Yesterday happy today not happy valve adjustments =)

Started by Old Rider, September 14, 2016, 10:05:13 AM

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Old Rider

So yesterday i finally got my bike running after valveadjustment and some carbtrouble.It did run smooth quiter and seemed to have more power.
Today i have been riding some more and the bike runs good but and after some little harder driving than yesterday the engine started to make tikking sound most from left side.The bike runs  stable on idle also.
When finished adjusting the valves 2 of the exhaust valves  got a litte loose they are 20.5 and 20.4 is that enough to make tikking sound?
Also tink i mayby did something wrong ...i think i adjusted some valves on the exhaust stroke instead of the compression stroke is that possible?
all valves where checked vhen the lobes facing away fom eachother.
when the camlobes are facing away from eachother can that position be both tdc on compression and exhaust stroke?

Pat Conlon

Cam lobes facing away from each other is not the way to do it.

Cam lobes facing away from the valves is the correct way to measure. i.e. cam lobes 180 degrees away from the shim.

The point is to measure the clearance from the base circle of the cam to the shim. The position of the piston does not matter.
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Old Rider

Today i reshimmed my valves  and now the tikking noise is gone.I checked a litte more on the camlobepositions .At TDC the camlobes are facing away from eachother and that is the compression stroke.You can then measure all four valves on that cylinder.At TDC on exhauststroke it is not possible to take measurements as the camlobes is facing toward eachother.I also checked the measurements with the camlobes facing 180degre away from the valve and it was exactly the same measurements.But when using 180 degre away from valve you can only measure one valve at the time and you have to crank engine 4 times to measure all four valves on one cylinder so its definitly faster with the camlobes facing away from eachother.It suprises me that the valves was so loud tikking/knocking they where only 0.4 and 0.5 out of spec. 20.4 20.5

FJ_Hooligan

There is the FAST way and there is the CORRECT way.

You ask questions but do not seem to follow the advice. 

You should be able to measure 2 valves at a time.  With a half turn of the crank, you measure the next cylinder in the firing order.  Do all the intakes first then go to the exhaust side and repeat.
DavidR.

Old Rider

Yes and when the lobes are facing away from eachother is the correct way and also fastest :yes: you then measure 4 valves on that cylinder and when you crank engine 180 degrees the next 4 valves on the next cylinder is in position for measurements and so on.when lobes are 180 degree away from valve is also correct but slower as you can only measure 2 valves .As i said i tested and the clerance  measurements are the same with lobes facing 180 degree away from valves and when they are facing away from eachother.Also in the manual the picture of how to measure valvclerance shows the lobes facing away. :smile:

FJmonkey

Quote from: Old Rider on September 19, 2016, 04:28:01 PM
Also in the manual the picture of how to measure valvclerance shows the lobes facing away.
What manual are you using? Some manuals have errors. Your method requires that the cams are machined to a precise diameter for more than 180 degrees of rotation. It makes common sense that it is how they are machined. But not required. Quality control can only catch what they are told to measure and control.
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4everFJ

Not sure how you guys check valve clearance, but 'Old Rider' is absolutely correct.

When a piston is at TDC all valves are closed and you can then measure all 4 valves. This is how I resently did it and also how it is described in the Yamaha factory manual.
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tmst08

The valves may be closed, but I wouldn't be so sure that you're going to get the maximum clearance measurement unless the the lobe is pointing 180 degrees away from the valve. If it's not actually the maximum clearance point, then you're going to be shimming it on the loose side. Safe, but probably not what you want.

The factory manual may recommend this "TDC" method due to the convenience and safety of it rather than accuracy.

aj52

I try to upload a video on this topic,hope it works.
It explains where camlobes should be

https://m.youtube.com/watch?v=zCa556ObEi8
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1991 FJ 1200 ABS
1991 FJ 1200

racerrad8

What Pat already said...

The smallest portion of the cam is the base circle. If you always point the tip of the lobe 180* away from the valve you ensure you are at the proper place for measurement.

Using the Yamaha directions by using the timing marks can lead to problems. That method does not compensate for timing chain stretch.

Whatever you do, make sure you are at the base circle to ensure proper measurements and not on any point of the lobe "ramp"

Randy - RPM

Randy - RPM

ribbert

Quote from: aj52 on November 16, 2016, 01:15:57 AM
I try to upload a video on this topic,hope it works.
It explains where camlobes should be

https://m.youtube.com/watch?v=zCa556ObEi8

While on the subject of threads, anyone see the flawed head bolt re torquing technique in this vid?

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

fnlyafjat51

I have to agree with what has already been said. With any engine, you should set the valves from the base circle to get the most accurate adjustment. TDC is not always the best way. They could be as much as .020-.030" off the base circle at TDC, but not actually on the lobe yet. Best to play it safe.
Just my 2 cents worth.
Brien

Old Rider

Quote from: fnlyafjat51 on December 08, 2016, 07:50:45 PM
I have to agree with what has already been said. With any engine, you should set the valves from the base circle to get the most accurate adjustment. TDC is not always the best way. They could be as much as .020-.030" off the base circle at TDC, but not actually on the lobe yet. Best to play it safe.
Just my 2 cents worth.

Sure its never a good  idea to follow the Yamaha enginers advice in the fabric service manual  :yes:

ribbert

Quote from: Old Rider on December 10, 2016, 02:08:53 AM
Quote from: fnlyafjat51 on December 08, 2016, 07:50:45 PM
I have to agree with what has already been said. With any engine, you should set the valves from the base circle to get the most accurate adjustment. TDC is not always the best way. They could be as much as .020-.030" off the base circle at TDC, but not actually on the lobe yet. Best to play it safe.
Just my 2 cents worth.

Sure its never a good  idea to follow the Yamaha enginers advice in the fabric service manual  :yes:

You no doubt said that tongue in cheek but since the beginning of time workshop manuals have been full of errors, poor advice and in particular, convoluted procedural instructions. Pre internet, it was common practice for mechanics to buy workshop manuals for popular makes and models (I recently threw out about 40) They are written by the engineers who design them, not the mechanics who work on them.

One engineer might write a procedure and 20,000 mechanics find it's wrong or unnecessarily complicated, I'll go with the hands on findings.

What's the first thing the manual tells you to do when checking valve clearances on an FJ - remove the fairing! and how much time do you spend trying to get the cam chain tensioner to mount up side down.......

I haven't read much of the FJ manual but from the little I have it appears no different to every other one I've ever read. The best way to use a manual is take the technical data you need from it and follow your nose with how you go about it.

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

Old Rider

I dont know about haynes or clymer manuals ,but i use the one written by yamaha motor company 3rd printing .It says it is intended to be used by qualified yamaha mechanics.
It does not tell to remove upper fairing to adjust valves.It says remove upper fairings airinntake ducts .It dosent give any wrong info at installig the camtensioner either.
As i mentioned earlier when i checked clearenses i did a test and i got same measurements when lobes facing 180 degres away from the valves as when inntake and exhaust lobes facing away from each other as its says in manual,so its clearly possible to measure with the 180 degre away to.I however chose to use the workshop manual as its faster too.
:good2: