high comp piston and stage 2 cam...seems not worth it??

[prnstr4life]

i did a 12:1 JE piston and a hotcams stage 2 to my 400ex and it almost seems it wasnt worth it. ened up costing me $320 for everything. I have the carb jetted with a DJ165 and 1.5 turns out, hmf slip on, open aluminum airbox, stock headpipe ported out and head ports cleaned up and ported some.

WHen i rode last week it seemed a little rich so I am going to adjust it...but still dont know if it was worth it

[Honda#4]

With that setup I would have bought a Full system exhaust

[prnstr4life]

I had already had the exhaust ill get a hmf headpipe when i find one used

[zrpilot]

Really, did you re-bore or just put in a new piston? Could the cylinder be out of specs ?

Sounds like something is not right... other then seat of the pants, how does it run?

I recently built an 11:1 416 kit with an HRC cam, HMF full exhaust, FCR carb, ported and polished and for a 416EX it really rips. nice improvement.

[underpowered]

Originally posted by prnstr4life
I had already had the exhaust ill get a hmf headpipe when i find one used

not gonna find a used HMF head pipe. they actually mod your slip on because the outlet on thier header is bigger. you eitehr have to send your slip on back to them, or but a different header like a powerbomb.


but anyway, something may not be right. who put it together? could be an install problem, clearance problem. i got a huge gain with my cam and 426 over just a pipe, then with a P&P and a carb the gain was unbelievable. somethin ain't right, i would get it jetted right first.

[prnstr4life]

I did all of the work. it definitely needs to be rejetted. I didnt think i needed a different headpipe. Maybe i need to get nerf bars. hahaha.


my buddy suggested running 50/50 93 octane and race gas. This one kid i ride with has a z400 with stock everything but a slipon and he was still pulling on me. to me that seems kinda off. I know stock vs stock they tak a 400ex but i figured now i should pull on him. I know jetting is the key. I have stock pilot, 165DJ, clip 3 down from top.

[Honda#4]

with your setup you should waste that z400 like nothin

[underpowered]

well to me the jettin sounds about right.

and as long as you don't have deto, a mix of race fuel is not needed.

you should pull on a z if you are both good riders. even in a drag, a rider still makes a huge difference.

[prnstr4life]

I pull on him but he still seems to pull harder. I am going to rejet tomorrow and then go riding. its about 50-60 degrees here lately so its a tad rich from riding at 30-40 deg.

any other ideas??

[moorhous]

is it stronger than it was befor?? jetting it right will help alot!

[XtremelyCrazy]

I did the 416 with 10.8:1 piston and a Hotcam, 172 / 42 Keihin jets, with an FMF s/o and an open airbox and its definitely better than the FMF s/o with stock airbox.

.

[400exrider707]

I ran an 11:1 stock bore with a stage 1 hotcam, and FMF slipon and a UNI filter without the lid. 155 main, 42 pilot, 4th clip on the needle 2 1/2 turns out on the air screw, and I could wax my buddys Z with a pipe and filter, and I had two people on my quad. From top to bottom and I still had higher top speed, and we were both running 20" rear tires with stock gearing.

Something is wayyyy off with your quad.

[ilpadrino113]

did the piston seat correctly? I'd test the compression to see if there's any loss.

[Honda#4]

I'd test the compression to see if there's any loss.


I would suggest this also.

[prnstr4life]

what should the compression be with this piston??

[krt400ex]

Originally posted by prnstr4life
I did all of the work. it definitely needs to be rejetted. I didnt think i needed a different headpipe. Maybe i need to get nerf bars. hahaha.


my buddy suggested running 50/50 93 octane and race gas. This one kid i ride with has a z400 with stock everything but a slipon and he was still pulling on me. to me that seems kinda off. I know stock vs stock they tak a 400ex but i figured now i should pull on him. I know jetting is the key. I have stock pilot, 165DJ, clip 3 down from top.


ok, your jetting is off. #1, go back to the stock brand keihin(SP?) jets. #2, go to a 155 or 158 main, 42 pilot, and needle in the 3rd position. that should put you right about where you need to be

[prnstr4life]

ok i am on www.jetsrus.com and the pilots come in 2 sizes 23.5mm and 28mm. Which do I get?

[CDCHONDAS]

[i] stock headpipe ported out and head ports cleaned up and ported some./B]

I don't know what you did but you can make mistakes there pretty quick, the "ported some" what has me concerned

stock headpipe shouldn't be a problem, I've seen 440's that did fine with just a slip on

+1 for Keihin jets

is the cam timed correctly?

another problem is I have ridden enough of the z400's that come through my shop that are close to stock and can tell you some run better than others for no reason, my best friends little brother has a z400 and has beat alot of other z400's, e-series is all he has he isnt that great of rider either maybe this phenomenon is just in my area???

[prnstr4life]

thats the same as my friends 06z400 with e-series slip on.

timing is on, porting...that was just cleaning up the intake and exhaust ports, nothing crazy. with the stock headpipe there is a wicked huge weld at the openings where it bolts to the head and we grinded it down and smoothed it out.

which size is our pilot jet, 23.5mm or 28mm???

[GPracer2500]

The stock 400EX carb uses a Series 26 pilot jet (23.5mm).
http://www.sudco.com/images/n424-26.gif


But, the more common Series 21 (28mm) will work.
http://www.sudco.com/images/n424-21.gif


The only difference is the length of the jet from the threaded portion to the slotted end. The 400EX carb has ample clearance for the longer version. However, if you have a choice there's little reason to not get the Series 26--that's what the carb was designed for.

[prnstr4life]

ok. now I will order the jets recommended above. 42 pilot, 155 and 158 main jets!

[prnstr4life]

jets have been ordered. I am going to get a new airfilter and an outerwears also. I was flipping through my owners manual and noticed there is 2 plugs that can be used....dpr8z and dpr9z (i think). anyone what to shed some light on this???

[GPracer2500]

The DPR8Z is the standard plug and (IMO) is probably the "best" choice for many people. Although either one will work, on mostly stock engines the 8 will be less prone to fouling and may perform better immediately following start-up.

The DPR9Z is identical except it is a "colder" plug. That means the 9 dissapates its heat into the head faster then the 8. Hot vs. cold plugs refers to the opertating temperature of the plug itself--it does not translate into a hotter or colder running engine. Plugs must maintain a certain temperature to work effectively. You don't want your sparkplug getting too hot or not getting hot enough. Plugs control their temperature by regulating how well/quickly they conduct heat into the surrounding cylinder head.

EX's that have been modified to produce more HP (and hence, more heat) may be better off with the 9 plug if the 8 is overheating. For those that really want to know which heat range is best for their engine, plugs can be run, removed, and examined to determine if they are opertating at the correct temperature.

[prnstr4life]

sounds good...guess it couldnt hurt for me. i need to get this baby running tip top!

[prnstr4life]

Well i put the jets in. 42 pilot/155 main. fuel screw out 1.5. its running a tad rich, i think the pilot might be to big. It does not seem to have the power that is should. On the trails i realized my main problem. i need new rear tires!! damn thing does not hook up. i never got a new plug either. i was out riding abandoned roads last night with a friend and his z400 and wide open his pulls on me still. we were wide open in 5thand kept pulling. His mods are JUST a white bros slip on. no jetting done. this just boggles my mind.

i need to get a new airfilter, plug, and getting jetting right. what could i be doing wrong? i doubt its the piston install becuase i have no smoke and it has good compression. would a powerbomb headpipe do the trick?? i dont know what else to do here!

[sandshots]

Originally posted by prnstr4life
Well i put the jets in. 42 pilot/155 main. fuel screw out 1.5. its running a tad rich, i think the pilot might be to big. It does not seem to have the power that is should. On the trails i realized my main problem. i need new rear tires!! damn thing does not hook up. i never got a new plug either. i was out riding abandoned roads last night with a friend and his z400 and wide open his pulls on me still. we were wide open in 5thand kept pulling. His mods are JUST a white bros slip on. no jetting done. this just boggles my mind.

i need to get a new airfilter, plug, and getting jetting right. what could i be doing wrong? i doubt its the piston install becuase i have no smoke and it has good compression. would a powerbomb headpipe do the trick?? i dont know what else to do here!

your buddy is holding back. he has stuff on his z that he never told you about.
if youre on bald tires test your bike on asphalt or concrete

[prnstr4life]

trust me hes not holding out. as i stated before we were riding old roads racing around and i was getting better traction. my rear iRazrs lasted a year.


I am frustrated with it. i think the pilot i put in it is too big.

as of right now here is the setup

JE 12:1 high comp piston stock bore
Hotcam stage 2
HMF slip on
ported engine side of stock headpipe
cleaned up intake and exhaust ports on head
155 main Keihin
42 pilot Keihin
Dynojet needs 3rd clip from top
stock airfilter with open alum airbox
stock plug

[sc400ex_rider]

i cringed when i read this post cause i just spent about $600 on the same parts for mine

cam $135
11.1 piston $100
kibblewhite springs $100
450 chain seals gaskets $100
carb ebay $165
ported head, intake and header

carb was junk and had to go back. so i put the original carb back on. though it is faster......its not much faster, it will rev out 5th which is cool. i only rode it about 2-3 hours and it does seem to be getting faster as the rings seat. i was just trying to break in the cam that is ticking like hell.

i think we both need the carb to take full advantage of ower package

[prnstr4life]

this total cost me less than $350

i was just thinkin of a rev box but dont know which one to get. other than that idk what to do. a bunch of people tell me not to run a F+N air filter either. should i stick to stock with an outerwears?

i have been using his z400 for comparion as to how mine is running.

does a certain machine run a DPR9Z? i am getting some things from rockymountainatv.com but wont let me just search for that plug.

give me more info!!

[sc400ex_rider]

alot of people are running the procom box off ebay with no complaints. i gettin one soon because my battery just craped out:(

[prnstr4life]

i dont know what to do with this thing!!

[sc400ex_rider]

how about an update on this

[GPracer2500]

What fuel are you running?

[Nates400ex]

No offence, but why would you run a slip on with all those mods. A full FMF, LRD or other big name would certainly help out. Are you running at least 50/50 race/92???

[Old Head]

Just a thought but a non-bored motor sometimes will lose out when running a stage 2 cam instead of a stage 1

[prnstr4life]

well i took her for a good running today. i havent messed with the fuel mixture. i am running 93 octane. i was going to do a 50/50 mix though. am i better off getting different cam or different piston or just fine tune this? i am not looking for a drag bike, i am just using his z400 as comparision. i had the slip on from the start when i bought the bike, i ported out the end of the stock headpipe since it had those haggard *** welds so they are nice and smooth

any more pointers let me know!

[prnstr4life]

anyone have more suggestions?

carb? cdi? timing advance? gearing?

any pointers and specific brand parts would help

[GPracer2500]

I'd be surprised if it ran without deto problems with a 12:1 piston and pump gas. Are you hearing any clanking, knocking, pinging type noises under high load WOT running?

[prnstr4life]

not really...i might try to pick up some race gas and mix it. i really only hear the cam.

[eliasxr400]

Originally posted by prnstr4life
not really...i might try to pick up some race gas and mix it. i really only hear the cam.
According to everyone on here and on XR400 sites with a hotcam, they are loud. I took a stage 1 from my XR400 and put it in my 400EX and it was noisy in both.
Had it in my XR for over a year and never had a problem but the noise always concerned me.

[prnstr4life]

yeah


I got 5 gallons of 112 octane today. i should be riding tomorrow!