426 build list

[doublejz]

Ok a couple months ago I started thinking about doing a rebuild and the copper colored flakes are getting worse at oil changes and its losing power. So I've put a "final" list together and just wanted some input.

JE 426 Piston Kit 11:1.............................................. ...........................275.00
Hot Rods Complete Crankshaft Assembly - Heavy Duty..............................281.99
Hot Rods Crankshaft Main Bearing and Seal Kit..........................................75.99
Honda OEM Valve stem seals............................................. ....................20.00
Kibblewhite Valve Spring Kit............................................... ....................89.95
Kibblewhite Black Diamond Exhaust Valve 30.00 mm 1mm Over.....................59.90
Kibblewhite Black Diamond Intake Valve 34.00 mm 1mm Over.......................59.90
Hot Cams Camshaft (Stage 2)................................................ ..............136.99
Cometic Complete Gasket Kit............................................... ..................42.99
GThunder Head Studs(just to be safe)............................................. .......59.95
CRF450R or OEM Timing Chain............................................. ...................30.00
Honda OEM Clutch Kit............................................... ..........................102.99
2x - 14322-MAN-620 - BOLT (7X9.5) for 2005 HONDA TRX400EX.................13.16
1x - 14520-KCY-671 - LIFTER, TENSIONER for 2005 HONDA TRX400EX..........65.03
1x - 14560-KCW-851 - GASKET for 2005 HONDA TRX400EX..........................3.70
1x - 14620-KCY-670 - GUIDE, CAM CHAIN for 2005 HONDA TRX400EX...........30.26
2x - 90004-GHB-630 - BOLT, FLANGE (6X16) for 2005 HONDA TRX400EX........5.12
1x - 90005-KY7-000 - SCREW, PAN (6X6) for 2005 HONDA TRX400EX............2.38
1x - 91306-MG3-000 - O-RING (1.5X9.5) for 2005 HONDA TRX400EX.............1.99
1x - 95701-06025 - BOLT, FLANGE (6X25)............................................ ....1.99
1x - 14515-KF0-000 - COLLAR (6X9)............................................. ..........4.22
1x - 90417-360-000 - WASHER, DRUM STOPPER........................................1.9 9
1x - 14511-KCY-670 - TENSIONER, CAM CHAIN........................................64.80

Port n Polish............................................ ............................................????
5 Angle Valve Job............................................... ..................................????
Bore/Honing............................................ .............................................????
Valve Guide's checked........................................... ................................????
Dunk Tank/Steam clean whole motor............................................. ...........????

This is mainly a woods/trail bike.

[honda400ex2003]

thats a great list, what would make you decide to change a crank also? that will def breathe nicely with bigger valves and such in it.

steve

[doublejz]

I'm assuming that the copper colored flakes in the oil are coming from the crank. Can't really think of anywhere else they'd be coming from.

[honda400ex2003]

i suppose lol i just figured they were from one of the middle oil rings. i thought that one of the stocker rings was copper.

steve

[doublejz]

You could be right as I haven't had a 400ex open before. I plan on splitting it and looking at everything first. The bike has had 2 previous owners and with my luck, it probably already has a 88mm piston and a hot cam or something :-P I just hope it lasts for a few more rides this summer/fall.

[CJM]

Id do a tusk clutch, very much worth the cash and much cheaper than OEM.

Id also skip the crank, chances are its one of the rings-you can always order the crank later after you take the top apart.

Add yourself a spal 4 inch puller fan, attach it to the oil cooler. Also add a larger oil tank-cfm or um too aid with cooling.

Make sure you get the MLS cometic gaskets too, not the felt/paper ones.

It is you also good you replace the timing chain guides and tensioner while everythings apart. Use the CRF chain from a 2002-2006. Much stronger and cheaper than 400ex chain.

Also it is critical that you torque down the head nuts on the studs to 33 ft-lbs, and the rocker cover bolts (8mm head, 6mm shaft) to 6ft-lbs. I dont even use a torque wrench on them, I choke up on a 1/4 drive ratchet and make them snug. If you overtorque these bolts they will pull out of the topend and helicoiling them doesnt work to well.

[honda400ex2003]

lol i cant remember for sure, i just assumed thats what it was from. i havent had my stock piston out of the box in years. lol

maybe you will get lucky and have a hotcam in it already.

steve

[doublejz]

Originally posted by CJM
Id do a tusk clutch, very much worth the cash and much cheaper than OEM.

Id also skip the crank, chances are its one of the rings-you can always order the crank later after you take the top apart.

Add yourself a spal 4 inch puller fan, attach it to the oil cooler. Also add a larger oil tank-cfm or um too aid with cooling.

Make sure you get the MLS cometic gaskets too, not the felt/paper ones.

It is you also good you replace the timing chain guides and tensioner while everythings apart. Use the CRF chain from a 2002-2006. Much stronger and cheaper than 400ex chain.

Also it is critical that you torque down the head nuts on the studs to 33 ft-lbs, and the rocker cover bolts (8mm head, 6mm shaft) to 6ft-lbs. I dont even use a torque wrench on them, I choke up on a 1/4 drive ratchet and make them snug. If you overtorque these bolts they will pull out of the topend and helicoiling them doesnt work to well.

Good stuff.

I actually already have a SPAL 4" fan and I'm looking at a CFM tank but not sold on it due to how close it is to the frame and some people say it hits. I also don't know if the white brothers header pipe will fit.

Well I'll add all of this minus the chain to my list then. I'm also assuming the hot cam reuses the stock cam gear.

http://images.powersportsnetwork.com/fiche/images/HONDA/2005/ATVs/2857_CAM CHAIN @ TENSIONER.gif


2x - 14322-MAN-620 - BOLT (7X9.5) for 2005 HONDA TRX400EX.....................$13.16
1x - 14520-KCY-671 - LIFTER, TENSIONER for 2005 HONDA TRX400EX..............$65.03
1x - 14560-KCW-851 - GASKET for 2005 HONDA TRX400EX............................$3.70
1x - 14620-KCY-670 - GUIDE, CAM CHAIN for 2005 HONDA TRX400EX..............$30.26
2x - 90004-GHB-630 - BOLT, FLANGE (6X16) for 2005 HONDA TRX400EX..........$5.12
1x - 90005-KY7-000 - SCREW, PAN (6X6) for 2005 HONDA TRX400EX..............$2.38
1x - 91306-MG3-000 - O-RING (1.5X9.5) for 2005 HONDA TRX400EX...............$1.99
1x - 95701-06025 - BOLT, FLANGE (6X25)............................................ ......$1.99
1x - 14515-KF0-000 - COLLAR (6X9)............................................. ............$4.22
1x - 90417-360-000 - WASHER, DRUM STOPPER..........................................$ 1.99
1x - 14511-KCY-670 - TENSIONER, CAM CHAIN...........................................$6 4.80

[CJM]

Yep, hotcam reuses the cam gear.

I wouldnt go as far as all new bolts, but the guides and tensioner are usually a good idea to replace b/c they wear overtime.

[doublejz]

Well replacing those bolts are nothing. I just got done doing a complete teardown and powdercoat. Every single bolt/nut (plus a bunch of other stuff) was replaced with OEM.

http://www.exriders.com/vbb/showthread.php?s=&postid=4097002

I just want to make sure I do this right and don't take any shortcuts that I'll regret.

[CJM]

I hear ya. I just think the prices for them things are crazy. I can understand tho if your going for show quality.

For what its worth, to me it was never about looks. My quad has cut plastics, the frame I painted a bit (looked great before I rode it again), the plastics are spray painted (worked good till the pressure washer-electric at that lol), etc. Sure aint pretty-but its quick.

Sorry to derail, I dont think anyone knows mine looks like its beat to hell and back.

[doublejz]

Yikes, I didn't realize machining/head work was so expensive anymore.

To have GTThunder do the following they quoted me $756.

GTthunder head studs and installation
Cylinder bored to fit the new 426 piston (88mm) as well as rings cut/trimmed and installed on piston
Cylinder honed
Port n Polish
5 Angle Valve Job
Valve Guides checked
Head assembled with Kibblewhite valves\springs, OEM valve stem seals

I don't think I spent that much on the head for the last car motor that I built. Looks like this will be a "down the road" project :-/

I was also thinking about the copper colored flakes. When I had my quad powdered coated, they didn't plug the holes on the oil tank and pretty much filled it with sand when prepping it for powder coating. I flushed the tank for like an hour with gas/carb cleaner and oil but still found sand in my oil after the first oil change. From there on I've noticed the shavings. I guess I'll find out when I pull the head. I'm assuming I can just check for crank play by moving the rod around/side-to-side instead of tearing into the bottom end too?

[doublejz]

Well that's the best price I can find for machining/head assembly. Looks like I'll be saving for a winter project.

[CJM]

Should be able to check the rod for play that way, least thats the way i do it.

As for the motor work, you could try C&D racing, they are a forum sponsor and wont do you wrong. I also know CT racing also does the work you want, not sure on pricing for either tho.

Whats killing your pricing is the valve job, and port and polish-they aint cheap.