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TTP 904s Sports Big Bore Kit

TTP 904s Sports Big Bore Kit
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  • Description
  • Reviews



There are very few modifications you can perform on an engine that will improve power and torque right through the rev range, but TTP's 904s big bore kit is one of those modifications. Increasing cubic capacity and compression ratio give improved performance from idle to the rev limit, with no downside.

In use the extra top end horsepower is excellent for acceleration and top speed, but the revelation is the extra torque through out the rev range. It makes riding a Triumph twin far more exiting as when you open the throttle, the engine just pulls and pulls to the red line.

Designed by TTP, the 904s kit includes race quality pistons, a custom 904 MLS steel head gasket together with OEM cylinders which are bored, Nikasil plated and then powder coated externally to give a virtually new set of barrels.

Available for the air cooled Bonneville, Thruxton, Scrambler, America and Speedmaster from 2001-2016.

Kit Features:
  • 12:1 compression ratio.
  • Larger valve pockets for +2mm valves.
  • Tight quench to improve tubulence & combustion burn.
  • Anti-friction coating on the piston skirts.
  • Pistons hand balanced to within 0.1gms of each other.
  • Nikasil plated barrels give tighter cylinder/piston clearance.
  • Hand gapped piston rings.
  • Custom 904 MLS steel head gasket.
  • Optional OEM gasket kit.

**790/865 CYLINDER CORE EXCHANGE REQUIRED BEFORE SHIPPING**
Core must have no broken fins and no scratches on the bore or mating surfaces.
Shipping details will be on your emailed order receipt.

 
2 Product Reviews - Average rating 5 / 5 (Show All)

Click to review this product

Scrambler TTP 904s Big Bore ? Excellent!

- 22nd January 2019

For anyone that is thinking of laying out your hard earn't cash and buying this big bore kit from Triumph Twin Power, I would say go for it!

What a difference it has made to my 2016 Scrambler. From stock it was always a bit of a struggle when overtaking on the hills where the bike would run out of puff. Not now with the big bore kit and TTP tune installed. I just select fourth gear roll on the throttle and the bike eagerly launches forward and overtakes with ease. Snick it back into top gear and try and wipe the smile form your face! The mid-range punch this engine has now is really something all Triumph Twin owners would be impressed with.The engine is so responsive now and the bike really gets up and accelerates hard and fast right through the rev range. The difference really is night and day with this top quality modification, you will not be disappointed.

Hat's off to Mike at TTP for his extra work in getting the right tune sorted for me here in NZ, also to Mike at TT3 in Canterbury south island for his support and service in supplying me the parts via TTP in the UK. Service really is second to none when dealing with these guys.


Click to review this product

 
The later barrels have machined and polished edges which
after processing need to have the powder coat removed
and the fin edges polished back to a shine.

Like for like core exchange only.

Early Barrels  Late Barrels
Early Barrels                    Late Barrels
 
The Stage 2 Power Induction Kit comes complete with
fitting kit, DNA Performance pod filters, installation
instructions and the required jetting or EFI tune for
the 904s kit.

Carb Stage 2 Kit            EFI Stage 2 Kit
Carb Stage 2 Kit          EFI Stage 2 Kit
 
This gasket kit includes all of the OEM gaskets
required when installing the big bore kit.
(except head gasket which comes with 904s kit)

904s Gasket Set
904s Gasket Set
 
With a 904s Big Bore Kit installed,
the standard clutch springs are
pushed to their limit, so we offer
the Barnet Green clutch springs
along with a Triumph clutch case
gasket as an upgrade.

Barnet Green Clutch Springs
Barnet Green Clutch Springs
 
The Safe Start is a good preventative measure for
a standard engine, with the 904s Big Bore Kit
installed giving an increased compression ratio,
the Safe Start will give protection from the only
engine structural weakness of the air cooled
Triumph twins.

NB: If you're upgrading to the green clutch springs,
why not install the Safe Start while the clutch cover
is off, for complete peace of mind.

TTP Safe Start
TTP Safe Start
 
Installation of the 904s Big Bore Kit at our
workshop in Bournemouth, Dorset, England.
List Price: £922.00
   Discount on this product.
Price: £830.00 (£996.00 Inc. VAT)
€939.76 EUR (+VAT)    $1,051.30 USD    $1,522.91 AUD
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