Honda 300EX Camshafts

Honda 300EX Camshafts

CAM TYPE: DRI offers only Hardfaced camshafts for the Honda 300 EX which are made in the U.S.A.
Hardfaced camshafts are high performance camshafts made from welding, grinding and heat treating the stock OEM core. Reliability is excellent. DRI has discontinued Billet camshafts for the 300 EX.

CORE REQUIRED: Stock Camshaft for Hardfaced option only. If the customer does not send in a stock OEM camshaft core in good condition a $196.00 (additional) core charge will apply.

MC-1253-05B X5 Grind Cam (Billet) DISCONTINUED
MC-1253-05H X5 Grind Cam (Hardfaced)$249.00

MC-1253-25B X25 Grind Cam (Billet) DISCONTINUED
MC-1253-25H X25 Grind Cam (Hardfaced)$249.00


X5 Grind Camshaft
Part #MC-1253-05H (Hardfaced)
Specifications: All Around Cam, Lift: .336", Duration 249°
Application: Trail, Sand Dune Riding, MX Racing
Notes: 1, 4

X25 Grind Camshaft
Part #MC-1253-25H (Hardfaced)
Specifications: Midrange/Top End Cam, Lift: .370", Duration 272°
Application: Drag Racing, TT
Notes: 1, 2, 3, 4


1.HD Valve Springs are required for this camshaft.
2.Shortened Bronze Guides are required for this camshaft.
3.New or modified piston required for this camshaft. Additional valve pocket relief in piston is required due to increased camshaft lift.
4.If Hardfaced option is chosen, customer must send in stock camshaft core. If no core is supplied, customer must pay core charge of $195.00.

CAM SPROCKETS: These cams use stock OEM cam sprockets.

ROCKER ARMS: The cams uses stock OEM rocker arms. Due to poor quality OEM hardfacing, it is highly recomended that the (2) stock rockers are welded and rehardfaced to match cams. Additional $69.00 charge per rocker arm (2) applies. This is mandatory for warranty.



30-3041 Heavy Duty Valve Springs w/Titanium Retainers $169.95

30-3030 Shortened Bronze Guides 19.95ea


All camshafts will offer their maximum performance when used with a professionally ported cylinder head and professionally cut valve seats.

IMPORTANT NOTE When installing a high performance camshaft it is the responsibility of the engine assembler to check and confirm that the piston to valve clearance is adequate. Minimum clearance is .060" from valve to piston at peak lift. Tolerances can and will vary from engine to engine. There is not substitute for checking that these tolerances are correct. This is especially critical when mixing camshaft and pistons from different engine builders. One of the correct and easiest ways of checking this is by using the "claying the piston dome" method.
Call DRI or consult a professional technician.

What is the difference between a billet and hardfaced cam?
Billet cams are sold outright with no core required. They are machined in the USA and are specially heat-treated for wear resistance. Billet cams are used when problems arise in the hardfacing process of stock cams.

Hardfaced cams are made from stock cams. In the hard facing process, stock cam lobes are welded with a hard surfacing alloy to increase durability as well as provide additional stock for high-lift profiles. The stock cam (or stock core) can then be ground to almost any desired lobe shape. Some models such as YFZ 450 prohibit this type of modification because cam journals can distort in the welding process.

All DRI Camshafts are made in the USA to ensure the best quality. Camshafts are available in different power curve options to fit your riding and racing needs.
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