Feeling a build coming:)

[ridehonda400ex]

So i just got my sisters 300ex done tonight and boy does it purrr! So since the deal fell thru on the 450r i was supposed to get maybe ill freshen up the 400. If i do it i want to go to a 406 and 11:1 comp ratio. Also will probably put in a new clutch, tusk. Will i need the hd head studs? I wouldnt think so. And will the true comp ratio be 11:1?

[CJM]

Its a good idea to do the studs just because you never know.

I wouldnt even bother with a 406 tho, your not gaining much in displacement-416 is better. But, higher compression and the fact you will have 2 more bores before you have to toss the sleeve out is a good thing too.

[ridehonda400ex]

how much are the studs to get done? like shipping and installing and everything...the clutch could wait lol, and would i be fine running a stock cam?

[CJM]

A stage 2 cam is really a good idea if your gonna run a higher compression piston and have a larger bore-really helps the bike come alive.

Studs cost about 100 installed + shipping. While its a bit $, its worth the fact of knowing they wont pull out like the stock ones can.

[426kidz]

call GTthuder for studs! but Iidk if id worry bout it for that. i know many who have never had probs without them... just for your own ensurance.I would say no to the studs and get a nicer clutch like a Hinson!;)

[ridehonda400ex]

I'm FOR SURE going to do this build but i'm gunna wait till about july when i get my license so i can figure out my money situation. I'll have a job this summer and will make about $1,100-1,300. So heres my game plan. Wiseco 416 piston and gasket kit(dennis kirk), stage 2 hotcam, hd head studs, 450r front shocks.

So that would put me at about $600 roughly. My grandpa can do the boring for me so im saving on that.

Anything else you think i should do? And im gunna get the clutch sometime, just gunna do research on them first

[sneaky11]

grab a 450r carb and a slip-on. You can check for shaving a little bit off your flywheel too, it's only depends on what you wanna do with the bike..trail,mx??

But first, if you grab a set of 450 shock, look for revalve and resprung... combine that with a used set of ST +2 a-arms and that will be the best upgrade for your EX.

[ridehonda400ex]

Found this too. I'm considering it, has everything i could want, besides shocks.

http://www.partsforatvs.com/default.asp?p=2230&c=725&cn=M3Q+400EX+POWER


As for the carb, is it neccessary? i know itll make better throttle response and all but I'd be just fine with the stock, right?

[CJM]

^buying it all separate would be cheaper, plus you dont need some of it. Talking about 800 vs what they want

You dont need:
-The air filter, KN is ok but really the foam filters work better
-clutch in your bike is fine, they dont wear all that quick
-dynojet kit is absolute trash, you want jets buy keihin only from jetsrus
-full exhaust is nice, but the stock header is actually very good. just take it off and grind down the inner welds some on the very end of it.

Figure:
-piston $120
-Cam $120
-jet kit $30
-Slip on $300
-Uni filter $35

Still quite cheaper isnt it?

[ridehonda400ex]

I agree CJM, buying them seperately will be cheaper and i plan to do just that actually. Have you ever bought from that site?

[CJM]

Nope, Ive seen it before but never bought a thing since several items there I found cheaper elsewhere.

I usually buy from:
rocky mtn atv
motosport.com
bike bandit
ebay-specifically seller apex racing has treated me great! Bought my piston and cam from them about 2 years ago now and some other stuff recently.

Really I find motosport and rocky mtn to be the cheapest for alot of aftermarket parts and usually ship fast.

[ridehonda400ex]

the hotcam is the cheapest on partsforatvs.com, for what ive found. and if i go with a stage 2 hotcam can i run my stock valve springs? I'd be putting a 86mm wiseco 11:1 piston, which i think would make it a 416. Correct me if im wrong

[CJM]

87mm is 416, 86mm is 406.

You can run any hotcam with stock springs, however sometimes the springs can be worn out and out of spec a bit if the atv was used alot. Not enough to really worry tho.

If you ebay 400ex hotcam stage 2 apex racing sells it for same price. I ordered both that and my wiseco piston from them and got them to combined shipping :)
http://cgi.ebay.com/ebaymotors/NEW-HOTCAMS-HOT-CAMS-HONDA-TRX400EX-400EX-STAGE-2-CAM-_W0QQcmdZViewItemQQhashZitem35b07f1d63QQitemZ23059 4387299QQptZMotorsQ5fATVQ5fPartsQ5fAccessories

[ridehonda400ex]

Then whats an 85.5? and whats stage 2 hc good for??

[CJM]

85mm is stock 397cc (aka what they call 400cc)
85.5 is 402
86 is 406
87 is 416
88 is 426
89 is 435 (aka 440)

It is best to pick the middle of the road and go with 406 or 416 b/c they offer slightly more displacement than stock with slight gains. Also if you need to bore again you can do so if you do the 416, 426 is the limit for a stock bore before you have to get a new sleeve. What your really gaining is compression when you up from 9:1 which is stock to 10:1 or 11:1. compression is power.

Now in regards to the hotcams:
Stage 1 would work well for a stock engine or a 406 with a standard compression or 10:1. It is designed for a mostly stock setup and gives you good low/mid gains but tends to taper off alot on the topend.

Stage 2 is better for a modified engine such as a 416/426 with a 10:1 or 11:1 setup. It has good gains all around really imho but tends to be a more mid to topend gain. I have alot of mid range power on mine for example. If you want more lowend it can always be compensated for with a change in sprocket size as well.

Heres my setup just so you have an idea. I can keep up with and pass other 450 machines depending on work done to them and the rider. I have no issues keeping up at all.

416, 11:1, stage 2, stock sprockets (15/38), outwears airbox lid, uni filter, HD head studs (just incase), custom exhaust with a lexx slip on and stock header, and just jetted. It has good power all around, I can totally let off the throttle in any gear and blip it and have great torque. Ive never dyno'd it, but believe me when i say-many who ride with me and have 450s are amazed at the power I have-but I am also a very aggressive rider. Vs stock there is no real comparison.

Remember-more compression=more power. Thats where I am getting all the power from. My buddy who buildas bikes on the side agrees-there becomes a point where you overbore so much you sacrifice reliability-compression is always better. Thats why people who have a 440 find out they generally arent all that fast. If your worried about heat, so long as you use 93 octane and have it jetted right you will be fine. Mien runs quite cool even in 90F+, if I felt i was getting to hot, I have a cooling fan I can flip on if I wanted too.

Hope all that helps. I personally recommend everyone (as do a few others) a very similar setup for general riding and racing.

[2001400exrida]

would a stage 1 work with a 426, 11:1 PISTON

[CJM]

Originally posted by 2001400exrida
would a stage 1 work with a 426, 11:1 PISTON

It would work ok, but you gotta remember the duration the cam has may not allow you to really take advantage of the power you have with the higher compression.

This may help some, it explains cam grinds.
http://www.exriders.com/vbb/showthread.php?s=&threadid=392231

heres the really important part:


The lift is how far the cam opens the valve. The duration is how long it leaves it open. The more lift and duration the more aggressive the cam. Big lift and duration numbers work best at high RPM while more mild numbers are best for lower RPM. The more duration the intake valves have the more important it is to have a high(er) compression piston. This is because with lots of duration there is more opportunity for air to escape through the valves as the piston begins its compression stroke. Even on the stock cam, the intake valves are still open when the piston begins its compression stroke. With an aggressive cam some dynamic compression is lost through valves that stay open for a long time. This must be made up for with a higher compression piston. An aggressive cam with a stock compression piston may actually perform worse than the stock cam because too much compression is being lost through the valves being opened so much. I have personally seen this happen--dyno confirmed (although it wasn't a 400EX).

Now, realistically speaking: How many riders are in the lower RPM range when riding? i know my style of riding fast thru trails and dunes means Im in the throttle alot and wouldnt benefit much from less than what I have. I ride to fast and rev it out to much for a stage 1 to really work. Now if you putted along and cruised say in 3rd gear it might be ok, IDK for sure. What I can say is I FLY thru trails in 2nd, 3rd and 4th with no issues with mine.

[2001400exrida]

dammit, guess i gotta get a stage 2. i found the stage 1 in there to begin with, it was a suprise so i suppose buying one isn't gonna be much different.

[ridehonda400ex]

Originally posted by CJM
85mm is stock 397cc (aka what they call 400cc)
85.5 is 402
86 is 406
87 is 416
88 is 426
89 is 435 (aka 440)

It is best to pick the middle of the road and go with 406 or 416 b/c they offer slightly more displacement than stock with slight gains. Also if you need to bore again you can do so if you do the 416, 426 is the limit for a stock bore before you have to get a new sleeve. What your really gaining is compression when you up from 9:1 which is stock to 10:1 or 11:1. compression is power.

Now in regards to the hotcams:
Stage 1 would work well for a stock engine or a 406 with a standard compression or 10:1. It is designed for a mostly stock setup and gives you good low/mid gains but tends to taper off alot on the topend.

Stage 2 is better for a modified engine such as a 416/426 with a 10:1 or 11:1 setup. It has good gains all around really imho but tends to be a more mid to topend gain. I have alot of mid range power on mine for example. If you want more lowend it can always be compensated for with a change in sprocket size as well.

Heres my setup just so you have an idea. I can keep up with and pass other 450 machines depending on work done to them and the rider. I have no issues keeping up at all.

416, 11:1, stage 2, stock sprockets (15/38), outwears airbox lid, uni filter, HD head studs (just incase), custom exhaust with a lexx slip on and stock header, and just jetted. It has good power all around, I can totally let off the throttle in any gear and blip it and have great torque. Ive never dyno'd it, but believe me when i say-many who ride with me and have 450s are amazed at the power I have-but I am also a very aggressive rider. Vs stock there is no real comparison.

Remember-more compression=more power. Thats where I am getting all the power from. My buddy who buildas bikes on the side agrees-there becomes a point where you overbore so much you sacrifice reliability-compression is always better. Thats why people who have a 440 find out they generally arent all that fast. If your worried about heat, so long as you use 93 octane and have it jetted right you will be fine. Mien runs quite cool even in 90F+, if I felt i was getting to hot, I have a cooling fan I can flip on if I wanted too.

Hope all that helps. I personally recommend everyone (as do a few others) a very similar setup for general riding and racing.


What is your jetting at? You have the setup that im gunna go with. You dont have a P&P job do you? Im not gunna do it but i will clean the ports out in a parts washer. I also have an UNI and have the stock airbox lid, HMF slip-on, and stock carb

[CJM]

Im still dialing it in perfectly since I recently switched to OEM keihin and threw away the DJ.

Running a 172 main, 42 pilot (helps with cold starting) and needle on 2nd clip. Im very close to sea level too. Runs pretty dang good.

[ridehonda400ex]

Thats good, i only use Original Kehein Jets. Im around 600ft elevation so that will probably workk good for me. Im going to dumont and coral pink this thanksgiving also:)

[ridehonda400ex]

Could somebody tell me about where i need to be for jets on a 416 bore, stage 2 hotcam and hmf slipon

[CJM]

This is the ticket and what I used (props to steve!) http://www.exriders.com/vbb/showthread.php?s=&threadid=445695&highlight=jetting+placement

Incase anyones wondering: 170 main, 42 pilot, needle 2nd clip, air/fuel screw 2.5 out for a 416.

I needed to richen mine slightly to 172, 3rd needle clip (Im still playing with it) b/c I also have an open air box and a host of other goodies.

[ridehonda400ex]

Thanks steve. I'm soooooo excited to get this build going! just need the money. I think im going to get some nice rims also. I like my Dunlop stockers for tires tho.