MarkinAR

Normally that symptom is caused by timing 180 degrees out. Lucky the piston hasn't smacked a valve yet. I havent timed a Polaris but on some hondas theres a couple marks then an F timing mark and a T timing mark. Pretty common to time to the wrong mark.

Good tip for future searchers of the forum. Thanks for posting!

Looks like the rings are seized into the piston. Can you move them around freely? If not, then there's your compression loss. Fairly normal for a motor that has sat for a while.

Good point @gillies_robert If valves aren't sealing it would also have no compression. That head doesn't look too chunky but it doesn't take but a micron to keep it from sealing.

That rust line looks like its below the rings so it should be ok. It's pretty worn so you might want to check it with a bore gauge. 40 psi was probably due to a ring stuck on the piston bc thats pitiful compression. If it's in tolerance hone it a bit to give it a good crosshatch, set of good rings and I bet you get compression back.

Caltric CDI is probably one of the better chinese junk CDIs. For what it's worth, NGK will do a lot better in a jap motor than e3. What is the orange wire? I'm not familiar with that harness. Where does it go?

Understood. I've had a bunch of Kawasaki Bayous and those were great but that 750 is a whole different animal. My oldest sons buddy bought a couple of parts bikes because he keeps bending valves, timing chains stretch, etc. They are extremely powerful and run great until they break. Then they're a money pit. Maybe though my sons friend runs his hard too and they just don't do as well in mud and water.

From what i've heard Houser and JD are fine as are Laeger, GT Thunder. I've read to stay away from Full Flight. But then again, they're all pretty much 4150 ChroMo so who knows if there really is a difference.

Assuming the CDI you replaced with is a chinese cheap one? i'd put the OEM back in then continue testing. Check the plug wire and plug boot also with a connectivity setting on a multimeter. I've seen boots go bad.

Did you test the battery with a multimeter? Sounds like low voltage. Can you start it with the pull start and it run?

Take it back. The Brute Force 750 has a fairly well known issue with dropping valves around the 1300 hour mark. When it drops a valve it ruins one of the cylinders, piston, valves. They are great bikes until they aren't....and then they are very costly to rebuild.

Both sound like carb issues. Modern fuel has ethanol and it starts to break down about 2 weeks into it's lifecycle. When ethanol breaks down it draws water from the atmosphere. Drain and flush the tanks, clean the carb, refill with fresh ethanol free fuel. Pretty sure both will be back to normal.

Welcome to the forum. 1. I usually go 2 turns and then adjust by ear where it's the happiest at idle. That may be anywhere between 2 and 3. 2. You'll probably have to readjust fuel screw. Not having the resistance of an air filter on the carb messes with everything. If the only remaining piece is the hose that goes to the box, try to use that with a filter on the end. The air filter is better off further up towards the back shielded than it is close to the hot motor. Carbs aren't a fan of hot air...the cooler the better.

while 15 degrees doesn't seem like much, i wonder if that would affect the pickup tube or oil draining back down the cylinder. I would doubt there is a clear answer to that question. Maybe take the clutch cover off, tilt it 15 degrees and give it a look? Sounds like a neat project though!

You can't really test a CDI, they are a bit elusive. You have to troubleshoot everything else that has to do with spark and if it all tests good, then the CDI would be the last option. You might also try the "baking" technique for the CDI. Sometimes you can bake them for a few minutes at very low temp and drive off moisture enough to get it to work again. @Frank Angerano is a better resource on baking CDI's.

The thumb throttle adjustment is the only "legit" way to limit speed. Yes, it does get faster on flat ground, up to the speed corresponding to thumb position and it may even go beyond that down hill. I would think even if there were an adjustable rev limiter in the CDI it would still behave the same uphill and flat ground. The only way that i see to not have it slow uphill and fast downhill would be a speedometer limited throttle like a modern vehicle so that it will only do say 15mph uphill and 15mph downhill/flat ground.

The rancher ones are still available but there's like 3 in the US left right now for the 300 and they are bringing $800 or so. Keep in mind a year ago these were $179. Thus why the search for an alternative

Beautiful country, thank you for posting.

I'm not sure if they still do it but Napa used to make about any brake line in house.

Armortech is basically an OEM clone for the Honda 300 so their universal muffler might work fine. It's not going to be a direct bolt on though I'm sure. Probably have to fab a bracket at least.

It's either over full or excessive blow by. My money is on blow by and just needs rings.

I've made hard brake lines for years for auto. I'm not sure that's the route to go with ATV though bc its likely the rubber hose portion is collapsed. Its also likely the wheel cylinder or caliper is seized. The orings in both fall apart if not used and then the cups rust.

It should be straight, I have a couple of chinese clone carbs for a bayou 220 in the shop and they are all straight. I don't think it would try to straighten it though b/c that brass is pretty soft. If it were to break off down low then the bowl wouldn't hold any fuel. It should be fine as it is if you don't have another bowl to use. That's just there so if the float sticks it allows fuel a way out instead of flooding the head with fuel. BTW, that bowl gasket looks like dirty as*.

I've thrown electrical fire more times than I can remember but never fuel fire. Caught a screwdriver in a ring gear. Caught a finger in a ujoint. Nearly broke an arm with a steeper bit the other day sizing the hitch on a 300 for a D ring. Yes a 19V cordless will indeed snag with a stepper and try to break an arm!

Oil is moved by the oil pump low in the motor and then makes it's way up to the top of the head. If it's not getting oil at the upper most banjo bolt/fitting then either there's a blockage in the line or the oil pump is bad. You can take the outside oil lines and banjo bolts off and check all of them for flow. If there's not flow through all of the above, likely oil pump is weak or just not pumping. Oil travels to the top and then drips back down via gravity through the head and back into the crankcase.