I have a 04 Rancher that I think the wrist pin is bad. Has anybody replaced one before theirselves? What all does it include to do. The guy I bought it from had a ring go bad and had that fixed but I think they should have replaced the wrist pin too but they didn't.

Thanks for any info

 

DR,
I suspect that you havs a knock comming from the top-end and this is the reasin for your inquiry. Top-end knocks can come form a variety of areas like cam chain and/or tensioners, Piston/ring issues, and, yes, the wrist pin. Even some lower-end noises can sound like they are in the top-end. In your case however, considering there is a history of ring failure in this engine, I would bet that you have another ring failure or a piston problem possibly caused by the previous ring failure. Maybe even a damaged cylinder that was not attended to after the last failure.
All of the above scenarios require the removal of the top-end of the engine in order to access them. The only reason I bring up the options is so that you don't overlook something while you have it apart to replace the suspect wrist pin. Which, incidentally, is the least common of all the listed possibilities. To answer your question regarding ease of removal, once you have the cylinder off, its easy to replace the wrist pin. In fact, if you have a problem with your piston, the wrist pin will be accessed when you remove it.
If you plan to tear into it yourself and lack some confidence and/or knowledge, I strongly suggest that you buy a manual and follow it step by step. And get an inch/lbs torque wrench.
Once you have it apart, have your local shop inspect the parts including cylinder run-out.

 

Just got thru tearing it down. The cyclinder looks good with no pits or scars or wear lip at top. The piston looks good with no broke rings or cracks in piston also the rings look to be strong. I grabed the piston and pulled on it and pushed on it up and down motion without rotating the crank, no slop is noticed. The piston slid side to side smoothly.

Now with the wrist pin, I did notice some slop when I tried to go up and down with each end of the piston on the sides of the ends where the wrist pin slides on and off, I know that is complicated wording in other words I put my hands on one end say towards the back of the atv and the other towards the front of the atv and went up and down with the piston it had slop. I know the wrist pin goes thru the rod for about 1/4 to 1/2 inch then thru the piston is this normal slop? if not it would seem that the rod may be the contributor with the outsides of the surface area being larger than the middle causing the slop. Or is it the wrist pin? Or maybe the wrist pin and piston togather? I'm going to take it to the shop hopefully tomorrow and get him to check it out, But I would like to see if I could find out the problem myself and get him to confirm!

Any info JS DS ?

 

If you have any vertical movement between the rod and wrist pin or between the wrist pin and piston, you have a problem. From your description it sounds like you dont. The piston sliding sideways is not an issue. I'm haveing a hard time understanding your description of where you felt movement so I offer the following:
Pull the wrist pin out and see if there is a groove where it goes through the rod. Any groove is an issue. If the wrist pin is grooved (worn), were is rides on the rod, the rod will also be worn and will require replacement.
Have the wrist pin journal of the piston measured along with the wrist pin and the rod, small end. Have them measure the cylinder for run-out as well.
Hondas don't usually have these kind of problems with their engines. What caused tthe ring to break?
I have go now but I will log back on later or tomorrow.

 

js, if ring failure is very common, would this cause oil in airbox at random times, im experiences this now, also when replacing rings, is there anything extra i can do to prevent this issue in the future?

 

The piston slides side to side smoothly on the wrist pin shaft, which is good I know, but tilting slightly up and down on each end of the wrist pin is what I'm not sure of. You can almost see the slop on each end of the wrist pin when you try and make this movement

I'm not sure what happened in the first place with the ring issue. I don't even know what all was replaced, I do know that the cyclinder was replaced because it looks new from the outside.




A note to Little Bill is that I had a lot of oil in my air box when I bought this rancher from when the ring went bad, the carb was sucking the oil from the bottom of the air box and thru the filter into the motor and causing it to smoke a little. But it's not doing that now tho.

I know my Rancher sounds ragidy but it looks like brand new with lift and ITP wheels and tires 26" 424 kit I just have this issue with the knocking sound that is driving me crazy, and I'm eventually gonna fix it !!!

 

Oil in the air box is caused by excessive crankcase blowby. This is where compression leaks past the rings, sending the gas/oil mix into the crankcase. Most companies vent the blow-by into the air filter housing so that it can mix with the intake air and be burned in your engine instead of blowing to atmosphere. The oil part of the blow-by is heavier and settles in the bottom of the filter housing. This is somewhat normal but the more your rings leak (wear) the more blow-by and oil accumulation. Hence DoubleR's broken ring filling the air box sinario.
If your oil build up is intermittent, I wouldn't worry about it. Holding the throttle wide open increases the amount of blow-by so when you ride it hard, you will have more oil in the filter housing. I'm not sure how much is normal on the rancher 400 so maybe others can post their findings as well.
When replacing rings, be sure to have the cylinder hoaned properly and stagger the ring grooves at 90 deg from eachother. Keep a clean air filter and make sure its not allowing dirt to get by.

DoubleR,
The wrist pin may rock a little bit side-to-side inside the rod depending on the width of the rod surface. It should not move inside the piston, that should be a snug fit. Remove the piston from the rod. Then slide the wrist pin (by itself) into the rod and see how sloppy it is. Do the same with the wrist pin in the piston. Ultimately though you should have them measured for wear over tollerance or just simply replace them, not that expensive. I would have the rod small-end measured though, that may be your problem and that will cost ya.

 

thanks for the help, but i have a 350 not the 400 , although my issue is, on cold start up it can dump up to half a quart in the bike, or it can run flawless for 400 miles

 

a 1/2 quart is way over the excessive mark. How well do you maintain the oil and oil level?
If the oil is overfilled it will eventually end up in the air filter. I have reached limits of my knowledge on specific rancher details but maybe it can happen if/when the quad is proped up on the rear wheels, like when transporting it. or it may have something to do with air box restriction. You have to think about the events leading up to the time it pukes oil into the air box. Does it happen right after an oil change? Has it been sitting for months prior? Did you roll it? Did you prop it up on the back wheels for a while? Did it run crappy while the oil was puking?
If you don't have an answer after that, start a thread asking the question. Provide as much info as you can and maybe somebody else has had the same issue and was able to figure it out.
Good luck

 

I took the rancher to a shop today where I know the guy and he looked at the wrist pin to the piston area and he said it looked good their, then put the wrist pin in the rod and that was where the problem was, too much clearance. He said the only way too fix it would be take it down to the crank and put a new one in. That is way past my comfort zone. When we bougt the Rancher it came with the extra waranty that we are gonna check more closely to get everything transferred to my name. When the ring went bad previously the guy had Honda fix it because all the internal parts even the gastets, cyclinder, piston where Honda parts. My guy I had check it told me to put it back togather and take it to the Honda shop and try it. So I called my honda shop and told them my situation with the knocking and the previous problem. They told me to bring it in and they would check the vin number in Honda waranty and tell me more, if its still got waranty and not owners abuse that caused the problem. I'm worried that since the rod aint hanging out the side of the block they won't fix it. Anyway I put it back togather tonight and it fired up just like before runs good as hell just knocking. I'm gonna take it probly Thursday.

Stay Tuned !!!