Crossflow vs. Looper

[Skools Out]

Originally Posted by THEFERMANATOR

Mine blows those numbers out of the water. I've got a 145 on one bank both cylinders, and 150 and 155 on the other side. Mine is a bare to start without dual batteries, or at least a good group 27.

Does your motor run hot? More compression means more fuel use and higher temps.

[76GMC1500]

The 205 psi is in my 1987 CR 250 dirt bike, but it is a looper so I thought I would throw it in here.

[bigshrimpin]

I thought any two stroke above 145psi couldn't run on pump gas. That was the rule I heard . . . :P

[Skools Out]

I run VP12 114 Octane racing fuel in my jetski with the 230 PSI. I have run it on 93 Octane in her but doesn't like it much, only $5.99 a gallon for that puppy. That bike isn't a looper actually it's the same as my jetski they are called piston port motors. whole different world in 2 strokes.

[THEFERMANATOR]

Originally Posted by Skools Out

Does your motor run hot? *More compression means more fuel use and higher temps.

It doesn't now, but the previous owner kept having issues with it(hence how I got it). It's got stock heads and flat top looper pistons, mine was an early one and came stock with the bigger rods. Mine was also before they lowered the compression for unleaded gas. They offer the low compression heads for it, but why change it. It runs great, I've got close to 200 hours on it since I did anything to it internal. And I even run it on 87 octane with no spark knock at load(but does rattle a little at idle on the low octane). It seems to get great economy to boot for a V4. 7-8.5GPH @ cruise and burns around 13GPH WOT.

[Skools Out]

hey that's not bad the highr compression will give it more power arrrr oh yeah more power

[THEFERMANATOR]

Yep, it runs pertty good. Like I posted earlier, it pulls off the same top end as a 150 SUZUKI on an identical hull. And there was a guy on the local lake none to happy when his 18' hydro stream with a 150 EVINRUDE XP couldn't catch me. It also didn't help that there was 5 in my boat and he was by himself in his ;D.

But those hydro streams can move, a buddy has an identical hull with an old built up 2.4L MERCURY said to putting out around 280HP. He's GPS'd it @ 98MPH before he ran out of lake with 2 on board. He figures he's had it up around 102 before, but no GPS at that time.

This is some great stuff u-all. What is the difference between a big bore and a small bore looper ? Also where do i look on my OMC to find the motor numbers.......ps also how many hp is 2.7 liter ?

[Skools Out]

the small bore has 3.500 pistons which were in all pre 1988 loopers and big bore have 3.685 bore in 1988 up looper 120,130,140,200,225,250,275,300 hp motors


V-4 Models
1.6-liter Crossflow, 1983-1987, and 1988-1990
1.8-liter Looper, 1985-1987
2.0-liter Looper, 1988-1990

V-6 Models
2.5-liter Crossflow, 1983-1990
2.6-liter Crossflow, 1983-1990
2.7-liter Looper, 1985-1987
3.0-liter Looper, 1988-1990

V-8 Models
3.6-liter Looper, 1985-1987
4.0-liter Looper, 1988-1990



the 2.7 was a small bore and has either 200 or 225 HP depends on what carbs you have and jets. do the carb butterfly's have 2 or 3 screws holding them in? 2 will be 200 Hp *carbs and 3 will be 225 Hp carbs.

[reelapeelin]

Again w/ the OMC Spec Wallpaper. ;D ... Skools, couldya just be a little more specific ;D ;D ;D ...