difference between 13:1 and 13:8:1

[450rboy]

i was just wondering what the difference is between the 13:1 and 13:8:1 piston. the pistons are from JE too.

[400ex45]

ahhh .8 :D it just has alittle more compression. i think.

[chris46250r]

Originally posted by 400ex45
ahhh .8 :D it just has alittle more compression. i think.

Uhh that would be .7 wouldn't it.:D

[pro-rider46]

Originally posted by chris46250r
Uhh that would be .7 wouldn't it.:D

no i think its .8

[chris46250r]

Excuse me, I thought he was saying 13.1:1 and 13.8:1. Another fine example of the poor punctuation on here.

[reptikes]

Its 13:1 or (13 to 1 compression) & 13.8:1 or (13 point 8 to 1 compression, which is dam near 14:1) = more COMPRESSION!!!!!


What number is bigger 13 or 13.8 ? AHHHH, I SEE, I SEE:chinese:

[4bidden]

There are likely more differences than that. The 13.8:1 is likely their "race piston" which has better features than the 13:1, which is probably just a high compression shelf piston.

Its just like CP....they have a standard 13:1 and then a race piston which is 13.8:1. If I were you, I'd check out the CP race piston. I've run quite a few pistons and think I'll run the CP from now on.

[pro-rider46]

Originally posted by chris46250r
Excuse me, I thought he was saying 13.1:1 and 13.8:1. Another fine example of the poor punctuation on here.

funny how we all understood it...



jk im just busting your nuts

[redrider05]

well the regular 13-1 je is a 3 ring design piston so its more likely something a regular person can run year round without problem

the 13.8-1 is the pro series which is a 2 ring piston...which means shorter piston skirt which means faster reving ,lighter design.but also means more maintainence ie:new rings or even a new top end.

guess you would have to decide if having alil more get up is worth the trouble of possible tearing a top end down more frequently..

my .02 is to get the 13-1 and be done with it till end of season

[esr250r86]

I have a question. Can you run a 13:1 standard bore piston with a on 91 octane pump fuel? Or does it have to be run on 110 race fuel? I am currently running mine on 110 race fuel but I heard that you dont have to run race fuel and it just messes up your valves? What is do you guys run in your hi-compression motors?

[chris46250r]

Originally posted by pro-rider46
funny how we all understood it...



jk im just busting your nuts

Well I guess nobody really understood it since he spelled out that he wanted to know the difference in a 13 to 1 and a 13 to 8 to 1. I've never heard of a 13 to 8 to 1, or as he put it 13:8:1.

[hawk-trx]

Originally posted by esr250r86
I have a question. Can you run a 13:1 standard bore piston with a on 91 octane pump fuel? Or does it have to be run on 110 race fuel? I am currently running mine on 110 race fuel but I heard that you dont have to run race fuel and it just messes up your valves? What is do you guys run in your hi-compression motors? if you live in high alt. and run a fairly big cam you might get away with it. but i wouldnt recomend it. you dont need 110 either. 100 would be plenty safe.
its funny how the 250f bike run 13.5-1 on pump gas but the load that a quad is under along with the larger engine maks it unsafe for a 450 quad.