Drz 400 E - 2002 - Top End Troubles

[UsernameTaken]

Hi
My Drz stopped working about three months ago, but have only just had time to take the top end off. It just wouldn't start. Sent it to a garage and they said they wanted £500 to sort it out. Didn't have that sort of cash so am trying to do it myself.

This is my first time doing any sort of engine work with the most basic set of tools.

Having dismantled the top end... I am now stuck, not really sure what I am looking for or where to go from here.

Below are some pictures of what I have found.

Any help/advise/next steps would be greatly appreciated!

https://i460.photobucket.com/albums/qq322/UsernameTaken_01/Engine%20Troubles/photo1_zps44f97d2c.jpg

The piston needs decoking I think - how would I go about this?
Also, the IN valves have clearly hit the piston, but it doesn't appear to have left any lasting marks (once cleaned up).

https://i460.photobucket.com/albums/qq322/UsernameTaken_01/Engine%20Troubles/photo2_zpse5202714.jpg

The valves - not sure what colour they are supposed to be. The EX valves are the chalky ones and the IN valves are covered in carbon.

https://i460.photobucket.com/albums/qq322/UsernameTaken_01/Engine%20Troubles/photo3_zpsa95fe5a6.jpg

The barrel looks ok?

Any help would be appreciated - apologies if I am asking/end up asking stupid questions.
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[Fizzer Thou]

Not silly questions at all.To check to see if the inlet valves are bent,pour something like white spirit or parrafin into the combustion chamber and see if it flows away through leaking valve seats

https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/CIMG2951.jpg

If the bike had been over-revved,it is quite likely that the valves are bent.
As the inlet valves are black,this could be oil or a rich mixture.Check the end gap of the piston rings within the bore and if the valve guide seals have perished.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[base]

so what did the garage actually say was wrong with it?

[UsernameTaken]

Thanks for the replies.

The garage basically said a new top end would be the cheapest option as the valves were pissing petrol.


I think I may have rode it with the choke on (stupid mistake and one that I haven't made in 5 years of riding) which would explain the blackened inlet valves?

'Check the end gap of the piston rings within the bore and if the valve guide seals have perished.'
What would this entail?
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[Fizzer Thou]

Take the piston rings off the piston,place them within the bore,square them within the bore using the loose piston and measure the gap between the ends of the rings.If they are over a specified limit,or even close to,then hone the bore and install new rings.

If the inlet valves are damaged,they are normally cheaper than the exhaust items.You might get away with just lapping in the new valves and check for leaks again.But if the valve seats are pock-marked,then you might have to have the seats recut if grinding them in does not work.

The Clymer manual https://www.amazon.co.uk/Suzuki-Dr-Z400e-2000-2009-M477-3-Diagrams/dp/1599693631/ref=sr_1_1?s=books&ie=UTF8&qid=1360601829&sr=1-1 is a known good product if you do not already have one.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[UsernameTaken]

A manual is on the way, should help speed up the process!

After pouring white spirit through, found out the inlet valves are leaking. Looking out for a valve spring compressor so that I can get them out and get a look at them/the seats.

Haven't had chance to check the piston rings yet. Will wait for the manual to arrive before attempting that.

Decoking the piston head, is it as simple as just cleaning it off?

Thanks again.
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[Dr. Quack]

Might be a silly thing to say, but the Mikuni carbs on the SK's are problematic in regards to the needle valve.
Also the seals can be an issue with the keihin carb.
For winter they both need adjusting, especially with older DRZ's.
Mixture screw turned out 1/2 a turn, or a tad more normally helps in winter.
https://www.drz400uk.org/viewtopic.php?f=21&t=4015
https://www.drz400uk.org/viewtopic.php?f=21&t=5210
(Just with you saying it stopped working, and looking at the dirt it looks like and SK or even an E)
Also all models need the manual cam chain tensioner after so long, so just wondering if the cam chain slipped.

[unitynotsocri...]

check the valve guides and valve seals as well,looks mostly healthy although it looks like its been running rich or stuck choke for a while.
____________________
nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[UsernameTaken]

The carb was dismantled, cleaned and checked, was the first thing that I did when it died. So that should be ok. (it is an E model)

Trying to find a nicely priced valve compression tool so that I can get the valves out and have a look at them.
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[UsernameTaken]

Ok, just managed to get the inlet valves out to have a look. They don't appear to be bent, go into the 'hole' with little resistance and don't feel as though they have any pitting...

But I could be completely wrong!

https://i460.photobucket.com/albums/qq322/UsernameTaken_01/Engine%20Troubles/ValveSeats1_zps3500a863.jpg

https://i460.photobucket.com/albums/qq322/UsernameTaken_01/Engine%20Troubles/ValveSeats2_zpsc3ce7856.jpg

https://i460.photobucket.com/albums/qq322/UsernameTaken_01/Engine%20Troubles/Valves1_zps18269ae6.jpg

https://i460.photobucket.com/albums/qq322/UsernameTaken_01/Engine%20Troubles/Valves2_zps8514b907.jpg
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[Nexus Icon]

I'd be tempted to change the seals, etc. and lap those back in. I've seen far, far worse in running vehicles so I can't believe ones like that would stop your bike starting at all.

I'm no bike expert though.
____________________
Greetings from Shitsville!

[woll]

I'm with nexus. They don't look bad at all. Seen hell of a lot worse come out of running tractors. Personally I'd wap new piston and rings in. Change valve stem seals, lap valves in. Check for leakage. If they dont leak jobs a good un. Put back together and hope for teh best
____________________
Current Bike- Suzuki DRZ400 SM K6
Previous bikes - Derbi Senda Xtreme50r, Honda CBR 125, Kawasaki ZZR 250, Yamaha DT125R, Suzuki Bandit 600, Gas gas ec 250, Honda CBR600FW
Damaged spleen, damaged kindey, 2 popped lungs, 2 broken ribs, broken face, broken wrist and 5 back fractures... remember kids walls hurt

[UsernameTaken]

Ok, will check the piston rings tomorrow hopefully.

Will the piston definitely need replacing?

Nothing seems to stand out as to why it wouldn't start, just don't really want to risk putting it all back together for it to not work!

Thanks for all of the help so far!
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[UsernameTaken]

Just checked the piston rings end gap in the cylinder head and they are both at 0.2mm. Manual says that 0.5mm is the service limit.

So surprise surprise no issues there either
Unless the gap is too small?
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[P.addy]

Did you try all the usual things before stripping it down...

As Nexus says, lap em in, new seals.

Reckon you should rebuild, get a proper compression test and check that the engine turns over properly.

Check the coil and make sure its actually creating some spark.

[UsernameTaken]

Yeah before it was stripped down I checked the carb completely (stripped and cleaned), checked there was a strong enough spark (and changed the plug) and checked there was plenty of compression.

Hence the strip down. Hopefully lapping the valves back in and fitting new seals will sort it.

Time to rebuild...
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[bikenut]

dont forget to fit the valves the right way up...........

looks as though the inlet valaves may have been hitting the piston, no vlave clearance or minus valve clearance so open and stricking the piston??

bent inlet valves?? was there much compression before strip down?????

[P.addy]

[bikenut]

those marks on the piston made by the inlet valves aint normall dudes, also fit valve springs the right way up.

[UsernameTaken]

Waiting for gasket set, piston rings and valve seals to turn up now.

Have just assumed that the marks on the piston are a combination of the bike running rich/carbon build up therefore making the piston/valves 'thicker' and hitting each other.

Reseating the valves etc as I throw it all back together should hopefully solve any issues. Will triple check valve clearences once back together before putting the top cover back on.
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[UsernameTaken]

Disconnected the CDI and turned the bike over with the plug against a head bolt...

Then my neighbour came over with some homemade spark plug testing contraption which was placed in lieu of the spark plug.
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[UsernameTaken]

Just gave leakdown testing a google, sounds interesting, definitely something to consider 'next time'.

Have checked the obvious end of the HT lead, will check the other end when I can.

Considering it was ran with the choke on for a while, could I have just 'gummed' everything up?
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[bladerunner]

If the piston has hit the valves and they leak ....get new valves. No point pissin about with trying to lap them in etc. probs been caused by over reving at some point if it's the inlet valves only. As for the difference in colour between inlet and exhaust. They look ok. Inlet valves get cooled by the inlet charge and have a larger surface area to transmit the combustion heat to the head....whilst the poor exhaust valves get hotter as they get fried on both sides by hot exhaust gasses. Rings and piston look ok as no scores or blow by visible in the pics but whilst you have the motor out if you can spare the cash then fit new ones. Bikes like the drz give pistons a bit of a hard time so always a good idea to replace whilst your in there.
____________________
Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[UsernameTaken]

Thanks for the reply, and explaining the different colours of the valves.

Am replacing as much as possible whilst I have the engine in pieces...

A parcel arrived today with my top end gasket kit.

Could identify all the bits that came apart from these...

https://i460.photobucket.com/albums/qq322/UsernameTaken_01/Newbits_zpsa3e5dfa2.jpg

Are these valve stem seals?
____________________
CBT => Passed 23/09/07 Theory => Passed 18/07/08 A2 Test => Passed 30/07/08

[Fizzer Thou]

Yes,they are the valve guide seals.

Use moly grease on the valve stems when reinstalling.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'