Valve Clearance problem Left Intake

[Sg6]

Helo,

I have control my valve clearance this weekend and have seen something very strange... I found it very strange.

It's been 2 mounths now that i have changed the valves with Ferera valves. A company have done the seat cutting and has check if the valves are closed.

The first time that I controled the valve clearance the motor has turned for about 3h and anything was normal for me.

The list below is what i have note down when i measured the clearance.

The second time that i have measurde on 18/03/2007 I have seen that the clearance from the left intake has decreased to a small 0.10mm and then I have changed the shim from 268 to 265 and what i have measured is a small 0.12mm

I know for the first time that is seems to be normal because of the brake in period. But now after another mounth a have the same results if you look to the last measurment.

What could cause this?? In my eyes I don't think it's normal. The valves are ferera valves and i use the DRZ double spring kit for the valves. Could it be that there is something wrong with the coating or something with the seat of the valve? Or is this normal?

The bike has ran now for about 12h.

Hopefully you guys can help me out with this but I guess that you will tell me to open the cilinderhead.

19-02-2007

EX: Left side : Shim 290 - Big 0,25mm

Right side: Shim 272 - Big 0,22mm

IN: Left side : Shim 268 - little 0,13mm

Right side : Shim 262 - little 0,14mm

18-03-2007

EX: Left side : Shim 290 - Big 0,24mm

Right side: Shim 272 - little 0,22mm

IN: Left side : Shim 265 - little 0,12mm

Right side : Shim 262 - little 0,13mm

30-04-2007

EX: Left side : Shim 290 - big 0,24mm

Right side: Shim 272 - little 0,22mm

IN: Left side : Shim 265 - big 0,10mm

Right side : Shim 262 - big 0,12mm

[William1]

Certainly seems like a 'sinking valve'.

Either the valve coating is gone/worn off (were the valves lapped?) or the seat is sinking or the valve seat cutting was done incorrectly.

Before the problem ges worse and leaves you broken down or causes a bigger problem, I suggest you remove the head and the troublesome valve and check it.

[Wayward Son]

valve recession.needs new valves and a valve job.

[Sg6]

just 1 intake valve or 2 intake valves?

How can i be sure it doesn't happen a second time then? What caus this problem now?

Andries

[DRZ-HEAD]

How's your air filter?

Do you ride in dusty conditions?

[Sg6]

i'fe got a powerlid on top for the big dirt and in inside I have a twinair that i every time change after a ride.

I ride in dusty conditions but i think that was 2 times so i think that would not be the reason. I have drive before more in dusty conditions and the valves never decreased in clearance.

[William1]

just 1 intake valve or 2 intake valves?

How can i be sure it doesn't happen a second time then? What caus this problem now?

Andries

I would do them both. Cause can be

Improper seat cutting when they were last installed

No 'Hard Coating' on the valve

Dirt in the air

There are other possibilities but this covers about 99%

My money is on the first two possibilities.

I would contact Ron Hamp or Eddie and see if they can get you the right valves. I would even consider sending the head to Eddie to have hime do it right. Transit time from Belguim to Colorado is not too bad and worthwhile Vs. another possible failure.

[Sg6]

i will contact eddie...

[Sg6]

Hello,

Today I have open the head but I don't see something strange on the valve or seating.

And now?

[Wayward Son]

are you sure your measurments were correct?

it is normal for the valve to settle some.

[Sg6]

yes I am sure.

I have check it at least 3 times to be sure.

After every measurement a turn the motor till I come back on TDC and then i measure again and compare my results and they are always the same.

What should I do before I put it together?

[vanram]

Check the valve seat contact area with a marker and setting the valve in the head and turning it enough to get a contact area. Mark both seat and valve. If the seat is within specs, check everything else thoroughly, put it back together and keep an eye on the clearance. Good Luck. vanram

[Sg6]

i have check the seat and valve with a marker. Everything seems to be fine to me. I have a great seal between the parts.

I am just afraid if i put it back together that after a mounth a must reopen the head.

[Sg6]

I have also check if I have axial clearance on the cam shaft after tighten the bolts ans I feel just a little bit that i can move the camshaft up and down. In my thoughts it will not take effect after the cam chain is tighten up. Correct me if I am wrong.

Also i have put the valve under the microscope and it's like new for me. I know sounds crazy.....

[Sg6]

hello,

it's been a while that i have post the latest news about my valve clearance problem.

I have give my cylinder to a workshop to give it a control check. They didn't found something strange and all valves are closed.

After that i have changed the shims to the specified clearance. After measurment i had a littel 0,13mm on left and a big 0,14 on the right.

Now after a mounth, let say 4, 5h intensive driving on MX circuit i made the control again. I did the measurement without looking to the measurement that i write down the last time. I turn the cams 4 times and measured again. It was the same measurement. Then I compare my results with the one of the last time and they are exactly the same.

Me happy of course!

Up to a great summer!

Thx for the backup TT

Regards

Andries

[CsHoSi]

Hi Andries,

That's great to hear! Just read your thread today and all the posts were educational.

Cheers! ?

[Sg6]

helo,

it's been a very long time that i have been on this forum.

Yesterday I have check again my valve clearance.

On the first page you can see what kind of values I had last time.

Now after a least 48h of driving MX and onroad I have measured this (I copy the last measured clearance also in this thread):

19-02-2007

Running Houres: 3h

EX: Left side : Shim 290 - Big 0,25mm

Right side: Shim 272 - Big 0,22mm

IN: Left side : Shim 268 - little 0,13mm

Right side : Shim 262 - little 0,14mm

18-03-2007 -

EX: Left side : Shim 290 - Big 0,24mm

Right side: Shim 272 - little 0,22mm

IN: Left side : Shim 265 - little 0,12mm

Right side : Shim 262 - little 0,13mm

30-04-2007 Running Houres: 12h

EX: Left side : Shim 290 - big 0,24mm

Right side: Shim 272 - little 0,22mm

IN: Left side : Shim 265 - big 0,10mm

Right side : Shim 262 - big 0,12mm

13-06-2009

Running Houres: 48h

EX: Left side: Shim 290 – big 0,24mm

Right side: Shim 272 – little 0,26mm

IN: Left side: Shim 262 – big 0,10mm

Right side: Shim 260 – big 0,12mm

My first though if I read this measurements I would think it's normal worn of the valves. If I think then further, how long will this take? After howlong should a renew my valves?

Also I prefer stabilised measurements sow I can thrust my motor.

Should I redo the seat cutting with new intake valves or do you guys think this is normal?

My setup:

- Hotrod Stroker crank + Eddy Shim

- JE Piston

- compression of almost 13:1

- Hotcams with ATDC

- TM 36 carb

- Full Yoshi exhaust Line

- MCCT from TT store

Best regards

Andries