Need Help On Motor Decisions

[Waynes400ex]

I have a 400ex that is setup for mx, but now my stock motor is tired and I need a rebuild. I was wondering what you guys recommend. I'am pretty sure i want to run a fcr and put a carrillo rod in it. I dont want to spend a bunch of money on it maybe like 1200 or 1500 , but i want it to be reliable and be noticeably faster than my stock motor cuase out at Glamis it feels like a turd!!. 416 or 440. Please help cause and dont be affraid to be detailed thanks!!!!!!1

[F-16Guy]

I really like my 416. I also had a Carrillo rod installed for assurance that I won't be picking up pieces of cylinder half way up comp hill. I think a 416 with a good cam, a 39 or 40 FCR and a top end cooler would do you up good. If you're careful about where you shop, you could pretty easily stay in budget. Buy the rod directly from Carrillo, it's $175 vs. $240 elsewhere. A 40 FCR is $350 from Service Honda (or you could buy a used 39 FCR). I had ProFab rebuild my top and bottom end. Call Scott or Jeff at ProFab, tell what you want, and they'll give you an estimate. Go to www.profabatv.com for a rough idea of what they charge. This is where I got my top end cooler from: www.alamomotorsports.com . Click on the Perma-Cool master listing on the left side menu, and then look for the universal ATV cooler kit. ProFab will install the fittings while they have your motor apart if you want them to (they did mine). To mount it, I used a universal cooler mount kit ($4), and made my grill from a piece of expanded metal from Home Depot ($8). A top end cooler makes a big difference in how hot your bike runs, and with a 416 kit, I highly reccommend it.

[Waynes400ex]

Will the 416 have good torque? Also did you do port anf flow our three angle valve job and what cam and springs? thanks

[chad502ex]

Originally posted by Waynes400ex
Will the 416 have good torque? Also did you do port anf flow our three angle valve job and what cam and springs? thanks

Wayne, 440 has more torque than 416. More displacement, more torque. I think 416 is alot better, faster, quick reving than 440. Woods cam for more torque, race cam for hi-rev hp setup. springs yes with cam to keep valves from floating in higher rpm on new agressive cam. three angle valve job is typical, try getting a 5 angle valve job from FastByGast. 5 angle valve job sounds kewl, it sounds like cups clashing (without breaking). Hope this helps. my 0.02.

Chad502EX.com

[F-16Guy]

No port and polish (wasn't in my budget). I used the stage 1 HotCams because I didn't want to loose the bottom end that I love so much with this bike. From what I understand, the stage 2 still has lots of bottom, but even more mid-top end. I might try one down the road, but right now, it runs too good to mess with. Since I'm running the stage 1, I kept my stock valve springs. No need for heavier springs, and less stress on the valve train. Chad's right, no replacement for displacement. If you want more torque, think about a 440 stroker.

[heavy]

The 416 gives you a lighter piston and it will rap faster. I went with a xr400 cam witch is very close to a WB all around cam. Its a bolt on and has a decompressor cam lobe for easy starting. You can use stock valves and rockers. Grind out the weld in the end of your exhaust pipe. It will open improve flow big time. Recarb and check around the posts before your decide on a aftermarket exhaust. I went with a WB slip on because they can be tuned to the bike. There is a ton of very good info in this forum!! Read on and get the best info out there to be had. Good luck :D

[INFANTRY RACING]

send you cylinder of to terry at marcums for a 416 kit-
150-200 dollars
Send the crank out to powroll for a 4mm stroke and carrillo rod-
600 dollars
Get a TC racing cam and have him shave the flywheel-
300-350
get a port and polish-
??? matters on the builder
a good pipe and carb

you should be happy

[Waynes400ex]

Would you still go with a 416 if it was stroked instead of a 440? you dont need headwork with the tc cam? How much of a difference does the flywheel make?

[INFANTRY RACING]

the 416 piston with a 4mm stroke is 440

tc's cams are drop in but porting will help

the flywheel shaved will allow the motor to rev faster but it will be easier to stall.