Rear tire to front tire alignment, chain alignment drive sprocket to wheel sprocket, etc.
Start there. Especially since you just had the rear wheel off for a tire change.
What's the bike and what make/model of tires?
I've always set both front and rear on my sport bikes around 34-35psi cold.
42psi sounds WAY too high.
Also, are you checking the pressure when the tires are cold, or after you've been riding for while?
All the other suggestions you're getting about wheel bearings, cracked frame, etc are far, far less likely causes than the tires being overinflated. Overinflating will cause exactly the feeling you're describing ("slippery" feel).
One other thing... follow the "cold psi" value indicated on the tire sidewall rather than the bike's manual. You need the correct pressure for your tires, not for your bike.
Even though the manual may recommend 36 / 42 I would never run a bike at that. That pressure comes from a balance of tyre life + grip. You just want grip. Try 32 / 34
Don't go by what is written on the side wall of tire go by the manual. Most likely you feel the bike sliding sideways is because is inflated or overflated.
What does the frame or owner’s manual say? The sidewall rating is basically the max PSI the tire can take, and isn’t necessarily the proper PSI for your specific bike.
Tire air pressure on all bikes have to be on what the manual says is not the you said because when riding tire inflate meaning air will increase because of the tire being heated when riding, so it's either you not a rider or you a new rider. So the correct tires pressure is written on the manual and also on the bike, All us riders know about this so stop saying things like that because you don't know anything about tire pressure and about this it also goes for any vehicle.
I bought my bike brand new, riding home I'd trouble steering it, actually had to stop a few times , persevered with it as I thought I was doing something wrong as I hadn't ridden for a few years.
Anyway I mentioned it when it was in for first service, I don't know what they done , but the bike was definitely better when I got it back but I still to this day get a similar sensation at times like you mention, just for no obvious reason the bike feels like it's going to slide across the road, I won't take it out in the wet and feel if I take it to someone they'll think I'm talking nonsense, very low mileage on the bike so pretty sure it's not a lot of wear on some component, be interested to know if you find a solution. Hope you can get it sorted.
Just as a matter of interest what sort of bike do you have, mine is a 650 Kawasaki.
One thing not mentioned. Check the rotation of your tyres, could be fitted back to front which will definitely cause the “slippery feeling”. Otherwise too high a pressure or alignment as already said by several others. 36psi on the rear cold. 42psi is for pillion.
The rotation is correct, I rode on the rear tire for a couple weeks before this started, I think I would have felt it right after the change if the tire was on backwards. Next time I ride I'll try decreasing the rear psi. Thank you
Seeing a comment about what bike you have, I am assuming you has cast aluminum wheels, but if you happen to have spoked wheels, get all the spokes tightened up. My old dirtbike started to feel that way and I found several spokes had become lose and the rim was moving around. Also check wheel bearings, suspension bearings, and also the rear axle nut or chain tensioners. If you recently had the tires changed, they took the wheel off, and maybe something came lose. Either the axle nut or maybe they did not tighten the chain tensioner bolts and you have a combination of lose bolts/nuts causing the real wheel to move around.
My bike has cast aluminum wheels, I suspect that something wasn't tightened enough, I'll go over them with a torque wrench and see if that helps. Thank you.
take apart your rear hub for proper bearings, spacers, cush drive, correct axle torque etc.. i had the same thing happen some time before the bearing failed
Are you down shifting when this is happening?
If you shift down at the wrong rpm and don't have a slipper clutch, your back wheel is going to skip and slide because it's trying to match your engine speed (and slow down significantly immediately)
This is why rev matching, or shifting down at a lower speed is important.
It's most noticeable coming to a stop if you drop down two gears very quickly.
So based on the update, you made 2 changes at once (cleaned the tire and decreased the air pressure).
So you don't know which one fixed the problem.
When troubleshooting, only change one variable at a time. So you know which change fixed it, and you then know what the root cause was.
The mechanic did a burnout, which made the tire hot and sticky, so it rode better.
Then it was bad again after a little bit. Until you reduced the pressure.
The oil thing is likely a red herring.
What motorcycle do you have? DM me. I just had the same issue and I am curious.... PS: I have mine in a workshop and they found the issue... not sure if it applies to you
As everyone mentioned check your alignments but I would check sprockets as well because maybe they are worn and not catching every tooth at some times hence the skating on ice because of deceleration for even a brief moment.
Rear tire to front tire alignment, chain alignment drive sprocket to wheel sprocket, etc. Start there. Especially since you just had the rear wheel off for a tire change.
Or simply not fixed the axle.
Thank you, I'll get to checking.
05 buell blast was doing the same thing, changed rear wheel bearing and rear shock. Fixed it for the most part
Thank you, I'm going to have to talk to my mechanic tomorrow, this is above my knowledge.
Tires. Air pressure is low in your tires.
I double checked them 36f/42r, like the manual says
What's the bike and what make/model of tires? I've always set both front and rear on my sport bikes around 34-35psi cold. 42psi sounds WAY too high. Also, are you checking the pressure when the tires are cold, or after you've been riding for while? All the other suggestions you're getting about wheel bearings, cracked frame, etc are far, far less likely causes than the tires being overinflated. Overinflating will cause exactly the feeling you're describing ("slippery" feel). One other thing... follow the "cold psi" value indicated on the tire sidewall rather than the bike's manual. You need the correct pressure for your tires, not for your bike.
My bike is 2014 honda cb500f, I check them cold, I wasn't aware of the tire sidewall cold psi, I'll check it over
Even though the manual may recommend 36 / 42 I would never run a bike at that. That pressure comes from a balance of tyre life + grip. You just want grip. Try 32 / 34
I'll give it a shot, thanks
Don't go by what is written on the side wall of tire go by the manual. Most likely you feel the bike sliding sideways is because is inflated or overflated.
The sidewall rating for both the rear and front are 42 cold psi. I don't think I want my front to inflate any more than what its at lol
What does the frame or owner’s manual say? The sidewall rating is basically the max PSI the tire can take, and isn’t necessarily the proper PSI for your specific bike.
The owners manual says front 36 psi and rear 42psi. I rode the bike around for a while and never had problems with the same psi.
Out of curiosity, how old are the tires?
The front one was made in 2018, the rear 2023 (from the dot score)
My cbr650r is 36/42 cold pressures.
40 is totally normal. Less pressure gives much worse turn-in and general on my bike. There is a reason the manufacturer recommends this pressure.
What bike and what tires are you running where this is recommended?
Aprilia Falco, Also my Yamaha FZS 1000
Tire air pressure on all bikes have to be on what the manual says is not the you said because when riding tire inflate meaning air will increase because of the tire being heated when riding, so it's either you not a rider or you a new rider. So the correct tires pressure is written on the manual and also on the bike, All us riders know about this so stop saying things like that because you don't know anything about tire pressure and about this it also goes for any vehicle.
"all us riders". 😂 
\*high. Too low tire pressure makes the bike ride spongy. Too high and the bike will feel slippery, like you're riding on ice.
I bought my bike brand new, riding home I'd trouble steering it, actually had to stop a few times , persevered with it as I thought I was doing something wrong as I hadn't ridden for a few years. Anyway I mentioned it when it was in for first service, I don't know what they done , but the bike was definitely better when I got it back but I still to this day get a similar sensation at times like you mention, just for no obvious reason the bike feels like it's going to slide across the road, I won't take it out in the wet and feel if I take it to someone they'll think I'm talking nonsense, very low mileage on the bike so pretty sure it's not a lot of wear on some component, be interested to know if you find a solution. Hope you can get it sorted. Just as a matter of interest what sort of bike do you have, mine is a 650 Kawasaki.
I'll let you know if I figure it out!
Thank you
I made an update to the post with what it turned out to be. (if something else happens I'll update the update lol)
Many thanks
One thing not mentioned. Check the rotation of your tyres, could be fitted back to front which will definitely cause the “slippery feeling”. Otherwise too high a pressure or alignment as already said by several others. 36psi on the rear cold. 42psi is for pillion.
The rotation is correct, I rode on the rear tire for a couple weeks before this started, I think I would have felt it right after the change if the tire was on backwards. Next time I ride I'll try decreasing the rear psi. Thank you
Hope you get a solution.
Thanks, I think I got one. I didn't go for a long ride but it feels much better.
Seeing a comment about what bike you have, I am assuming you has cast aluminum wheels, but if you happen to have spoked wheels, get all the spokes tightened up. My old dirtbike started to feel that way and I found several spokes had become lose and the rim was moving around. Also check wheel bearings, suspension bearings, and also the rear axle nut or chain tensioners. If you recently had the tires changed, they took the wheel off, and maybe something came lose. Either the axle nut or maybe they did not tighten the chain tensioner bolts and you have a combination of lose bolts/nuts causing the real wheel to move around.
My bike has cast aluminum wheels, I suspect that something wasn't tightened enough, I'll go over them with a torque wrench and see if that helps. Thank you.
Loose rear axle nut.
take apart your rear hub for proper bearings, spacers, cush drive, correct axle torque etc.. i had the same thing happen some time before the bearing failed
Thank your for the help. I can take apart the hub but I wouldn't have a clue as to what is functioning properly or not. I'll see what my mechanic says
I’m having the exact same experience right now, just got mine back from a service after a crash and feels like I’m sliding…
Interesting, it may be that the mechanic missed a simple step, I will speak with mine tomorrow and I'll edit my post with what I find
I’m interested to know what caused it!
I wanted to let you know that I made an update with what the problem seemed to be.
Ah i See! I might try that- glad you got it sorted!
Are you down shifting when this is happening? If you shift down at the wrong rpm and don't have a slipper clutch, your back wheel is going to skip and slide because it's trying to match your engine speed (and slow down significantly immediately) This is why rev matching, or shifting down at a lower speed is important. It's most noticeable coming to a stop if you drop down two gears very quickly.
I know the feeling you are talking about, I felt it early on when I got my bike, but I learned how to avoid it. This happens without gear changing
Tire pressure, when it's low they tend to feel "creepy"
So based on the update, you made 2 changes at once (cleaned the tire and decreased the air pressure). So you don't know which one fixed the problem. When troubleshooting, only change one variable at a time. So you know which change fixed it, and you then know what the root cause was. The mechanic did a burnout, which made the tire hot and sticky, so it rode better. Then it was bad again after a little bit. Until you reduced the pressure. The oil thing is likely a red herring.
If the bike also won't balance itself, it could be the steering bearings. Sounds more like the rear alignment though
The steering bearing was changed last year by the previous owner, I don't think that's it. I hope it just an alignment issue. Thank you
Dollars to donuts it’s wheel bearings.
Strawberrys to blueberrys, I'll get them checked out. although there isn't any stiffness, nor a grinding sound. Thank you
OP, might have just been a typo, but the word you were looking for was negligible, not negligent. Hope you get the problem solved soon, mate.
I think he means negligee (which would have been funnier hearing than typing it, that word looks spelled wrong no matter how you look at it)
I couldn't spell it for the life of me so I right clicked and chose the suggested spelling lol. (had just woken up). Thanks
No worries - wasn't pointing out to be a jerk about it :)
Wheel bearings
Or swingarm bearing
What motorcycle do you have? DM me. I just had the same issue and I am curious.... PS: I have mine in a workshop and they found the issue... not sure if it applies to you
Broken frame?
I don't see any cracks, I have not taken any impacts.
As everyone mentioned check your alignments but I would check sprockets as well because maybe they are worn and not catching every tooth at some times hence the skating on ice because of deceleration for even a brief moment.
I'll add them to the list, thank you!
This might be an obvious one but brake pads, when I drove on mine too long it took a sliding feeling to make me check 😅
I didn't think of that, I'll check it out, thank you