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View Full Version : JE 13:1 Piston -- Installed! WOW!


RedRacer44
10-18-2004, 02:32 PM
This past friday, JH Racing, installed the JE 13:1 piston in my TRX to replace the JE 11.5:1 piston I had and I must say...WOW money well spent! Major power gains on the bottom end, just rips off the bottom. It compliments the stageII HotCam very nicely, evens the power out and makes a nice hard pull from the bottom all the way to the top RPMs. It is also very easy to start even with the higher compression...I can kick it sittin down on the seat like when it was stock.

It is a beast in the trails also, lots of useable power down low...even at low RPMs. I am very pleased with the piston and kicking myself in the *** for spending the $$$ on the 11.5:1 in the beginning.

Can't wait to take it to the MX races to see how the motor works on the track!

I recommend this piston to anyone who is racing and/or a serious trail/dune rider who can afford the $$$ for the piston and to run race gas.
Blown 331
10-18-2004, 03:48 PM
Sell me the old piston.
RedRacer44
10-18-2004, 04:07 PM
Dont have it sorry....left it at JHs shop. You'd have to re-ring it anyways...
benwa450r
10-18-2004, 07:46 PM
I like mine too. Thought I would loose top-end... but didn't. I love it on MX track. You can lug-it in a corner, hit it... and it goes. Bottom is great.
RedRacer44
10-18-2004, 07:51 PM
Did ya get any good gains out of your head work?? Been considering a port/polish and FCR carb sometime....
kazpr
10-18-2004, 08:39 PM
Ya benwa450r please let me know also :)
tj but
10-19-2004, 10:53 AM
Would you have to run straight race fuel or can you run pump gas with the 13:1
and what about the 13.8:1
:devil: :devil: :devil: :devil:
dunebuggie66
10-19-2004, 11:02 AM
13.8:1 you brtter plan on running some good race gas, like vp c14.
RedRacer44
10-19-2004, 01:43 PM
Heh, with that high compression....its a must that you run race gas. no ***** *** pump gas for my motor!

I run TrackTek 105 oxygenated race gas.....works great!
Kilabanshee
10-19-2004, 01:47 PM
What the largest/best displacement piston were you can still run 93. I wouldn't mind mixing 2 gallons of vp to 3 gallons of 93 to get the octane were it needs to be but there is no way in hell ill run strait race gas just dont have that kinda money,
Colby@C&DRacing
10-19-2004, 01:51 PM
You will need to run some good gas but not near as high of octane of most people think. look at the dyno charts for the crf450 bike you go over 104 octane and you will loose HP lots of it, and the bike has 12.5:1 comp stock. THe new 4strokes are designed to run on less octain and will not perform well with really high numbers.
benwa450r
10-19-2004, 02:43 PM
I cleaned up the head at same time I put piston in so I don't know how much it helped. I pulled valves out and cleaned up casting on intake side and cut a little and polished up exhaust side. I did it myself... in about 2 hours. I'm sure it made some difference, just not sure how much. I know it has more power everywhere. :D
quadjeff
10-19-2004, 03:04 PM
I use the same piston and I have some pretty heavy head work complete. I run 93 76 gas and it rips... The piston along with the head work along with the new iginition will smoke anything.. I had the head on the flow and had a 6% gain.. Not bad for a few hundred bucks.....
kazpr
10-19-2004, 03:50 PM
Jeff what is 93 76 gas? 93 octane on the 13:1? Thanks alot as the 13:1 Je is alot cheaper than the 12:1 sparks.
quadjeff
10-19-2004, 04:14 PM
Yes, 93 octane.. Just 76 gas company.. My JE is working great..
RedRacer44
10-19-2004, 10:34 PM
Running 93 octane with your 13:1 pison?? Wow, i'd be scared to run it....only place around here that has good 93 octane is QuickTrip and they're only in Tulsa. I'm going to run the 105 oxygenated fuel at the MX races and then run like a 50/50 mix of 110/93 when at the dunes or woods. Going to the dunes this weekend so I'm going to see how the 50/50 mix works out for me.
kazpr
10-20-2004, 01:45 AM
Ya red let me know :)
Kilabanshee
10-20-2004, 06:42 PM
Nobody really answered my question so sorry for asking again I may have not explained it clearly. What is the best aftermarket piston a larger bore or compression which you are still able to run on 93 thanks alot!
kazpr
10-20-2004, 08:36 PM
I am going to be running 13:1 w/93 will let you know how it goes whenever I get it done :)
team_450_88
10-22-2004, 11:42 AM
U can run 93 with a 13:1...but it will improve ur throttle response alot if u run race gas with that high comp of a piston
TrX450rKiD
10-22-2004, 03:13 PM
Originally posted by team_450_88
U can run 93 with a 13:1...but it will improve ur throttle response alot if u run race gas with that high comp of a piston

Are you sure that is 100% safe? Because if so ... then I maybe be buying a 13:1 JE within the next year :devil:
team_450_88
10-22-2004, 03:50 PM
Positive...Im not gonna be doing it im gonna use turbo blue but my engine wont be finished for a couple more weeks...But my good friend that I race everyweekend runs 93 octane ( pump gas ) and dont mix race gas or anything...and this is a yfz with 13:1 piston and cam !!
team_450_88
10-22-2004, 03:51 PM
lol sh** race gas isnt much more than 93 NOWA DAYS !!:p
quadjeff
10-22-2004, 04:07 PM
I am using 93 octane and have not had a problem with my 13:1..
kazpr
10-22-2004, 04:37 PM
Got this pm from Colby @ C&D racing.


WE use an anti friction ceramic based coating on the skirt and a thermal coating on the dome. THe thermal coating reduces the temp of the piston and prevents predetination of fuel due heat buildup and low octane fuel
Kilabanshee
10-23-2004, 09:47 AM
Yeah I heard that you can get some coating on the sleve and it reduces temperature buy almost 50% alowing you to run lower octanes more safely.
RedRacer44
10-24-2004, 05:40 PM
I ran a mix of 3 gallons of TrackTek 111 to 2 gallons of 93 octane this weekend at the dunes, worked fine. Ran great too.....I'm going to continue to run straight race gas at the MX races but probably run a mix of race gas and 93 at the dunes.
twisted threads
10-24-2004, 10:50 PM
Originally posted by quadjeff
I use the same piston and I have some pretty heavy head work complete. I run 93 76 gas and it rips... The piston along with the head work along with the new iginition will smoke anything.. I had the head on the flow and had a 6% gain.. Not bad for a few hundred bucks.....

Jeff who did your motor work and were are they located??
proquad_20
10-26-2004, 12:20 PM
http://www.nybro.com.au/images/atv/batv4.jpg
Zeke
10-28-2004, 01:30 PM
how much is racing gas? i got a 13:1 JE pistion sitting in my garage but i cant use it cuz i dont got race gas.
quadjeff
10-28-2004, 01:34 PM
Holz racing...... www.holzracingproducts.com did my motor. This thing has been flawless....
RedRacer44
10-28-2004, 01:37 PM
I buy it by the 5-gallon can here in Oklahoma. I costs me $27/can for TrackTek 111 octane and $33/can for TrackTek 105 oxygenated fuel. The oxygenated stuff is awesome but much more $$$. Or you can buy Elf race gas that is like $57 for a 5-gallon can but thats some BAD *** ****!

You can get away with running a mix of race gas and premium, I ran 3 gallons of 111 octane to 2 gallons of 93 octane at the dunes. Ran just fine...