anyone heard of a 620 stroker on a 400 ex?

[arsinal310]

im just wondering if this guy i raced this sunday was full of it he said he had 620 stroker on his bike, that it was built for stadium racing or something like that.if not what's the biggest he could go on that thing?bye the way it's a 400 ex it sounds like a beast really choppy too, but he couldn't keep up.:devil:

[gcart2]

i no a guy with a 460... it was a 300ex tho :blah:. it can be done... just a lot of work

[vett_09]

I've never heard of a 620 kit for the 400ex. The largest I've ever heard is FST's 500 kit. I would say it's BS because I don't see how the engine would hold together. It's air cooled, and to bore out that large would leave the sleeve too thin.

That is unless it's a hybrid.

[Acid Motorsport]

I believe 500cc is the biggest you can go. I have a FST 500EX myself.

[vett_09]

Originally posted by Acid Motorsport
I believe 500cc is the biggest you can go. I have a FST 500EX myself.

How well does that hold up? What kind of problems have you had with it?

[Acid Motorsport]

Well I did everything to it for cooling so that part is good but sometimes when I ride at high speeds for a while the valves float a little and I lose power. Then I just give it a break for a bit and it's ready to go again. So it's a good reliabe kit by far, some of the 440's I've seen don't hold up as good as this kit does. But make sure (if you ever plan on getting this kit) to go for very stiff valve springs.

[REDRIDDER]

500cc ex man can you tell me a little about that beast i seen it at fst before and wanted it but i got the 426 kit instead.How much did your motor work and machine work come to.Also how long have you owned that 500ex?has it proven to be reliable does it over haet much and how much hp = tq does that put out.thanks

[400exrider707]

As far as I know, 505 was the largest EX ever made... and I think that even that size was disupted heavily. Ask chad502ex, he would be able to tell you

[Acid Motorsport]

Well I did this machine as a full on project. The 500 kit is just a small part that I had done to the bike along with a very long list of other handling, suspension and cosmetics. And I don't really care how much it cost so I threw the receipt out a long time ago. It's a great machine that I don't plan on getting rid of any time soon. I just remember spending a total of around 9k on the machine. I can list the stuff I bought for it if you want.

[REDRIDDER]

Originally posted by Acid Motorsport
Well I did this machine as a full on project. The 500 kit is just a small part that I had done to the bike along with a very long list of other handling, suspension and cosmetics. And I don't really care how much it cost so I threw the receipt out a long time ago. It's a great machine that I don't plan on getting rid of any time soon. I just remember spending a total of around 9k on the machine. I can list the stuff I bought for it if you want. come on give some insite on your quad speed,accelleration,power,ect..im realy interrested.

[REDRIDDER]

post pics and list you mods thanks.

[Acid Motorsport]

Power is very strong down low and midrange power is good to. It just isn't a top end screamer, a '06 and up HRC 450R will beat my quad so its not amazing. I'd say it puts out around 48-49hp, but the EX is not made to build amazing hp it's all about torque. Never had this machine dyno'd cause I don't really care, so I do not have any numbers to give anybody. And lol........ I don't have a digi cam to post pics, so I'll have to describe how it looks. It has Maier orange plastic on it, DWT shamrock wheels with ITP tires, Works G series front shocks and a Ultracross rear, Tag black bumper, +1 taller steering stem, Renthal bars, and a TC shorty exaust. Plus much much more.

[REDRIDDER]

Thanks alot