what else to do to 406 for max power?

[ranger400ex1994]

i am going to be building a 406 ross 10:6.1 compression piston and i am pretty sure i am going to go with the stage 2 hot cam. but what else could i do to my motor to get the fullest out of my 406. i got a full system exhast and i still want to be able to run 93 pumped gas. but any ideas.

[K_Fulk]

Major stuff: carb, port and polish, oversized valves.

Minor stuff:degree key, lightend flywheel, get the piston ceramic coated maybe your exhaust ports too.

[hondarider2006]

Spend a little extra $, and get the 416:)

[Quadzilla]

I also say 416. I don't think that a 416 piston is any more $ than a 406. I would also question the Stg 2. Don't get me wrong, I love the top end power, but it left me wanting more in the low and mid range. If you primarly trail-ride, go with the stg 1. If you do dunes, major hill climbs (long, flat, rock free) or do a lot of drag racing, go with the stg 2. I have read that porting and bigger vavles don't help much until you go above a 416 (425 on up). The famous Mickey Dunlop has stated this....

[K_Fulk]

Originally posted by Quadzilla
I have read that porting and bigger vavles don't help much until you go above a 416 (425 on up). The famous Mickey Dunlop has stated this....

It may not make as much diffrence as it does on a 440 but it still helps. And he was asking what to do to make a little more power with pump gas. And they would be there if he wanted to go bigger then.

[cals400ex]

do you guys actually think the 416 would make more power? just wondering. he already has the 406. also, when i bought my 406 piston they said if you had 2 identical bikes one with the 10.6:1 406 and another with the 10.8:1 416 you would not be able to tell a difference in either bike. so, i don't think you would notice it but who knows.

how much of a difference do the oversized valves make?

as for the carb, i don't think you get out of them what many claim. you gain a lot of throttle response but for drag racing it didn't help me much at all.

on the cam, i loved my stage 2 in my 406. however, the top end power was more important than down low. if you do woods riding or a lot of slow riding, the stage 1 might suit you better. you can notice at low rpms that the power band doesn't kick on yet. however, when drag racing you didn't notice this because you were never at low rpms except in 1st and the bike had plenty at low rpms in 1st. i can tell you my stage 2 had a harder hit than my buddies stage 1. the stage 1 gave a nice power deliever throughout the power band. you can tell the stage 2 produces more power though. but, the power range is not as broad as the bike likes to be in mid and upper rpms. i guess that is for you to decide. :)

[K_Fulk]

I don't think 1mm of piston size is going to make much diffrence. If you want power from bore your gonna have to go up a few sizes.

The big valves in the smaller motor your not going to have the torque you would if you had a 440.

But if you had 2 motors same compression same mods but one with a stock bore and one with a 440. The bigger one will be faster but it will still come down to rider ability in a drag.

[Chanman420q]

im also concidering throwing in 1.5mm bigger valves on my 416. Both exhaust and Intake. I do plan on going 440 some day. Maybe next season. But Would i notice any power diffrance with then on my 416?

[K_Fulk]

Originally posted by Chanman420q
im also concidering throwing in 1.5mm bigger valves on my 416. Both exhaust and Intake. I do plan on going 440 some day. Maybe next season. But Would i notice any power diffrance with then on my 416?

I dont know about the exhaust valves never had them. But you will notice a diffrence. But if you don't have a good carb I would get that first.

[cals400ex]

i am debating on only going 1mm on intake and stock sized exhaust valves. i think chef has 2mm bigger but his bike may need it. i have a feeling the +1 intake may be too much for my 11:1 426. i don't know. i will have to do some more reading on that.

[K_Fulk]

The valves should benefit you with that piston.

I would like to see a picture of chefs combustion chamber to see how they got those valves in there, theres isnt much room in mine with just the intake oversized 1mm.

[tdsongster]

I saw a dyno chart that shows the drop in hp as stock carb throttle bodies(don't remember exactly what the part is called) open. I notice the drop in hp from time to time when hitting the gas or coming out of a turn.

They are pricey though...

Just my 2 cents

[cals400ex]

yeah, i am not sure how they fit either. he has a ton of custom work at a very expensive price. i thought he had over 1K in just the intake. that may not even include the exhaust valves. i don't remember exactly.