My son has a Foreman 450ES that ran out of oil. I have done a fair amount of tinkering with my Polaris, including reassembling the 2-stroke after having it machined. So, I am competent, but not real savvy. And I know little about the Honda, but my son has a Clymer book.

When it ran out of oil, it started pinging real loud and was shut down immediately. Opening the oil filler indicated no oil, and some smoke came out. After oil was put it, it sounded real tight at first (and noisey), then it turned easily. I don't have a compression gauge that fits this atv, but it does not have enough pressure to move my finger.

Here's my question: what all should I expect to replace? Should I start by just tearing apart the head, or should I assume the worst and deal with top and bottom of engine? Which is easier: pulling the entire engine or working with it on the atv?

THANKS!!

 

i would say you burnt the rings out and possibly the piston...it depends on how long it ran with out oil but if you shut it off as soon as it ran out you might get lucky and only have to put rings in it. but you do have to take the engine off.

 

How did he manage to run it out of oil???? How much oil did it take to fill it back up???

Depending on how low it was, the stuff in the bottom end may or may not still be ok. I don't know how far you have to go before it dosen't get to the oil pump, yet may still have enough for the transmission and crank bearing?

I would look at the oiling diagram in the manual, and figure out just what it was that didn't get oiled, and take a real good look at those areas when you take it apart. But, if you don't know how low it actually went, you will have to go through the transmission as well.

 

make sure it didnt make any big scratches on the cylinder wall, if it did you might have to have them bored out. And when you take the oil plug out watch for any metal shavings to run out with the oil, that will be an indication if theres anything seriously wrong.

 

I would say there's no way to know for sure without taking it apart.

Roller bearings tend to tolerate low or no oil pressure very well, as long as there wasn't a load on the bearings w/o oil for significant time.

Most likely the cylinder, rings, and piston are trashed.

If it were mine, I think I'd take down the top end with the engine in the frame first, and see how things look.

 

<div class="FTQUOTE"><begin quote>JeffinTD
Most likely the cylinder, rings, and piston are trashed.
</end quote></div>
That was my assumption.
<div class="FTQUOTE"><begin quote>JeffinTD
If it were mine, I think I'd take down the top end with the engine in the frame first, and see how things look.</end quote></div>
Okay, and if the valves look okay, but the cylinder, rings and piston are trashed, what would you then do? Wobble the arm to see how much play there is? Peak into the bottom end looking for wear? Basically, what else can I/should I look for before deciding to pull the bottom end?
<div class="FTQUOTE"><begin quote>[b]400exrcr[b]
when you take the oil plug out watch for any metal shavings to run out with the oil, that will be an indication if theres anything seriously wrong.
</end quote></div>
Good suggestion. Oil was poured in after the fact. It took quite a bit. Extra shavings would then mean I should plan on tearing out the bottom end too. But the bearings would not let off much metal, right? How can I tell if the bearings are shot?

 

<div class="FTQUOTE"><begin quote>Okay, and if the valves look okay, but the cylinder, rings and piston are trashed, what would you then do? Wobble the arm to see how much play there is? Peak into the bottom end looking for wear? Basically, what else can I/should I look for before deciding to pull the bottom end? </end quote></div>

I guess I'd decide once I was able to lay my eyes on it. There might be bits of metal, a whole lot of slop in the rod and or crankshaft or whatever that would make it a no brainer (full teardown).

If everything looks fine, feels tight and rotates smoothly, I might consider just doing the overbore, rings, piston... Then run it around a bit. I'd be taking a risk that it might knock or whatever and I'd be going back into it. Hopefully if the bottom end was trashed bad, you would know it rigth away and wouldn't do any damage to the new rings/piston during a brief run.

 

If I can ask, what is the cost for something like that? Mine 450 foreman stalled too? Was low on oil, there was a little rattle then it lost power and stalled. It turns over fine, has spark, seems to get fuel but won't catch and start up?

Does the machine on this post start up and is very noisy or will it not start either?

How much oil should show up on the little dip stick?

Thanks,

C

 

I would say the cost could vary hugely.

If all it needs is the cylinder bored and you did the other work yourself, you would end up with the machine shop charge plus the cost of new piston and rings plus an upper end gasket set.

On the other hand if you brought the whole machine to a dealer, and the bottom end bearings and other additional parts were trashed it could cost thousands.

To check the oil on Hondas you wipe off the dipstick and then set it against the treads w/o screwing it in...

 

Take a good look at the oiling diagram, and see at what level the intake for the oil pump is. That was the low level, when the pump quit delivering oil to the top end and things started to get nasty. That will tell you something about what the bottom end had left to. If the oil intake is way down in the bottom of the sump, you are out of luck.

Don't get cheap! While you have it apart, replace anything and everything that is suspect, otherwise you could be tearing it back down again real soon.