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jstatham

1996 Foreman 400 Rebuild project-Top end Help!!

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Hello everyone.  I am in the process of rebuilding a 1996 Foreman 400.  When it was parked about 15 years ago it was smoking like a freight train so I knew it needed new rings.  I bought a 450 top end kit off ebay. I installed in a few month ago and fired it up for about a minute and everything seemed fine.  I then tore the entire thing down to just the engine and the frame.  I have been redoing the brakes,tires,paint,carb, etc. Today I got it but back together enough to fire it up. I figured I would let it idle for about 15 minutes then turn it off and change the oil and filter.  In this process I discovered the new top end it cracked.  I have oil seeping out between the fins.  Is there something I did wrong or did the cheap ebay kit have a bad casting.  What do I do now?  Have the OE bored out?  Try another ebay kit?  Anyone with experience I would love some advice.

 

Here is the kit I bought.

https://www.ebay.com/itm/Honda-Foreman-450-Top-End-Rebuild-Kit-Cylinder-Piston-Gaskets-Std-90mm-1998-2004-/363223986276?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=711-127632-2357-0

 

Here are a few pictures of the leak.

 

https://youtu.be/-vkzcF9gLgg 

 

Any help will be greatly appericated.

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I would try and clean it up with starting fluid and see if you can see the leak start back up

If not, I would suspect drip down from valve cover or a leak-out through the cylinder stud hole oil passage

/head gasket area that goes up to oil the rockers and valves

If it is indeed a flawed casting or similar you should contact the seller for warranty/replacement/exchange

My money is on a simple leak but let us know what you find out

 

Also not sure on the audio, but ii kind of sounds like you might have timing chain or failed chain tensioner slapping around in there as well

 

PS WOW that is a pretty cheaply priced kit for sure, I pay more than that for an  OEM piston alone- lol

AKATV

Edited by AKATV

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I can literally see it bubbling out from the casting . Looks like there is a hairline crack going down.  You can see it in the video. It’s dry everywhere but there. It’s hard to film.

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Man I’m sorry to hear that that’s a real bummer

I would try to make the supplier either warranty or replace it or something along those lines but unfortunately I think the cheapness of the kit probably speaks of the quality of the kit

You might just be better off in the long run going with something a little more quality or a used OEM one

But in all honesty, being what it is- just a cylinder with a liner, I would think if they replaced it for you you’d be good to go

There’s just not too many things to go wrong that I could think of but that’s just my opinion

Have you had any contact with the seller since having this issue?

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I sent the seller a message and they are forwarding to their engineers. I hope they don’t give me a hard time but there is nothing I could do to make hairline cracks in the jug. What kills me is where is located is a long was from the piston and I don’t see how how could get to where it’s pushing out strange. If you watch that video at the very end you can see it bubbling out.

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One of the cylinder stud holes in the jug is actually an oil galley to the upper end for the valves and rockers

Since oil travels up through one of the stud holes to the top end,  I suspect it is that stud hole area in the cylinder is cracked out

How that would happen is beyond me, but would be interested to see what their "engineers" say, it might be casting flaw as well

I was wondering if it was a new cylinder or a refurb?

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They are sending out another tomorrow.  Fingers crossed it will be good.  Should I just replace the jug or do the piston and rings as well..  The piston and rings on it have only ran at 10 minuets at and idle.

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If it was me I’d put new rings in, but with a good hone I would think that your rings that you had probably not even had a chance to completely seat yet

It’s cheap enough to put a new set of rings in and not have to worry about it and know that the job was done right

 

Maybe see if they’ll send you a whole new kit and you can just return the old kit since it was defective to begin with?

Edited by AKATV

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The kit will come with everything so I am going to put in the new rings and jug. They told me they have sold over 100 of these kits and mine is the 1st one with this problem. Lucky me.

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Keep us updated on how it goes. 

 

I won't say I never use china parts, but I don't ever use them on anything that isn't super easy to replace (so no china parts if it involves engine parts).

 

Sometimes they work, sometimes they don't, but the frustration created when they don't is enough to kill my enjoyment I usually get working on these things.

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Hopefully I will get it right this time.  While I am in there do you know the specs on the Rod Bearing play and how to check it.  I want to make sure I'm not wasting my time.

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I just grab the rod and pull straight up and down on it.  If it moves, you need a crank rebuild. 

 

That said, what is much more likely to be wrong with a connecting rod is the small end being worn.  Take a new wrist pin, stick it in the rod until the end of the pin sticks out a hair, then wiggle the long end.  If you have any play there, your rod is shot.

 

I normally err on the side of "rod is bad" if there's any question.  Nothing worse than having to go back through the whole process again for the $225ish that a crank rebuild costs me from Vince at Mr Crankshaft.

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Thank you I’ll check that while I am in there. What about side to side play?
 

 

 

 

I sent the seller a message and they are forwarding to their engineers. I hope they don’t give me a hard time but there is nothing I could do to make hairline cracks in the jug. What kills me is where is located is a long was from the piston and I don’t see how how could get to where it’s pushing out strange. If you watch that video at the very end you can see it bubbling out.

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Some side to side play is normal.  Specs are probably in the FSM, but I've never seen one that had much side to side play that didn't also have a worn wrist pin hole and/ or up/down movement in the rod, so I would concentrate on up/down and the wrist pin hole.

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Thanks again.  Here is what I am seeing in the manual.  I'll post a video when I get it broke down.  I am sweating bullets hoping its not bad.

 

 

image.png

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35 minutes ago, jstatham said:

Thanks again.  Here is what I am seeing in the manual.  I'll post a video when I get it broke down.  I am sweating bullets hoping its not bad.

 

 

image.png

 

I've been getting Vesrah 500 rods for about $100.  I normally send two at a time to Vince, and I think the last two I sent ran my $230  ($115 each) for him to install the rod, true and clean the crank, and send it back.

 

So for $225ish (figuring in shipping them to him) I get a "new" crank that is as good or better than new. 

 

If there's any doubt, send it to Vince.  Then you'll know what you have is good for a LOOOONG time, assuming you take care of it.

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50 minutes ago, jstatham said:

OK I just broke it down and I believe the bottom of the rod is fine but I would like your opinion on the top.

 

https://youtu.be/J9-Dp9mM1is

answer: TOO MUCH TOP END PLAY !. and too much side to side play as well, rod is bad.

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You should NOT be able to wiggle the wrist pin up and down at all 

That side to side play looks a little extra sloppy just to my eye 

 

 

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Yep, that wrist pin will rattle like ! under load and ruin a new top end in short order.

 

Vince is in Benton KY, which is right along the path that storm took a few days ago.   Hopefully he came through the storm ok, but with the amount of damage that thing did his shop might be out of commission. 

 

http://www.mrcrankshaft.com/

 

You can get the rod a hair cheaper here, but with shipping and tax might not be worth the hassle vs Vince's price.

 

https://www.denniskirk.com/vesrah/connecting-rod-kit-va-1017.p145326.prd/145326.sku

 

Assuming Vince is ok, you might call him and talk to him.  He is a great guy and I spent a long time talking rods/cranks with him on the phone before I sent him the first crank for a rebuild.  He's done about a dozen for me since, and every one of them has been perfect, with a turnaround time usually under a week including shipping time. 

 

Again, with the storm things might be a little iffy at the moment, but under normal circumstances he is 100% where to go for a quick and reasonably priced quality crank.

 

 

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I am pretty sure Vince came through ok because I have been emailing him about the crank.  I found him on another thread researching my issue.  I am torn on what to do.  I am suppose to have this thing ready by Christmas and if I break it down and do the crank there is no possible way.  I am also not sure I have the skills to completely rebuild it.  I have done Boat motors, small engines and do my own auto maintenance but never done an ATV before.  If I do roll the dice and just put a top end on it how long would I have before it needs rebuilt completely.   If I can kick the can down the road 6 month to a year I would have a better budget and more time.  What all parts do you replace when you do a bottom end rebuild.  I am assuming crank, all bearings, gaskets and timing chain?  Decisions,Decisions

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1 hour ago, jstatham said:

I am pretty sure Vince came through ok because I have been emailing him about the crank.  I found him on another thread researching my issue.  I am torn on what to do.  I am suppose to have this thing ready by Christmas and if I break it down and do the crank there is no possible way.  I am also not sure I have the skills to completely rebuild it.  I have done Boat motors, small engines and do my own auto maintenance but never done an ATV before.  If I do roll the dice and just put a top end on it how long would I have before it needs rebuilt completely.   If I can kick the can down the road 6 month to a year I would have a better budget and more time.  What all parts do you replace when you do a bottom end rebuild.  I am assuming crank, all bearings, gaskets and timing chain?  Decisions,Decisions

 

Yeah, I emailed Vince checking on him and he said he came through the storms ok.   Lucky for him and for us.

 

Here's a 500 thread i did a while back.  Your engine shouldn't be too much different. 

 

 

Mainly what you're doing is taking it apart, CLEANING everything very thorougly, and putting it back together. 

 

If you see/ feel a bearing that's iffy, by all means replace it, but I have only replaced one main crank bearing out of probably 12-15 rebuilds I've done.  Most of the time cleaning them out and oiling them leaves me with perfectly serviceable bearings.

 

I replace the crank, timing chain, shifter seal, output shaft seals, reverse seal, and crank (under pullstart cage) seal.  Hondabond for the case halves and gaskets for the front and rear cover (if the covers come off without tearing the gaskets I reuse the gaskets).

 

You can put the top end on it and let the recipient run it.  What will likely happen is a rattle that will get progressively louder, and eventually your cylinder will oval and it will start smoking again.  I've been riding my 09 with a rattling wrist pin (smokes pretty good under load, but doesn't under light use) for a couple of years now.  I recently rebuilt an extra engine to swap in but held off as I loaned that Foreman to my daughter's boyfriend to use during duck season.   If he blows/ seizes the engine up, not a huge deal since I have a rebuilt unit ready to swap in.  Wouldn't have loaned it out if I'd already put the new engine in, so it worked out well for him LOL.

 

So running it as is will require a top end rebuild, sooner or later.  Depending on how bad it is, it might destroy the piston leaving it not-running.  More than likely it will just be loud and start smoking sooner rather than later.

 

So you'll have to decide whether you want to throw a top end on it knowing you'll be redoing it fairly soon, or fix it right the first time, but maybe be a hair late for Christmas. 

 

Where are you located again?  I have a 400 bottom end in the shop that I got with a pile of parts.  Crank might be good in it, but likely not or it wouldn't have been torn down and in a pile of parts LOL.

 

Point being, when you have an extra engine you can keep running/driving a wheeler while you take your time going through the bottom end.  Get it built right at your own pace, while still being able to use the ATV.  Then you can swap the engines out in a half a day, which minimizes down time on the wheeler.

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20 minutes ago, jeepwm69 said:

 

 

Thanks Jeep I am in Powder Springs, Ga. How much would you sell that 400 bottom that you have? Where are you located? Also another factor is I don't have a workshop and have the ATV torn into 1 million pieces in my garage in my wives parking spot and that's not going to well since its winter and freezing.

 

 

 

 

 

Quote

Yeah, I emailed Vince checking on him and he said he came through the storms ok.   Lucky for him and for us.

 

Here's a 500 thread i did a while back.  Your engine shouldn't be too much different. 

 

 

Mainly what you're doing is taking it apart, CLEANING everything very thorougly, and putting it back together. 

 

If you see/ feel a bearing that's iffy, by all means replace it, but I have only replaced one main crank bearing out of probably 12-15 rebuilds I've done.  Most of the time cleaning them out and oiling them leaves me with perfectly serviceable bearings.

 

I replace the crank, timing chain, shifter seal, output shaft seals, reverse seal, and crank (under pullstart cage) seal.  Hondabond for the case halves and gaskets for the front and rear cover (if the covers come off without tearing the gaskets I reuse the gaskets).

 

You can put the top end on it and let the recipient run it.  What will likely happen is a rattle that will get progressively louder, and eventually your cylinder will oval and it will start smoking again.  I've been riding my 09 with a rattling wrist pin (smokes pretty good under load, but doesn't under light use) for a couple of years now.  I recently rebuilt an extra engine to swap in but held off as I loaned that Foreman to my daughter's boyfriend to use during duck season.   If he blows/ seizes the engine up, not a huge deal since I have a rebuilt unit ready to swap in.  Wouldn't have loaned it out if I'd already put the new engine in, so it worked out well for him LOL.

 

So running it as is will require a top end rebuild, sooner or later.  Depending on how bad it is, it might destroy the piston leaving it not-running.  More than likely it will just be loud and start smoking sooner rather than later.

 

So you'll have to decide whether you want to throw a top end on it knowing you'll be redoing it fairly soon, or fix it right the first time, but maybe be a hair late for Christmas. 

 

Where are you located again?  I have a 400 bottom end in the shop that I got with a pile of parts.  Crank might be good in it, but likely not or it wouldn't have been torn down and in a pile of parts LOL.

 

Point being, when you have an extra engine you can keep running/driving a wheeler while you take your time going through the bottom end.  Get it built right at your own pace, while still being able to use the ATV.  Then you can swap the engines out in a half a day, which minimizes down time on the wheeler.

 

 

 

Edited by jstatham
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1 hour ago, jstatham said:

 

Thanks Jeep I am in Powder Springs, Ga. How much would you sell that 400 bottom that you have? Where are you located? Also another factor is I don't have a workshop and have the ATV torn into 1 million pieces in my garage in my wives parking spot and that's not going to well since its winter and freezing.

 

 

 

 

 

 

 

 

 

Oh man, I feel you there on being in the wife's view while trying to fix something. 

 

I'm about an hour SW of Memphis, so not really feasible to get it to you.  I have in-laws in Alpharetta but won't be over that way again until April.

 

I'll dig it out and see how the crank looks.  If it doesn't look bad I can pull it and ship it to you, but I wouldn't hold my breath on it being good.

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