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Discussion Starter · #1 ·
The dyno used was at Woodstock Triumph/Harley/Ktm.
The first picture with one red line is my t120 with Vance and Hines slip on. The torque is immediate!!! We started the run at 2100rpm, I am sure we could have begun at 1500 and seen the same result.

The second picture is stock vs slip on. The blue line is the slip on, the red is the stock. The stuttering is due to the catalytic converter. We will be working on a cat free system!
 

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Thanks for that dyno run, even tho the T120 sounds good there is still some restriction in the exhaust, would guess that the spaghetti converter is a major restriction.
look forward to your neutered cat solution.
 

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Looks great. Did the Vance and Hines have the DB killers removed?

Looks better than the Remus dyno on horsepower
 

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Discussion Starter · #4 ·
Looks great. Did the Vance and Hines have the DB killers removed?

Looks better than the Remus dyno on horsepower
Yes I did remove the DB killer. The Vance and Hines showed some decent gains for a slip on. The Vance and Hines is also substantially lighter than stock.
I am not keen on the appearance the Remus pipe. Hopefully Norman Hyde will develop pipes for the new T120. Hyde already has a Street Twin pipe.
 

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70 RWHP AND 76 FT LBS

If we can only find a way to get past 90 ft lbs at the rear wheel
 

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70 RWHP AND 76 FT LBS

If we can only find a way to get past 90 ft lbs at the rear wheel
Personally, I'd want a new cam...one that doesn't fall on its face at 5,500 rpms. The torque curve looks great up to that point & a power peak at least 1,000 rpms or so higher would certainly add to the fun. And I'd wager that you'd also see a bump in torque that is commonly realized when moving away from a mild/emissions cam...

YMMV,

--Rich
 

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Thruxton pistons may also be a good add but I'll stick to boltons for the first couple years
 

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The stuttering is due to the catalytic converter. We will be working on a cat free system!
I only spent a couple days training on the dyno at AMI but the restriction from the cat should be smoothing the exhaust flow. Usually the small spikes were from the rear tire slipping on the drum.
 

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Personally, I'd want a new cam...one that doesn't fall on its face at 5,500 rpms. The torque curve looks great up to that point & a power peak at least 1,000 rpms or so higher would certainly add to the fun. And I'd wager that you'd also see a bump in torque that is commonly realized when moving away from a mild/emissions cam...

YMMV,

--Rich
My understanding is the Thruxtons and T120 use the same cam. I would not be surprised if the cam timing was different though.
 

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My understanding is the Thruxtons and T120 use the same cam. I would not be surprised if the cam timing was different though.
I was thinking aftermarket, but just looked at Bike Bandit and you're correct...same part number for all the 1200 cams. Valves are the same too. Makes you wonder what is different in the high torque vs. high power motors...
 

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I was thinking aftermarket, but just looked at Bike Bandit and you're correct...same part number for all the 1200 cams. Valves are the same too. Makes you wonder what is different in the high torque vs. high power motors...
Higher compression 11:1 vs 10:1, 45% lighter crank, bigger airbox, less restrictive exhaust, and "tuned" for for higher RPM power(whatever that means, but I'm guessing different cam timing)

The reason I think it may have something to do with cam timing, is that retarding the cam timing moves power up in the RPM range.
 

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I was thinking aftermarket, but just looked at Bike Bandit and you're correct...same part number for all the 1200 cams. Valves are the same too. Makes you wonder what is different in the high torque vs. high power motors...
Same pistons, same conrods, same cams, same valves. Differences are cylinder head itself and crankshaft.
 

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Higher compression 11:1 vs 10:1, 45% lighter crank, bigger airbox, less restrictive exhaust, and "tuned" for for higher RPM power(whatever that means, but I'm guessing different cam timing)

The reason I think it may have something to do with cam timing, is that retarding the cam timing moves power up in the RPM range.
cam timing wont change power out put that much. The thrux has to be breathing better that's what it takes to make hp on the bigger twins.
 

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cam timing wont change power out put that much. The thrux has to be breathing better that's what it takes to make hp on the bigger twins.
It's breathing better due to the airbox and exhaust, but it's torque curve is also higher in the RPM range.

My theory is that the cam timing is moving the torque curve higher up in the RPM range, and the breathing is making it broader, keeping it from taking a nosedive like the T120's engine does. The compression also bumps the torque(and resulting power) up as well.

Combine the extra torque and power with a lighter crank, shorter gearing, and generally lighter weight of the bike, and it really transforms things.
 

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I wonder if the airbox is swappable. Since its the same fram with just a differant subrame is possible. Its a mess in there with all the wires and the T120 only has a little snorkel what sticks out the left side. It could probably boost high rpm performance as well
 
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