if you have a 416ex please tell me your mods to the last detail including piston and bore, cost etc....jsut put mine in the shop for a 416 kit and wanted to compare...oh, and what have you raced, and how does it compare to the 426 and 440 and banshees and r's etc etc....thanks!!!!!

 

87mm JE 10.8:1 lightened piston. Mild head porting, polished combustion chamber, XR cam, ported stock header pipe running thru a stock silencer (soon to be a modified stock silender), XR250 CDI box, modified air box, and properly jetted.

Haven't done much drag racing, but have done some XC racing. With the stock exhaust, most everyone that sees it initially assumes it's stock, after they see it run and/or race against it in an event, I get many comments, so something is right.

 

Hey gabe,
Not to be nebby or anything, but how much was each of your parts? and the total price?

I have my whole engine apart right now to get my spark plug gap heli-coiled...

My piston top and head is all black and crap.
is that bad?? looks bad to me...

anywayz, I was thinking of getting a few mods, but it can't total over about, 250-300.

Will i get any performance gain with just and Xr400 cam?, is that possible? or will i have to get special rockers or something. Also, is it possible to run a .20 over JE pison and cam alone? or will i have to get something hardened, ported, etc.?

PS: is porting expensive, and what exactly is it.

ALSO, "ported stock head pipe" does that mean you polished off the nubs on the inside of the stock header? or did you hit the inside of the engine with the dremel too?


Sorry to bother you that bad, lol, but hey, it's a question forum.

 

What do you mean by polished combustion chamber? I was specifically told to leave the intake rough to help atomize fuel better due to a carbs low fuel pressure. Or are you talking about something different?

 

He port matched the intake and exhaust due to casting errors, and yes, after my crying, there have been several people who look in the intake side of their exhaust pipes and see the weld bead that takes up to 10% of their tube diameter and diegrind it out so it is all flush. The piston is about $160 with all new gaskets and the cam is about $120 from servicehonda.com.

 

How do your 416's compare to others?

Gabe you said you do MX racing. Well what do you race and how does it compare to them?

 

Yes the intake path is left rough cast, but the combustion chamber itself is lightly polished & smoothed (not that it is very rough to begin with)....

 

Not to be nebby or anything, but how much was each of your parts? and the total price?

I spent a little over $400.
$100 machine work - including head work
$130 Piston & rings
$110 XR Cam
$80 XR250 CDI box
$25 gaskets

My piston top and head is all black and crap. is that bad?? looks bad to me...

My engine was pretty clean when I took it apart. But I took a friend's apart and it was like you describe... That bike was run on 10w40 oil for most of it's life and was smoking. When we switched it to a heavier weight it quit, but we disassembled it shortly thereafter. Your black "crap" is probably either too rich a mixture or oil burn....

Anywayz, I was thinking of getting a few mods, but it can't total over about, 250-300.

I would buy:

$165 GThunder cam
$130 JE 10.8:1 87mm piston
$25 Top end gasket kit
$30 Machine work - bore cylinder
----------
$350 Total

You could subsitute an XR cam to get you back down to about $300... The XR cam does not have the duration at max flow the GThunder cam does.

If that's still too much, just go with the JE Piston, that's probably where most of the difference is.

Will i get any performance gain with just and Xr400 cam?, is that possible? or will i have to get special rockers or something. Also, is it possible to run a .20 over JE pison and cam alone? or will i have to get something hardened, ported, etc.?

Yes, you can run any of this stuff by itself. They work better together, but if I were only going to do one thing, it would be the piston. Using either the XR cam or the GThunder cam, you should be all right without hardening your rockers. Head porting is not necessary, but I would go ahead and do a little port matching while you are in there, that's a pretty easy task.

PS: is porting expensive, and what exactly is it.

Typically, it is not really necessary on a mildly modified 400EX... Even on a full race engine I've been told it's only good for about 1hp. Mild cleanup work is best for the EX, and that isn't very expensive.

ALSO, "ported stock head pipe" does that mean you polished off the nubs on the inside of the stock header? or did you hit the inside of the engine with the dremel too?

Yes, we cleaned the weld out of the pipe. We also did a little work to the exhaust port side of the head....

 

Well, I haven't been to the MX track since my mods... However I have raced 2 XC races since then, I haven't had anyone run away from me yet. I have had many people comment on how well the bike runs & ask what's been done to it (people assume it's stock at first due to the stock pipe).

It's nothing spectacular, but it does run good, has a very nice powerband, and is very competitive in the State series races I run (in the most recent event I won the Pro class as well as the overall, there were about 65 total entries. I was the only EX in the Pro class of about 12 people). This is how they should run stock....

 

hey thanks alot gabe, you helped me out alot... I am probably gonna go for uor recomondation. thanks again