400EX Head studs will pull the threads loose in the cylinder anytime that the cylinder gets too hot breaking down the aluminum. There are several causes of this including overheating of the cylinder during resleaving and poor matching of fuel octane to the engine.

Critical Note:

These heavy duty studs cannot be used if the cylinder was drilled and tapped for Helicoils or drilled and tapped for any other oversize studs with a differant thread diameter and pitch.

Installation Instructions

  You need to first drill and tap the cylinder to accept the new studs. 

Hole machining

7/16-inch course thread. Drill holes with a 3/8 inch bit. It is always best to have a machine shop do this procedure in a vertical mill to ensure proper alignment.

Be sure to hone cylinder after studs are installed. 

Install the new studs using Permatex sleeve retainer on the threads. 

Be sure to install to the correct height. 

The studs must be the correct distance out of the top of the cylinder. 

Front – 2.436”

Rear – 3.188”

Sides – 1.929”

Stock vs. Heavy duty

400EX

400EX Heavy Duty Head studs............................#01-001....................$59.95

MORE HEAD STUD INFO

400EX CDI... 1500 RPM Higher rev limit, aggressive timing curve, great for XC and MX racing........................................$150.00

400EX Front Shocks

MORE INFO

 400EX  XC Link..................................#04-001...........$175.00

MORE XC LINK INFO

400EX  MX Link................................#04-002............$175.00

MORE MX LINK INFO

400EX Swingarm Skid Plate.........................#04-135.......$59.95

MORE INFO

400EX Belly Skid Blank (no hardware)...............................$25.00

400EX Heavy Duty Timing Chain........#GT-HDTC............$89.95

MORE INFO

400EX 8 Plate Clutch Kit....................04-E001..................$212.95

MORE INFO

400EX XC A arms...........04-102...............$895.00

Honda Lower Ball Joint.....#07-007....$39.95

Honda Upper Ball Joint...#07-006....$39.95

Honda G T Thunder Bushing kit...#05-004...$125.00

Lithium Ion Battery Kits

Chassis skid blanks (poly) - no hardware...................................$25.00

Rear Shock Conversion: Includes revalve, respring, and a link........$345.00

Do It Yourself Kit: High flow piston, shims, rear link, and a new rear spring.....$445.00

TRX400EX Heavy Duty Head Studs

Part Number 01-001..............................................................$59.95

  These head studs are for repairing the 400EX cylinder after the thread in the cylinder are damaged or can be installed in a new cylinder to help prevent head gaskets failing as quickly. They have shown to have over 70% more holding strength then the stock head studs due to the increased diameter and the longer threaded area on the studs.

  They can be installed with the cylinder on the quad but we prefer to machine the cylinder for the new studs on a mill for better accuracy.

400EX Heavy Duty Stud Kit #01-001..........................................- $59.95

Stud Installation - $55.00

HOW TO BUY THEM

Call us at 330-674-7122

Buy them thru any of our authorized retailers.

Or order them online from one of our authorized retailers.

Online ordering - Click here