406/416 question

[justinh]

do these require new cylinders, or boring of stock cylinders, i would assume so, alteast with the 416 kit, i know the 440 requires the larger cylinder.....

[wyndzer]

Yes anything over the stock piston will require cylinder boring. The 406 is like .040 over stock the 416 is .080 over stock bore and the 426 is .120 over stock bore the 440 does require resleeving the cylinder and then boring to fit the piston depending if you go with a 88.5 mm piston or a true 440 piston which is a 89mm piston.

[justinh]

thanks!
i figured that it would have to be bored but wasn't sure, i guess its because all the 440 kits are advertised with the sleeve and the others aren't.....so i can go 426 with the stock sleeve? how noticeable is the difference between a 426 and 440?

on another note, the guy i bought mine from said that the je piston in it is 11:1 but the other day on this web-site someone said je's were 10.5 or 10.8 if you went with the xr head gasket, i tried calling him last night.. i want to find out,....or i could go look at the box...

[Tommy 17]

406 is bored .40 over and it cost me 35$ to get it done.

[400exJOE]

HATE TO SAY IT BUT YOU GUYS ARE WRONG. UP TO A 416 IS .080 OVER AND YOU ARE JUST BORING THE SLEEVE (NOT A BIG DEAL). IN ANYTHING BIGGER LIKE A 440, YOU REMOVE THE STOCK SLEEVE, BORE OUT THE CYLINDER, AND PUT IN A LARGER SLEEVE THAT COMES WITH THE PISTON KIT.

[400exdad]

I have a friend who has a 425 and another who use to have a 440. You hear folks say that a 416 is a revver and run good without porting. Well both my friends 425 and 440 are/were torque :macho monsters. You have to ride them a gear high all the time. The guy on the 425 just came from a 250R so he's having a difficult time changing. At any rate, I think when you get above 416, porting is in order if you want to rev it. That is just my opinion.

[wyndzer]

Sorry if I wasn't clear enough for you. But boring the "sleeve" is most of the time reffered to as "having the cylinder bored". Thanks for all of your helpful information that you added to the post!!!!!

[Tommy 17]

i got porting wit my 406 400exdad....

[justinh]

HEY!!!
man, i leave for a few hours to go to church and come home and half the board is on my post!! rock on...

anyway wyndzer answered my question in his first post, but thanks for all the other input! i realize now that the 440 kit is a larger sleeve thats cool