Hi i am wondering what kind of hp should i be pulling out after i modd one of my engines.. its a 400ex engine... stock for now.. im sending it out this summer to get the work done.. a 440 kit 13 1/2:1 compression,, web cams, port job, 1mm over size intake valves, k&N filter, FMF powerbomb header with FMF silencer,, 6mm stroker crank,, so that would make a 460 or a 470 i think,, weighted flywheel, Big gun rev box.... then what ever carb i need i will get.. i will just call carb parts wearhouse and they will set me up.. thats about all i can think of for now.. im looking to run with the 450's or even out run them.. mainly the yfz... would this put me where i need to be?? thanks.. i think the 400ex is 30hp stock?? or 28hp somewhere like that....

 

stock 400ex is like 25-26hp....

 

reading your post leads me to think that you should learn more about motor builds.
It's not that your doing things wrong, but rather there may be better ways.

Whether it'll run with the 450's is another issue.
Your going to spend a ton of money on the above. It may be better to sell the 400 and get a 450 (TRX).
Another issue of stroking and the 440 kit is reliability.

TCracingengines.com
Tom is a 4 stroke king. He may be able to give his opinion.

Unless your only drag racing, you need suspension first to go faster.[img]i/expressions/face-icon-small-wink.gif[/img]

 

I have the suspention and A-arms.... bought those couple of months ago.... im buying the 400ex for 600 bucks... and just want to spend a quick grand in the engine and proformance parts..... so i got total for 1600 bucks to 2000 and have a mean bike... I dont want a 450.. just because everyone and there granny has one!! I know everyone has a 400 also but i havent seen many of them 100% tricked out.. like plastics engine A-arms and suspention... so this will be something that i take pride in not just go to the dealer and spend 6000 on a stock bike... so do you understand my point?? I am looking for a fairly reliably bike to build... i just dont want to be replacing everything every month... every year is ok with me.. I do the regular piston change and valve change and stuff like that no problem...

 

I see your point. [img]i/expressions/face-icon-small-smile.gif[/img]
Did you get a quote for the 440 PLUS stroking it? 1000 seems low for all that work.

 

Yes i can buy the 440 kit with a 13:1 compression piston for$180... have the head ported and I buy the over sized valves for it and have them put in by the same place... its a local shop right down the road i go 2.. there only gonna charge me 80 bucks for all the labor... then I order my crank for $550 i think... i will install that.. along with a weighted flywheel.. and clutch... also the cam is Around $200.. it all came to be around 1500.... bucks thats with carb and filter and pipe... so i cant really complain.. I just hope it holds up... Im thinking about getting a Z400 also and just putting a port job PIPE and filter and 440 kit on it.... IDK yet...

 

I see this is about 1 month old but i came across it searching for something else. first I got a question on if you finished the build yet and what carb you went with and how happy with it are you.


2nd if not, my girl has a 04 YFZ, ist got a K&N, jetted with DRD race pipe, and one tooth down up front. I was riding a 460 big bore stroker, P&P, hot cams stage 2, FMF powerbomb and FMF powercore4, dirt digger clutch, also one tooth down up front from stock.

we drag raced in moses lake about 6 times, always wound up with the YFZ about 2 lengths ahead, we even switched bikes and made a few runs to check it out and again the YFZ was a couple lengths ahead. YFZ had ITP sand stars, ones without the secondary paddles inside, and honda had geckos. it stil has a stock carb though so Im sure its starving that engine, I just worked out a deal with the guy to purchase this bike and Im gonna put on a FCR from a YFZ I think, guy who built the engine reccomendeed the carb.

 

oh also I personally wouldnt put a rev box on a BB stroker, just wouldnt want mine trying to turn that fast, of course you dont always have to hit the limiter so if youre careful I guess it could be ok.