Is there machine work required for the 416 kit

[kaneman23]

With all of this talk of the 416 kit and XR400 cam I am thinking about doing it. Is this kit completely drop in or will I have to get some machine work done? Also, what are the steps to installing a kit? I changed my own oils and adjusted my own valves but other then that I have never torn into a 4 stroke motor. Is it simple? Does the kit come with instructions? Sorry for all the questions....

Justin

[VegasEx'r]

To answer your first question, yes there is some machine work involved. You will have to take apart the top end & take the cylinder to a machine shop & have it bored out. Most places around where I live charge 50-65 bucks to do that. Everything else is "drop in", but it'll take a while to do the work. I don't know all of the details, since I haven't done this to my quad yet, but you have to remove the plastic, gas tank, carb etc. to get to the top end. Then you have to take the head off, & I think to do that you will have to also loosen or remove the valves, cam, cam chain, etc. Then you can pull off the cylinder & get it bored (have the 416 piston with you at the machine shop so they can match the bore to it). Then you have to reassemble everything, tune the quad (rejet, etc.) & you're set. This kinda sounds like a nightmare to do, but I don't think it's that difficult. Whoever you buy the parts from should be able to help, and you can always post questions here, because there are many who have done it, or are doing it right now. Another thing you can do is take lots of pictures as you tear it apart, that way you can see how it should go back together, and a shop manual will help, too. I hope this long winded reply is of use to you. I ordered the piston & cam earlier this week, so I will probably be doing all of this next week, so if you want more detail, just PM me.

[kaneman23]

Vegas,

I really appreciate the info. Yes, you answered everything I wanted to know. Please let me know when you do the kit. Again, Thank you,
Justin

[oynot400]

Get yourself a manual, it will walk you through the whole proceedure.

[ChadEXer]

While you got the head off go ahead and get it ported and polished too. It makes a difference. Makes the bike even sound better. Im glad I had mine done. I paid $100 to have the full race porting and polishing to mine along with porting a little in the headpipes and the metal sleeve coming from the carb.