I feel like I could cry

[400exmxrider15]

As you all may now, my 400ex was going to get a 11:1 Wiseco piston. Well, my mechanic took a look at it, and when he had the piston off, he said there is alot of up and down play in the upper piston pin journal. He said its best to get a new crank.....I dont know what I should do. I'm broke. He said around $1200 for a whole motor rebuild.

[finsteratv]

1200 holy chit.
ive seen motors on craigslist from shops going like 700 tops. id just get another engine and see how much it would be to swap the aftermarket parts yourself.

[finsteratv]

and get a quote from another mechanic...

[400exmxrider15]

I don't trust anyone else with my motor other than this guy. He has been honest about everything, I will try and see a final price on it...

[tri5ron]

Originally posted by 400exmxrider15
my mechanic took a look at it, he said there is alot of up and down play in the upper piston pin journal.
Upper Piston Pin Journal ???

The Connecting Rod has 2 bearings.
One that connects the Rod to the Crankshaft, (crank bearing)
and One that connects the Piston to the Rod, (wrist pin/bearing).

By your description, I'm going to assume you are reffering to the Wrist Pin. is this correct ???

Is he ALSO reffering to the Crank Bearing at the lower end of the connecting rod???

If so,... you are looking at a new Piston, Connecting Rod, and probably a new Crankshaft, if it is marred. Of course there is the rings, gaskets, various bearings, timing chain, guides, tensioner,etc.,...
so while your at it,... may as well do the cam too.

Realistically, the only way a 400EX burns up the Crank Bearings, and Wrist Pin, is from getting Waaaay too hot, Too high of RPM's, and/or insuffecient oil supply.

In other words, Somebody has ran the piss out of that thing, and has not regularly maintained it.
It's a hard and expensive lesson to learn, but ,...you generally only need to learn it once,
and you'll never forget it again.

Now is the time to start saving your cash, and deciding what you REALLY want it to do.
Since you are facing a potentially total rebuild, you can pretty much do anything you want with it.

but keep in mind,
for every HP inducing, High Performance mod you choose to do,...

...there also comes additional maintaince issues, cooling issues, and reliability issues.


You can do alot with a 400EX,
But the thing for you to FIRST consider is,
"How Reliable do I want it to be?",
"To what level am I capable of maintaining it?",
and ,
"What am I Realistically Expecting out of this machine?"

This will help to Govern, just how far you will want to build it up, and how high you want to take it.

Ask yourself,
"Am I going to really use this bike to be competetive on the MX track?"
"Am I looking for a decent XC/GNCC machine?"
or,
"Do I want a near Bullet Proof, Trails/Woods machine?"

This too, will help to determine what you should build, and how far you can "Take it".

After that,....
it's all about Cash....
and how much of it you are willing to work for, and spend on your bike.

[400exmxrider15]

I'm looking for a pretty decent performing MX quad....Its been burning oil and I have been trying to check it everytime i ride....I change oil every 5-6 rides....

[Thumpin440ex]

I would like to see pics of the crank journal it self.. If there isn't any scouring on the journal, you need a new piston, rod, bearings.. A journal on a crank doesn't just wear away... PICS



John

[400exmxrider15]

I finally got the idea of what all mechanics are like.....If there is one small problem that would possibly lead into a big cost effective job, they are gonna say something....I'm gonna do a top end only, new tensioner, new exhaust studs....blah blah

[Thumpin440ex]

Have you seen the crank shaft journal???

John

[400exmxrider15]

Originally posted by Thumpin440ex
Have you seen the crank shaft journal???

John

I dont even know what that is. Im just saying what my mechanic said..

[tri5ron]

Originally posted by 400exmxrider15
I finally got the idea of what all mechanics are like.....If there is one small problem that would possibly lead into a big cost effective job, they are gonna say something....I'm gonna do a top end only, new tensioner, new exhaust studs....blah blah Bryson,
Doing a job half assed, leaves you plenty of time for more important things,...

like saving up even MORE money, to do it right the second time around.

Seriously, I'm not trying to insult or degrade you at all. I'm just saying that you would benefit from seeking advise from someone who has a little more experience than you do.

It dosen't need to be a "Professional Mechanic", or a specific "Motorcycle Mechanic".
It only needs to be someone with some mechanical experience.

A Parent , or a Family Friend maybe ?

If you continue to go the route the you are currently taking,
You are going to end up wasting ALOT of cash,

Best of luck to you.

[Thumpin440ex]

With the piston journal I am assuming your talking about the pin, that the piston floats/rides on?? The rod journal is what is on the crankshaft.. I am not sure why he would suggest a new crank if the rod at the pin end is wore out or the pin hole in the piston.. You need to have somebody take a look at what you are being told if you are not sure, or you will get the run around..

John