front of the solenoid to be able to leave the flaps always open. If I am getting into a check situation I can activate the switch and the flaps move to close.

Thanks for your answer.

Best regards

Mark
 

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remove the circlip holding the spring cover on (other side to cable) you will see the spring, carefully lift with long nose pliers and hold the spring where it locates on the exhaust, (you will feel it trying to unwind) now turn it 1 full turn clockwise to put more tension on the spring and refit, this should stop the flap closing at high speeds.
Sometimes the solenoid can still pull the flap closed if the cable is connected particularly if the airbox flaps and cable have been removed.
I personally have disconnected both my cables and it runs very well.
 

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,If i take the cable off the exhaust do i need to turn anything to make the flap stay open? or if the solenoid is electricaly disconnected is the exhaust flap open? also will it make the bike too loud for track days , with a devil end can on, or even with the standard one.(oulton park is 105db)
 

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Discussion Starter · #10 ·
Hello Hector,

the flaps open at at 4000RPM anyway. Therefore it is no change for a track. If you disconnect the solenoid electrically the exhaust flap can still be pushed by the exhaust gas into closed position. You will recognize this at the engine becomes getting tired at 220km/h.

The exhaust flap closure issue applies as far as I know only to the model years 2005 and 2006.

Best regards

Mark
 

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hector the valve (flap) is always in the open position, only when you start the engine is the solenoid valve energised which closes the flap, and as mark says power is cut to the solenoid at about 3600 to 4000rpm which allows the flap to open, I run a devil on my 05 TNT and the noise levels with or without the valve working (at low revs) is very similar especially with the baffle left in.
I did think without the valve connected on the 05 TNT it made the idle a little erratic but I’m not so sure it did, there is definitely no noticeable difference to the idle with or without the valve connected on my 07 TNT. I know I keep on about it but the thing that is worth doing is moving the thermistor out of the airbox if you want a picture of the new position let me know, cutting the cable and extending it to reach the front would not be any real problem as it is not a resistive or compensating cable.
Terry
 

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Ok, so if i remove the (mechanical cable)to the exhaust,the flaps should stay open or should i remove them altogether?
sorry for bieng a bit of a div on this one:confused:
 

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Ok, so if i remove the (mechanical cable)to the exhaust,the flaps should stay open or should i remove them altogether?
sorry for bieng a bit of a div on this one:confused:
yes thats right, it will stay open without the cable attached as the cable pulls it shut.
Hector have you removed the airbox flaps?
 

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Thanks VTX, ive already removed the air box flaps so now i think i will just disconnect the solenoid and leave the cable in place.

Thanks Simon.
 

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Thanks VTX, ive already removed the air box flaps so now i think i will just disconnect the solenoid and leave the cable in place.

Thanks Simon.

Simon, sounds good to me, :) also if without the cable connected it looks like the flap is sluggish to spring back open when you twist it shut, put more tension on the spring (as i described on a recent post) then you know it will not try and close on its own.
how do you find the induction noise and power since doing the airbox mod?
 

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The power is definitly improved with smoother acceleration and the noise must be louder because more people seem to be turning to look whats coming.
Thanks for the help guys.
 
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