Race gas or pump gas?
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Thread: Race gas or pump gas?

  1. #1
    Member evaneyeball's Avatar
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    Race gas or pump gas?

    i am having LED do my motor 86 250r to a 269 cc and the current head is a 23.5 cc dome. it will have a hinson clutch every thing a hot rods crank and pro x piston do i need to run race gas or not he says i most likely will. also ct ported it and he has to do some small porting changes. i will also pretty much only run it in the dunes.
    does anyone know what piston i should use instead of pro x because i am not sure if i want to use another or go with the tried and true wiseco
    Last edited by evaneyeball; 01-20-2020 at 01:56 AM.

  2. #2
    Senior Member american opel's Avatar
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    piston has nothing to do with compression.i love the cast prox pistons.i he should be able to set it up for either..but i would go race fuel.alot more power.

  3. #3
    Senior Member acecarlos's Avatar
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    Quote Originally Posted by evaneyeball View Post
    i am having LED do my motor 86 250r to a 269 cc and the current head is a 23.5 cc dome. it will have a hinson clutch every thing a hot rods crank and pro x piston do i need to run race gas or not he says i most likely will. also ct ported it and he has to do some small porting changes. i will also pretty much only run it in the dunes.
    does anyone know what piston i should use instead of pro x because i am not sure if i want to use another or go with the tried and true wiseco
    All of these questions are 'Best' answered by the builder doing all the work on your engine or cylinder, as well as providing all the proper parts....he/she should fully advice, provide parts and any/all needed information, specially since it is their "build".

    Carlos
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    Senior Member The Norm's Avatar
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    I would definitely call Arlen and have him set your compression for the gas you want to run. If you run race fuel (110 octane) in an engine set up for pump gas (92 octane) you are wasting money. You gain nothing hp wise from running race fuel in a pump gas engine! My 12 year old boys R's have 13.5:1 compression and running 92 octane pump gas. They routinely embarrass yfz's and raptor's with bolt ons. Arlen knows all this as he is a very experienced engine builder. My builder (Pete @ Hybrid Engineering) suggests setting up for race fuel because you have a better quality of fuel. I chose pump gas for my boys R's because they ride more than me lol
    american opel likes this.
    When you lie down with dogs, you get up with fleas!

    Current: Hybrid Engineering 391R
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  6. #5
    Member evaneyeball's Avatar
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    i am just looking for another opinoin i know he is experiencd and thats why i am having him do the work. but also i am dropping off my cases on Wednesday. i am also wondering how this thing ran super strong before i took it apart to fix my cases. it has a 87-89 crank 85 cylinder a 86 piston and a 86 23.5 cc head with no base plate. in 86 cases if that makes a difference.

  7. #6
    Senior Member The Norm's Avatar
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    What dunes do you ride? We mostly hit Winchester.
    When you lie down with dogs, you get up with fleas!

    Current: Hybrid Engineering 391R
    Hybrid Engineering 310R (super 310)
    Hybrid Engineering 265R
    Hybrid Engineering 250R

  8. #7
    Senior Member american opel's Avatar
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    Quote Originally Posted by evaneyeball View Post
    i am just looking for another opinoin i know he is experiencd and thats why i am having him do the work. but also i am dropping off my cases on Wednesday. i am also wondering how this thing ran super strong before i took it apart to fix my cases. it has a 87-89 crank 85 cylinder a 86 piston and a 86 23.5 cc head with no base plate. in 86 cases if that makes a difference.
    no way you were running a longrod crank with a short rod piston without a spacerplate.the piston would have came out of the top of the cylinder and hit the head.

  9. #8
    Member evaneyeball's Avatar
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    mostly Winchester, riley ranch and sand lake. but Winchester and riley are about 4 hours away so day trips are sandlake. but this spring my family and some friends are going to st.anthonys dunes and possibly Moab too
    Last edited by evaneyeball; 01-21-2020 at 02:22 PM.

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    Member evaneyeball's Avatar
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    i know the piston would have hit the head but it didnt and it ran super strongly too. the only explination is the head was bored to 23.5 cc could that have made a diffrence. but i am going to LED tomorrow so if nobody here knows he might know. i will post pics of every thing soon

  11. #10
    Senior Member acecarlos's Avatar
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    Quote Originally Posted by evaneyeball View Post
    i am just looking for another opinoin i know he is experiencd and thats why i am having him do the work. but also i am dropping off my cases on Wednesday. i am also wondering how this thing ran super strong before i took it apart to fix my cases. it has a 87-89 crank 85 cylinder a 86 piston and a 86 23.5 cc head with no base plate. in 86 cases if that makes a difference.
    Quote Originally Posted by evaneyeball View Post
    i know the piston would have hit the head but it didnt and it ran super strongly too. the only explination is the head was bored to 23.5 cc could that have made a diffrence. but i am going to LED tomorrow so if nobody here knows he might know. i will post pics of every thing soon
    You asked, and I will answer; that's not a Honda ATC/TRX250R piston....it is a YZ250 piston setup in an OEM cylinder. With no cylinder decking, and a bit of dome work. Nothing real special, old school thinking.

    Askcarlos.com aka askbdtmotorsports.com, aka askmeanything250r.com....LOL

    Carlos
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