DRZ400E Engine rebuild due to seized camshaft

[Torque Curve]

Threads about recently purchased bikes should start with farkles and ride pics, but unfortunately mine starts with an engine rebuild. The bike performed 100% when I got it and the oil was free of any contaminants. I accept that all damage was done over the past 800km under my use.

I thought that I had run out of fuel last Saturday, but the tank was half. On trying to restart it I was met with a few pops and back-fires, so onto a bakkie it went.
I spent two evenings cleaning and checking the carb and when it still would not start I decided to remove the valve cover as the start of deeper search efforts.
I discoverd that the inlet camshaft had seized on both journals and this caused the camshaft cap to develop a large Y-shaped crack. The left inlet valve is stuck 5mm open and there is a slight metal to metal rub mark on the inlet side of the cylinder wall. I also flushed about 1/2 a teaspoon of metal shavings and particles from the motor.
I discovered that the valve cover, head and cylinder had been removed before and possibly on two different occasions because different sealant residues were present on joining surfaces.

I changed the oil and filter as soon as I got the bike (Castrol Actevo and OEM filter) and found no particles on the magnetic sump plug or in the old oil, so I am quite confident that all damage was caused during the approx. 800km that I put on the bike. So, please be clear that I'm not looking to point fingers or seek any clarification from previous owners.

An entire new head assembly (read good used) is required, new inlet camshaft and at least a cylinder hone and new rings. But since the motor needs to be split entirely to check and measure all components I might as well do what ever work is required to the clutch, replace the timing chain and all oil seals.

I'm looking forward to doing the work on this motor - a lovely bonding experience between man and machine.

[eikeboom]

Eina!
Success with the rebuild 

[Skipskop]

Eina ,that's is really bad luck . The bike still looking so good on the pic ,what is the mileage . Good luck with the rebuild.

[Torque Curve]

Eina ,that's is really bad luck . The bike still looking so good on the pic ,what is the mileage . Good luck with the rebuild.

Thanks Skipskop. Onder 12000 km en ek dink nie die bike was ooit off road voor ek hom begin RY het nie. Het ook getrek soos 'n trein en 20km/l gegee tot net voor die seize!

[Skipskop]

Now that I think back ,the KLR has a bush thingy that the filter locates onto an sometimes a mechanic that does not know about it will toss it away with the old filter without noticing, result ,no oil pressure. Your case sound just to co incidental for my liking . Dunno what your knowledge of these motors are and also not pointing ,but I would dig very deep to find the reason for the seizure ,it all points to oil starvation on the cam to me.

[Torque Curve]

Now that I think back ,the KLR has a bush thingy that the filter locates onto an sometimes a mechanic that does not know about it will toss it away with the old filter without noticing, result ,no oil pressure. Your case sound just to co incidental for my liking . Dunno what your knowledge of these motors are and also not pointing ,but I would dig very deep to find the reason for the seizure ,it all points to oil starvation on the cam to me.

Expert is having a look tomorrow. The last oil change on this bike was done exactly like the five oil changes on my previous DRZ.

[katana]

Just a though...  Sealants that get squeezed inside the engine have a nasty habit of blocking oil passages.  It seems that there was no oil to that cam only? 

[capeklr]

Just a though...  Sealants that get squeezed inside the engine have a nasty habit of blocking oil passages.  It seems that there was no oil to that cam only? 

My thoughts as well, being in the motor trade, I have seen a few seized engine because of sealant. Check all the oil passages very carefully!

[Torque Curve]

Just a thought...  Sealants that get squeezed inside the engine have a nasty habit of blocking oil passages.  It seems that there was no oil to that cam only? 

No proof of excessive sealants so far.

[Torque Curve]

Right, all oil passages were inspected and there's no sign of blockage anywhere in the motor. The metal deposits cause by the seize is every where so this proves oil has free movement throughout the engine.

Based on the damage to the cap and camshaft the concensus here is that the inlet cam was not pressed into place correctly in the past and/or the cam cap was not torqued correctly. This resulted in oscillating camshaft rotation which over time developed into cam failure. Left inlet valve is bent, valve guide is damaged and conrod still needs to be checked.

[Heddles]

Very nice motor to work on. Use the correct tools and take as many photos as possible, to help you remember where all the bits go. Even the genuine manual doesn't cover every single detail. Mine is still running well without a very important looking washer that was left over after I stripped it. (",) And don't overtighten bolts.. Adhere strictly to torque specs...

[Torque Curve]

Very nice motor to work on. Use the correct tools and take as many photos as possible, to help you remember where all the bits go. Even the genuine manual doesn't cover every single detail. Mine is still running well without a very important looking washer that was left over after I stripped it. (",) And don't overtighten bolts.. Adhere strictly to torque specs...

Thanks, Hedley! can these heads be rebuilt and line-bored or is a replacement my only solution. Lots of American DRZ400S heads on e-bay and then add Hotcams stage 1 to get close to DRZ400E specs, I guess?

[Heddles]

Anything can be rebuilt. It depends on the skill, enthusiasm and ability  of the person doing the work. I am sure, just looking at your broken example that it could be repaired. However. You have to consider the cost to do the work, as opposed to the cost of a unit which can be purchased, serviced and fitted with a new set of gaskets.
There are loads of reports of guys doing different modifications to these motors. I would not be able to vouch for the reliability of the motor after such a rebuild but generally, I am lead to believe that they hold. However, mine, with it's standard carb and pipe setup, is more than able.. I wouldn't even consider modifying it. But then, I am just over a year from fifty and have been riding bikes all my life. The bike is a 2001 and has had a lot of mileage put onto it. I am not sure how much. Stripping it to try and find a noise, revealed a really strongly constructed motor and gearbox. The wear was so minimum that I would say it has done 10% of it's lifespan already. Though I know it has high mileage, I am confident it will last me till I die, even if it was the only bike I owned.

I am not sure whether there is a ny difference between the head of an E and an S.. I am inclined to believe not. However. If you contact Suzuki and ask them if the part numbers differ, you should be able to start to work it out. As far as I know, the exhaust and the carb is the only difference in spec between the two bikes. I am lead to believe the cams are the same as well...

[Torque Curve]

Anything can be rebuilt. It depends on the skill, enthusiasm and ability  of the person doing the work. I am sure, just looking at your broken example that it could be repaired. However. You have to consider the cost to do the work, as opposed to the cost of a unit which can be purchased, serviced and fitted with a new set of gaskets.
There are loads of reports of guys doing different modifications to these motors. I would not be able to vouch for the reliability of the motor after such a rebuild but generally, I am lead to believe that they hold. However, mine, with it's standard carb and pipe setup, is more than able.. I wouldn't even consider modifying it. But then, I am just over a year from fifty and have been riding bikes all my life. The bike is a 2001 and has had a lot of mileage put onto it. I am not sure how much. Stripping it to try and find a noise, revealed a really strongly constructed motor and gearbox. The wear was so minimum that I would say it has done 10% of it's lifespan already. Though I know it has high mileage, I am confident it will last me till I die, even if it was the only bike I owned.

I am not sure whether there is a ny difference between the head of an E and an S.. I am inclined to believe not. However. If you contact Suzuki and ask them if the part numbers differ, you should be able to start to work it out. As far as I know, the exhaust and the carb is the only difference in spec between the two bikes. I am lead to believe the cams are the same as well...

Thanks for the encouragement. The only thing shying me away from a total rebuild is the R7500 price tag on a new head. R5000 for a used one off e-bay. The cam caps and the head is a machined match and not sold separately. The money required to rebuild this motor to 100% guaranteed condition exceeds R10000.

The E-cams are quite different from the S-cams: longer opening and more lift on both sides and different opening timing as well. I read somewhere that the valve springs are also different part numbers for the E- and S-models.
This from www.4strokes.com: These specs are directly from Suzuki PR:

Suzuki DR-Z400E
Valve Lift Intake: 8.9mm
Valve Lift Exhaust: 9.3mm
Intake Open: 14 BTDC
Intake Close: 66 ABDC
Exhaust Open: 65 BBDC
Exhaust Close: 29 ATDC

Suzuki DR-Z400S
Valve Lift Intake: 8.5mm
Valve Lift Exhaust: 8.2mm
Intake Open: 20 BTDC
Intake Close: 55 ABDC
Exhaust Open: 56 BBDC
Exhaust Close: 19 ATDC

[Heddles]

There we go.. Now there is no doubt. I also know now why the E's go so much better than the SM.. Yes. The caps are matched sets with the heads.. Machined together.

Dunno bud.. At that price, I would be trying to find someone who is able and interested, to do the job.. Although, at today's prices, I can't see it being much cheaper than the prices you are talking about... Do a bit of asking around...

[mtbbiker]

Hi
Have you looked for a 2nd hand motor. I have just finish rebuilding my DRZ's motor after 65000 km, Replaced camchain, new piston, nicasil the barrel, new valve seals, new rings, re-wire stator. Why did I do it?? My stator decided to dislodge the 3 bolts connecting it to the generator cover ( I think the auto electrician forgot to use thread locker  ). As an after thought I think I only really had to replace the stator and not rebuilding the engine as above parts were still in good condition I only decided to do a rebuild because the engine was opened and after that amount of hours on the motor I could lengthen its life - Did I mention I like my DRZ . Also in hindsight, I think next time I will do the work myself - It looks like a relative easy motor to work on and there is heaps of information available

Oh it was just under R9K  I feel your pain

[Torque Curve]

Hi
Have you looked for a 2nd hand motor. I have just finish rebuilding my DRZ's motor after 65000 km, Replaced camchain, new piston, nicasil the barrel, new valve seals, new rings, re-wire stator...
Oh it was just under R9K  I feel your pain

Ja, now add the cost of a new head and two inlet valves to your total and it gets to R15000 quickly. I'll post a list tonight of all parts I need to replace, with quoted values.

[Heddles]

The used motor is definitely a worthwhile option bud.. Start to look. I have heard of a few that are stripped. Haven't investigated what is left but I am sure that if you start to look, you will find stuff for them..

[Torque Curve]

The used motor is definitely a worthwhile option bud.. Start to look. I have heard of a few that are stripped. Haven't investigated what is left but I am sure that if you start to look, you will find stuff for them..

A used motor is R15000, and none available at the major breakers. The parts I need, priced on www.partshark.com includes a new head, all seals and gaskets, new piston and rings. New camshafts and re-nickasil of cylinder not included


            
Total:
   
$1,245.08 = R10.500

[Etienne2T]

R10.500 is not too bad as you'll have a new motor then?

As I understand a LTZ 400 motor also fits.