426 Big Bore

[400exhauck]

Ok, i have an '05 TRX400ex and am very pleased with the performance... I have put on a K&N Air filter and removed the lid of my airbox... i have also put on a dynojet kit (3rd groove, 165 main jet)... My next step is a full HMF exhaust, and then i want to bore it out... I have heard that the 440 kit is a less reliable setup, and i dont want to fork out the money for just a 416... so i figure i might as well go with the 426... i have looked into a wiseco piston, hotcams stage 2 cam, but what would i need to bore out my stock sleeve? if anyone has any info or a tutorial or a site that explains everything about this upgrade, i would appreciate it... thanks!

[RiderTRX400ex]

machine shops gutta bore it...

[spazzy973]

why go with the last bore on a stock sleeve stick with the 416 it has alot of power and you still have another bore when you fry the rings or have other engine trouble

[400exredrider]

yeah 416 and 426 you wont notice much of a difference, if you cant afford a bore go with a high comp stock bore a cam maybe a port job and a carb with that HMF full.

[416mx]

Originally posted by spazzy973
why go with the last bore on a stock sleeve stick with the 416 it has alot of power and you still have another bore when you fry the rings or have other engine trouble

YOU WILL LIKE THE 416, MAYBE IF MONEY ALLOWS ON NEXT BORE JOB GO WITH 426 AND PORT THE HEAD, YOU WILL REALLY LIKE IT, THAT'S THE WAY I DID MINE>

[Natertot426ex]

C&D sells a sleeve that starts out at a 426 and can go from there. Contact them about it.:D

[416HiRoller]

I really like the power of my 416. It is really torquey and it also has a lot of upper end power.

[TC426EX]

Originally posted by 416mx
YOU WILL LIKE THE 416, MAYBE IF MONEY ALLOWS ON NEXT BORE JOB GO WITH 426 AND PORT THE HEAD, YOU WILL REALLY LIKE IT, THAT'S THE WAY I DID MINE>

Theres no difference in how much it costs to do a 416 or a 426. If you can afford the 416 you can afford the 426

[prepracing]

I think the machine shop has to bore it .80 for 416 and .120 for 426 ( that is unless you have a cylinder boring machine). But you will need to take them the piston and rings along with your jug so they can mic everything to be sure on the bore size. Also whoever says they can't tell much difference in a 416 & 426 to a stock one with highcomp piston must have been riding a sick one. Its true people that just bore stuff out and don't do anything else to compliment the bore( like porting&polishing the head, which by the way is a major powergain mod when you do those bores or if you stick with the stock cam instead of an aftermarket) will not feel very big power gains. But I also understand that some people only do these bores because that was the only option because their cylinder is worn out. #1 thing to remember, always consult a quadmotor buider or highly recommended quad shop before starting into this stuff. Because theres lots of money that can be wasted if you don't start out correctly !!! Just my opinion though !

[400exredrider]

i was comparing the 416 to the 426 not 416 and 426 to stock 416 and 426 to stock is night and day

[416mx]

Originally posted by TC426EX
Theres no difference in how much it costs to do a 416 or a 426. If you can afford the 416 you can afford the 426

This is true as far as piston cost the 426 might be a couple of dollars more but close. But as was said before there is no need to go all the way out on your first bore and have to buy a sleeve on your second bore , plus another piston. Porting , a cam, and a pipe along with the 416 will really wake it up big time.:)