Almost 8HP gain on the YZ250...

dv12.com
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dv12.com
Edited Date/Time 6/14/2018 9:12am
I decided to start a new post. We should have the engine tomorrow or Wednesday and we'll try to display it in A1:

I guess, Reptil Racing (my dad), did a good job on the engine. Almost 8hp more than the stock bench mark. Check out the photos:

http://dv12.blogspot.com/2011/01/yz250-engine-is-ready.html
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Hoodie
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Hoodie 1/3/2011 9:08am
1/3/2011 9:08am
46 is stock? 54 hp should be fast.
Hoodie
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Hoodie 1/3/2011 9:13am
1/3/2011 9:13am
Also on a full blown pro sx bike, how often does a 2 stroke need refreshed?

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dv12.com
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dv12.com 1/3/2011 9:16am
1/3/2011 9:16am
NeWskoolmxer wrote:
Wow! How many Hp down is it from a race prepped 450?
You'd have to test on the same dyno to have a good comparison. Dyno numbers fluctuate so much and it's tough to be accurate. We will go to FMF to try some pipes and I will bring a 450 to compare but it will happen after A1...
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Hoodie
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Hoodie 1/3/2011 9:16am
1/3/2011 9:16am
keeptwostrokesalive wrote:
I just wish i new how much horsepower the fully modded 450s are putting out.
Talking to Ron Hamp he said 70 at the crank is the most he has ever built. But that was for flat track racing.
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dv12.com 1/3/2011 9:17am
1/3/2011 9:17am
Hoodie wrote:
Also on a full blown pro sx bike, how often does a 2 stroke need refreshed?
Should go 6 races without any maintenance needed...

We have another engine for practice
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Hoodie
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Hoodie 1/3/2011 9:18am
1/3/2011 9:18am
Hoodie wrote:
Also on a full blown pro sx bike, how often does a 2 stroke need refreshed?
dv12.com wrote:
Should go 6 races without any maintenance needed...

We have another engine for practice
Thanks for the reply!
BornA'Lil2Slow 1/3/2011 9:22am
1/3/2011 9:22am
Hoodie wrote:
Also on a full blown pro sx bike, how often does a 2 stroke need refreshed?
after every single night, sometimes once during the night, on a 250 2s. at $120~$150 a pop.

plus, 2 clutch changes every weekend, at $100 a pop, on a 250 2s.

DV, has anyone ridden it? 8hp is omg wow by the way, question is, is it ridable or is it like JS's 05 kx250, hp was way up there and the bike had JS afraid of it!

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Hoodie 1/3/2011 9:24am
1/3/2011 9:24am
Hoodie wrote:
Also on a full blown pro sx bike, how often does a 2 stroke need refreshed?
BornA'Lil2Slow wrote:
after every single night, sometimes once during the night, on a 250 2s. at $120~$150 a pop. plus, 2 clutch changes every weekend, at $100 a...
after every single night, sometimes once during the night, on a 250 2s. at $120~$150 a pop.

plus, 2 clutch changes every weekend, at $100 a pop, on a 250 2s.

DV, has anyone ridden it? 8hp is omg wow by the way, question is, is it ridable or is it like JS's 05 kx250, hp was way up there and the bike had JS afraid of it!

DV12 says no maintaince for 6 races.
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dv12.com
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dv12.com 1/3/2011 9:28am
1/3/2011 9:28am
Hoodie wrote:
DV12 says no maintaince for 6 races.
We'll have to change clutch plates after 3 races which is 3 hours and 9 starts at the most...
williamsmotowerx 1/3/2011 9:33am
1/3/2011 9:33am
The RPM where peak torque occurs has been raised, and the peak HP RPM has been lowered.

That hurts the driveability tremendously. May be a fun playbike but for SX I hope the rider is a gear banger.

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web mx
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web mx 1/3/2011 9:34am
1/3/2011 9:34am
DV,after the 6 races you run with it maybe you could put out an itemized list of the exact amount of parts that were actually used ...Smile
smental
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smental 1/3/2011 9:35am
1/3/2011 9:35am
how many races has cedric signed for ? and will he stay for outdoors if all goes well?
keeptwostrokesalive 1/3/2011 9:44am
1/3/2011 9:44am
smental wrote:
how many races has cedric signed for ? and will he stay for outdoors if all goes well?
hes signed up for 6 races. He starts at phoenix then ends at san diego i believe.
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dv12.com 1/3/2011 9:49am
1/3/2011 9:49am
web mx wrote:
DV,after the 6 races you run with it maybe you could put out an itemized list of the exact amount of parts that were actually used...
DV,after the 6 races you run with it maybe you could put out an itemized list of the exact amount of parts that were actually used ...Smile
That's the plan...

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Rupert X
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Rupert X 1/3/2011 9:49am
1/3/2011 9:49am
smental wrote:
how many races has cedric signed for ? and will he stay for outdoors if all goes well?
keeptwostrokesalive wrote:
hes signed up for 6 races. He starts at phoenix then ends at san diego i believe.



Yes, his win streak will start at Phoenix and then they will find a way to outlaw the bike.

Called it. First.
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dv12.com
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dv12.com 1/3/2011 9:50am
1/3/2011 9:50am
smental wrote:
how many races has cedric signed for ? and will he stay for outdoors if all goes well?
keeptwostrokesalive wrote:
hes signed up for 6 races. He starts at phoenix then ends at san diego i believe.
You are following really well K2TA... ;-)

Phx -> SD -> France... hahaha
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BornA'Lil2Slow 1/3/2011 9:51am
1/3/2011 9:51am
i think he will be ok if he doesnt get hurt. The main place hes going to be in trouble is the start unfortunately. But I think he will make the night show and the main baring injury. I honestly am cheering for the guy.

DV, seriously, and this isnt a 2s vs a 4s deal for me. would you be comfortable giving us a break down of parts used during a saturday? I think alot would be shocked and its interesting as hell to me.
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mac3-d 1/3/2011 9:52am
1/3/2011 9:52am
Hoodie wrote:
46 is stock? 54 hp should be fast.
ok go from here 4 stroke stock is what (yz 450f) 52.4 HP works + 8 = 60 HP ?
TerryB
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TerryB 1/3/2011 9:57am
1/3/2011 9:57am
BornA'Lil2Slow wrote:
i think he will be ok if he doesnt get hurt. The main place hes going to be in trouble is the start unfortunately. But I...
i think he will be ok if he doesnt get hurt. The main place hes going to be in trouble is the start unfortunately. But I think he will make the night show and the main baring injury. I honestly am cheering for the guy.

DV, seriously, and this isnt a 2s vs a 4s deal for me. would you be comfortable giving us a break down of parts used during a saturday? I think alot would be shocked and its interesting as hell to me.
Sounds to me like you will be the one who is shocked:

after every single night, sometimes once during the night, on a 250 2s. at $120~$150 a pop. plus, 2 clutch changes every weekend, at $100 a pop, on a 250 2s.

Some of you 4-stroke kool-aid drinkers are a little misguided.
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Blake 1/3/2011 9:58am
1/3/2011 9:58am
williamsmotowerx wrote:
The RPM where peak torque occurs has been raised, and the peak HP RPM has been lowered. That hurts the driveability tremendously. May be a fun...
The RPM where peak torque occurs has been raised, and the peak HP RPM has been lowered.

That hurts the driveability tremendously. May be a fun playbike but for SX I hope the rider is a gear banger.

Some guys like screamers, others like torquers.

Dyno sheets and curves are pretty much BS.

I can make anything look like a turd on a dyno. And 2 seconds later make it look like a hero engine.

Born 2 slow, if they cant get a good 6 races out of a top end, somethings wrong.

They arent running N02 or Turbos with 20 Lbs of boost, and even then...........


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testuser 1/3/2011 10:01am
1/3/2011 10:01am
williamsmotowerx wrote:
The RPM where peak torque occurs has been raised, and the peak HP RPM has been lowered. That hurts the driveability tremendously. May be a fun...
The RPM where peak torque occurs has been raised, and the peak HP RPM has been lowered.

That hurts the driveability tremendously. May be a fun playbike but for SX I hope the rider is a gear banger.

Blake wrote:
Some guys like screamers, others like torquers. Dyno sheets and curves are pretty much BS. I can make anything look like a turd on a dyno...
Some guys like screamers, others like torquers.

Dyno sheets and curves are pretty much BS.

I can make anything look like a turd on a dyno. And 2 seconds later make it look like a hero engine.

Born 2 slow, if they cant get a good 6 races out of a top end, somethings wrong.

They arent running N02 or Turbos with 20 Lbs of boost, and even then...........


Isnt there a gay Sled forum you should be hanging out on? No one cares about snowmobiles. they R gay
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Tim507 1/3/2011 10:11am
1/3/2011 10:11am
DV what type of carb is on that motor?
BornA'Lil2Slow 1/3/2011 10:13am
1/3/2011 10:13am
as quoted by 2 factory mechanics, one for ktm in 94 and 95, and the other suzuki in 98 and 99, plus 2000-2002... after practice, do the top end depending on conditions. but every thursday when they got to the next race, tear the bike down to the frame, about redo the topend.
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ratonmacias 1/3/2011 10:15am
1/3/2011 10:15am
williamsmotowerx wrote:
The RPM where peak torque occurs has been raised, and the peak HP RPM has been lowered. That hurts the driveability tremendously. May be a fun...
The RPM where peak torque occurs has been raised, and the peak HP RPM has been lowered.

That hurts the driveability tremendously. May be a fun playbike but for SX I hope the rider is a gear banger.

@ Williams:

Why would ride ability be hurt? i can see that the modded engine has to be revved harder to get to the peak torque figure. but i also see that the modded engine has more torque at any rpm setting and that it reaches the maximum stock torque figure way before in the rpm range.

i also see that the power band is fuller from the low end all the way to the top and again the stock maximum horse power figure is reached at lower rpms.

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