HI, I am going to be helping my friend rebuild the top end on his 400ex and he get some upgarde's for it like a cam and a high compression pision and I think that is it. any of you have a tip's for me?? I everhad a 400ex apart before. I think my friend need's some help becuase he was talking about push rod's Idunno where he got that from!! LOL thank's

 

They run the forced air injection accelerator. You'll find them between the combustion enhancer and lythium crystals. [img]i/expressions/face-icon-small-happy.gif[/img] lol!



J/P. He may have been thinking about hardened rocker arms? I don't know.

 

if he is talking about push rods, he is in horse crap over his knees. first thing, he NEEDS a service manual for a 400ex. this manual will take him thru step by step. he needs to read all sections describing the processes before tackling the job. he needs to make sure he has all of the tools required. he will need sockets, rachets, torque wrench, allen wrenches, lock tite, mallet, assembly lube, new gaskets, oil, oil filter, etc.

a few good tips:
1. don't drop the timing chain in the bottom end. tie it up with a string.
2. drain the oil first, otherwise some will spill out. you will still get some coming out of the head, but not as much if you tip the bike on its right side which will help the oil drain to the bottom end.
3. if your running a hotcam or another that doesn't use the decompression assembly, you will NEED to remove the spring and plunger in the head. it may be flying around in the head if you forget to remove it.
4. have a spare person there. for the first time, a few extra hands help out a lot.
5. watch out for the dowels in the engine. there will be some under the head cover, head and cylinder. it will say this in the manual but you don't want to drop these in the bottom end either.
6. when re-installing the timing chain tensioner you don't need to make that tool it says to in the manual. you can turn it with a really small flat blade screwdriver and hold it in position when tightening up the 2 small 8mm bolts that hold the tensioner on. after tightening them up, pull the screwdriver out and you should hear a snap.
7. wash the bike off extremely well before going into the engine. you don't want dirt to get in.
8. spray the new cam off really well with a contact cleaner. even some of the best cam manufacturers don't remove all of the shavings off the camshafts.
9. coat your rockers and new cam with assembly lube.
10. remember to adjust your valves after you have the bike back together. remember, your clearances will more than likely change with the new cam. contact the cam manufacturer for the clearances.
11. dump a little oil in the valve cap holes after you have the engine back together. this way the the top end has oil immediately instead of the second or two it takes the pump to force it up there.
12. remember to add oil and a new filter. a new engine won't last long without oil.
13. rejet the bike!! more than likely your jetting will lean out. this is not good, especially when breaking it in do the the extra heat.
14. move at your own pace and have fun.

 

ok thank's Yea he need's help, by the way what is a rockervalve?? lol I think he was talking about rocker arm's,, But anyway thank's I will see if he have a book..

 

i would assume he means rocker arms too. certain cams require hardened rockers. others don't. you need to check with the cam manufacturer on that.