Newbie to the forums I have read a lot hear but need to ask.
I purchased my 2001 Honda 400ex early this year. It already has the following mods:
White Brothers eSeries Full Exhaust
Hot Cams Stage 1
K&N Filter and Power Lid
Dyno Jet Jetting (Not Sure which but spark plug looks good)
14/39 Sprockets
Works Front Shocks
Extended front A Arms
Lonestar Swing Arm and Bearing Carrier
Stainless Steel Brake Lines Front and Back
Nerf Bars
I love the quad and it’s a lot of fun to ride. I mostly ride Forest Roads and ATV trails. The torque is awesome but the top HP is lacking when playing with my buddies Stock Raptor 660 and yfz450.
I don’t care if I loose a drag race just want to be competitive and keep the engine reliable on 93 pump gas.
I am an amateur mechanic at best but I can follow directions fairly well. I am a 2 stroke guy so the 4 stroke is a new world to me.
So my question is, what would be the best plan of action with what I have and what riding I like to do. I am 6’5” and 300 pounds so I need to make up the weight with HP 🙂
I have done a bunch of research but can’t really narrow down what I need for a 416 vs 426 vs 440. What compression for 93 octane and what cam, valves, CDI, etc. for the rebuild.
Looking for a reliable trail bike that is faster than what I have without sacrificing too much torque.
I have a hmf slip on but it runs the same as stock and it’s also jetted for the pipe. Need help on this I done eveything I know to do thanks in advance
Im trying figer out the jetting on my honda 350x with a high comprshion piston and a dg pipe ,After I gas it full throttle its back fires loud does this mean I’m under jetted
Ok. So my 04 400ex is getting a lot of upgrades all at once and I’m looking for suggestions on where to start the jetting. I would rather start rich and have to lean in out then start lean and blow it up with all the money I’m dumping in it.
The old setup was all stock with a gutted stock pipe and holes in the air box lid. And I think we had the main jet at 165. Not sure but think it was that. And I believe a 42 pilot.
Here’s everything it will be at when done.
Grinded out the welds in factory header. Hmf slip on exhaust. Stock filter with no lid and using an outerwears pre filter. Ported and polished head flowing best possible (ported by a professional). Bored .040 over (1mm) to a 406 using a wiseco high compression piston (11:1). And also installing GT Thunder heavy duty head studs.
It’s been a while, and I’ve come back to make sure she is still running in tip top shape.
So I pulled the plug, and want to know how you guys think it looks.
I’m running a full FMF powercore4 exhaust, and 400ex carb running a 175main and UNI filter with drilled air box.
im running a pro circuit stainless steel header and a big gunevo R series slip on im using a dno jet kit with stage one and 2 jets in it. the directions say to use the dyno jet needle on groove 4 for below 5000 feet (im at 451 feet) then it says to use the dyno jet main adapter dja001 and to use main jet dj118 with an after aftermarket exhaust below 3000 feet an to set the a/f mix scew 3 turns out this dose not work at all iv checked to make sure i did it right over and over iv adjusted the needle height and the a/f mix screw with any combination you can imagine nothing really works any one got any tips? my machine ran 100% perfect be for here a pic https://www.facebook.com/photo.php?f…6626465&type=1
Ok guys and gals this one has me stumped. I was working on my buddies quad that was smoking alot on our ride over the weekend and i was doing a compression test on it and came up good on his. And my quad was right next to it and i couldnt help myself so i did a compression test on mine. My fsm says 100-128 is good. I do it on mine and i get 140………….thats where i try it 3 more times and its 140 everytime. Is it possible for there to be that much soot built up in the combustion chamber? Or would this mean i am high compression or what? If someone worked on this quad they are a magician because all the bolts dont have any marks on them and i would say i am positive it hasnt been apart its so clean. But that high of compression has me stumped. Any info would be highly appreciated!
ok so i just recently got an 04 400ex over the winter. well over the weekend was the first chance i got to really ride it. valves are adjusted perfectly. installed a manual tentioner to fix the wasted auto one for the timing chain that was on it and get rid of that noise. well we went riding saturday and sunday both. now when we left i was full on oil. day 2 i was riding with different people and they were telling me how bad the quad was smoking. so today we did a compression test which held at 120psi so its good. was’nt blowing past the intake or exhaust valves. but it felt like when i was riding that it just had a real lack of power and was bogging. well we pulled the valve cover and the seals looked good so we then pulled the head.
found the head gasket appeared blown in one spot the timing chain was stretched beyond belief. the one timing chain gide was wasted probly from the bad auto tentioner that it had when i bought it. and the cylinder has zero cross hatch left in it as well. the rings were worn out and almost all lined up on the end gaps as well.
so here is where my questions start. the one guy says just go to a 416 high comp which is .080 over bore at 87mm. should i just do that or go for the 85.5 or 86mm over bore options? 85.5 is .020 over, and 86mm is .040 over. and i didnt see an 86.5mm option when i was looking.
and what year crf 450 timing chain is the upgraded chain that will fit? because im going to get that as well. anything else i should really inspect or address closely? it all looked pretty good from what i could see otherwise.
i work in an engine machine shop so im taking the jug and head with me to work tomorrow to start cleaning up.
oh and yes the cam looked great to as well as the rod. looking to start ordering parts tomorrow asap in the day to get it back on the road asap so quick responses would be awesome.
ok so i just recently got an 04 400ex over the winter. well over the weekend was the first chance i got to really ride it. valves are adjusted perfectly. installed a manual tentioner to fix the wasted auto one for the timing chain that was on it and get rid of that noise. well we went riding saturday and sunday both. now when we left i was full on oil. day 2 i was riding with different people and they were telling me how bad the quad was smoking. so today we did a compression test which held at 120psi so its good. was’nt blowing past the intake or exhaust valves. but it felt like when i was riding that it just had a real lack of power and was bogging. well we pulled the valve cover and the seals looked good so we then pulled the head.
found the head gasket appeared blown in one spot the timing chain was stretched beyond belief. the one timing chain gide was wasted probly from the bad auto tentioner that it had when i bought it. and the cylinder has zero cross hatch left in it as well. the rings were worn out and almost all lined up on the end gaps as well.
so here is where my questions start. the one guy says just go to a 416 high comp which is .080 over bore at 87mm. should i just do that or go for the 85.5 or 86mm over bore options? 85.5 is .020 over, and 86mm is .040 over. and i didnt see an 86.5mm option when i was looking.
and what year crf 450 timing chain is the upgraded chain that will fit? because im going to get that as well. anything else i should really inspect or address closely? it all looked pretty good from what i could see otherwise.
i work in an engine machine shop so im taking the jug and head with me to work tomorrow to start cleaning up.
oh and yes the cam looked great to as well as the rod. looking to start ordering parts tomorrow asap in the day to get it back on the road asap so quick responses would be awesome.
