I ask for help with service.

[Onibaka]

 Which type of oil is making your gearbox wet?

 

I use Eni Rotra MP 80W90 (mineral)

[Chuck]

I understand that English isn't your first language, but I think what Docc is saying is to smell the oil and see if you can tell if it is engine oil or transmission oil. It is not uncommon for an engine breather hose to leak and get oil all over everything. 

A way to find out where it is leaking is to thoroughly degrease the area, and spray powdered athlete's foot medicine all over it. Make it white. Leaks will quickly show up. 

[Onibaka]

I was replacing the breather hose to a new one. I'm sure that I have leaks of exactly gear oil. Also I checked those two bolts, they do not leak. Since the gearbox is now removed, I'll try to replace the oil seals and reseal with sealant. After that I'll see if there will be new leaks. It seems to me that one of the main leaks comes from the vent. Probably there was more oil than necessary or should i consider to change the oil.

[docc]

Thank you, yes, I was trying to ask if the leak is motor oil or gear oil.

 

With the gearbox removed, is it very wet in the housing around the clutch?

 

If so, and it is gearoil, Pete Roper is saying that the most likely leak is the seals for the clutch pushrod coming form the slave cylinder behind the gearbox.

 

My Sport was also leaking motor oil from the flat gasket for the crankcase breather tube at the top right.

[Onibaka]

I have a question on setting the valve clearance.

This winter, I took off the heads of the cylinders to replace the o-rings that flowed. After assembly, I adjusted the valves, and after some mileage I checked them, they were tightly clamped, I adjusted the gaps in the T.D.C position again and later I was confused by the strong knock of the valves.

I started checking gaps again and found that in the T.D.C position the gaps were not the biggest.

When the crankshaft rotates, when the exhaust valve opens, the intake valve clearance increases (relative to T.D.C), and when the intake valve is open, the clearance of the exhaust valve increases (relative to T.D.C).

Thus, at different positions of the flywheel, the valve clearances increase by approximately ~ 0.05-0.07mm relative to their adjustment in the position of T.D.C. It looks very strange, and I thought that there should be maximum gaps in T.D.C. If this is not a normal situation, then I do not know how to regulate the valve. Should the gaps be set according to TDC or according to the maximum clearance of each valve?

The issue is both with the right and left cylinder.

I will attach a video where I try to display the situation (usually I set the gaps at 0.15 / 0.20, but on the video they are set to 0.10 / 0.15)

 

T.D.C 0.10 / 0.15:

 

exhaust pinched - intake clearance 0.15 (~+0.05)

exhaust pinched - exhaust clearance 0.20 (~+0.05) 

 

 

[Chuck]

Are you sure you are on the compression stroke of the engine at TDC?

[Onibaka]

37 minutes ago, Chuck said:

Are you sure you are on the compression stroke of the engine at TDC?

Mark "D" for the right cylinder and in the spark plug hole I see that the piston is at the top. 

In addition, this is the only location of the flywheel when both valves have clearance. The other two videos show that the opposite valve is pinched

 

[Onibaka]

 But I don’t think I have this case. In the TDC position, the gaps did not change much after tuning.

[Chuck]

Ok, you are doing it right. Unfortunately, if the clearance keeps closing up.. it sounds to me that the cam may be wearing. I don't know of any other cause for that to happen.

Maybe someone else will come up with a reason I haven't thought of..

[gstallons]

"If" the camshaft were wearing , or any of these components were wearing , the clearance would be opening instead of closing . 

 The only time clearance closes , is when the valve stem height goes "up" or gets taller . As when valve seat or valve face wears . 

Don't worry about this for now . 

 Please make sure you are taking these measurements at TDC  compression . Remove the spark plugs so you can rotate the engine . If you have a bike stand ,  get the bike up on the stand and put the transmission in high gear , use the wheel to rotate the engine to get the piston on TDC . One TDC will give you valve overlap , the other will give you what you are looking for . Adjust these valves and go to the other side and repeat the procedure .  

When you are finished , Take a break , then  recheck your work .  

[Onibaka]

It seems to me that you did not quite understand the problem I described. I am sure that I put the valve in TDC, I took out the candles and rotate the generator nut to the D and S marks and to the desired engine cycle. I have adjusted valve clearances many times and this procedure does not cause me any difficulties.

An initial reduction in clearance was expected, as I bored the valve and valve seats and changed the valve spring gaskets. All this sat down and finally worked out and the valve clearance decreased. After that I re-clamped the cylinder head (gaskets changed) and adjusted the valve clearances to 0.15 / 0.20.

That was about a month ago

The other day, I heard the knock of valves and decided to re-check the clearance. In the TDC position, the clearance did not change, it remained ~ 0.15 / 0.20, but if you rotate the crankshaft further, at some points (after exiting the TDC) the intake and exhaust clearance may increase by more than 0.05mm.

 

For the video, I adjusted the valve to 0.10 / 0.15 in the tdc position (video 1), and you can see:

Video 2 - 0.15 intake clearance, after crankshaft rotation (in tdc - 0.10)

Video 3 - 0.20 exhaust clearance, after crankshaft rotation again (in tdc - 0.15)

 

I think this is not very similar to the wear of the crankshaft. Perhaps it looks like he's bent, but I don't know ...

 

I want to watch the gap situation a little more. Only I would advise in what position to adjust the valve. In TDC or each valve individually at the time of maximum clearance (this will reduce its clearance in the TDC position)

[gstallons]

No , you want the piston at TopDeadCenter . when the piston is at it's maximum travel , then adjust the clearance of both valves . 

 

 Good luck 

[Onibaka]

2 minutes ago, gstallons said:

No , you want the piston at TopDeadCenter . when the piston is at it's maximum travel , then adjust the clearance of both valves . 

 

 Good luck 

And the fact that the valve clearance may increase when the piston leaves the TDC is wrong? Or maybe it's okay and I'm worried for nothing 

[LowRyter]

3 hours ago, Onibaka said:

Mark "D" for the right cylinder and in the spark plug hole I see that the piston is at the top. 

In addition, this is the only location of the flywheel when both valves have clearance. The other two videos show that the opposite valve is pinched

 

You can be on TDC on the compression stroke or TDC on the exhaust stroke.  For the later, the valves will be open, the former has them closed.  Typically, if you can't get a feeller cage in, it means you're on the exhaust stroke and need to take another 360 degree turn.  If you still don't have gap, that sound like a problem.

One hint I use, I mark the fin on the alternator with a marker at 12  o'clock on the right side TDC.  One full turn and past to 3 o'clock will be the left side TDC.  I always check it with the timing marks but it's much easier to do that when watching the marked fin.

[Onibaka]

8 minutes ago, LowRyter said:

You can be on TDC on the compression stroke or TDC on the exhaust stroke.  For the later, the valves will be open, the former has them closed.  Typically, if you can't get a feeller cage in, it means you're on the exhaust stroke and need to take another 360 degree turn.  If you still don't have gap, that sound like a problem.

Yes, I know about this fact. Adjusting the valves is not a problem for me. Oh... you don’t seem to understand what I was trying to explain

8 minutes ago, LowRyter said:

One hint I use, I mark the fin on the alternator with a marker at 12  o'clock on the right side TDC.  One full turn and past to 3 o'clock will be the left side TDC.  I always check it with the timing marks but it's much easier to do that when watching the marked fin.

Thanks, it will be interesting to try it