change valve stem oil seal and cleaning piston carbon deposit ?

[Andre]

Grog, these kind of pics are usually done with a camera attached to an endoscope. That's a fiber-optic tube of the type they use to look into your stomach or other places and take pics through them. They are also available for automotive (etc.) stuff.

Looks like only the damaged cylinder was running lean. All others look like they were getting a rich mix.

I am not surprised that he was still using it. When my 3rd cylinder didn't run (spark plug failure) I didn't even notice while riding. Ok I was pooped (running my self only on one cylinder lol) and noticed not until I got in the driveway and took the helmet off that engine sounded different. Held my hands in front of the two cans and felt that the exhaust stream was weaker on the right can.

@rollerfish01 Before sending the injectors in you can test if they are clogged yourself. Lots of videos on youtube about this. Also see the workshop manual 4-46 for electrical testing of injector.  But sending them to the company (see link in previous post - thank you Seth) is the best way and costs only around 60 quid for all 4! Besides initial and final testing, cleaning, they usually replace micro filters, o-rings, spacers and caps. They will get them just about as right (no matching and no new replacements) as new.

Replacement injectors are expensive (who  would have thought). There are inexpensive chinese replicas. T24 has them and reports that they are alright but deliver a bit too much fuel. Adjusting fuel pressure (T24 has an external regulator on his) takes care of that.

For what a new original injector costs I have seen a lot of decent used throttle bodies that come with the injectors as well as TPS and STPS. The last 2 items do wear - slowly but they do.

[rollerfish01]

At the very beginning when I first notice the "problem", it was cylinder no.2 sometimes not firing, gasoline smell came out from the muffler. I changed spark plugs, ignition coil & new battery, it will fire every time. But when checking the exhaust head pipe (at idling) with an infrared temp device, it was always 60-70 degree celsius lower than the other 3 cylinder's head pipe. (I wish I had check this before buying the bike ), so the problem hunting started.

@Andre very much agree with you about to check the injectors & TB first. Actually I did all as you said. I tested all the injectors & cleaned with throttle cleaner (as you said learned from youtube), injectors were all fine also the electrical test ok. I also tried to swap the injectors between different cylinders, do TB balance, the problem remains. Then by chance I bought a very good condition 2nd hand TB (with all parts and good wiring/ connectors), tested then replaced the original one,  problem remains. So I guess can eliminate the factors caused by injectors/ TB/ TPS. STPS. And maybe this is pointing to next step...the valves/pistons/camshaft/cylinder head...

@grog About the photos. Surprise! you can take the photos easily with your smart phone ! just need to take off the exhaust head pipe (better take off the oil cooler too), put the smart phone camera near to the exhaust side and shoot. I found using video mode with fill in light on is better, just record steadily for a while and change different angles. Then you can play back and capture the screen, save as a photo; also can do that on PC. Yes, I think the further checking steps may go as you say. Its good to hear more opinions and suggestions from all of you ! (Also all the resources here is a great help  )

[rollerfish01]

duplicated

[rollerfish01]

About the endoscope, I do have a cheap usb one and took some pistons photos, however it's resolution is not high and a bit difficult to control the direction .

[Andre]

Well... cough... the last pic of #2 looks like the other three in Reply #12. And fits the pic of the #2 piston as well.

Wow, you put already a bunch of work into this.

On to grog's checks

[rollerfish01]

bought a spare cylinder head and finally got time to clean it, fit new oil seals and do valve lapping

[rollerfish01]

then take the old cylinder head out of the bike and ....almost cannot trust my eye
at the cylinder 2 a Ex valve was broken 

[rollerfish01]

Anyway forget the old one and do cleansing to the pitsions and put the spare one on 
although the old valves and pistions were full of carbon, the pistion wall are as new (the bike 78k km on clock).
After putting everything back, I am very exciting and afraid of anything will go wrong...
Luckily the engine just start up perfectly, the moment was so touching 
And I think the engine problem of the bike was resolved.
The power of the 14 and the sound of Yoshimura just returned. 

[KiwiCol]

Excellent work & pic's Rollerfish01.  Determination won through in the end.  Well done mate. 

[DTTW]

Wow. Nice work Rollerfish01!

Glad you sorted everything. Just makes me wonder what could cause the valve to break.

Enjoy your ride 

[Andre]

Congrats Rollerfish, big relief when everything works for sure.

Valve play or carbon buildup on valve seat most likely. Lean condition could do this also but combustion chamber doesn't look lean.

[grog]

Well done Roller, great work. Make sure you get air/ fuel mixture checked. That valve was burnt by being lean, nothing else. Yoshi Can did i see mentioned? Top job mate.

[rollerfish01]

Dear mates, Thanks for all the comments ! 
As the cylinder head is healthy now, today ordered a PCV to see how much improvment it can bring

P.S. It seems the oil pipe inside the cylinder head is different from 2002 to 2007, the 2002 had a bigger hole.