P500 P500 engine rebuild

[70Bones]

Hi guys, when my 2017 P500 was new, I swamped it and got muddy water inside the engine. Now, at about 1000 miles, it's burning oil and i'm thinking of rebuilding the top end.

My first question: is the cylinder hardened or coated in any way? Meaning, to get an engine as good as factory, would it be ok to get it bored .025 or .050 over, (depending on condition?) or should I buy a new cylinder?

Second question: Can I do it in-situ, or should I remove the engine?

Third question: Is there value in replacing the piston?

Fourth...: are they any tricks or Honda specific issues I should be aware of?

I appreciate any help,
Steve

 

[Admin]

 

[Duckhunt]

Hi guys, when my 2017 P500 was new, I swamped it and got muddy water inside the engine. Now, at about 1000 miles, it's burning oil and i'm thinking of rebuilding the top end.

My first question: is the cylinder hardened or coated in any way? Meaning, to get an engine as good as factory, would it be ok to get it bored .025 or .050 over, (depending on condition?) or should I buy a new cylinder?

Second question: Can I do it in-situ, or should I remove the engine?

Third question: Is there value in replacing the piston?

Fourth...: are they any tricks or Honda specific issues I should be aware of?

I appreciate any help,
Steve

There is a steel/iron sleeve inside the aluminum cylinder. They make oversized pistons so it's okay to bore them larger, usually .020 (.5mm) is standard oversize they do make larger but I personally wouldn't want to go that big in the stock sleeve.

You can do the top end with the engine in the machine. You have to remove the seat support. I recently just removed my entire engine to do top end and a cam, there's only two motor mount bolts but you do have to loosen the differentials and slide the drive shafts back and fwd from engine, I had to remove front anyway to get front cover off. But for me (and my back!) so much easier on a bench in front of you, than leaning over the machine all the time. Engine is heavy but not "that" heavy. I'm a big guy but don't think I'm above average strength, and I could carry engine around, just used a come-along to lower it in. There's another application motor mount on the left side I used a 3/8" 6" long bolt, and on the front right side of cylinder head there's some metric threaded holes (6mm or 8mm can't remember) where they use another motor mount in quads. These two points is where I connected chain to lift and lower engine. Just my $0.02. At the moment I decided to remove engine instead of pulling seat support I had motor on bench in like 65-70 minutes. That's unhooking all the electrical connectors, loosening battery box just to move it away, rear differential/driveshaft, starter & shift motors, lower water hose and, motor mounts. Hopefully not forgetting something but you get the idea!

I never swamped mine but after 2500 miles there was maybe two score lines in the cylinder I COULD NOT grab a finger nail on. Still good cross hatch. I know your situation is different but when I was an engine machinist 99.99999% of Honda single cylinders that came in the shop to get bored from burning oil and weaker compression had nothing more than glazed cylinders still within spec. Meaning they really just needed a quick light hone and new rings. But if your cylinder is scored where you can feel the lines I highly recommend reboring and therefore new piston. It could be cheaper just to buy a cylinder/piston kit on EBay too.

I don't know of any issues. I'd remove your lifters and mark them so you know what hole they came out of. Techincally they don't need to be removed but in the case you roll the engine to look inside while you're swapping pistons (if you're going that route) or whatever you don't have to worry about them falling out and not knowing what hole they came out of!

 

[70Bones]

There is a steel/iron sleeve inside the aluminum cylinder. They make oversized pistons so it's okay to bore them larger, usually .020 (.5mm) is standard oversize they do make larger but I personally wouldn't want to go that big in the stock sleeve.

You can do the top end with the engine in the machine. You have to remove the seat support. I recently just removed my entire engine to do top end and a cam, there's only two motor mount bolts but you do have to loosen the differentials and slide the drive shafts back and fwd from engine, I had to remove front anyway to get front cover off. But for me (and my back!) so much easier on a bench in front of you, than leaning over the machine all the time. Engine is heavy but not "that" heavy. I'm a big guy but don't think I'm above average strength, and I could carry engine around, just used a come-along to lower it in. There's another application motor mount on the left side I used a 3/8" 6" long bolt, and on the front right side of cylinder head there's some metric threaded holes (6mm or 8mm can't remember) where they use another motor mount in quads. These two points is where I connected chain to lift and lower engine. Just my $0.02. At the moment I decided to remove engine instead of pulling seat support I had motor on bench in like 65-70 minutes. That's unhooking all the electrical connectors, loosening battery box just to move it away, rear differential/driveshaft, starter & shift motors, lower water hose and, motor mounts. Hopefully not forgetting something but you get the idea!

I never swamped mine but after 2500 miles there was maybe two score lines in the cylinder I COULD NOT grab a finger nail on. Still good cross hatch. I know your situation is different but when I was an engine machinist 99.99999% of Honda single cylinders that came in the shop to get bored from burning oil and weaker compression had nothing more than glazed cylinders still within spec. Meaning they really just needed a quick light hone and new rings. But if your cylinder is scored where you can feel the lines I highly recommend reboring and therefore new piston. It could be cheaper just to buy a cylinder/piston kit on EBay too.

I don't know of any issues. I'd remove your lifters and mark them so you know what hole they came out of. Techincally they don't need to be removed but in the case you roll the engine to look inside while you're swapping pistons (if you're going that route) or whatever you don't have to worry about them falling out and not knowing what hole they came out of!

Thank you, that's great info that I needed. The reason I asked about cylinder coating is that I also have a BMW motorcycle, and the cylinder walls are nitrided or nicasiled or something to harden them more than steel, I wasn't sure if these Honda engines had something like that. I guess I'll disassemble and see how much damage there is, then order parts. Thanks again!!!

 

[BLZI]

i actually have a question that pertains to this.. 2019 500 i also took in water and after getting it back running it started to smoke while driving. i checked the cylinder bore and it was in good shape so i ran a quick hone in it and installed new rings (with the ring gap spaced about 1/4 turn or so for each ring) and installed gaskets. this worked good for about 4 months or so then started smoking again.. is there anything i may have missed? i let it idle for a couple of hours a day for about 4-5 days. about to do it again and just wanted to check

 

[Duckhunt]

I bet the cylinder glazed over from idling. I'd run it normal variable rpm for the first few hours to get the rings to seat. Idling, with lower compression gases, can cause too little force on the rings against the cylinder wall, therefore they don't spin and glaze the cylinders over, and cause blow-by and oil burning.

Back in my engine machining days 9-10 Honda single cylinder 4 strokes I bored out was absolutely perfect except for glazed cylinders. I seriously could not get over it and even told the shops that brought me the stuff they just needed to put a cross hatch in it and new rings and every time they just told me to bore it. But I pieced together most of these cases were farmers that idled their machines A LOT.

My 2 cents anyway.

 

[BLZI]

nice info.. bet you are right.. thanks for the info!!

 

[70Bones]

I bet the cylinder glazed over from idling. I'd run it normal variable rpm for the first few hours to get the rings to seat. Idling, with lower compression gases, can cause too little force on the rings against the cylinder wall, therefore they don't spin and glaze the cylinders over, and cause blow-by and oil burning.

Back in my engine machining days 9-10 Honda single cylinder 4 strokes I bored out was absolutely perfect except for glazed cylinders. I seriously could not get over it and even told the shops that brought me the stuff they just needed to put a cross hatch in it and new rings and every time they just told me to bore it. But I pieced together most of these cases were farmers that idled their machines A LOT.

My 2 cents anyway.

Are you saying that the rings move around the piston when the engine is running? Maybe I read that incorrectly, but rings don't move after you install the piston...

 

[Duckhunt]

Are you saying that the rings move around the piston when the engine is running? Maybe I read that incorrectly, but rings don't move after you install the piston...

Yes. They do. On four strokes. Google it all day long. I don't want to start a pointless argument but they have to!

 

[NitroxDiver]

Hi guys, when my 2017 P500 was new, I swamped it and got muddy water inside the engine. Now, at about 1000 miles, it's burning oil and i'm thinking of rebuilding the top end.

My first question: is the cylinder hardened or coated in any way? Meaning, to get an engine as good as factory, would it be ok to get it bored .025 or .050 over, (depending on condition?) or should I buy a new cylinder?

Second question: Can I do it in-situ, or should I remove the engine?

Third question: Is there value in replacing the piston?

Fourth...: are they any tricks or Honda specific issues I should be aware of?

I appreciate any help,
Steve

When you say it’s burning oil is it smoking or just using some oil? I started using synthetic oil in my machine at 1000miles and it uses oil now no smoke. I’m going to switch back to conventional oil next service and see if it stops.

 

[906UP]

Are you saying that the rings move around the piston when the engine is running? Maybe I read that incorrectly, but rings don't move after you install the piston...

Yes. They do. On four strokes. Google it all day long. I don't want to start a pointless argument but they have to!

@Duckhunt is correct, only 2 cycle engines have the locating pin so the ring end/gap doesnt catch the edge of the exhaust port.

 

[Bastardchild]

I redid the topend of mine a while back. Im sure I documented it on here somewhere, and I came to the conclusion that if I ever had to do it again I would just throw a big bore kit in it. I seen a 550cc bigbore kit floating around on the internet somewhere that requires the same amount of work as redoing the top end back to stock. Thats 75cc bigger than stock. I didnt pull the engine. Just the rear rack and fenders and the metal crossmembers that support the seat and had a decent amount of room to get in there and work. Whatever you do post pics!

 

[Splorin]

When you say it’s burning oil is it smoking or just using some oil? I started using synthetic oil in my machine at 1000miles and it uses oil now no smoke. I’m going to switch back to conventional oil next service and see if it stops.

Cat converters can sometimes mask the visible 'smoke'.

 

[ehart814]

Should be a pretty easy job. No overhead cam makes it easy. My 500 used a bit of oil and it was never swamped. I ran synthetic oil in it since the 2nd oil change. If I coasted down a big hill, engine braking, it would blow a puff of smoke when I got back on the throttle sometimes. I had removed the cat from my 500. Had over 4000 miles on it when I sold it. I think to some extent all the 500's will use some oil after some miles. I suspected the valve seals might be bad, but after hearing other reports I think it's just a characteristic of those engines that they will use a little. If it's smoking excessively, then yes I'd at least throw rings in it and crosshatch the bore. I'd put new valve seals in while I was at it.

 

[70Bones]

Well guys, I stand corrected, and learned something new today, thank you! Piston rings can move around the piston as they seem fit. They may, or may not, but I guess it's common knowledge or 2 stroke engines would not have their rings pegged.

This means that it really doesn't matter where we offset the ring gaps when rebuilding, other than at "first fire" they be spaced and minimize oil burning. They may be offset for many hours, or forever, or they may line up and cause pressure in the crankcase which blows oil fumes through the PCV into the air filter for burning.

This may be what @BLZI is looking at, where he put new rings in and after a few hours the engine started smoking, maybe the ring gaps have aligned. Maybe a couple more hours of operation and the rings will move a bit more and it will stop burning oil?

 

[70Bones]

I redid the topend of mine a while back. Im sure I documented it on here somewhere, and I came to the conclusion that if I ever had to do it again I would just throw a big bore kit in it. I seen a 550cc bigbore kit floating around on the internet somewhere that requires the same amount of work as redoing the top end back to stock. Thats 75cc bigger than stock. I didnt pull the engine. Just the rear rack and fenders and the metal crossmembers that support the seat and had a decent amount of room to get in there and work. Whatever you do post pics!

I agree with you, if or when I tear mine apart, I'd like to go with a big bore kit. Only question is, with fuel injection, would the injector require replacement? Would an aftermarket FI controller be required to make up for the extra fuel required?

 

[Duckhunt]

Well guys, I stand corrected, and learned something new today, thank you! Piston rings can move around the piston as they seem fit. They may, or may not, but I guess it's common knowledge or 2 stroke engines would not have their rings pegged.

This means that it really doesn't matter where we offset the ring gaps when rebuilding, other than at "first fire" they be spaced and minimize oil burning. They may be offset for many hours, or forever, or they may line up and cause pressure in the crankcase which blows oil fumes through the PCV into the air filter for burning.

This may be what @BLZI is looking at, where he put new rings in and after a few hours the engine started smoking, maybe the ring gaps have aligned. Maybe a couple more hours of operation and the rings will move a bit more and it will stop burning oil?

Yup no worries! I learn something new everyday! I just learned today from a millenial my work cell (never owned my own cell) can operate off my home wifi if we gotta work from home. Cell service is a negative number at my house.

I agree with you, if or when I tear mine apart, I'd like to go with a big bore kit. Only question is, with fuel injection, would the injector require replacement? Would an aftermarket FI controller be required to make up for the extra fuel required?

You don't need a new injector, I have the big bore kit and the power commander V with autotune. It does not struggle to meet the same afr's by going -6 to +23% fuel over stock. And at top end it actually does not need to trim fuel much at all, when it is injecting the most. But you will need a fuel controller. They will provide/sell their program for a power commander V, but personally I'd still run an autotune then you know you're getting good afr's. Plus the power commander you get ignition advance. But Dobeck is easier and requires no cu'puter.

 

[Timmy]

@Duckhunt is correct, only 2 cycle engines have the locating pin so the ring end/gap doesnt catch the edge of the exhaust port.

Swamped my p500 in a deep creek. Engine fires, fuel pump is running, fuel injector sprays fuel. Engine won’t run. If I dribble gas in the intake it will run. Done compression check. It has 130 lbs of compression. Can anybody give me any suggestions?

 

[trigger]

Swamped my p500 in a deep creek. Engine fires, fuel pump is running, fuel injector sprays fuel. Engine won’t run. If I dribble gas in the intake it will run. Done compression check. It has 130 lbs of compression. Can anybody give me any suggestions?

Are you snorkeled and vented? If not, my guess is water in the fuel tank?

 

[NTCPrezJB]

Swamped my p500 in a deep creek. Engine fires, fuel pump is running, fuel injector sprays fuel. Engine won’t run. If I dribble gas in the intake it will run. Done compression check. It has 130 lbs of compression. Can anybody give me any suggestions?

Did you drain the fuel tank?

 

[Duckhunt]

Will it stay running after dribbling in gas? If not dead give away what they said. Drain your gas.