more low end 400ex

[stevo3176]

I bought a used 400ex and it runs like no other 400 I have owned. The bike had a bunch of after market parts that I sold to make stock again. I also changed the front sprocket 14T to make it a torque monster. I had not run it since i bought it and replaced the parts to stock. Anyway I put it all together and take it for a ride. It isn't torqy at all to my surpise. It only rips from half to full throttle. I mean it pulls up 1st and second gears no problem without any effort from me. Anyone have any ideas like jetting or such that can get more low end power out of this bike?

[boricua]

why did you remove the mods that came with it? anyhow, put the 15t back on. it wont give you more torque per say, but it will move you forward sooner with out pulling up the front end so much. a stock ex will still hang the wheels pretty easy. can you explain exactly what performance youre looking for?

[stevo3176]

I want to have a woods machine so i want the power really to be on the low end. I don't need top end speed. I have had stock 400's before and the power seem to be comeing hard on the top like a two stroke. If I mash the throttle going slow is tries to catch up and sputter which is uncharacteristic for a 400. The bike has stock jetting but something just isn't right. Oh I took the aftermarket stuff off because I need to be quiet and honda reliable. It wasn't a race machine just a loud one.

[underpowered]

does it have a cam in it? if so that would cause it to run like it does. my 400 with just a cam ran great on top wut had little bottom end. once i added a pipe it brought he low end back.

[below100hz]

i have a 426 kit with a stage 2 cam, k&n, dj170, wbR3 and head pipe and i have deffinatly lost alot of low end with the cam, i cant creep up steep dirt hills in 1st gear anymore it just boggs out so im interested in a way for me to gain some lower end back

[boricua]

i dont have a cam, not yet. according to others it sounds like you might have one. but you said youve ran stock 400s before and they still didnt have enough bottom end, hmm, my stocker respectable bottom end, maybe there is a problem. also a higher compression piston could give you a bit more snap at the bottom. not sure if you wan the front end to pop up super easy, if so you could run the 14t with the higher comp. piston.:(

[bmurray]

sounds like a cam. I think a larger mainjet will take away a bit down low. Check that it has the stock size. You can check the cam with a test or travel indicator on the rockers. Compare the lift to stock dimensions. good luck.

[stevo3176]

Hmm never though about a cam.. Does makes sense I was wondering if it ha been punched out or something but a cam makes more sense. When i got the bike it was a fixer upper that someone got as a trade for a car so I have no history on the bike. Would an after market cam sound louder (on the valves) than stock? I do not notice it making any more noise. I do like the low end power on a stock 400 but I meant the one I have now hits up top like a 2 stroke.

[nicktrx400ex]

i ve got crazy low end on my 400ex with out any motor mods done all i have is whats in my sig i can do a wheelie in any gear any time right now and no im not lying i also have a 15tooth front sprocket on so tell me what ya think.

[stevo3176]

Like I said I know a regular 400ex has goobs of low end power. I have had 2 already that were just fine. But the one I have is now it only has good power from 1/2 to 3/4 throttle which in uncharteristic for a 400. Also the power that it has up top is way more then any 400 I have ridden. If i did not know what bike I was riding I would swear it was a 450r and not a 400ex.

[sixer3]

does it smoke at all even a little at any time?....small amounts of blow-by could cause low rpm power loass but at higher rpms less noticable with small amounts of blow-by....a cam would also creat an effect of no bottom end power.....especially if the duration is too aggressive for your stock motor....not all cams are going to make the notorious ticking, but yes in comparison to a stock motor the valve train should make a bit more noise due to the higher lift, should be enough to be noticable if you compare it to a stock motor...hotcams would be noticable even if you didnt have a comparison...heh