Finally ready for the 426!

[yub350]

Hey guys im going to start working on my 400 and turn it into a 426. The only problem is I don't know what parts to buy. Im am going to have a mild port and polish done to it. Looking to still use pump gas on it. So I really just need help with like what piston, cam, hardware, gaskets, and anything else i need buy and that will be the strongest and most reliable. My other question is can I still use my stock carb? The bike is an 05, so i think the carbs a 38mm. Also im currently running the stock pipe on it with a White bros slip on, should i look into a new header pipe? Sorry about all the questions, but i really apprieate(SP) the feed back. Thanks

[TC426EX]

If you want to use pump gas still, youll need to buy an 11:1 88mm piston. You can get it bored out on the stock sleeve, so youll just have to pay for the boring. As far as a cam, Id at least go with a stage 2 or 3 hotcam. If you want to spend some more money you could look into one of the TC, Sparks, HRC, or Web Cams, some of which require hardened rockers + heavy valve springs.

Youll want to add a CRF450 cam chain for 25 bucks for added reliability, as well as a set of GT Thunder HD head studs for 60. As far as your carb goes, it will be fine. I used the old stock 35.5mm carb w/ the choke removed for a little while before getting the FCR. An 8-plate clutch conversion like Sparks sells would be beneficial to you as well. Its just over 130 bucks and will really help with the extra power. Finally, youll want to look into selling that slip on and getting a good full exhaust of your choice...With these mods and the porting youre getting, you wont recognize your bike when youre done...

[yub350]

Thank you for the reply. What brand of piston would you recommend.(wiseco, JE)? Also as for cooling, should i put on a bigger oil cooler and if so who sells them. thanks

[400exredrider]

JE or Ross

[TC426EX]

Wiseco makes a good 11:1 piston, and is usually cheaper than the other brands. In any event, JE and Ross are also great, so just go with whatever you can get the cheapest. As far as cooling goes, I added a 4 stroke tech auxillary cooler, which wasnt much money and it helped alot. It does require you to drill and tap your rocker and clutch covers to re route the oil flow. Worthwhile mod if you have the skills to do it, or know someone who could do it for you...

[yub350]

I was thinking of doing that and putting in another cooler, but i just wanted to see if theres an easier way. Like just getting a bigger cooler or bigger oil tank. By the way, where did you get the cooler at? thanks

[400exredrider]

he got his from Mickey Dunlops Four Stroke Tech

[tdsongster]

Does four stroke tech even have a web site anymore. I was thinking of doing this mod to my 400ex.

[yub350]

Hey TC426EX or anyone else, I was looking for a site to buy a JE piston at, do you know of any? Thanks

[TC426EX]

Originally posted by yub350
Hey TC426EX or anyone else, I was looking for a site to buy a JE piston at, do you know of any? Thanks

Got mine from Legacy ATV

[cals400ex]

Originally posted by tdsongster
Does four stroke tech even have a web site anymore. I was thinking of doing this mod to my 400ex.

he has a new one:

http://www.fourstroketech.net/

[FoxRacing81]

C&D can get you a full 426 Kit with JE or Ross piston 11:1 compression that comes with piston, rings, sleeve, and top end gasket kit for 245.

[yub350]

Thanks for the replies, the one from C and D is a really good deal. But i thought i don't need a new sleeve, I can just bore my stock one out.

[FoxRacing81]

C&D may have a different deal that doesn't include the sleeve.

Just curious, but if you bored your stock sleeve to a 426, would there still be a lot of sleeve left? or would if be like paperthin?

-Justin

[cals400ex]

boring to a 426 is a hair over the limits of the stock sleeve. however, most just do it. there is no way i was going to just for added insurance. but, you can do what you want. you can buy everything from C&D, you don't need to buy a sleeve if you don't want one. just tell them what you want.

[Dave400ex]

If you go with the 426 it might be smarter to just go ahead and get the different sleeve. Is it 100% needed, maybe not, but it's best to do everything the best and right way the first time.

[yub350]

Thanks for info guys, i'll probably go though c & d and get there kit.