[YellowRancher]

2004 350 rancher 4x4: the motor started knocking, sounds like it is the connecting rod , from what iv heard rancher's are bad about the wrist pin hole getting wallered out creating alot of play. I would like some opinions on should i just get a connecting rod done to it or get both crank and connecting rod?i was going to send it off to mr crankshaft but wanted some feedback if they were any good or not. Also topend has about 20 hrs on it if not less and started smoking agian any ideas?

 

[Jeepwm69]

Need more info.

Has it been sunk? Was top end bored and honed by a competent machinist?

Mr Crankshaft has a good reputation. If you have play in your crank rod bearing or the wrist pin you need to have a rod kit installed on your crank.

 

[shadetree]

if I remember right ?, you rebuilt the top end awhile back, correct ?, and we told you if the crank was bad ?, been sunk ?, that the motor would need to be split, and cleaned out. you are correct, the trx350 ranchers just don't hold water on their crank rods. yes, you can replace the rod, or, just go all out, and replace the whole crank. your top end did not last because I bet the rod was bad, and it wore out the new rings which prob was not bored out, and a new piston kit installed ?. you can't just toss a top end at a motor, and think it will be good to run ?!, it does not work like that .

 

[YellowRancher]

Yes the 4 wheeler has been sunk, i didnt know that your rod was not suppose to have side to side play and thats my stupidity for not knocking or check with you guys. It has been ran completely out of oil some times due to it smoked alot and when i was riding i would forget to check it. No boring just a litfke honeing to the new jug. I don't know why i never listen to shadtree he has been through this kinda stuff more than i have, but i just wanted to slap it together in order to make a ride with a girl on the mountain. I have a man who owns a atv shop near me who is going to help me slip the cases and take it all apart and do it right for a change. Should i order a new crank and rod or just send it off to mr crankshaft and see if its fixable? Btw when i was rebuilding it tjis past time i noticed some heat wear on the rod but my dad said its kinda norman so we went with it, my mistake for not takeing it out to begin with. This time its going to be done right, and seeing about a cam and high comp piston.

 

[shadetree]

Yes the 4 wheeler has been sunk, i didnt know that your rod was not suppose to have side to side play and thats my stupidity for not knocking or check with you guys. It has been ran completely out of oil some times due to it smoked alot and when i was riding i would forget to check it. No boring just a litfke honeing to the new jug. I don't know why i never listen to shadtree he has been through this kinda stuff more than i have, but i just wanted to slap it together in order to make a ride with a girl on the mountain. I have a man who owns a atv shop near me who is going to help me slip the cases and take it all apart and do it right for a change. Should i order a new crank and rod or just send it off to mr crankshaft and see if its fixable? Btw when i was rebuilding it tjis past time i noticed some heat wear on the rod but my dad said its kinda norman so we went with it, my mistake for not takeing it out to begin with. This time its going to be done right, and seeing about a cam and high comp piston.

bluing on the crank is normal. don't waste your money on a high comp piston, not worth it, you won't gain much, if anything ?!. it's cheaper to replace the rod than the whole crank, but its faster to replace the whole crank. splitting the cases is best, and doing it right !. soooooooo, with all that said, here is what you need to do, buy a complete engine gasket kit, complete engine oil seal kit, new cam chain ( D.I.D ), split the cases, clean it out very well, a tube of yamabond or hondabond where there is no gasket for sealing it up. have the cylinder mic'ed and bored to next size piston, buy a piston kit to fit it, put her all back together..and maybe stay out of deep crap ?, and it should last you a very long time, if not ?, then you will be right back where you are right now, with a broken atv that needs another 200-500 dollars put back into it . old saying goes, if yer gonna play ?, then your gonna pay !..lol. I am not trying to sound like a jerk here bro ?, I am giving you straight up facts on how to make that atv last.

 

[YellowRancher]

Already has a new timing chain, tentioner and guides. Hondabond havs 3 tubes of it but yeah i completely understand were your coming from, my dad says the exact same stuff because he knows how it is, thats all he use to do until he stopped going through mud. Im just going to send my whole crank, and see what needs to be done, if its just the rod then do the rod if its crank and rod looks like im going to be rebuilding a crank or finding a used one. My shop class at school has a broing machine so all that can be done. But mrcrankshafts prices are cheap for what all they do so im going to let them figure out the bottom end.

 

[Jeepwm69]

Yep, Mr crankshaft will fix it. Side to side play is fine but up/ down play is not, and neither is any slack in the wrist pin to rod fitment.

I had a 420 crank that had no play on either end, but was tweaked just a hair. Tore the motor down thrice before I figured out the rod was barely tweaked/ bent.

Tear it down, send the crank to Mr Crankshaft, CLEAN THE BOTTOM END OUT REALLY, REALLY well, and reassemble with a bored top end with new piston and rings.

Google "youtube 420 crank" and there's a 4 part video showing the process on a 420 motor. Very similar to a 350 Rancher motor other than the timing chain is in the back on the 350 and the front on the 420.

 

[YellowRancher]

Why a bored topend? I have a good cylinder and piston with stock bore just need new rings because i lost one when taking it off. No scratches or lips on it.

 

[retro]

....It has been ran completely out of oil some times due to it smoked alot and when i was riding i would forget to check it. No boring just a litfke honeing to the new jug.

....

I have a man who owns a atv shop near me who is going to help me slip the cases and take it all apart and do it right for a change.

....

This time its going to be done right, and seeing about a cam and high comp piston.

Why a bored topend? I have a good cylinder and piston with stock bore just need new rings because i lost one when taking it off. No scratches or lips on it.

Don't ask why, the reason(s) is self-evident. Have your friend measure your cylinder bore in several places. If it is out of spec (properly honed) it will have to be bored oversize with a new piston set in hand at the time of machining. You promised you were going to do it right this time. You are getting solid advice here... we haven't given up.

Your turn.

 

[YellowRancher]

Okay, so boring it is. I have 3 diffrent cylinders should i try to go with the one that needs less boring?

 

[retro]

No, you'll need to measure the best cylinder you have to see if it will be within spec (after honing) or not. If none of your jugs are fit for work then you'll need to have one of them bored. In that case the machinist should have the oversize piston set on hand during the rebore/honing so he can precisely clearance the piston for that new bore. G&H are great at doing that. Don't buy a piston or rings until you find out what will be required. And have fun..!

 

[Jeepwm69]

Do you have a local machine shop that does boring and honing?

Your cylinders likely aren't perfectly round due to wear. Even though they might look good, we're talking 1000's of an inch so you won't be able to tell without measuring with the proper (very precise) tools.

Once they measure your cylinder, they may say "it just needs a hone" but more likely you will need to bore the cylinder oversize (thus making it perfectly round and matching the size precisely to the new oversized piston, which the machinist will use to determine the exact size to bore the cylinder out.

So, take cylinders to machinist, have him measure. If it needs to be bored, ask him how much oversize it needs to be (a lot of the time mine have had to go straight to .5 over as the wear was too much for .25 to cover), and then buy the appropriate piston and take it to the machinist with the cylinder, and he will bore the cylinder to match that piston.

Make sense?

 

[Manny]

I wouldn't stop there, I would take the cylinder head as well to have a 3 angle grind done, valve guides checked, along with fresh valve stem seals.

kinda pointless to do everything below that and not finish up with the head.

 

[misterclean59]

You guys are much more patient than I am. I've had my shop for over 34 years now and it is very difficult to try to help out somebody like this.........in fact I will not anymore.

 

[Jeepwm69]

I wouldn't stop there, I would take the cylinder head as well to have a 3 angle grind done, valve guides checked, along with fresh valve stem seals.

kinda pointless to do everything below that and not finish up with the head.

Good point.

Definitely have this done too. My machine shop charged $30 to do it before they went out of business. Now I just remove the valves, put some grinding compound on the seats, spin it a bit, clean it up, and put in new stem seals.

Well worth it.

 

[YellowRancher]

Iv understand the boring. Alot of the work i can do at school as like i said earlier webhave a machine class which has boring machines, lays, presses,etc... I am going to pull the motor sometime this week and hope that it is not too bad.

 

[fishfiles]

I tell you how I just handled my 450 that had looseness at the crankshaft end of the connecting rod , I bought a new OEM crank and rod $300 , bearings $35 each , all gaskets and seals , new timing chain and sent the cylinder to G+H who bored bored it , sent an new piston , rings and wrist pin with gaskets $200 , and threw in new clutches , all the parts and bore job was $700 even , you might save a few dollars with a machine shop , doing the crank work and cylinder service , but for me it was a lot faster and less chance of things going wrong going the way I did

 

[YellowRancher]

So i have to buy a new timin chain and tentioner and what not when i tear it down?

 

[shadetree]

So i have to buy a new timin chain and tentioner and what not when i tear it down?

nope, just the cam chain should be bought new, adjusters last a long time on the ranchers. soooooooooo, you need either a whole new crank ( or a new connecting rod pressed on ) ?, piston kit to match the cylinder that will get bored over, all new gaskets ( complete engine set ), all new oil seals ( best to do this while your tearing the motor apart ), new cam chain, then learn how to not only take it all apart ?, BUT TO PUT IT BACK TOGETHER AS WELL !..LOL.

 

[YellowRancher]

Lol, iv had it close to splitting the cases last time. My only trouble is organizing the bolts and where they went.