Had one of those once. They need piston swap. They can rev over 9 grand if everything is working. Took that engine and swapped it into a 81 SRX. It performed really well in the lighter machine.
Hi i had a 84 440 liquid it was doggy atbottom end kawasaki had same motor but more horse power to bring the jd up to the same power we changed heads ,bumped compreshion bumped timing @ rejetted it turned the track around wanted to go not stop this made a world of diference
Correct, adjusting needles will have no effect beyond half throttle. Adjust the main jet for 1/2- full throttle. Also I HIGHLY doubt the heavier clutch would be the culprit unless it's 2-3X the weight of the stock clutch. Putting a heavier flywheel on smaller 2-strokes like 125's and 250's doesn't hinder their ability to rev. If these have the same carbs as the Invader which I assume they do, there is a power jet that is for 1/2- full throttle also. Might need to tinker with the power jet
There's no rev limiter to speak of the primary clutch spring controls the top RPM. 8000 is where it makes the most power so that is where it is clutched for.
The liquifire was advanced for its time and actually has an electronic rev limiter. It’s mostly a fail safe for if you blow a belt, but they’re known to go bad and cause all sorts of gremlins to show up
Had one of those once. They need piston swap. They can rev over 9 grand if everything is working. Took that engine and swapped it into a 81 SRX. It performed really well in the lighter machine.
Cool transition at 3:45
Nice find. Gotta love those JD sleds
Carb jetting my first thought!
Hi i had a 84 440 liquid it was doggy atbottom end kawasaki had same motor but more horse power to bring the jd up to the same power we changed heads ,bumped compreshion bumped timing @ rejetted it turned the track around wanted to go not stop this made a world of diference
Surprised it didn't burn down if it was that lean at full throttle.
Surprisingly, the spark plugs never looked like they were lean.
Sounds to me you need to raise your needle on your slides to get more top end power
Raising the needle would affect midrange throttle, not top end
Correct, adjusting needles will have no effect beyond half throttle. Adjust the main jet for 1/2- full throttle. Also I HIGHLY doubt the heavier clutch would be the culprit unless it's 2-3X the weight of the stock clutch. Putting a heavier flywheel on smaller 2-strokes like 125's and 250's doesn't hinder their ability to rev. If these have the same carbs as the Invader which I assume they do, there is a power jet that is for 1/2- full throttle also. Might need to tinker with the power jet
So you gained 20 mph with that adjustment?......
Yep, basically the power jet in the carb was never coming in, so now it’s actually getting all the fuel it needs
Also if you have vent lines from air box to carbs make sure they're hooked up
There's no rev limiter to speak of the primary clutch spring controls the top RPM. 8000 is where it makes the most power so that is where it is clutched for.
The liquifire was advanced for its time and actually has an electronic rev limiter. It’s mostly a fail safe for if you blow a belt, but they’re known to go bad and cause all sorts of gremlins to show up