Reliable big bore kits

[99400esex]

Thinking about ordering a big bore kit sometime in the next few months so I can build it over the winter. As of now my motor internally is stock, what is a reliable kit for my 99?

[Thumpin]

I'd build a 416 big bore, they run about as cool as stock, love to rev and can still build very impressive torque. They are very reliable, and pretty cheap to build. I can smoke many 450's in the trails with mine!

[CJM]

Having a 416 done up right now. Was rather cheap considering all factors vs say a 440.

[mtrombla08]

if ur gonna do the work and spend the money just do a 440 kit. i did mine about a year ago and im glad i did it. i got a new jug, 11.1 weisco piston, and gasket kit for 400 one ebay. the bike rips now. it kicks my buddies in their ltz400's asses. im pulling 35 hp. there is no replacement for displacement.

[TRX01]

you should be pulling way more than that id think ^^^^^

[TRX01]

you should be pulling way more than that id think ^^^^^

i have seen peoples dyno slips on this site with a 416, pipe, carb and cam making 35 and higher HP

[JOHNDOE83]

They are all equally reliable, there is really no loss of reliability from one to another.

[ish416]

I have a high compression 416 and I am extremely happy with it. They run much better than a 440 without a bunch of work done to the head. Another thing to consider is that once the cylinder is ready to be bored you can just step up to a 426.

440's are over rated without the proper mods. Also, they require a good bit of cooling and don't really offer any more power unless it's well built or a 440 stroker. That is an 87mm piston with a +4mm stroke.

I am not trying to say that all 440's are weak but all that I have ridden or raced are slower than my 416.

[PaRedneckRiders]

if i were u i would just run a 416 with a 12:1 JE
GTT head studs and a stage 2 or 3 cam
I think u would deffinitly b happy with a nice little setup like that
then mayb a 450r carb

[99400esex]

This 416 kit sounds pretty promising.................

[PaRedneckRiders]

ya there deffinitly a good kit

One of the plus sides to the 416 is if u plan on keepin your 400 for a while u can always go to the 426 with out having to resleeve like u would with the 440
Plus the 416 will still produce good power with just a few mods like i mentioned b4

[Honda4life05]

Originally posted by Thumpin
I'd build a 416 big bore, they run about as cool as stock, love to rev and can still build very impressive torque. They are very reliable, and pretty cheap to build. I can smoke many 450's in the trails with mine!

you can beat any 450 on the trails huh? :rolleyes:

[99400esex]

Originally posted by PaRedneckRiders
ya there deffinitly a good kit

One of the plus sides to the 416 is if u plan on keepin your 400 for a while u can always go to the 426 with out having to resleeve like u would with the 440
Plus the 416 will still produce good power with just a few mods like i mentioned b4

Well I am planning on doing a hot cams too, what other mods would work well with the kit? I plan on getting a full system fmf exhaust and rejetting the carb.

[99400esex]

Originally posted by Honda4life05
you can beat any 450 on the trails huh? :rolleyes:

This thread has nothing to do with who can beat who so that means nothing to me. All Im asking is opinions on big bore kits. I would like a little more power because I ride with 2 700xx's and its hard to keep up at times.

[wali2408]

I got a few questions for you guys i might plan on going a lil bigger one day.

I think i would go for the 416 kit for the reliability. i race hare scrambles and trail ride. What 416 kit would you get i know wiseco makes one and hetrick but idk many others.

Would i have to make any other mods like air scoops, hd studs, or any thing else?

[99400esex]

Originally posted by wali2408
I got a few questions for you guys i might plan on going a lil bigger one day.

I think i would go for the 416 kit for the reliability. i race hare scrambles and trail ride. What 416 kit would you get i know wiseco makes one and hetrick but idk many others.

Would i have to make any other mods like air scoops, hd studs, or any thing else?

I have heard that the wiseco kits are pretty reliable. When I order mine I think thats what im going to go with.

[ish416]

My setup is a JE 12.5:1 piston, XR400 cam, FCR carb from 06 450R, ported head, FMF powerbomb header, White Bros E series muffler, KN filter.

With my setup and 15/38 gearing on 20 inch rears, I can pull it up in 5th gear from 25 MPH up to about 65MPH without much of an issue, that means not clutching it up. It is a torque monster and revs out pretty well.

Most people are quite surprised when my EX is hanging with them in a drag or a fire road when they are on their 450s or 660+cc quads.

In a race against my KFX450 and my friends built 450R it will be side by side until the top of 4th before either of the 450s pull anything on my 416.

As for reliability, I have been running this setup for about 5 years with the exception of the FCR carb and have never had a single issue with it.

[tayyo789]

Go for the 416 for multiple reasons.

1. Runs cooler, more reliable, makes almost as much power as a 440.

2. Doesn't blow head gaskets as much. At least that I've seen.

3. If you ever need to go bigger, you can. If something goes bad, you can go up in bore

[CJM]

Like I said, I just put a kit together and cant wait to have it all finished.

I did:

-87mm 11:1 wiseco piston (for 416cc bore) so I can use pump gas.
-Had GT Thunder bore and do the HD head studs for later (might do a 426 later)
-Hotcam stage II
-cometic gaskets

For all of that it cost me about 400-500 bucks. GT Thunder wanted 200 to do all the work, piston was like 80 or 100, cam was 100, wasnt to bad at all.

Gotta remember too I am doing all the work like lapping the valves, cleaning everything and putting it all together

[PaRedneckRiders]

Ok well u already said u would have a hotcam and a 416 kit

I would just run a 450r carb

Then u could also go with a mild port and polish just to clean it up and let it flow a little better

U could also use an xr400 head gasket(its a little thiner and will bring the compression up just a little)

U could also ditch the base gasket and use a High temp silicone same concept as b4

thats just some stuff to get u started

[brokenmike]

My 440kit has been togeather since 2003 and never blew a head gasket without HD studs

[tayyo789]

From personal experience, and what Ive read and heard, about 75% of people that have 440's have some sort of problems with it. I just don't think the gains are worth the risks over a 416

[JOHNDOE83]

Ive had my 440 for over three years and never once had a heat issue or anything break.

I dont have the heavy duty studs, I dont have the heavy duty cam chain. and I drag race and run the hell out of my bike.

If your bike is jetted correctly, and you have the right fuel, you wont have any problems.

440 is the way to go.

[dalejiw25]

Originally posted by JOHNDOE83
Ive had my 440 for over three years and never once had a heat issue or anything break.

I dont have the heavy duty studs, I dont have the heavy duty cam chain. and I drag race and run the hell out of my bike.

If your bike is jetted correctly, and you have the right fuel, you wont have any problems.

440 is the way to go.



Agreed - 440 Is The only way to Go.