2007 Honda foreman 500 4x4 es smoking

[Mech]

Yup.. See how many people are viewing the posts.. It's why I post long detailed posts..  Other people will get something that will help them, if not now, then in the future. They will remember.. the mech reckoned...

[Ejwill]

Thanks everyone, I’ve got a lot to consider. Can you do the top end without pulling the motor. If I need to pull the motor I might have to recruit my neighbor to help no way I’ll get it out and on the work bench in my wheelchair.

6 hours ago, Cj Winds said:

Most likely the oil ring. You should rebuild top end, bore cylinder and use bigger piston.

what part of this would I need the dealer or someone to do. Bore cylinder, get bigger piston??

[Ejwill]

I have a question about the crankcase vent line. It goes into the air filter box. Does it supposed to have some kind of filter on the end of it, like a foam filter. I remember when I changed the air filter I saw one of the lines and I think it was the crankcase vent line. It had what looked like someone had made a foam filter to go on the end of it it looked homemade, it was folded over on the end and tie rapped down . I blew compressed air through it and it went through no problem, I was just wondering how much restriction the vent could have before causing it to pressurize the crankcase. This one was definitely a homemade job. I didn’t notice if the smoke got better or worse when I had the vent line disconnected. Should I check it with the vent line loose and check the smoke or would that even make a difference? Sorry if I’m getting too long winded here. Thanks again for everyone’s help.

[Mech]

It's normal for vents to push a little air out, but not really with much pressure if you just put your finger over it for a few seconds. If it starts to build up pressure you can feel firmly almost straight away,  well that's a bit of a bad sign. It can mean worn rings.

If the vent isn't sending out a steady high flow, or pressure then it's probably not the problem. Check the colour of the smoke, and see if it lingers in still air.. See whether it smells like burnt oil, or evaporated oil..

As for the vent hose, it's pretty common for the main vent hose to go up the front of the bike, up high, and then often turn around and come a little down in height again.It gets the end of the pipe as high as it can because that lets it go through deeper water, and the lowered bit so dirt or splashed water doesn't just go down the hose.

That main vent hose often has a branch off it down near the engine and that branch goes to the air-box.When it gets to the air-box it has some restriction, or, there is a pushed in restriction in the hose. The idea is that if you go into deep water, and the crankcases are cooling and the air will get sucked in as it cools, well, if you have a small restricted inlet for air, that water won't get sucked down the main hose. Air from the air-box will get sucked into the crankcase instead. The restricted air comes from the air-box, the last thing that's going to get flooded before the engine stops..

Oh, and your compression figures sounded fine to me..

[Gwbarm]

What he said! Glad to have you back Mech 👍

[Cj Winds]

Yes you can rebuild top end without pulling motor. Cylinder and new piston should be brought to a machine shop that can bore small cylinders. The vent line that goes into air box will have a small foam filter at the end.

[jen]

Jeff will like that.  Just pulling the "jug"  off as he called it.  Maybe the machine shop would install the new rings and piston into the cylinder as i am sure he does not have a ring compression tool.  ???

[Cj Winds]

Piston and rings will be installed on connecting rod first. Then cylinder (jug) is installed onto piston with rings compressed using only your hands, no tool needed.

[jen]

I looked up rebuilds ..They have complete rebuild kits from amazon and  Niche (BTW Fredrich Niche was famous philosopher "That which does not kill us makes us stronger")

The kits have new cylinder ...wow everything..$115.00.  Jeff would need to make sure of exact model .

 

[Ejwill]

“That that does not  kill us makes us stronger “ evidently he never had a car run over him when he was riding a motorcycle. If it doesn’t kill you, it just makes you suffer longer. Hey maybe I’m one of them philosophers.🤪

[Gwbarm]

That philosophy only applies to younger riders. As you get older you take a fall, you get up very slowly, first thing is to make sure everything still works. You dont just shake your head and go about your business as you did when you were younger. 

Im a motorcycle rider also , after my last spill i got up slowly and noticed my left shoulder down my rib cage was not working. Went to the Dr got  X rays nothing broken but in severe pain for a month couldnt lay flat, still have trouble walk different i think it knocked my spine out of alignment. Needless to say i dont really ride much anymore, certainly not on interstate or heavy traffic, people have very little respect for motorcycle riders.

Sorry to hear about your suffering!  

[Ejwill]

You are right, people say motorcycles are dangerous but it’s not the motorcycle it the people around you that make it dangerous to ride bikes. Plus I got hit by an IAD. Illegal alien driver no insurance no driver’s license. He fled the scene of an accident that had serious injuries which is a felony in Georgia. I had to tell the district attorney it was a felony and give him the code. He shouldn’t have been here and sure shouldn’t have been driving, didn’t know you couldn’t turn left on a green light with oncoming traffic. Now I can take my left leg off when I get tired or go to bed.

[Ejwill]

10 hours ago, jen said:

I looked up rebuilds ..They have complete rebuild kits from amazon and  Niche (BTW Fredrich Niche was famous philosopher "That which does not kill us makes us stronger")

The kits have new cylinder ...wow everything..$115.00.  Jeff would need to make sure of exact model .

 

Thanks for finding that for me, it’s not as bad as I thought.

Well, I know that’s a deep subject. But I hope I haven’t screwed up but I have the cylinder head cover off. I was starting on the cylinder head when I noticed one of the cylinder head nuts were loose I took it off with my fingers. Could this be causing some of the problem. It was even screwed down all the way. I didn’t know if this could cause an oil problem or not. Like smoking.

[jen]

look up kit based on your exact model.   it has a picture of what is included.  

[Cj Winds]

The cheap top end kits that include a cylinder are mostly junk

[Gwbarm]

I have never used one, always thought they were to cheap to be high quality parts. I always go back with OEM parts when it comes to piston and rings. I have used many Niche parts and they are one of the better aftermarket manufacturer, never had a problem with any of their parts, I looked up the rebuild kit and it only got 2.5 stars, pretty low satisfaction rating. I did notice that one of their(Niche) kits come with Weiseco Piston so if the rings are also Weiseco i wouldnt have a problem using that, just read the specs very carefully before you order.

[Ejwill]

I’ve got the cylinder off and now have to pulll one of the clips holding the piston rod in. Not sure what to use. Also the valves and area are caked in carbon. Do you have to use the spring tool to remove the valves or is there a way to do it without the special press. The cylinder wall looked ok no scratches or gouges. What is the oem piston size mm diameter. How clean does the combustion camber have to be get all the loose carbon off or take it down to origin metal? If it’s the latter It’s going to take a long time, I’m getting most of it off, down to where it looks smooth but not down to bare metal. The valves are still in, it’s clean around where the valves open just below where the seat would be. And again do I need to get the spring compressor or can it be do another way, c- clamp with a large socket over the spring. I know I would have to remove the stop that holds the spring so if I tried that I would have to modify a socket so I can get to it. I’ll see how much one cost for a power sport or motorcycle one before I go to all that trouble.

I found them on Amazon for little over $20 that’s what I do. They are for atv’s and motorcycles.

Edited July 13, 2025 by Ejwill

[Ejwill]

I put the spark plug back in and filled the combustion chamber with solvent. It’s coming off better now down to the original metal. Wish I has ordered that tool sooner. Question how can you tell if the rings were bad?

[Ejwill]

I saw where you can put the old ring just in the cylinder square them up and see how they fi all of them but the oil spacer rings were very tight, butting together with no gap, the first one you put on the oil spacer rings, was so loose it fell through the  cylinder. It was a lot smaller than the others were. I don’t know if this is a good way to check your rings or not. Does anyone know? I’m just trying to figure out where the problem was. I’ve ordered new rings, I hope that will do it.

[jen]

i have used ring compressors that fit around th piston to hold rings tight.   then slide the ppiston with rings up into cylinder.'howevr GW sauid tou probably can use hands to compress.

[Ejwill]

Thanks Jen, I don’t have one so will probably try my hands. I can do fantastic things with my hands.🤩.

[jen]

like what...????  do you massage ?   Are you hairy ...I love hairy guys LOL.

[jen]

just kidding...i think the rings can be fitted around the piston an then fitted into cylinder. remember to stagger the ring edges...let me see the kit you get.

[Gwbarm]

Sorry guys I have been gone for a week, looks like i missed all the fun stuff. I didnt take my computer and didnt keep up. 

Where are we at on the rebuild now.

I will try to answer a few of your questions. Yes you need to remove all of the old carbon from valves and piston.

A ring compessor is nice and i have one but i generally use my hand to press down the spring and remove the keepers with a magnetic tool.

I would put the rings in the cylinder and check the ring gap with a feeler guage the manual will tell you the servicable limit, Butting together with no gap means there is no ring wear. But check it with the feeler guage to measure the gap. When you put the ring in the cylinder put the piston in behind it an bump slightly to level up the ring and then check the gap.

[Ejwill]

On 7/16/2025 at 11:42 PM, Gwbarm said:

A ring compessor is nice and i have one but i generally use my hand to press down the spring and remove the keepers with a magnetic tool.

All I can say is you’re one hell of a man. Probably have a “S” on your chest and can fly. Now me, I have to use the compressor and it takes all I’ve got then.

[Gwbarm]

They are sometimes tough i guess i have done it so long i know just where to press and how hard. How is the rebuild going? Any problems.

[Mech]

Howdy folks.

I suspect Gw meant ring compressor, not spring compressor, as in valve spring compressor. You do need spring compressor for valves.

Most jap bikes have enough taper at the very bottom of the cylinder that you don't need a ring compressor to slip the cylinder down over the piston..

That cleanness around the valves generally is a sign of oil burning. A clean running engine has carbon, dry carbon, right to and over the valves.

The oil ring that fell through the bore is probably the wrong size for the bore, perhaps someone had fitted it years ago. They don't wear that loose, and they don't overheat and soften like top rings can do.. It will be a wrong part I'd be sure. Someone, probably the person that left the head nut loose, probably bent an oil scraper while fitting it to the piston or into the bore, and so slapped some old ring they had laying around in there..  It happens !

[Mech]

That oil ring will be plenty enough reason for it to smoke.  You could put a compression ring in the bore and measure it's gap top, middle and bottom of the bore and compare the measurements. The gap will change at about three times the bore does, so if it reads as a three thou gap at the bottom and around nine thou just below the top, if means it has about three thou taper.

If the bore is good, and the ring grooves in the piston seem good, I'd check the rod for sideways lean to try and detect any play in the bearings, then get a new ring set and slap it back together. I'd do a valve grind and check the guides and fit new seals at the same time and it will probably go for years.

When you are taking the piston off or on, and if possible before you even lift the cylinder off the piston, it's a good idea to slip a rag in around the rod so no broken ring or circlip can drop into the sump. Same when putting the piston circlips in, make sure to have a rag around the rod.. It's simple to drop a circlip and then it's a whole heap of trouble..  haha.

[Ejwill]

Yeah, I had shop rags packed in the opening and I dropped one circlip. I pulled the shop rags out trying to be careful and when I got them out I couldn’t find the clip. I thought oh no now what. We usually blow out the garage with a leaf blower. But I decided to sweep out from under the wheeler. I made one pass under it and looked and there was the clip. Talking about lucky, I just knew it had fallen in with the crank. If I had blown it out I would have been wondering and waiting for something to happen. So finally I got lucky, I hope it stays with me putting this thing back together I’m sure I’ll need it and some help from you pros. I had lost one of the spring holders that go on top of the spring, and while I was looking for a masonry bit in my drill case, I found it didn’t even remember picking it up. But was sure glad to find it. A lot of my parts some cost $10.00 and have $9.00 shipping. And get a message saying if you spend another $139.00 you get free shipping. I don’t think so. Anyway thanks to everyone that comments. I really appreciate it. Hope my gaskets come in tomorrow or Tuesday. That’s all I need to get started. Going to be real nervous when I hit that starter for the first time. Mech I guess it’s about 2:57 pm there, its 11:57 pm here. You got most of the day left. All y’all take care and be safe.

[Mech]

Yup it was about 2:57l.. I'm in N.Z.