Bore Kit Overheating Question

[MrThumper]

HEy
i was considering a 416 or 426 kit for my 400ex... i ve been told you have to run Racegas or they will over since they are air cooled...is it a big problem?? I can't afford race gas ..( i work at shopko:D ) could i get away with runng 92 ocatne pump gas and adding a bottle of octane boost to my gas jug. Also who makes the best bore kit??? thanks any info appreciated

2002 Yellow 400ex
Pro Circuit T4 Slip ON
AC Nerfs
Ac Front Bumper
Renthal Bars
Kenda KNarlys on douglas .190s on the rear


****ATVING IS NOT A CRIME****

[jb400exxx]

i run octane booster but mine is stock, i just feel like using it. i'm kinda hoping it does the same thing as higher octane cause when i get my 11.1:1 piston i don't wanna run race gas. it does give a little tiny bit more power on my stock engine though so it does do a little.

[jerry-89-250R]

i have a heavily modded 440ex "since 2000" that has run just fine on 93 octane,

[d-14 rider 27]

i got a 465 ex and if i could figure out a timed injection pump, i could almost convert it to diesel im runnin sunoco 110 with a bunch of octane boost and it still pings and knocks and carries on. but anyways, your smart goin with the 416 bore cuz you can keep your stock sleeve, 440s are a waste i think, and ive run them about the whole time i raced, the heat transfer in stock sleeve/cylinder is better than a pressed in one. and as for your fuel, you would get away with premo and octane boost if you stay with 11:1 compression

[jb400exxx]

jerry, what compression ratio is it?

[MrThumper]

Thanks for the info evryone keep it coming..where should i buy a 416 at??prices???

[Glamis400ex]

I heard from several peeps here that octane boost makes your valves red....not good.

Not sure, you may want to ask...

Glamis

[MrThumper]

Any truth in this???

[bklyn400ex]

i was wondering the same, is there much or a power difference between a 416 and 440, i want my bike to be as reliable as possibl, but i want more power, i dont race i just play around. if a 416 dont have to be re-sleeved, i could have a shop do the bore and prob. install myself what do u think will it be easier to install a 416 or a 440?

[YZROOSTINYA]

sig


any place that sells pistons should be able to get you a 87mm(416)

get a 10.8:1 , no race gas needed.

then get your stock sleeve bored .080 over

i like mine

[YZROOSTINYA]

if your runnin ocatne booster in a stock motor your pissing in the wind

YOU ARE DOING nothing BENEFICIAL

you are probally LOSING power

[ill_lil_romey]

The octane you run is based solely on your compression ratio.

[northern]

Does anybody know what the HP difference is between the 416 and being stock?

[YZROOSTINYA]

about 5-7 hp peak. about 10-12 in spots of the powerband with a stage 2 cam

[northern]

Do you know if a guy needs different valve springs for the stage 2 cam?

[YZROOSTINYA]

nope, i didn't. lok at sig

put them in if your getting a rev box

[d-14 rider 27]

you only need heavier valve springs if you put on a rev box. at high rpms with stock springs your valves will float (not close by the time the cam comes around again) if you got the head off already it might not be a dumb idea to put them in you might put on a revbox down the road sometime

[northern]

Does anybody know what the HP difference is between the 416 and being stock?

[bklyn400ex]

yz how much was the JE kit and will it give me similar power to a 440??

[bmw500hp]

man I have went back and forth on that topic with myself and other for weeks...

2 days ago i rode a (416) 12.5:1 JE with a HRC, an X6, and reputable port job... running cam-2 premium....

In the upper mids the quad came on like gangbusters...It flat out roared and ripped....also started and idled right off, at 38% outside temp with the choke removed... mine wont idle that good till it's warm..

The question is how much more torque do you get with the 440...maybe more usable power in the lows and lower mids ...and on pump with a 11:1 how does that compare to a 416 Race gas motor up at 12:5...????

Mickey Dunlap says a 425 is the way because you still have sleeve thickness and a quick revving motor ... Like to see some thoughts on this......

i was wondering the same, is there much or a power difference between a 416 and 440, Hardly any at all :rolleyes: :D


easier to install a 416 or a 440? Ok now I am being serious, deff the 416 is a lot less work and expense.


Do you know if a guy needs different valve springs for the stage 2 cam? A guy or girl for that matter doesnt "need" the heavier springs but it would be better and there only about $50.00-60.00. I was floating them valves real easy with the stock springs.


The question is how much more torque do you get with the 440...maybe more usable power in the lows and lower mids ...and on pump with a 11:1 how does that compare to a 416 Race gas motor up at 12:5...???? Search around I think there was a member who was trying to get out of the race fuel and went to a 440 10.8:1. try searching "have you decked the cylinder" I think the info was there.


A note for you guys comparing HP (first off you should be more concerned with torque) You need to think of it this way. If you take a stk engine and bore it out 2% of its current size and do no other mods and keep the same "actual" comp ratio etc what do you expect you will see? Unless the old piston had problems I dont think you will see a big diff and that goes for the 10% larger bore of the 440 also.

Now if you make additional changes to compliment your new larger engine cc's you can expect much larger gains. This happens cause you get more torque from higher compression (other benefits also) and get more hp and torque by going with a higher lift cam or better flowing head from porting etc.

There are also some very intricate little issues with these motors that will make or brake a larger cc motors performance, and you can even gain in some areas and loose in others. This was and still is a major issue with people who did the 440 kits but none of the other things that make it work properly.

I had this same problem and basicly it just wasnt set up correctly and had good bottom but very poor mid and top. If rode right it would pull most others in a drag for the very beginning but couldnt hold it due to the way it was set up.

If you really want to know what you need for any size overbore I do suggest you take some time (a lot of time) and search thru the site cause there has been some excelent threads on this in the past that will both answer most of your questions and bring up a whole new bunch of questions as well.

Sorry for the long post but I hopw it helps those who are deciding on what to do to get more power, and maybe if everyone took the time to read thru the site they would have known this allready.

[YZROOSTINYA]

actually 440, thanks for the long post

my 416 with gaskets cam and bore was like

200 piston gaskets
52.$$ for bore
145 for cam direct from hotcam, you can get them on ebay for 110-130, plus 25 to press off and on broach
another 30 for jets, oil, misc.....

was like 400 give or take 50 for the deal

my full system was 442 and k@n was 50 with outerware. you will at least need a slip on with a high comp/bore/cam

[cals400ex]

if i was doing it, i would do a 416. the 440 will probally give more toque but it also get hotter. now we only have aircooled engines. i am not saying a 440 can not be reliable, but with you not racing or anything i think the 416 would suit your needs better. some people will agree and others will disagree... personal perference

[Drtridr18]

In my opinions, from what i've read and heard that a well put together 416 or 426 will match or beat a typical 440 bore for power in most areas and most likely rev faster, and to really make a big bore like a 440 wake up to its FULL potential, it needs to breath thru a port job, a long cam, and a carb. I'm sure your typical 440 bore/sleeve, cam, pipe combo will more than rip worth the money, but unless going allll the way with it, why not get a 416 or 426?