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-   -   The drz400s rebuild, stronger...faster...somthinger! (http://www.advrider.com/forums/showthread.php?t=831995)

focallength 10-05-2012 05:27 PM

The drz400s rebuild, stronger...faster...somthinger!
 
Ok, so my drz has 12500 miles on it, I do regular msintenance and keep her in good condition. I have her all set up like I want, and just put a new fcr-mx carb on a week ago.
So engine mods have always been an after thought.
2 days ago while coming home from a ride in the moutains, she up and died on me, wouldnt start, wouldnt crank...so as I sit :cry on the freeway it suddenly dawned on me...i can make her better, what a great opportunity!

So I set about pulling her engine, seperating the head and cylinder.

Visions race through my head, big bore kit, headers, exhaust, hot cams, ti valves!

So heres the plan, I got the head and cylinder off, ill pull the piston doon and check for crank play. I have to check the oil and water pump and inspect bearings. I may split the case and do s bottom end rebuild along with gears. Im going to have to get a new head but I can have a bomb proof head built. Maybe 440 big bore kit. But first things first, I have to see how far the damage goes and what condition the internals are in after 12500 miles.

Now I have medic school in 3 months and when that starts the bike wont be touched if shes in pieces so, the goal is christmas.

Btw its an 08, I would like to keep the reliability and get a little more oomph, im willing to trade a little reliability for power. Ill most likely do a 434 bn with e cams or stg 1 hot cams. My mechanic says he can build a top of the line bomb proof head. New blank head will run me $600. Built will prob be $8-900


Pics to follow as well ad updates stay tuned!



Muched exhaust cam side race, for some reason I lost oil, head just seized, good thing is damage looks limited to the head
[IMG]http://i303.photobucket.com/albums/n...0-05151621.jpg[/IMG]

focallength 10-05-2012 05:42 PM

:puke 12500 miles, despite 91 octane gas, regular oil changes, regular plug changes/inspections, look at those deposits...
[IMG]http://i303.photobucket.com/albums/n...0-05151632.jpg[/IMG]

Spacelord 10-05-2012 05:48 PM

Big bore
FCR
MRD exhaust
either hot cams stage 1 or cams from a E model

Nice horsepower and torquey.

focallength 10-05-2012 05:49 PM

So the piston sezied, I had to hit it down with a rubber mallet so I could pull the cylinder.
once the cylinder was off the piston/engine turned over easily by hand. Some scoring on the cylinder walls, piston edges has some chipping and...sand in the cylinder...how the hell did I get sand in there?!
Anyway heres the top of the piston in the cylinder
[IMG]http://i303.photobucket.com/albums/n...0-05151648.jpg[/IMG]

Cylinder, not gouged those are piston deposits, from when the piston seized and deposited metal onto the cylinder walls.
[IMG]http://i303.photobucket.com/albums/n...0-05153037.jpg[/IMG]

GAS GUY 10-05-2012 06:31 PM

Wow, I would like to know what the root cause is.This seems like a premature failure.

Off the grid 10-05-2012 10:02 PM

Why not just get a different bike? There are many better bikes out there than a DRZs.

And a grenaded engine at 12k miles? :huh

focallength 10-06-2012 01:46 AM

Havent pulled the side coverd so I dont know if the pump failed.
i do know the bike was running hot and burning oil. I had done an oil change a few days prior. No smoke, when I went to drain the oil there was very little in there. The drain bolts were tight so no leaks. There was also little coolant despite recently changing it. No oil in the coolant. Hopefully some questions will be answered when I dig into the engine.

Why would I get a new bike? I can build an engine for less than a grand, I can build a 50 hp engine for 15/16/1700, a new bike will cost 3-4x that minimum plus all the hassle/cost of new farkles. Cheaper to rebuild it in any form.

WayneJ 10-06-2012 06:07 AM

Quote:

Originally Posted by focallength (Post 19759535)
I had done an oil change a few days prior. No smoke, when I went to drain the oil there was very little in there. The drain bolts were tight so no leaks. There was also little coolant despite recently changing it. No oil in the coolant.

Quote:

Originally Posted by Off the grid (Post 19759121)
...a grenaded engine at 12k miles? :huh

Quote:

Originally Posted by GAS GUY (Post 19757988)
Wow, I would like to know what the root cause is.This seems like a premature failure.

Owner/operator error.

If you don't put oil and water in an engine after you drain it out, it will go :kboom

focallength 10-06-2012 06:47 AM

Really?! You mean the engine dosent just magically create its own oil and coolant? Im shocked...shocked I tell you.


Quote:

Originally Posted by 955616846 (Post 19759592)
You're right. The bike is worthless as it sits and they are cheap to rebuild.

Here's to hoping the transmission and crank are okay. Even if the crank is toast they are surprisingly cheap.

A new head is the expensive part, top and bottom rebuild kits run roughly $500 total.


One thing I did notice, the front lower engine mount bolt gets pretty coroded. Being as these bolts have no seals, liberal waterproof grease is in order when I reinstall them.

markk53 10-06-2012 07:21 AM

Quote:

Originally Posted by Off the grid (Post 19759121)
Why not just get a different bike? There are many better bikes out there than a DRZs.

And a grenaded engine at 12k miles? :huh


But with the cost of those "better bikes" the OP could do his engine with a big bore, pipe, and maybe a carb, even pay someone for the work, and pocket the difference.

If he does the work he ends up with a great engine for probably grand, could have the suspension tricked out and maybe still be around maybe $1500 and have a great ride.

So what is going to be better for a grand, even two grand?

HighwayChile 10-06-2012 08:34 AM

ceramic coating internals might be worth checking into as well if you are keeping it long term
I"ve heard of aftermarket gear sets, plenty of $ Im sure is it the entire set or just an OD 5th?

focallength 10-06-2012 12:29 PM

Clutch side cover off, everything looks good, cant detect any visibe gear wear even on the plastic gears. Everything turns smooth and easy. Clutch basket has some visible wear.

[IMG]http://i303.photobucket.com/albums/n...0-06122204.jpg[/IMG]

I dont see any bluing of metal, so everything looks ok, ill still split the case to replace the main bearings and countershaft bearings at the minimum.

Im torn between stock and BB...i like the reliability of stock, maybe just some e cams and e base gasket, combined with the fcr-mx carb should yield nice results. I hear the 434 BB only yields 4 hp. so...

Does anyone make metal gears to replace the plastic ones?

Spacelord 10-06-2012 03:54 PM

I have 4K on my big bore, no issues.
I expect it will easily do 12K.

DR650SEDDY 10-06-2012 04:09 PM

After ur done rebuilding ur engine you'll have a blast. I know many who've done the big bore kit and they're happy with the results, i was gonna do this SUZUKI JE DRZ400 DRZ 400 BIG BORE 434CC CYLINDER KIT just for the heck of it. Keep up the good work focallength.

focallength 10-06-2012 04:58 PM

Im just concerned about the reliability of a BB, I dont want to tear the engine down every 6k miles.


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