416 bore kit. questions

[2007TRX400EX]

I have been reading about the 416 bore kit, and i want to know every thing that i need to do to my quad in order to make it run. what are the necessities in doing this, will this mess up the 400ex's know reliability. I would appreciate any help at all.

Thanks

James A

[honda400ex2003]

well the least amount of stuff you will need is a piston kit and a gasket kit also a bore to install the piston. you may want to go with a cam to help out the performance of it along with going to something like 11:1 compression and a stage 1 or 2 cam for better performance in certain areas. otherwise you can add an exhaust, to the mix also with an hd cam chain for added reliability along with valve seals while you have the head off since they are prone to wearing out. otherwise it is a reliable build when done correctly, I have had mine for well over a year and know a ton of guys on here with the same setups and like it alot. I like my setup in my sig for power with the stage 1 being for low end and mid and the stage 2 for more mid and top. this is up to you. you could get away with right around 500 bucks if you find the parts on ebay or something and do the install yourself. steve

[2007TRX400EX]

Thanks. Would it be worth doing the instilation myself? I feel as if i would beable to do it. what dose changing the compression due, in terms of reliability. would it be worth running stock compression or would it be a waste of money to do without bumping up the compression? Thanks, James.

[CarGuy7a]

More compression = more power.

Like honda400ex2003 said when you bump compression up, you'll want to go with a cam so it will breathe correctly.

Higher compression with a stock low opening cam just wouldn't run right. Don't get me wrong it "would" run but not to it's full potential.

Also higher compression will require you to run higher octane fuel. I believe 11:1 is still good for pump 92 or higher, or you can run 100 - 110 octane race fuel. Someone correct me if I'm wrong.

If I was doing this build I would definately go higher compression than stock. That is where you will see the biggest improvement is in your compression.

[2007TRX400EX]

Thank you, what changes would i have to make to my card, im running a 146 main dyno jet. with a t-4 and a k&n.

[TURBO-530R]

go with 11 to 1 get a stage 2 hot cam as you will have the cam out they are cheap on ebay and a 150 or 152 main jet.

[2007TRX400EX]

i would go with a stage 1 for low to mid range, i ride woods trails and sand. what about going with just a high compression piston and no bore? or is that point less? hb a 406?

[bkelley]

What exactly are the octane needs of the compressions? I thought anything under 11:1 was 92 pump safe and anything over needed high octane fuel. Is that correct?

[Wheelie]

Originally posted by bkelley
What exactly are the octane needs of the compressions? I thought anything under 11:1 was 92 pump safe and anything over needed high octane fuel. Is that correct?

In theory, yes. But that's not always the case. Some people experience pinging with 11:1 on pump gas, some don't.

I ran my setup a couple times on pump gas without any pinging (this was before I advanced the timing) and my compression is nearly 11.5:1. The cam makes a big difference in whether or not a marginal pump gas build makes the grade or not.

[bkelley]

So, would I be safe running a 10.8:1, stage 2 and maybe one of your keys with 92 and the occasional 92/100 mix? Not trying to thread jack here, just had a quick question.

[Wheelie]

Personally, I wouldn't attempt to run pump gas on a 10.8 or 11:1 engine with the timing advanced.

As I've stated before, 100octane for 11:1 with one of my keys.