400ex valve seal???

[pepshocks]

my 400ex smokes when its cold but after 2 or 3 mins it clears up. is this a easy job? helpful ideas would be great. also is a 40 pilot jet good enough for a stock motor, very hard to start when cold, is a 42 too much?

[honda400ex2003]

imo without the proper tools it isnt an easy job. I dont have the proper spring compressor and such to get the valve springs off though. if you do, then by all means it isnt bad. just undo the head and take everything off of it. I got the springs off, just couldnt get them back on without a good compressor.

on the 42 subject, theres alot of debate. I say that it is fine but some say that it is too rich. I say that putting a 42 in and going to around 2.5 turns out is fine for winter.

steve

[pepshocks]

Turn the a/f screw out?

[honda400ex2003]

if you want to... turn it out the 1/4 turn. i would try the 42 and see how it does without changing the f/a though i suppose. a 1/4 turn is nothing really. Do you already have the 40 in there or the stock 38? if you have the 38 try to turn the f/a out to 3.5 turns and see how it does for the winter. it might be enough to help it out a bit with the choke on for the cold. this would save some money also since you wouldnt have to change the jet. the 42 is also nice for summer though too if you turn the f/a in a bit. it is really up to you as to what you want to try and how you want to set it up. there really is no perfect way to get it dialed, it is how your engine responses to what you do.


steve

[hocman123]

if u have a large c clamp and i piece of gas pipe the u can make ur own tool to remove the springs. u just need to cut i little window into each side of the pipe so u can work. i have used this 2 times and the hardest part is getting the springs back on but once u figure a good method it goes ok.

i am about to do this job for the third time so i just got the right tool from rocky mountain is not that much and me and my friends seam to need it often

[CJM]

Yep, we used the tool I made with some gas pipe. Hardest part was keeping the clamp on it and getting the little half moon clips to go in right. Buy the tool, its worth it..

[rubbersdown]

You can make one out of some pipe but if your going to be working on 4 strokes just go buy one. They arent expensive, if you want one specifically for smaller motorcycle/atv heads you can get one for like $30. If you dont have any small motorcycles or atv's then just buy a standard spring compressor used on cars, the 400ex head is big enough that it works no problem. I got my craftsman one at sears for like $18. Well worth the money.

[rubbersdown]

Originally posted by CJM
Yep, we used the tool I made with some gas pipe. Hardest part was keeping the clamp on it and getting the little half moon clips to go in right. Buy the tool, its worth it..
If using a cut piece of pipe and a clamp, the keepers (half moon things) can be a super ***** to get in! Little trick to use next time. Coat the keepers in Vaseline or any type of grease. They will then stick to the valve and you can put them in place very easy. The first time you ride the bike the vaseline or grease will just melt away and blend with the hot oil and cause no problems sense its petroleum based anyway.

[pepshocks]

Originally posted by honda400ex2003
if you want to... turn it out the 1/4 turn. i would try the 42 and see how it does without changing the f/a though i suppose. a 1/4 turn is nothing really. Do you already have the 40 in there or the stock 38? if you have the 38 try to turn the f/a out to 3.5 turns and see how it does for the winter. it might be enough to help it out a bit with the choke on for the cold. this would save some money also since you wouldnt have to change the jet. the 42 is also nice for summer though too if you turn the f/a in a bit. it is really up to you as to what you want to try and how you want to set it up. there really is no perfect way to get it dialed, it is how your engine responses to what you do.


steve is the a/f screw right buy the choke lever? any pics? im sorry i never had this problem and never played with jetting on these

[honda400ex2003]

it is the flat head brass screw toward the front of the carb on the bottom. It is in its own part just about centered on the carb in front of the bowl in a cylinder looking assembly. if you have a 05+(i forgot to look in your sig) it isnt really changeable easy since it requires a D shape tool to change. the older ones are flat head style adjusters though. I dont think i have any pics of it on my imageshack account but i will look quick. it really isnt a problem to leave it alone or adjust it. some people adjust their f/a every time they ride, it is really just a fine tune type of adjustment but is mostly concerned with the pilot circuit.

check out a schematic of it on Bike bandit or service honda before you dig into it for an idea of what you are working with.

steve

[Scro]

You might as well replace the rings on the piston while you have the head off. Worn rings could also cause it to smoke on start up.