440 big bore with everything else stock. How does it run?

[WeTDrEaM]

Was just wondering how a 400 ex would run with just a 440 big bore and nothing else done (stock exhaust, head, etc) except just carb tuning. Rebuilding a ex that needs a new piston and rings but wanted to upgrade...

Thanks

[ilpadrino113]

you wouljd definitely feel an improvement, but the the improvement would exponentially increase with the addition of a pipe, carb and rejet.

an upgrade in gaskets, head studs and cam chain would not gain any hp, but it would make yer bike a hell of a lot more reliable

[troutman561]

Yea without HD studs your going to blow head gaskets left and right..

[DOHC]

Originally posted by troutman561
Yea without HD studs your going to blow head gaskets left and right..
Not true i have stock studs and my motors is 2 years old without any problems.

[PismoLocal]

IMO If you move to a 440 with a stock compression ratio I don't think you will have a head gasket issue as long as you use quality gaskets. However if you plan on moving to a higher CR than HD studs should be a consideration. Its up to you. There many people that build 440's with out HD studs and have no problems at all. It seems that blown head gaskets are the problem most run into with there 440's. I had HD studs put on mine when I re-built because I wanted mine to be as reliable as possible.

As far as the 440 kit with no other mods I can help you with an opinion on that . When I bought my quad all It had was a 440 kit with no other mods except an R-4 slip-on, jetted carb and a K&N airfilter. It was a faster out at the dunes acceleration wise compared to my buddies 400ex that had a full system exhaust and K&N airfilter. It wasn't a night and day difference though. Once It needed a rebuild I installed HD Studs, CRF cam chain, 11:1 piston, Stage 2 hotcam, rebuilt head, yoshi fullsystem, 450r carb and a goldenwest cycle CDI. The difference was phenomenal. It didnt even feel like the same motor.

I have had my 440 for almost 3 years now and i have never blown a head gasket once.

[WeTDrEaM]

What compression ratio should I run on this engine to keep it reliable and on pump gas? All I'm going to do is the 440 bore possibly with a stage 2 hot cam and thats it aside from jetting the carb. While the engine is apart I may just "freshen up" the head but no porting or mods just a regrind and seals. Quad is an 03 so I thought that would be a good idea from blown the top end out with the new bottom end.

[ReconRider25]

11:1 is highest youd wanna go on premium pump gas. (91) also highly reccommend an exhaust for the 440 to help reach its potential power wise

[79400ex]

I won't go with a 440 if you want to stay stock with everything else. Instead, I would go with a 416 no need for a new sleeve for the clyinedr. Just need to get it bored. And you still can use pumo gas.

[4door5g]

were can i get the studs and head gasket?

[WeTDrEaM]

What about this..

http://cgi.ebay.com/ebaymotors/Honda-400EX-416-Wiseco-piston-w-stage-1-Hotcams-cam_W0QQcmdZViewItemQQcategoryZ43977QQitemZ1101027 84350QQrdZ1QQsspagenameZWDVW

How much jetting will be needed with this kit and stock everything else??

[gregrob]

IMO call Colby at CD racing and go with the 416 kit.

staying at 11:1 there isn't a big power difference btw 416 426 440 and you can always go bigger in the future if you only step up to 416 now.

You could also do a 426 now but the 416 is cheaper because you don't have to install a sleeve. With the 426 you need to install a sleeve.

Again there's not a big power difference btwn the two at 416. Now if you go beyond and do a 13:1 drag bike and run race gas, then more bore the better, but 416 should run real nice and torquey at 11:1, and won't break the bank either.

Just over 200 for new JE piston, Cometic gasket set and stock cylinder bore.

FYI you want to use the thinner Cometic gasket set to get the JE to 11:1, stock gasket thickness the JE is 10.8:1

Just call Colby

[QuadJunkies]

I have a Duncan PC 4000 kit on mine and have NEVER once had an ounce of issues.
If you get the proper 440 kit and install correctly, a 440 will last as long as stock

Also, if your going to get a Big bore, you really should get a full system and do a 450r carb to get the most out of your performance.Doing half the job on the motor will only get you half the performance your expecting. Also get P&P.

Its all in what you want.... Me personally, I wasnt all that up on the 416 and I have already had the 426,the 440 was a much better choice for me personally.

I think about the only thing I would maybe look into on minein the future is stroking it ...
someday if I still have it and maybe a dirt bike Cam at some point.

[gregrob]

I'm curious as to why you would want a dirt bike cam over the stage 2 you have now. Are they better for some reason?

I need to make a cam decision on my build soon.

[QuadJunkies]

Originally posted by gregrob
I'm curious as to why you would want a dirt bike cam over the stage 2 you have now. Are they better for some reason?

I need to make a cam decision on my build soon.

I know a retired Pro rider locally who ran one and it made a significant difference.Actually there was 2 guys locally who ran them.I always knew there was someting different about his quad and wondered why it ripped..!
But it was also about 500.00-600.00 in price too! lol

I forgot to mention- Cam chain, I have never ran anything but stock and have only had to replace mine once since Ive owned my quad. WE checke mine recently and its looking a little stretched this time around so it will get replaced.Its been 2.5 years since Ive had to replace it .
I also run the same rockers.
We do very routine maintence and do everything to spec. so Im guessing that has something to do with it.
It also doesnt hurt that my Husband is a fantasic mechanic on all our quads:D

[GPracer2500]

Just so we're all on the same page, the Duncan PC4000 isn't your typical "440 kit". It does away with the stock cylinder completely. I've no doubt it's very nice--but apples to oranges compared to the typical bore jobs and re-sleaves of the stock cylinder.

[QuadJunkies]

Originally posted by GPracer2500
Just so we're all on the same page, the Duncan PC4000 isn't your typical "440 kit". It does away with the stock cylinder completely. I've no doubt it's very nice--but apples to oranges compared to the typical bore jobs and re-sleaves of the stock cylinder.
Ive have had the Stock cylinder as well with a bore .No problems there either. No your right.. this kit separates itself from the rest for sure!

I just felt the 426 ran quite abit hotter than my 440 does ,therefore I get alot better power now. ;)

[drsnugfit]

Originally posted by QuadJunkies
Ive have had the Stock cylinder as well with a bore .No problems there either. No your right.. this kit separates itself from the rest for sure!

I just felt the 426 ran quite abit hotter than my 440 does ,therefore I get alot better power now. ;)

I have been watching this thread with some interest, I have just magaed to pick up a 440 kit for a good price, I know where to get the head studs(gt thunder) but where do i get the fexsteel head gasket?

thanks guys.

[PismoLocal]

Contact colby at C&D racing they are one of the site sponsors here. I'm almost positive he sells them.

[drsnugfit]

Originally posted by PismoLocal
Contact colby at C&D racing they are one of the site sponsors here. I'm almost positive he sells them.


thanks mate

[PismoLocal]

No problem glad I could help. :D