MarkinAR

Dirty float valve and seat. Just needs cleaning good inside and out and it'll quit leaking fuel.

I only pull mine off when I forget and spray carb cleaner all over my hand and 2 minutes later my finger catches fire....because I forgot to take my ring off for the 95th time as my oldest laughs and says "I wondered how long it would take for you to pull it off THIS time"

I had a carb apart recently that had a bit of sand through it (mud/water 4x4) and it scarred the slide and throat. Just had to take it out and work the slide and throat real good with a brown paper bag. Slid up and down flawlessly afterwards.

You'll just have google what you're looking for and read some reviews. In ATV parts there are chinese junk parts, chinese decent parts, OEM, japanese aftermarket. Quite a few options, just have to do a bit of legwork. If it looks really cheap (like $60 for a cylinder, rings, piston and gaskets) stay away from it. Same with consumable parts like chains and sprockets; there's a reason the pretty red chain is only $16.

TRX90 is about like most of the little honda motors. Slip on exhaust, Rick's CDI, polish the head. You can twist a little more power and a little more rev out of them but it's not going to be night and day. It'll perk up a bit with a good tune up including carb clean and new NGK plug and slip on exhaust like Big Gun, FMF, etc. You can also look into a size smaller rear tires to drop the gearing just a bit so you can pop the front up a little more. They'll never really fly but they're fun anyway. There is a whole market for the ATC70 as a toy like the TRX90. Just fun to play with little bikes. Really depends on how much money you want to spend. There's even a 106CC big bore kit....

It won't keep up. The 300ex is only like 15lbs lighter than the 400ex and 25% less displacement. You'd be better off financially to sell the 300ex and buy a 400ex. Would be cheaper than trying make the 300ex go fast. Or just rip it and have fun knowing on the straights its just not as fast.

Its not a BRP, it's a Taiwan Honda clone. Still a decent little motor though. They built it as a cheap entry level ATV. Not bad at all, just not a Honda. the power to weight ratio on the 420 is astronomically higher. Belt drive though is a plus as it's extremely simple. Just keep an eye on the belt bc it gets water in the housing and slips the belt sometimes. Not a big deal, just something to be aware of

Absolutely. I buy the $7 ones in the aux lighting section at Autozone. A 4 pole relay is a 4 pole relay. You may have to double check current flow. I had to repin the plug on a Kodiak once but it's only 4 wires.

@davefrombc No disrespect on the Rotax name, I am aware of the history. My suggestion is that there's not a huge group of riders to pull info from. My 300FW for instance there is a huge active FB group along with this site. Rotax? One or two people really know what they are doing?

Also make sure if you clean with a single strand of copper wire that all of it comes back out. I may or may not have lodged a copper wire fragment in a jet once. That's a nightmare. @cameron walton hold up, you said it's a brand new jet? is it an OEM new jet or a chinese jet from a cheap carb kit? I've thrown away a dozen jets in chinese carb kits for being stamped the wrong size, not stamped at all, etc. They are WILDLY sized incorrectly.

I have a couple inches of wire from some old car amp wire in my cleaning kit. Strip it back a bit and use a single strand to clean the pilot jet. My torch tips aren't small enough to clean the pilot. Best $4 i've spent at harbor freight otherwise!

@Nick Brooks I Looked at a DS650 a bit ago, pretty cheap, lot of power. Just didn't jump at it because I know NOTHING about the Rotax and there's not much of a support community if I ran into issues. Guess you found the same issues....

Eh, depends. DS250 was a bit high on seating posture, a bit low on ground clearance and a bit narrow. Can be a bit tippy. The motor in those is also a Taiwan Honda clone. Properly maintained they seem to have held together ok, but they aren't really a true Can Am. $700 seems cheap enough that you could probably get back out from under it if she doesn't like it. Hope she's pretty small though, those are really more of a 12 year old kid's ATV.

All the prep work in the world will only allow paint to stick for so long. That ABS on ATVs isn't quite auto bumper ABS so it won't quite last the same. You might get a year of it looking good. There has to be some heat or other method to really bring life back plastic...it just hasn't been found yet. Oh, and tried plastidip. It comes off at your heels in 2 hours. Sticks decent as long as it doesn't get rubbed.

Welcome to the forum! Glad to have a bonafide powersports tech in the room.

Banjo bolts and oil line flow ok? Assuming those are good I would think next step would be oil pump just in case its functioning but low volume. Pick up screen in the bottom clean? Odd issue for sure.

Slow return to idle generally is caused by a lean condition. Lean condition can be caused by either too small of a main jet or too much air rushing in. I'd check for vacuum leaks personally. When you bypassed the oiler, did you block off that port? I would seriously doubt it's caused by too small of a jet, but i guess could be a partial obstruction. May also check the throttle butterfly closing without the cable attached. I had one a bit ago that had a bit of stickiness in the throttle just enough to not slap shut the way it should. Ended up needing a good soak and some light oil and it slapped shut afterwards and stopped the slow return to idle.

@Lance Workman I assume it will occasionally spark when using the electric start? And I bet there is no sign of spark if you rip the pull start? Occasional spark, especially when letting off the push start button generally indicates bad CDI as the spark is actually spare voltage leaking off from the battery when you let off the push start button. I've seen quite a few Honda 300's with spark only when letting off the start button as I described. Wonder if the Bayou will do that too....

If you premix, be sure and block off the oiler line into the carb though. It's pretty standard on older 2 cycle Polaris motors to block off the dripper and run premix.

That's interesting. I guess somehow the reverse gear rev limiter is interfering with forward gears as well. Some of them have a reverse limiter lockout on the handlebar, so i wonder if grounding or breaking ground would just disable the reverse rev limiter completely.... Neat find!

Probably have to get a repair manual and start testing everything with a multimeter. Coil, stator, regulator, etc. I've never seen one fry a harness though without a direct short somewhere to ground and even then usually only fry the wire that's grounded. That's gonna be a fun one.

Fuse blew I'm sure. Probably several possible fuses on a 2020. Just google fuse locations, I'm sure one blew. They are there for that purpose.

@Frank Angerano If its anything like my boys 300FW the one way clutch is going out so the starter spins a couple extra rotations. If it dies he hits the starter again before it's done whizzing...that's a sure fire way to knock teeth off a starter.

Reading along here...it's not completely unusual for a starter on an small block chevy to quit working due to oil gumming up the brushes. You can pull the starter off and it spins, but not under load. If it were me, i'd wash the starter good in gas and spin it quite a bit by hand. Hit it with compressed air and let it dry then reinstall and try again. I'd almost bet there is debris or corrosion keeping the brushes from contacting enough to pass a high enough voltage to turn the motor over.

Golf cart tires work ok as long as you keep the speed really low. They will balloon pretty bad with much speed because they are meant for low speed, soft compound driving on grass. I've done trailer tires before that are almost identical and they worked great b/c they are speed rated. I used them on an old Bayou 220 for packing dirt and it worked like a champ.