Bad news turn into good news!

[jfor]

I bought my 400ex a couple of months ago for 1400 bucks. The guy I bought it from had bought it used so he didn't know anything about it other than it was "stock".

Well last weekend it started grinding when in second. All the other gears were fine. This past weekend I got bike stripped down and removed the motor. As I was taking off the cylinder I notice that the rod had "Hot Rods" stamped on the side. Hmm... I thought. Then, when I looked at the piston it had some numbers stamped onto the top of it. I went to my computer and searched the part number and found out I had a Wiseco 440 Big bore Kit!!! Man was I shocked to learn that! I am working on getting the case split now so that I can find out what is wrong with second gear and get it fixed..

[ImplodedMindZ]

Nice....Score 4 you. Well assuming someone did the work right and you will have a "reliable" 440.

[Honda#4]

Sweet!! Hope it holds up well.

[jfor]

Everything looks to be in good shape. Its a good thing I found when I did before it starts getting to hot down here in bama. I have been running mid grade and 87 and 89 octane gas in it. Now I know that I don't need to run anything less than 93 octane in it.

ALSO,
does anyone know how to tell if a cam is the stock cam or an aftermarket cam?

[Bill Fuller]

Sounds like the transmission needs to be rebuilt. 2nd gear is usually the culprit. As far as the cam check for any numbers to help identify.

[Ruby Soho]

If its a hotcam it will say HotCam on the side

[400exrider707]

Originally posted by Ruby Soho
If its a hotcam it will say HotCam on the side

Mine didnt...



Also check what compression it is. This will help to determine what octane you really need to be running.

[jfor]

it is 11:1 compression.

[400EXTRA]

Originally posted by ImplodedMindZ
Nice....Score 4 you. Well assuming someone did the work right and you will have a "reliable" 440.


THERE IS NO SUCH THING AS A MOTOR THAT IS BORED OUT THAT WILL EVER BE RELIABLE

[ImplodedMindZ]

Originally posted by 400EXTRA
THERE IS NO SUCH THING AS A MOTOR THAT IS BORED OUT THAT WILL EVER BE RELIABLE
Youre intitled to that as your opinion but i and im sure others wont agree w/ you. BTW no need to yell.

[ZSK]

That's not an opinion, it's a fact worth yelling about.

[ImplodedMindZ]

ignorance is bliss

[ZSK]

Please if you could, elighten me as to a reliable only significantly bored quad.

[DF400ex]

Well, 440's can be as reliable as stock, IF you use the right parts, and it's done by some one who know's what they are doing, and you take care of it. And by the right parts I mean everything.
But, just like stock, if you abuse it, it will eventually break.

[ImplodedMindZ]

Unreliable built motors usualy result from people skimping on good quality parts or cutting corners. Like when going to big bore high compression piston and not gettin bigger headstuds and a good head gasket set. Blown head gaskets result.

Also people dont take into account the extra amount of heat generated by a bigger bore and thinner walled piston sleve. People dont upgrade oil coolers, get bigger oil tanks or take some other precaution to keep the motor @ a reasonable temp. Fried rings, blowby, burnt piston, and eventual engine failure results.

Im sure you aren't enlightened b/c most people are set in their ways about this kinda subject but worth a try.

[ZSK]

Once you start building any aspect of the motor you need to upgrade every part in the motor and even that isn't enough. The 400's motor is designed for optimum reliability at ~27HP stock. My 440 was only hitting about 35 and it was an unreliable PITA. I didn't trust it on longer trail rides and it always ran hot. I did HD studs, HD rod, billet clutch basket, stock clutch fibers and steels, HD valve springs, hotcam, crf450 cam chain. I ran compressions from 9:1 all the way to 12:1 and blew headgaskets at everyone of them with or without HD studs. I even had my head and cylinder machined true after the first blown headgasket (Cometic 3 layer I might add) and it didn't solve a thing.

With air scoops, CFM large oil tank, full synthetic oil, and dual oil coolers it only ran cool enough to my liking at about 40°F and 60 mph.

This motor was never run lean, always had a minimum of 93 Octane (at 9:1) and had full 110 race gas when it was at 12:1.

A motor bored anything over stock will never be as reliable as it is stock. Reliable is a skewed definition by others. I expect my quads to run be able to run a 70 mile enduro or 2 1/2 hour XC race and not worry about grenading the motor under me.

406 416 425 426 (stock sleeve) 426 (bored cylinder new sleeve) 440 all are ticking time bombs. The best I got was 6 months on my 440 before something else went wrong. I easliy had $2000 in my motor alone. If the 400 had a stock motor, I would still own it. It handled great, was great for the woods and trails, even on the motocross track it handled nicely.

[northwest Texas]

Many times we tend to think what happens to us is across the board. It's a shame you have/had your troubles but you are certainly the exception and not the rule.

Technically, any additional power generated beyond stock should in theory reduce reliability. But lets not argue semantics because there's far too many other factors that can alter the reliability more so than performance mods.

[mic 902]

Originally posted by ZSK
Once you start building any aspect of the motor you need to upgrade every part in the motor and even that isn't enough. The 400's motor is designed for optimum reliability at ~27HP stock. My 440 was only hitting about 35 and it was an unreliable PITA. I didn't trust it on longer trail rides and it always ran hot. I did HD studs, HD rod, billet clutch basket, stock clutch fibers and steels, HD valve springs, hotcam, crf450 cam chain. I ran compressions from 9:1 all the way to 12:1 and blew headgaskets at everyone of them with or without HD studs. I even had my head and cylinder machined true after the first blown headgasket (Cometic 3 layer I might add) and it didn't solve a thing.

With air scoops, CFM large oil tank, full synthetic oil, and dual oil coolers it only ran cool enough to my liking at about 40°F and 60 mph.

This motor was never run lean, always had a minimum of 93 Octane (at 9:1) and had full 110 race gas when it was at 12:1.

A motor bored anything over stock will never be as reliable as it is stock. Reliable is a skewed definition by others. I expect my quads to run be able to run a 70 mile enduro or 2 1/2 hour XC race and not worry about grenading the motor under me.

406 416 425 426 (stock sleeve) 426 (bored cylinder new sleeve) 440 all are ticking time bombs. The best I got was 6 months on my 440 before something else went wrong. I easliy had $2000 in my motor alone. If the 400 had a stock motor, I would still own it. It handled great, was great for the woods and trails, even on the motocross track it handled nicely.

Before I did my rebuild mine was a 440. Stock rod, valves, valve springs, clutch..... Everything except the big bore and the flowed head and cam... It lasted 2 years of racing and riding every 2nd weekend. And it was never ridden easily. Never had a problem with it. :macho

Not trying to start an argument. Maybe yours was a lemon. :confused:

[firefighterjosh]

My sotck banshee engine was getting weak after 1 year of riding.

Didn't change a thing with gas/premix ratio and I have 3 years + of racing and riding on it and it still runs strong on a 40 over bore with vitos pistons;)

[ImplodedMindZ]

Originally posted by mic 902
Before I did my rebuild mine was a 440. Stock rod, valves, valve springs, clutch..... Everything except the big bore and the flowed head and cam... It lasted 2 years of racing and riding every 2nd weekend. And it was never ridden easily. Never had a problem with it. :macho

Not trying to start an argument. Maybe yours was a lemon. :confused:
Well you must be mistaken b/c that is just not possible. Acording to zsk a bored over motor cant be that reliable. Well since his wasnt your motor cant be, b/c of coarse its the same motor and all.

ZSK did u do all the work on your motor or did u have a shop to it?

[ZSK]

An engine builder did all of my work for the first year or so. The cost was outrageous having to pay $60-80 an hour for labor. I started doing all the work myself and it ran better for longer. You just don't hear about that many built 400 motors blowing up because there are realitively few these days compared to 3-4 years ago. I wanted relaible power so I have a YFZ now, the 250R is for fun.

[firefighterjosh]

Originally posted by ZSK
An engine builder did all of my work for the first year or so. The cost was outrageous having to pay $60-80 an hour for labor. I started doing all the work myself and it ran better for longer. You just don't hear about that many built 400 motors blowing up because there are realitively few these days compared to 3-4 years ago. I wanted relaible power so I have a YFZ now, the 250R is for fun.

To tell you the truth I would bet money my "bored" 416ex with cam, pistons, vavles is more reliable then a stock YFZ.

[ZSK]

In two full seasons of XC racing I put a clutch it in, replaced the water seal, and did the regular maintenance.

[firefighterjosh]

Originally posted by ZSK
In two full seasons of XC racing I put a clutch it in, replaced the water seal, and did the regular maintenance.

In 2 season It hasn't had anything done:macho Some bearings wer replaced I guess.

My banshee also has 2 years of racing and its bored 40 over no problems.


So I guess I just don't get why boring wears a engine out faster?:confused:

[ImplodedMindZ]

Originally posted by firefighterjosh
In 2 season It hasn't had anything done:macho Some bearings wer replaced I guess.

My banshee also has 2 years of racing and its bored 40 over no problems.


So I guess I just don't get why boring wears a engine out faster?:confused:
Operator error?!?!?! Could be the reason, lol.

[firefighterjosh]

Originally posted by ImplodedMindZ
Operator error?!?!?! Could be the reason, lol.

Maybe:ermm:

[ZSK]

Boring the engine without upgrading any other component is going to stress every other part in engine. The cam chain will stretch, the clutch will wear faster, the surface of the gears will start to pit and will breakdown the hardened material. I've seen stock and aftermarket rods snapped like swigs from the extra stress from just an overbore.

From what I have seen an internally modded motor will never be as reliable as stock. Not a single person will be able to convince me different, and I can't convince a person to see my perspective. Politics or religion....

[krt400ex]

Originally posted by 400EXTRA
THERE IS NO SUCH THING AS A MOTOR THAT IS BORED OUT THAT WILL EVER BE RELIABLE


NOT TRUE AT ALL...OTHERWISE NOONE WOULD EVER BORE THERE MOTORS

[krt400ex]

Originally posted by northwest Texas
Many times we tend to think what happens to us is across the board. It's a shame you have/had your troubles but you are certainly the exception and not the rule.

Technically, any additional power generated beyond stock should in theory reduce reliability. But lets not argue semantics because there's far too many other factors that can alter the reliability more so than performance mods.


yes.

i have never heard of a 440 being unreliable. the worst thing i have heard is a blown headgasket if you are not running HD studs.

i actually know a person who built a 440 and has had it running strong for about 4 yrs...no failures, never needed to rebuild it, and about 300 hrs on it.

the 400ex is so overbuilt that 98% of the people that own them will never have a problem with them as long as they are maintained.

ZSK, i am sorry that you have had so many problems with you bored 400EX's, but having issues with a highly modded 400 is like searching for a needle in a haystack. apparently you just happened to come acrossed that needle.

[firefighterjosh]

Originally posted by ZSK
Boring the engine without upgrading any other component is going to stress every other part in engine. The cam chain will stretch, the clutch will wear faster, the surface of the gears will start to pit and will breakdown the hardened material. I've seen stock and aftermarket rods snapped like swigs from the extra stress from just an overbore.

From what I have seen an internally modded motor will never be as reliable as stock. Not a single person will be able to convince me different, and I can't convince a person to see my perspective. Politics or religion....

So lets say I buy a quad from the factory qwith 11:1 compression. The engine gets tired I bore it out lets say 20 over and install another 11:1 compression piston it is going to wear stuff out faster? The only was a new piston is going to prematurly wear out stock parts is if the compression is higher.

If you bore out your quad and snap a rod due to extra stress I bet money on the crank bearings were going out and they were not checked properly.

[brokenmike]

My 440 has been togeather for 5 years,I beat the crap out of it and do regular mantinence to it and it has never gave me ANY trouble,and I do not have heavy duty head studs in it and never blew a head gasket. My mods are in my sig. If an engine is built right,all tolerances checked and properly taken care of (proper mantinence) it should last a long time.I have alot of bikes (18 total)and most of them are not on my sig,most of them are very modded and I never had any problem with any of my bikes being unreliable ever!

[ZSK]

Perhaps I had an exception with an unreliable built 400 motor. Perhaps the others I've seen were exceptions also. For a stock 400ex I would expect nothing less than 8-10 years of reliable service given good, quality, maintenance.

Our Polaris, by many members' opinion, should have blown the engine at least 12 times by now. It has never given us a bit of trouble and it's now 10 years old. I should expect that a 400ex should be able to surpass that without any trouble.

My point in adding to this thread, whether anyone sees it as bashing anything other than a stock motor or trying to inform other members of my experiences, was that anything done to a motor needs to be carried throughout the entire motor and that each motor in itself is unique. Parts that are starting to wear with a stock motor will show themselves rapidly once you start to modify a motor. Just as many blown 400ex motors that I've seen, I've seen comparative relaible ones, stock and modified.

I tried to be specific in my wording and I'll clarify: A bored motor won't be as reliable as a stock motor.

It's obvious that I won't change anyone's mind, and that you won't change mine, can we leave it at that?

[TRFOXX]

Im with ya ZSK!

[AtvMxRider]

Originally posted by ZSK
Perhaps I had an exception with an unreliable built 400 motor. Perhaps the others I've seen were exceptions also. For a stock 400ex I would expect nothing less than 8-10 years of reliable service given good, quality, maintenance.

Our Polaris, by many members' opinion, should have blown the engine at least 12 times by now. It has never given us a bit of trouble and it's now 10 years old. I should expect that a 400ex should be able to surpass that without any trouble.

My point in adding to this thread, whether anyone sees it as bashing anything other than a stock motor or trying to inform other members of my experiences, was that anything done to a motor needs to be carried throughout the entire motor and that each motor in itself is unique. Parts that are starting to wear with a stock motor will show themselves rapidly once you start to modify a motor. Just as many blown 400ex motors that I've seen, I've seen comparative relaible ones, stock and modified.

I tried to be specific in my wording and I'll clarify: A bored motor won't be as reliable as a stock motor.

It's obvious that I won't change anyone's mind, and that you won't change mine, can we leave it at that?


You know I was looking for a good picture to put in here for you until you posted this. You are 100% right a modded motor will not be as reliable as a stock motor but that doesn't mean a modded motor will not be reliable if built right. If you half-*** build it then yes it is a ticking time bomb waiting to go off.

[mic 902]

ZSK, seems to me like you have let one bad build make you never want to do another big bore engine.... Personally i think thats stupid, like saying 'I had bad sex once... Never doing that again'
Just because something didnt go well every single time doesnt mean its hopeless and no one should do it. :)