Author Topic: race fuel in a 4 stroke.......  (Read 746 times)

Offline mxracer71

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race fuel in a 4 stroke.......
« on: April 16, 2019, 05:26:40 PM »
quick question for you guys... I just picked up a 10 crf450 with a pro circuit  high compression piston with some head work done to the motor. The guy ran race gas mixed 50/50 with pump gas. You think it would be ok to mix av gas 50/50 or just run the race fuel?  last thing i wanna do is blow this up and get stuck with a huge $$$$$ bill

Online Pokey

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Re: race fuel in a 4 stroke.......
« Reply #1 on: April 16, 2019, 05:59:37 PM »
interested in this.  I run T4 and it is getting pricey


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Offline Zeke27G

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Re: race fuel in a 4 stroke.......
« Reply #2 on: April 16, 2019, 07:14:37 PM »

U4.4 straight is the business!

Offline mxracer71

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Re: race fuel in a 4 stroke.......
« Reply #3 on: April 16, 2019, 08:36:01 PM »

U4.4 straight is the business!

Yea he just  sent me a text and he ran the u4.4 mixed 50/50

Offline Jesse833Mx

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Re: race fuel in a 4 stroke.......
« Reply #4 on: April 16, 2019, 08:50:37 PM »
U4 is a dirty fuel and has a Terrible shelf life .
Id either run T4 straight or 50/50 to save money.

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Offline Matt Fisher

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Re: race fuel in a 4 stroke.......
« Reply #5 on: April 17, 2019, 07:59:33 AM »
100LL may make a wee bit less power than T4, but it's resistance to knock is very good.  As long as you're not pinging, you should be good to go.  U4.4 is 103 octane, so at 50/50 with 91 you're at 97 octane.  100LL straight would be an improvement in that regard, while 50/50 would put you at 95.5.

Interestingly, my 13 YZ450 has the full GYTR package, including the HC piston.  I get a touch of low RPM knock if it's cold outside and the 91 pump is a few weeks old.  Admittedly it's tuned way down which decreases the likelihood of detonation, but when I tried straight 100LL it didn't seem to run any different.

Offline vet_sixT7

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Re: race fuel in a 4 stroke.......
« Reply #6 on: April 17, 2019, 09:25:38 PM »
T4 ain't that special.

Offline PCD771

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Re: race fuel in a 4 stroke.......
« Reply #7 on: April 17, 2019, 09:55:48 PM »
I run 100% unleaded.  8)

Offline Zeke27G

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Re: race fuel in a 4 stroke.......
« Reply #8 on: April 17, 2019, 11:05:36 PM »

Offline mxracer71

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Re: race fuel in a 4 stroke.......
« Reply #9 on: April 19, 2019, 01:42:20 PM »
Thanks guys, Im not looking for  any performance gain because for one i won't ride this bike to its full potential.. I was asking because i just dont want it to detonate on me.

Offline Mikeyam187

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Re: race fuel in a 4 stroke.......
« Reply #10 on: April 19, 2019, 08:21:15 PM »
Doesn't gasoline work anymore?  :P

Offline mxwingnut

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Re: race fuel in a 4 stroke.......
« Reply #11 on: April 26, 2019, 01:13:55 PM »

Offline Tiki

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Re: race fuel in a 4 stroke.......
« Reply #12 on: May 01, 2019, 08:09:11 PM »
How about that Klotz nitropropane http://www.klotzlube.com/power_additives.html Back in the 90's I used this in my 250 and wow, it was noticeable. I don't know what damage it caused, I stopped after one race.
she·nan·i·gan: usually used in plural b : high-spirited or mischievous activity