Has anyone here installed one of these? How much difference did it make (Bottom, midrange or Top end). Do you need to run race fuel with this setup or does it run fine on ultra?

Thanks

RaptorRider

 

Wiesco owns J&E so I suspect you really have a J&E Piston. I would not waste my $$ on a 100mm piston for a number of reasons. Go with the 102mm. Now, I have not ran the piston with a stock cam so I have no idea if the cylinder pressures will be high enough with the cam timing events to require fuel. I suggest you add a cam while you are at it.

 

Raptor720,

I was asking you about a problem awhile ago about my Raptor being flat on top. Well i made a couple high speed runs with the choke partially on and I got a higher top speed 2.5 MPH higher with my GPS. So this made me think it might be a little lean (hope this was the right thinking) I then increased the main Jet sizes from Dynojet 146,148 to Dynojet 148,150. While I had it all apart I decided to adjust the valves also. they had not been done yet and I probably have over 30 or 40 hours on the quad. What I found was they were tight, I could not get the feeler gauge in. I rotated the crank several more times to make sure it was on the right stroke when I was adjusting and it was. After adjusting them I took it out for a ride and damn it pulls all the way up now feels like it really revs on top now. Do you think this was more the jetting or the valve adjustment? I hate when you do more than one thing at a time!

My Mods in case you don't remember
R4 Slip on
K&N Jet Kit 148,150 Needle on the 4th clip down
Airbox mods..Snorkle flaps gone and 10-3/4" holes
0-300 ft elevation.
Northeast.

 

Tight valve clearances can tend to take away some top end but it should not change the fuel/air mixture. I suspect that the valves were only about .001" too tight and that the jetting change made the real diff.

Glad you are back in the smile range now.

 

Raptordude,
I and two others have had the valves tighten on us also! I chased mine forever, changing every carb setting possible!! Finally checking the valves did it, and boy was it a change!! When the others started doing it we realized what it was a bit earlier and it helped tremendously. One was so bad it didn't want to start and would not run with the choke.

 

raptordude
I have a j&e 102mm high comp piston, I used on my raptoy, but I used it in conjunction with a racing cam and valve springs. not sure how this would do without a cam. I would recommend a mid-range cam, and like 720 suggests might as well go with a 102mm piston while there. the results make a real strong motor, the racing cam I used has a 270 degree duration, which cuts some of the bottom end, I would recommend something with about a 260 duration which will preserve bottom end. that piston will require at least 93 octane

 

i have the fst 11.5:1 and cam. it will make an awesome difference all the way through. if you do alot of tight woods riding it will be rare that you use the power. when i added my pipe the top end fell off alot. i jetted up to 145-150 and it all came back. depending on where you live; the jetting you have right now may be enough after the work. you won't need as much gas in the cylinder with more comp. go ahead and get the cam too it will make a difference.

 

Only one prob Richie>>>> Your statement that "you won't need as much gas in the cylinder with more comp" cannot be accurate. When you raise compression, you also increase the burning efficiency of the engine. I have never seen this result in an engine running rich.

 

I am goin to get the wiseco 11.1 piston witht he powroll mid range cam for my Raptor. Is this a good combo? About how much Hp will i have with modds in signiture. Also will I gain on just bottom or all the way form botton to top? thanx

 

Sky,

Get the specs on the cam and I can better tell you the effective power range. lift, duration, opening and closing events. It is hard to say the 11:1 piston is correct without knowing the cam timing, etc.