Is race fuel worth it for 4 strokes?

R

Rubblemaker

Member

Dec 28, 2004

5

0

• Feb 28, 2005

• #1

I'm considering switching from pump gas to VP's Ultimate 4 race fuel in my '03 CRF 450. While talking to a VP dealer, he informed me that I would need to go up probably 2 main jet sizes when I switch.

My first question is for those of you who run race gas, is it a noticable difference, considering it's $10.75/gal? Secondly, did you need to make the above mentioned jetting changes?

Just a note, I ride at an altitude of about 5,500 feet.

 

R

Ray3667

Member

Mar 20, 2004

60

0

• Mar 1, 2005

• #2

I have run Race gas on a few occasions. I have found no measurable(seat of pants) gains. but I do live and ride at 7500ft +...

 

Patman

Pantless Wonder

LIFETIME SPONSOR

Dec 26, 1999

19,765

1

• Mar 1, 2005

• #3

Yes I run VP fuels in all our bikes. I don't know that the seat of the pants difference is huge but the bikes are more crisp and consistant, this was especially true when I ran VP MR2 in my Montesa 315R and in my XR284 which gets VP U4. Yes I did need to fatten the brass in the carbs a bit and am still messing with my son's CR85 because it's just not quite right yet.

 

a454elk

Mexicutioner

LIFETIME SPONSOR

Jun 5, 2001

7,529

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• Mar 1, 2005

• #4

Put this in the back of your mind as well, when done riding and if you won't be riding anytime soon, clear out the race gas, it'll gum up the carb, please! Yes, I learned my lesson the hard way, wasn't worth it to me, don't need no race gas to beat Texans like Twinny and Thump.

 

Patman

Pantless Wonder

LIFETIME SPONSOR

Dec 26, 1999

19,765

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• Mar 1, 2005

• #5

Yeah Carlo but your running that tofu pump stuff.

 

W

wornknobby

Member

Feb 5, 2004

625

0

• Mar 1, 2005

• #6

well i find it wierd that some of you guy's needed to fatten up the brass alittle, because i have my cr jetted perfect for vp and when i could use any thing but 93 from the pump, my jetting was still dead on. why is this?

 

C

cr lover

Member

Aug 6, 2001

78

0

• Mar 1, 2005

• #7

i have a 04 crf 450 and i run tt111 race gas 106 octain mixed with 92 octain pump gas 50/50 at 1300 sea level do i neet to go up on my main ?it seems to run fine with no backfiring.

 

Okiewan

Admin

Dec 31, 1969

29,550

2,238

Texas

• Mar 1, 2005

• #8

fatten the brass in the carbs a bit

Click to expand...

Oh.. you sexsay tuner you! Nuttin better than fat brass, lol!!!

 

Patman

Pantless Wonder

LIFETIME SPONSOR

Dec 26, 1999

19,765

1

• Mar 2, 2005

• #9

Okiewan said:

Oh.. you sexsay tuner you! Nuttin better than fat brass, lol!!!

Click to expand...

that's me :fft:

besides unlike Okie, Patman can't afford the 24K gold carb parts, but atleast you gots the fat brass. ;)

 

a454elk

Mexicutioner

LIFETIME SPONSOR

Jun 5, 2001

7,529

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• Mar 2, 2005

• #10

Fat brass rocks. I like BIG BRASS and I don't know why...

 

S

slideways11

Sponsoring Member

Apr 18, 2000

411

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• Mar 6, 2005

• #11

Hey Patman are you running the stock carb on your XR284??

 

Rich Rohrich

Moderator / BioHazard

LIFETIME SPONSOR

Jul 27, 1999

22,839

16,904

Chicago

• Mar 6, 2005

• #12

Yes, Pat currently has the stock carb on his XR284.

 

H

highmileage

Member

Jun 17, 2004

168

0

• Mar 6, 2005

• #13

Patman has stated that he was thinking of trying of new carb. Will it be Mikuni flat side, Keihnin FCR, or Edelbrock? Rich I know your watching...Is there any hope with the stocker if line bored to say 33mm?