Biggest Bore around for the 400's

[flyingbyfast400]

Just quick questions.. I dont plan on doing this.. But whats the biggest bore you can take the 400's to? Sum place I think I seen you can bore it out all the way to a 465? the would be a slow reving motor.. Anyone heard of anything bigger then a bore, and stroked 502ex? Sorry for the greenhorn questions...
:confused:

[Joe400ex]

no but that would be sick

the biggest i have seen is 465 by curtis sparks

[NacsMXer]

From Spark's site, it looks like their 465 is a 465 bore with no stroke. And I agree, such a huge bore would make for a sluggish piston. You can also take a 440 bore and stroke it to 465cc's for a lot more torque. For example, the total displacement on my motor is 452cc's. It has a 416 bore but it has also been stroked +7mm to achieve a total of 452cc's. The smaller piston still lets it rev quick enough while making monster torque at the same time.

I'm not to sure honestly what the exact bore of a 502EX is. It may be a 465 bore with a big stroke on it, but I don't have experience with 502 kits. Chad502EX on this site would be better able to address this question.

[400exrider707]

mickey dunlap of four-stroke tech. builds 500ex's

[K_Fulk]

The 465 bore motors arent weak in the power department by anymeans. :cool:

The 92mm 465 pistons are as big as your gonna find for the EX.

[NacsMXer]

I bet those 465's are torque monsters. But what I meant by sluggish is that it's the heaviest size piston you can possibly run since it's the largest bore. I assume they stroke it to get it to 502 That's gotta be a beast :eek2:

[K_Fulk]

The main advantage with the 465 piston is you can run a lot bigger valves, Since the compression chamber has more surface area.

Not very many people go this route. But it works well at getting more flow.

[cals400ex]

fulk, how does your buddies bike run that actually removed stroke from his bike (if that is even near the correct terminology).

[K_Fulk]

I havent rode it but he says revs pretty good and has power everywhere. It has a 91mm piston and destroked 1 or 2 mm to keep it at 450cc's. He pulled a 3rd place finish at one of the tt's in a A class so it can hold its own against modified 450's.

I have a 92mm piston and cylinder, and a 4mm stroker crank waiting for me to put together.
But I think im gonna keep the stroker crank with a 440 piston and the 92mm piston with my stock crank with a carrilo rod. After I get them both together I'll keep the one I like the most.

Now I just gotta get the $$$ to do that. :o

[400EX QUADER]

The biggest that i've seen is a 505ex.

[EPDP99]

I think chad502ex has a buddy thats got a 508. but not positive. Im running a 440 strocked +4 to a 465. 38 ft. lbs tq. and 56 hp. i love it but i wish i found this site before i did it. Not the best pick for the dunes since its best power is at like 5-7k rpm's. it gets the hell bent for fast and i smoke all but drag banshees up until like 2/3 hill at dunes then all the 450's catch me.

[400EX QUADER]

That's cool.:devil:

[markk]

Originally posted by 400exrider707
mickey dunlap of four-stroke tech. builds 500ex's




FST, Mickey Dunlap i think that his 500 kits are a 465 bore with the stroked crank. Just think about how long u want yoru motor to last and what u plan on actully doing with it before u go into big-bores.


Seriously i dont know what FST 500, or 502 make HP wise, but I would guess 50-60+ HP

[44oEX]

the FST 500 kit can go up to 511.
the hp is about 45hp

[redrider440]

Mike at FDO builds a mean 493, and I've heard from his son he is now building the 505.

[flyingbyfast400]

Thanks for the info guys. I thought the biggest bore was a 465. But ya I know all about the stroking and such. I was just a lil lost on the biggest bore out for the 400s.... My buddie has a 440 bore, and then stroked to a 465, all of it was done by TC and this thing hauls. But I have for a long time now wanted to get a spare motor and build a 500 + cc 400ex motor.. See what happens. Maybe sum day It will happen. But i just got done with my 440 build and I'm pretty happy with it. But not alot of ride time in on it yet
Vic

[flyingbyfast400]

Does anyone know the stroke to take a 440 to a 465, and then also a 465 to a 502 or so.... Thanks

[44oEX]

well the 440 it stock stroke ( 70mm ) with 89mm bore and the 500 (490cc) is a 77mm stroke with 90mm piston. and it can go to 92mm bore ( 511cc )

[markk]

Originally posted by 44oEX
the FST 500 kit can go up to 511.
the hp is about 45hp


for a 500cc motor, 45hp doesnt seem like that much to me!

[khen]

Originally posted by markk
for a 500cc motor, 45hp doesnt seem like that much to me! I'd like to see the torque curve on that though.. you could probably climb a tree from a 5th gear rolling start. :devil:

[44oEX]

yeah it's like 75 ft/pound of torque

[loons]

My buddy has a 485 ex on Alchohol. It is a stroked 465. It will beat my yfz, and I am not stock. He has it for sale right now for $5,000, and that is a steal.

[flyingbyfast400]

Ya the 500+cc built 400 motor would be real stump pullers. But 45 hp dones not seem like alot. But o well Thanks for all the info guys. Helped me learn a few things. :macho Gotta love atvriders.com
Vic

[cummingetit]

FDO is building 515s now. I dont know where you came up with 45hp because the 493s are in the 50s. On 30% nitro they make 65.

[Quad Dude]

does FDO have a web site

[chad502ex]

FST's 500 kit is a 496 not a 502.

Yes, my friend had a 508.

i still have the 502, and it's pulling just as strong now. I'm thinking of removing the head, doing DRG porting on it, then re-dyno'ing it for max hp. The dyno runs I have on the 502 are really old and in no way represent the current power it has.



One other note:

to me, hP on a stroker is meaningless information. Torque is what strokers are all about. On the 400ex application: forget the HP, build for torque.