[tylerjones]

ember
Join: May 2018
Posts: 12

about 18 hours ago · #1
I have a 2013 honda rancher trx420fm, it has snorkel, radiator relocated, 4x4, 26" tires on factory rims. It recently had the primary greduced gear removed to stock as with the clutch basket.
So I recently changed the gear reduction back to stock, then soon after i rebuild the front, got it running i realized the main clutch bearing is bad and as well it smoked now after reassembly. It has never smoked before until i removed and installed the front crank case It has a light oil smell with a pure white smoke cloud. It is not much smoke like a head gasket would be. Just very faint from the exhaust. I opened the dip stick and smoke had come from the front crank case as well. I think its the bearing heating up from being worn out. (My guess lol) How can the smoke go from the front case to the exhaust. Did I maybe miss a oil passage restriction plug on the block? I am replacing the clutch bearing tonight, is there anything i should look out for. I also changed the oil and oil filter, i replaced the filter and put ot back in the same way the old one came out.
In need of some good help or brain storms!
Im tearing it down now

 

[shadetree]

just guessing, DID YOU SINK THIS ATV ????. if so ?, well..now your gonna pay..lol.

 

[tylerjones]

No i did not sink it. The previous owner did and rebuilt the motor. It was running great until i swapped the gear ratio back to stock

 

[shadetree]

No i did not sink it. The previous owner did and rebuilt the motor. It was running great until i swapped the gear ratio back to stock

ok, you did not sink it, but it was sunk !. and the other owner rebuilt the top end, what ya wanna bet, he did not split the cases, wash it all out, and rebuild it the correct way ?. now your stuck with a motor that got sunk, had a top end rebuilt, never got cleaned and fixed the correct way, and now your back to square one....right ?. you can not sink a atv motor, just do a top end rebuild, and think this will fix it !. this has been explained over and over on the forums here. its a gamble to sink one, try rebuilding just the top end, and expect it to last ?..IT WON'T !!!. there is no way on gods green earth will a top end rebuild last, not in my book anyway. you want it fixed right ?, then listen : pull the motor, split the motor, clean the cases out, inspect the rod/crank for any wear ?..this means no play at both the bottom and top of the rod. inspect the oil pump, all oil galleys, all bearings must be inspected, cleaned, replaced if bad ?, all new engine gaskets, all new oil seals, replace the cam chain if worn too much ?, inspect your valves, valve guides. do not over look anything !. depending on the condition of the cylinder ?, if it calls for a bore ?, then do it !. if the crank needs replacing or just the rod ?, then do it !. you can't cheap out on any of this !!. do it right , do it once, be done with it ..OR DON'T DO IT AT ALL ! .

 

[shadetree]

oh, and the GR has nothing to do with why its smoking now !!!.

 

[tylerjones]

Shade tree you are awesome thank you so much for your advice i am going to take it in consideration! Im justcurious is there something i did wrong for it to all of a sudden smoke after what i did? Like i said it never did it till I r&i the crank case. Maybe disturbed something or left a journal out? Ive also read installation of the oil filter back words can cause such problems

 

[tylerjones]

Shade tree you are awesome thank you so much for your advice i am going to take it in consideration! Im justcurious is there something i did wrong for it to all of a sudden smoke after what i did? Like i said it never did it till I r&i the crank case. Maybe disturbed something or left a journal out? Ive also read installation of the oil filter back words can cause such problems

 

[shadetree]

Shade tree you are awesome thank you so much for your advice i am going to take it in consideration! Im justcurious is there something i did wrong for it to all of a sudden smoke after what i did? Like i said it never did it till I r&i the crank case. Maybe disturbed something or left a journal out? Ive also read installation of the oil filter back words can cause such problems

thanks for the kind words. yes, a backwards installed oil filter can cause trouble !?!, but you would see this in just a couple mins, not hours or miles ..lol. no, nothing that you did caused this mess !, the mess was before you got your hands on it. now your stuck with a motor rebuild, because the other owner failed to tell you the truth, the whole truth, and nothing but the truth ! ( sheshh..that was just wayyyyyy outta line..even for me !..lol ). want it fixed right ?, then you have been told how to do it ^^^^, if you skimp on ANY of what I explained ^^^ ?, you will be right back on here in no time, asking us why it's doing what it's doing ! .

 

[Jeepwm69]

What shade is saying is, when you sink a bike, you can flush out the bottom end, get fresh oil in there, but you never get ALL the grit out, so you put fresh clean oil in there, slap a new top end on it, and then ride it.

Everything is fine for a while, but that grit in the bottom end is slowly working its way into the oil, which is pumped up to your shiny new top end, and ruining it.

So if you have a sunk motor, the ONLY way to make sure it's good is to completely tear it down, clean out all the nooks and crannies, and then reassemble.

I'm guessing the previous owner's "rebuild" meant slapping a new top end on it and dumping it before it was run enough to start smoking again.

I've been there, done that. Sank my Foreman a while back. I went so far as to take the front and rear crankcase covers off and spray pressurized solvent to try to clean out the bottom end without actually splitting the cases. I got about 100 miles out of it before it was smoking like a freight train again.

I tore the motor all the way down, thoroughly cleaned EVERYTHING, and then reassembled with a freshly bored cylinder with new piston and it's been problem free since.

If you don't tear it all the way down, chances are it will never be fixed for long. Do it right and do it once, or keep throwing time and money at it and have it smoking and rattleing.

There is a 4 part video on youtube that shows teardown and reassembly of a 420 motor. It's time consuming but really isn't that hard. Google "420 crank youtube" and watch it.

Lot of guys here are happy to help, including me.

 

[tylerjones]

Thank you guys again! You all are really good help and so knowledgeable. Its a vlessing to have internet forums like this.

 

[Jeepwm69]

Google "420 crank youtube" and there's a 4 part video showing what's involved in tearing one of these down.

If you sunk it, tear it down, clean it out well, and put it back together. Doesn't cost a lot, just takes time. Replace seals while you have it apart, and I always replace the timing chain because they're only $20 or so, then you know the bottom end is good and you have it fixed right.

 

[shadetree]

Thank you guys again! You all are really good help and so knowledgeable. Its a vlessing to have internet forums like this.

yw. I know most atv owners won't go through the trouble of splitting motors when they are sunk ?, they think they can get by with just a flush ?, well...this is 100% a gamble !!. it may..or may not last ?. why would anyone go through the trouble of wasting time and money on sinking a motor, doing a flush, rebuilding the top end, then hours down the road, its right back to where it was from the get-go is beyond me !!!. I just don't understand the concept on this ????????. its a waste of time and money. if a motor is sunk ?, then tear that puppy down, split it !, wash it out, inspect everything in the lower end, replace all that needs it, put it back together the correct way, and not worry about if it will run, smoke, knock..all of this ?!. I just can't see this in some folks !..lol. when I take on a project ( as I am doing right now on a 2003 trx450fm ), I know the motor was trashed, sooo..i tear it all apart, and fix it the way it should be fixed. you CAN NOT skip this..it just wont work in the long run. want it done half right ?, fine..do a top end rebuild, but chances are , if you go this route ?, they will be right back here in no time, explaining to us, '' hey..i sunk it, did a top end rebuild..and its smoking again..what did I do wrong '' ??. wellllll..there you have it !.