CK1999_400ex

it probibly need a set of rings ... i have a 400ex motor that u use for racing and hill climbing that has done the same thing several times ... the oil ging looses it's tension and compresses into the oil ring grove on the piston ... i bought a heavy duty set of rings and put in mine and it lasted twice as long b 4 it needed rings again..the 400ex runs hot ... even from the factory and the stock jetting is a little on the lean side in most cases.. a little jetting will help with it running as hot ... i have 2 400ex's and 4 extra motors that i keep ready for a swap incase i need 1 ... i ride my machines pretty hard .. if the bore of the machine your are talking about is in good shape i would re ring it and see how it is .. also while u have ot apart you could put valve seals in it fairly easy .. an kill 2 bird with 1 stone .. so to say ... lol... if you have any more quastions about the 400ex just ask .. i have rebuilt many of the 400ex motors and have come across all kinds of things with them ..

the local sheriff's department has atv's they use at the fair grounds and they have also used them at local areas that people ride at to stop them and check to see if the atv's are stolen.. they have even used them when looking in the local river bottoms for drugs that are being grown ...lol

i have a 250 R honda that is a 1987 with over 5000 hours on it and who knows how many miles ... and it still looks and runs like new ... but maintace is KEY in the life of an atv ... im a mechanic and i take care of my toys ..... the pic of my 400ex under my name is a 1999 and it has the newer plastic on it .. but the original plastic looks as good as the new stuff .. and my atv is not beat up .. and i maintain it on a regular basis ..

i have a 2002 rancher 350 es that has had several shift problems and it usually leads to the angle sensor or the electronic shift actuator i have had these problems several times and had to replace both of them ..

i use rotella 15 w 40 in my honda 400 it lasts longer (dosent get thin as quick) as most other oils i use ... i have friends that race also and use it in every atv they have and race ... 1 friend is even sponsered by another oil company and he puts the oil from his sponser in his haul trucks motor and refills the containers with the rotella 15w 40 and puts it in his quad instead of the sponsers oil ... and most of the guys that i ride with and race with use the rotella

sprocket size changes will give you more grunt in the lower end but you will lose top end speed ... or vise versa depending on the sizes you use ..and its cheap ...

i know that you can get different bearings that will alow you to put the banshee hubs on the fron of the honda .. i have a friend that has them on his 400ex cause they are lighter than the honda hubs ... he uses his quad for drag racing ... i dont know the sizes of the bearings or if the year of the hubs matter but ive seen it done ...

it could also be the neutral lite sensor ... mine did that after some hard landings .... i replaced it and havent had a problem sence ...

the curtis sparks x6 makes the best torq an hore power boy far .. but they are very pricy... i have the white brothers promeg on mine with the race turn down tip on the muffler ... and it makes about the same torq an hp as the sparks .... and it's also a polished header an i powder coated the muffler can red to match the plastic ... it looks real good ...

i have had the same problem on my 400ex and i put some rtv sylicone on the threads and it keeps the lock nut from backing off ... and the spaces tube in the housing can also cause it to move if it has some ware on it ...

this is my pic of me jumping off a cliff at a local sand & gravel pit ..