500ex

[DragonGunner]

Heres some info on Chad Duvall's FST 500EX he raced in 2002 an 2003 seasons of the GNCC...info was found in dirtwheels, Sept.2002.

Wiesco 11:1 90mm piston
77mm stroker
Bored engine cases
Cross country cam
Some flow work done to head
Custom headers with Supertrapp exhaust
Stock Carb 162 main jet
K&N Filter with Outerwear Custom Airbox
IMS 4.3 gallon tank
Houser +1 a arms
Houser +1 Swingarm
High Capacity Pingry oil tank
Secondary oil cooler
Elka Suspension
Gearing 15/36
Maxxis 20X11-9 Razr's rear, 21X7-10 front
Modified CDI, rev. limiter removed.
Hydraulic clutch, heavier clutch springs.

With this set up Chad usually could run the entire 2 hr. race without having to pit. Just thought this might be interesting info to the younger guys that love 400EX's....an also, Chad won alot of races including winning the 2002 Pro-Production Clas that had just started that yr. I called an talked to FST awhile back in the "day" an they said the motor ran strong an realiable the entire season.

[SHIFTx450]

Any pics of the bike?

[djwilliams0822]

500ex with a stock carb? Wow it has way more potential if it had a bigger carb

[JOHNDOE83]

Originally posted by djwilliams0822
500ex with a stock carb? Wow it has way more potential if it had a bigger carb

And still running a 162 main jet? :huh

[05DodgeDakota]

what is required to make it a 500cc? The biggest Kits I see are 465

[BlasterEaten250]

stroker crank/rod

[finsteratv]

162 main?! maybe a different one besides keihn??? that is tiny!

[djwilliams0822]

Yeah that would be VERY efficient

[BlasterEaten250]

I'm sure there is a perfectly logical explanation for it, I don't think the guys at FST are dummies when it comes to building engines!

[djwilliams0822]

Just out of curiosity im just guessing is this Chad out of Mocksville?

[SHIFTx450]

Originally posted by 05DodgeDakota
what is required to make it a 500cc? The biggest Kits I see are 465


A good engine builder can make whatever setup they want.

[05DodgeDakota]

Originally posted by BlasterEaten250
stroker crank/rod

there's more to it than that. I mean what type of machining is nessicary

[DragonGunner]

I'll get some pics. up later today.

You have to rememeber when jetting u have to get the gas/air combo...162 was probably use because he probably ran a closed box alot because of all the water involved in XC racing. So that combo makes sense.

FST sold the kit or would put it in for you. It required a stroker an machining out the cases for a bigger cylinder sleeve.

[djwilliams0822]

That makes sense but a 500 with the air box on and stock carb a modded 440 could prob beat it

[finsteratv]

Originally posted by djwilliams0822
That makes sense but a 500 with the air box on and stock carb a modded 440 could prob beat it I doubt it unless the 440 has major compression. full exhaust sparks filter(BIG) and choke removed i have a 160..i just cant see a 162 but hey they know whats up.

[DragonGunner]

Best I could do right now...it was Orange an Yellow an it flew.

[SHIFTx450]

Now I remember. It looks almost like the one fst did liquid cooled. Think that was a 500ex as well.

Which issue is that?

[01boneless]

^^ shift did u ever get my pm??

[SHIFTx450]

Hang on I'll check

[SHIFTx450]

No pm.

[01boneless]

sent another i just am inteestd in the skid u have

[SHIFTx450]

What skid plate?

[01boneless]

the plastic underbody one you had on the for sale section?

[400exrider707]

You guys are looking at the jetting size all wrong. If the piston used has a really good seal to it, it will have a much stronger vacuum pulse on the carb and effectively pull more fuel through the same size hole. I've seen this a lot with high compression builds on the 450R's we've done. I've actually had to step down main jet sizes on larger builds vs. a stock bike with just a pipe/air filter.

I agree with the box too, they would probably run the lid back then too.

[DragonGunner]

Originally posted by SHIFTx450
Now I remember. It looks almost like the one fst did liquid cooled. Thumb that was a 500ex as well.

Which issue is that?


Dirtwheels Sept. 2002

[DragonGunner]

Originally posted by 400exrider707
You guys are looking at the jetting size all wrong. If the piston used has a really good seal to it, it will have a much stronger vacuum pulse on the carb and effectively pull more fuel through the same size hole. I've seen this a lot with high compression builds on the 450R's we've done. I've actually had to step down main jet sizes on larger builds vs. a stock bike with just a pipe/air filter.

I agree with the box too, they would probably run the lid back then too.


What??? Never heard of that...if it pulls more fuel then its going to pull more air as well, an the gas an air mixture going into the cylinder is going to be the same. Its not going to suck more gas but not suck more air. It all has to do with the gas/air mixture+temp/altitude=jetting.

[400man]

I wonder how good this bike would do against the 450's that the pros race today? it kinda looks like they were setup different back then compared to what the pros run now. I know most everybody now runs a fairly low, wide stance where it looks like that bike was setup with a higher ride height and not as wide?

[SHIFTx450]

Originally posted by 01boneless
the plastic underbody one you had on the for sale section?

No clue what you're talking about. You have me confused with somebody else.

**sorry bout the change in subject

Sept 02, got it. What about the liquid cooled 500ex that FST built way back when? Anybody remember that one and know the Dirtwheels issue it was in?

[DragonGunner]

Originally posted by 400man
I wonder how good this bike would do against the 450's that the pros race today? it kinda looks like they were setup different back then compared to what the pros run now. I know most everybody now runs a fairly low, wide stance where it looks like that bike was setup with a higher ride height and not as wide?

I have most all the taped shows of the GNCC from 2001 an up. Chad left his 250R an went to this an an stayed in the top 3 most races an even beat Ballance for the overall a couple times. In 2003 many guys switched to the YFZ450 that had just came out. Chads 500EX had no trouble with them either....but late in the year Chad had a falling away with FST an switched to the Yamaha to finish the season. Even that season an in 04' a couple guys were running 460EX's an doing great. Once Honda finally came out with their 450R there was no point in buying a 400EX an putting alot of time an money in them to compete though. Chad won the pro production class in 02' an I think maybe in 03' an both yrs stayed in the top 3 pro overall....the quads all had about the same stance an width.

[J51S]

400man I wonder how good this bike would do against the 450's that the pros race today? it kinda looks like they were setup different back then compared to what the pros run now. I know most everybody now runs a fairly low, wide stance where it looks like that bike was setup with a higher ride height and not as wide?

Thats because the bikes setup for woods racing, not mx.

[01boneless]

Originally posted by SHIFTx450
No clue what you're talking about. You have me confused with somebody else.

**sorry bout the change in subject

Sept 02, got it. What about the liquid cooled 500ex that FST built way back when? Anybody remember that one and know the Dirtwheels issue it was in?

lol OOOkkk then :huh

back to the thread!!!

[dxcody]

lol shifT714 has the skid boneless :p

[01boneless]

lol i just cought that lol the names thro me off lol sorry shift #2 lol back to the 500ex

[SHIFTx450]

June 2001 !!

found it!

http://www.exriders.com/vbb/showthread.php?s=&threadid=6120

[SHIFTx450]

liquid cooled sounds like too much work and too much money.

A nice oil cooler setup and some shrouds to direct airflow better would suffice on a stroker motor

[dxcody]

thats freakin awesome.

i am considering the GTT 450 kit, but idk how long they are supposed to last.

[SHIFTx450]

How long what is supposed to last?

[05DodgeDakota]

I've decided that one it's time to rebuild again, I'm doing a 500

[Chukkinsod]

There is a 7mil kit you can get from powroll, just not sure if they sell anymore. I thought of the 500 kit for drag but not sure power vs price would pay off for what I want. best bet in that class to get a great running high comp motor that runs consistant and you dont need to wrench on... just my 2c's. Although it is fun to have the shock factor to send a newer bigger bike to the trailer there is a cost !!! Keep it cool and tuned right and ride the hell out of it!

[fearlessfred]

Originally posted by 400exrider707
You guys are looking at the jetting size all wrong. If the piston used has a really good seal to it, it will have a much stronger vacuum pulse on the carb and effectively pull more fuel through the same size hole. I've seen this a lot with high compression builds on the 450R's we've done. I've actually had to step down main jet sizes on larger builds vs. a stock bike with just a pipe/air filter.

I agree with the box too, they would probably run the lid back then too. x2 I guess im dumb enough to agree with this

[thebig450es]

I have the gtt 450 kit, i love the tq of the 7mil stroke