Comments On Checking Valve Clearances

[mobikie]

These are a few notes, after having just finished checking the valve clearances on my 1990 VFR750F. My Haynes Manual says they should be checked every 24,000km, and I don’t know whether they were done at 24, 000km, but I did find that the fuel filter was installed back to front (its arrow was pointing the wrong way), as was the gasket between the head and the valve cover on the front cylinders (it has and arrow designating front). The speedo now reads 52,686km and it runs very well.

The exhaust valve clearances were 9,9,9,10,10,10,10,10.

The inlet valve clearances were 5,6,6,7,7,7,7,7.

The limits are 10 and 6 +/- 1 so they are all fine.

The only “hard” decision was whether or not to remove the front fairings (its not my favourite job) to improve access to the front head. I wasn’t going to, but did after seeing how cramped the area is with the fairings in position, I am glad I did.

I also had to spend time making sure I had the cams set correctly for measuring. The manual says to set #1 at TDC using the timing mark on the crankshaft. I checked inside the cylinder with a dowel to confirm this. Then I had to make sure that it was the firing stroke which led me into looking at the valves closing and opening to determine which TDC was the firing stroke……the one when they are both closed. There may be a better way of doing this.

I have wondered about the firing order for my VFR for some time, and read about 180 degree crankshafts etc but never really understood what happens. I enjoyed the YouTube video ( https://www.youtube.com/watch?v=MwEbwKBic6w) on how the VFR creates its unique exhaust note. When I first got my VFR I thought that the carburetion was out because it didn’t idle with an even beat!

I think I have now learnt a little bit more about the VFR and I will share it with you.

I wanted to know why we were told to do this to check the valve clearances:

…..Set #1 to TDC on the firing stroke and check it

…..rotate the crankshaft clockwise 180⁰ and check #3.

…..then rotate 270⁰ and do #2 followed by 180⁰ and #4.

So I made up the following diagram with this as the starting point.

Let me know if I have got it wrong or if there are things I am missing.

[MadFrog]

almost 75k miles on the old girl (~120k km) and I haven't checked the valves yet (I got her at 32k miles, and I have no idea if the previous owners ever checked them.) Popular wisdom says I don't need to worry about it, but I think I am going to check, just to make sure... I'll sleep better at night, which I supposed is worth spending the afternoon and the $$$ for the gaskets.

Great post by the way. Pretty cool figuring that stuff out, huh?

[V-FORE]

Great diagram!m I checked mine at 50k and all were in spec, she is now at 101+ and I have not thought about doing it again I just did the valve check on my NC700 @ 16k ( I think I was supposed to check them at 8k ) all were in spec. The NC took me 1.5 hours start to finish Got to Love Honda Engineering!!

[JTBakay]

Had mine checked at 10.000km, 5 were out of spec!! Cost me my 2 week paycheck, but runs so much better. 3000km since and pure bliss. I have heard that the older ones almost never go out. (Quoting my mechanic)

[Switchblade]

Well worth the money ....