I blew the motor on my drz and I am looking for some ideas as I start my first engine rebuild.
Rode the piss out of her for four days in the copper canyon, then parked it came back an hour later and tried to start her, bang bang bang siezed engine.

I drained the oil in the tank, found metal debris small but lots of it and one needle from a needle bearing, lots of debris in filter and frame reserve as well.  motor will not turn in either direction.  combustion chamber looks ok from the spark plug hole, and plug was undamaged.  

Thats about all I can say so far.  

heres what I want to know from the experts(you guys):

what other than obviously damaged looking parts should I check and replace?

should I probably go ahead and replace the top end bits as long as I am at it?

where are there bearings other than the crank that could have been the donor of the needle bearing piece I found?

while rebuilding it what mods would be recomended for a stock 2000 drz400e motor that will make it more reliable or improve performance without reducing the reliability?

Where would you think a novice might forget something key?

Is this do-able?
(I do all my own maintenance and have the tools and time, not afraid to try something, but if its probably something that will be harder than just disassemble, clean, inspect, part replacements and reassemble, maybe I should take it somewhere)

I know this is tough to say from such little info but throw out a number...whats it cost to rebuild a blown motor(gaskets bearings, maybe  the rod)  and what about new valves, springs, piston and rings while I am at it?

should I buy new stock stuff or are there better or cheaper after market parts that wouldn't decrease reliability?

Feel free to answer part all or none of this

thanks in advance for ideas

joe

also, would that debris have reached the top end or oil pump?

where would I find a strainer or screen other than on the botom of oil tank?

you need to disassemble it before we can give you the needed info.

being that it is a 2000,my bet is the cam chain tensioner let go and the result is piston to valve contact.

the metal in the oil is probably a by product.

but no way to tell for sure till its apart.

you can handle the disassembly.before removing the motor from the frame,take the top end off.

take some pictures.

as far as cost,well it could get ugly if its really bad.

hey burned,
there is tension on the chain with my manual cam chain tensioner.

would the valve piston contact seize it?

well rules out cam chain tensioner issues as long as it was set correctly.

its possible the primary nut cam loose and let the valves hit the piston.

yes,valve to piston contact will seize it.

does the motor actually have to be removed from frame?  it looks accessibly in the frame.  if so I remove the head and cylinder sleeve then remove it from the bike?

well I will pull the top end tonight and see what is up.  would that cause lotsa damage in the bottom end if it was valve to piston contact?

joemoto650 said:

In the frame you can take it down to cases and crank/trans

I will pull the top end and see whats up.  I will update as soon as I know

Just an FYI there is a guy parting out a drz with all kinds of parts including the motor.
http://cgi.ebay.com/...4515266924&rd=1  

Just in case ya need some stuff

joemoto650 said:

rod bent is what I have seen with all three piston to valve issues


Parts of the valve damage the head, and cyl.

So,, if you dropped a valve...

You can start counting on

Head, valves, cyl work, piston and rod

I am failing to understand if it was top end why the oil in the crankcase is full of metal and there are peices of bearing in it.

joemoto650 said:

The last two trashed motors I have seen,, had the piston broken out in one or more places.. that allowed trash in to the lower half of the motor.  Additionally.. I'm not saying it is your top end that is trashed.. Just answering your questions on whys and what if's.

you can take the topend off in the frame.

Oh I see.  the debris falls thru the piston.  yikes I was sleeping on that one

thanks

alright its time to get off my ass and start pulling this bitch apart

thanks for the info, and happy new years

pulled the top end.  Chain was broken, partially in one spot and had skipped timing.  Piston had two small indents form the exhaust valves, but no hole.  The exhaust valevs are bent a bit in their guides becuase they dont seat all the way.  Intakes look okay but as long as I am in there they will get replaced.  

NEW Q's

how do I know if the expensive head must be replaced? or is that just standard with this type of seizure, or could it be a case of a certain amount of damage to the guides?

If the piston has two half moon marks in the carbon from the valves, should piston, rings and connecting rod all be replaced?

if there was debris in the crank oil should I go ahead and replace all the bearings or would cleaning them be sufficient, if there is no visible damage?

At what point do I remove the engine in this process?

Is there a special tool to remove the valves from the head or will a valve spring compressor from the auto parts store suffice?

I know I need a ring compressor, what else should I need to buy as tools other than the ordinary tools I use to work on everything else on my bike?

Would cams get damaged in this?
they look okay, clean lobes and nothing outta place, what should I look for?

Is there a better option then just ordering stock parts from ron ayers?

If there are some good after market pieces that wont hurt reliability what might they be?

lotsa questions I know but this is my first rebuild, and I want it to be the first of my good rebuilds.  

love the drz, dont need more power, but if something is reasonably priced, wont increase problems and helps, why not?

you guys are really really helpful.

thanks

guess I will go try and get a spring compressor.  Maybe I will order up some parts tonite if I get some input.

joemoto650 said:

If your unsure,, its time to take it to someone who can look, measure, and tell you for sure. You new motor will quickly become trash if a damaged valve seat, guide is not repaired. Even if you sent pictures,,,, it still is a second hand guess, based on an internet connection..

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piston and rings for sure,, Rod? Well it sounds like the piston did not take that big a hit… But again…. You have to be sure.. The crank has to be taken out and apart to replace the rod.. Not something you can do at home.  This is another item I would suggest having a qualified tech look at for you. Or if you have more money than time,, have the rod replaced.

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This  one has me confused… as so far,, nothing you have said explains why or how debris would have gotten into the cases… You said you had a needle bearing and lots of metal trash in the oil???? Where did it come from??

As for replacing the bearings.. If it were me,, I’d split the cases,, clean everything.. and see what the bearings felt and looked like.. Any hint of roughness, by look or feel.. and they would get replaced.
First.. you need to find the source of the rest of the damage.

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Well mine would have already been on the bench… so I guess at any point now.

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Yes there is a special adapter that needs to be bought $$$$$$ or made $.50.   With anything but the perfect tools for the job,, it is a bit frustrating,, and a two person job.  Another reason to have a qualified shop check out the head,, then install the valves… Cost should be minimal for just that work.  Your saving HUGE by doing the slow, time consuming grunt work of disassembly and assembly. Don’t skimp on a few things, costing you big in the end.

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Never used a ring compressor myself on single cylinder bikes.. including the DRZ.. I think there really is no need.

The other tools is a really hard question,, as I have no idea what you have now,, or what you consider ordinary????

Not counting the head and crank…which I’ve spoke about. You will need to have the flywheel pulled for you,, or get a puller.. to split the cases you will need to make or buy a case splitting fixture. You will need a factory service manual.
A good torque wrench in inch pounds, and foot pounds.

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No.. not likely.

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The world (and it’s parts bins) are wide open.. it’s all up to your wallet.
You can go with a Wiesco piston, in stock or 13.5 CR (but then no more pump gas)
Was the cylinder damaged at all? If so then you can consider a a big bore kit from MT.
Gaskets can be had from the TT store in the Cometec brand.
Cams could be replaced with units from Hot Cams.

Figure out what you need,, and go from there.

At a minimum,, you need a piston and rings, gasket set, cam chain, valves.  More if you find more damage.

joemoto650 said:

If your just wanting the valves out,,, you should be able to do that no problem with a auto spring compressor and something rigged up to compress the retainer.. It's getting um back together that is the fun part,, and the need for the adapter.