128/131″ STREET FIGHTER

The M8 Street Fighter kit is for the customer wanting to go to a larger cubic engine and do an upgrade or refurbish to the heads. The heads will get new guides, +1mm intake and +1mm exhaust valves, and a performance valve job. These kits feature our 4.312 bore cylinder kits with our custom liners, made from 110,000 PSI ductile iron. These are made longer to support the piston at the bottom of the stroke. Also supplied are the new T-Man Premium High Lift Spring Kit, our custom-made, fully coated Wiseco pistons with 3mm oil ring and top-of-the-line Total Seal Rings. Pair this kit with one of our performance cams for big power and torque on a well-mannered touring bike.

$3,980

Price does not include shipping or sales tax

128/131″ Pro Street Touring

These kits feature our 4.312 bore cylinder kits with our custom liners, made from 110,000 PSI ductile iron. These are made longer to support the piston at the bottom of the stroke. Also supplied are the T-Man Premium High Lift Spring Kit, our custom-made, fully coated Wiseco pistons with 3mm oil ring and top-of-the-line Total Seal Rings. The head features our proprietary CNC port work, complete with oversized intake and exhaust valves. Intake and exhaust seats are removed and re-machined for oversized seats to ensure stability. This kit will take a 107″ to a 128″ and a 114″/117″ to a 131″ without any crankcase modifications. With this, you will also have your choice of T-Man cam, which will be determined by the power and torque desired and, more importantly, your riding style.

For more information on your build, you can contact us with any questions you have. We recommend viewing our videos on cylinder liners and external breather kits. Also, be sure to take a look at our Vented Dipstick (a must-have on all big-bore motors).

$4,664

Price does not include shipping or sales tax

139/143″ Pro Street 4×2

Introducing our Big Cubic inch, big power touring package. The 139” motor comes standard with our custom-lined cylinders that feature a longer bezel to keep the piston rock down and keep the piston much more stable in the cylinder. The Pro Street 4×2 head is fully CNC ported with all-new intake and exhaust seats, new guides, +4mm intake valves, +2mm exhaust valves, and our Premium High Lift Springs. Pair this kit with one of our performance touring cams and see huge torque and horsepower that jump right up and carry through the RPMs. This kit is perfect for the customer looking for big cubic inch power on a motor that can still be a legitimate pump gas touring bike.

This build does require a full bottom-end service. Below you will find a spec sheet for the top end only and one for the top and bottom end service. If you would like more information on our M8 Bottom End Service, click here for more information.

TOP END SERVICE ONLY

$5,049

TOP & BOTTOM END SERVICE ONLY

$10,003

Price does not include shipping or sales tax

M8 Oval Port Thumper Stage 1/Stage 2 Kit w/
Custom Lined Cylinder

We are now introducing the latest addition to our M8 lineup, the T-Man M8 Thumper Series, available in Stage 1 and Stage 2.  This head has undergone numerous changes to reach its current state. Both Stage 1 and 2 head feature our signature oval intake port. We start by welding the floor of the stock port, as well as plugging and welding both intake flange bolt holes. This allows us to raise the intake port and, most importantly, allows us to move the port horizontally where we can optimize the cross section of the port in relation to where the valves are in the head. This head must be used with our On Center Manifold and custom intake flanges. We recommend the HPI 70mm throttle body and our On-Center No-Loss Air Cleaner. Manifold is supplied with a fuel rail and a fuel line connector.

Both Stage 1 and Stage 2 Thumper Heads feature the oval intake, but what sets the Stage 2 apart is the oval exhaust port. The Stage 1 head has the conventional exhaust port on it, which allows our customers to use the exhaust that they already have or one that is available for their style of bike. The Stage 2 head with the oval exhaust port is the top of the line when it comes to an M8 exhaust port. The time that went into this exhaust port is staggering, but the end result is worth it! We start by opening the port and inserting an aluminum plug into the original port opening, plugging both exhaust stud holes. This allows us to weld the original opening closed without applying excessive heat to our head castings. When the machining process starts, we have relocated the complete opening and machined a new exhaust stud location. Unlike the Stage 1 head, the Stage 2 head will require a custom pipe. Our stainless pipe flanges are made in-house and mount solid to the head surface with a copper inlayed gasket to ensure a smooth transition from the head to the flange opening. Also, when designing our flange, you will notice we used the thick robust flange to continue our radius on the short side bend of the head. This, in a sense, makes the port longer and will make the transition from head to exhaust smoother, reducing any type of restriction. Also makes for less invasive transition to clear the front down-tube on your frame.

Thumper 1 $5,153
Thumper 2 $5,767

Price does not include shipping or sales tax

M8 Oval Port Thumper Stage 1/Stage 2 Kit w/
Billet Cylinders

We are now introducing the latest addition to our M8 lineup, the T-Man M8 Thumper Series, available in Stage 1 and Stage 2.  This head has undergone numerous changes to reach its current state. Both Stage 1 and 2 head feature our signature oval intake port. We start by welding the floor of the stock port, as well as plugging and welding both intake flange bolt holes. This allows us to raise the intake port and, most importantly, allows us to move the port horizontally where we can optimize the cross section of the port in relation to where the valves are in the head. This head must be used with our On Center Manifold and custom intake flanges. We recommend the HPI 70mm throttle body and our On-Center No-Loss Air Cleaner. Manifold is supplied with a fuel rail and a fuel line connector.

Both Stage 1 and Stage 2 Thumper Heads feature the oval intake, but what sets the Stage 2 apart is the oval exhaust port. The Stage 1 head has the conventional exhaust port on it, which allows our customers to use the exhaust that they already have or one that is available for their style of bike. The Stage 2 head with the oval exhaust port is the top of the line when it comes to an M8 exhaust port. The time that went into this exhaust port is staggering, but the end result is worth it! We start by opening the port and inserting an aluminum plug into the original port opening, plugging both exhaust stud holes. This allows us to weld the original opening closed without applying excessive heat to our head castings. When the machining process starts, we have relocated the complete opening and machined a new exhaust stud location. Unlike the Stage 1 head, the Stage 2 head will require a custom pipe. Our stainless pipe flanges are made in-house and mount solid to the head surface with a copper inlayed gasket to ensure a smooth transition from the head to the flange opening. Also, when designing our flange, you will notice we used the thick robust flange to continue our radius on the short side bend of the head. This, in a sense, makes the port longer and will make the transition from head to exhaust smoother, reducing any type of restriction. Also makes for less invasive transition to clear the front down-tube on your frame.

Thumper 1 $7,352
Thumper 2 $7,853

Price does not include shipping or sales tax