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Dyno Cams P-Open Grind, Welded Lobe, Clone 13 HP GX390 Predator 420

$149.00

The P-Open is intended for a full tilt modified or open class. This cam offers larger duration with a lower lift. Upgraded valve springs, billet rod, and billet flywheel are mandatory. Dual springs required. A 33mm or larger carb is recommended. The lobes are welded to increase durability, extending the life of this cam.

SPECIFICATIONS

Engine: 390cc Honda GX390, 420cc Predators, & 13/15hp Chinese OHV
Recommended Class: Modified / Open
Target (MAX.) RPM: 8000+
Spring Pressure (In / Ex): 65lbs dual spring
Valve Lash (In/Ex): .003"
Ignition Timing: 110 Octane 34 Deg. BTDC, Methanol 38 Deg. BTDC
Compression Ratio: 12.5-to-1 or higher

PROFILE

	Intake	Exhaust
Open:	71 BTDC	89 BBDC
Close:	88 ABDC	50 ATDC
Lift:	.363"	.367"
C/L:	106.0 ATDC	110 BTDC
DUR @ 50:	263 Deg.	269 Deg.

FAQ Accordion with Animation

Frequently Asked Questions

When will my order be shipped and how long does delivery take?

Orders containing in-stock items typically ship within 3–5 business days. Orders that include assembly will require 7–10 business days to prepare. Please note that during the holiday season (Thanksgiving through Christmas), processing times may be longer due to high order volume. Once your order has shipped, you’ll receive an email with tracking information. Most orders are shipped via Less Than Truckload (LTL) freight and generally arrive within 3–7 business days. Deliveries to remote areas (such as mountains, forests, valleys, or islands) may take longer. You can check the estimated delivery date on the carrier’s website using the tracking number we provide.

How your vehicle is shipped?

Unless otherwise noted, the vehicles we offer are shipped crated or on a pallet and do not come assembled unless you’ve selected our assembly service. Assembly typically requires a few basic tools and mechanical knowledge. If you're not confident in your ability to safely assemble a high-speed off-road vehicle, we strongly recommend selecting professional assembly or having it assembled by a local mechanic.

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Do you offer financing?

Yes. Buy-now-pay-later financing is available with our preferred partner, BreadPay® (please see their icon under product pricing for details).

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How can I get assistance if I have question on products?

Please call 888-886-5846 and talk to one of our knowledgeable sales representatives between 9am-3pm PST. Or send us email at orders@gokartsusa.biz.

What warranty is included with my purchase?

You're covered with confidence at GoKarts USA®. Your satisfaction is our top priority. Every purchase comes with manufacturer-backed warranty protection—including up to 12 months of engine coverage—to keep your ride running strong. TrailMaster products also include a 6-month parts warranty for added peace of mind.

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What does 95% or 98% Assembly Mean? What do I need to assemble if shipped in crate?

For shipping safety, most vehicles cannot be fully assembled prior to delivery.

Minor assembly is required—this typically includes installing mirrors, connecting the battery, adjusting handlebars, and other small components. Before operation, please ensure all screws and fasteners are tightened, engine fluids are at proper levels, and the battery is fully charged. Your factory warranty remains valid right out of the box.

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Dyno Cams P-Open Grind, Welded Lobe, Clone 13 HP GX390 Predator 420

Frequently Asked Questions

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