Higher compression Piston in YZ450

BAD10
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BAD10
My 2014 Yz450 has 105 hours on original top end and its time for a refresh. Thinking of throwing in a higher compression piston for 13.5:1, versus the stock 12.5:1.......... will race gas be mandatory?
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inthebadboycorner 8/8/2016 8:27pm
8/8/2016 8:27pm
These numbers are only indicitve of a "ratio" not true numbers,
Netherless, yes in my friends had to buy race fuel as it pinged on premium unleaded.
He also lost top end and gained on the bottom, not as broad power, so it became even a bigger handful for him, a novice rider.
The only other mod he had was a slipon.
After the first hour he regretted not getting an OEM piston.
CarlinoJoeVideo
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CarlinoJoeVideo 8/8/2016 8:33pm
8/8/2016 8:33pm
Went to a high comp piston on my KTM 250 SXF and am able to run VP T4 fuel which is a great step up from race fuel. And not crazy expensive.
BAD10
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BAD10 8/8/2016 9:28pm
8/8/2016 9:28pm
inthebadboycorner wrote:
These numbers are only indicitve of a "ratio" not true numbers, Netherless, yes in my friends had to buy race fuel as it pinged on premium...
These numbers are only indicitve of a "ratio" not true numbers,
Netherless, yes in my friends had to buy race fuel as it pinged on premium unleaded.
He also lost top end and gained on the bottom, not as broad power, so it became even a bigger handful for him, a novice rider.
The only other mod he had was a slipon.
After the first hour he regretted not getting an OEM piston.
Indeed to make the most of a higher compression piston it should be mated to a camshaft(s) with duration, lift, overlap, and the valve events that will make the most of that added compression.
Slosh 112
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Slosh 112 8/10/2016 4:24am
8/10/2016 4:24am
BAD10 wrote:
Indeed to make the most of a higher compression piston it should be mated to a camshaft(s) with duration, lift, overlap, and the valve events that...
Indeed to make the most of a higher compression piston it should be mated to a camshaft(s) with duration, lift, overlap, and the valve events that will make the most of that added compression.
Yes thank you!!

What is your average octane rating over there for standard pump fuel.

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Rogerson207
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Rogerson207 8/10/2016 4:56pm
8/10/2016 4:56pm
I put one in my YZ450 and like someone else said it didn't like pump gas when under a load like mud or sand or pulling a big hill and sometimes when getting on the gas coming out of a corner. I tried some of my friends T4 and it seemed to work better, I am debating on trying U4.4 or the VPR that I run in my two stroke woods bike.

I already had a set of builder series cams from Hot Cams in the bike when I installed the high compression piston.
pete24
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pete24 8/11/2016 7:14pm
8/11/2016 7:14pm
at 105 hrs bumping up compression puts more of load on everything else you may want to put a crank and timming chain and valve/job/or springs in that thing
ask me how i know this
adam8781
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adam8781 8/14/2016 12:27am
8/14/2016 12:27am
its a very small bump,

yes run the 13.5 and no you wont need race fuel unless you are running very aggressive timing or lowend cams (such as hot cams stage 1)

consider investing in the gytr tuner as well.

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