Notes on Valve Clearance Check

[mdisher]

For future reference a 21 fault code means you forgot to connect the thermostat/sensor connector on the end of the tube.

Gee, you mean you have to plug everything back in when you're done?

I'm famous for forgetting the two connectors under the tank (fuel pump and gas gauge).

Yep, it sucks to button it all back up, hit the key to start her up and see your gas gauge flashing at you. At least that's what I've been told happens

 

[Geezer]

I wouldn't use RTV either. Too messy to clean up later. But silicone grease is a good idea for seating those o-rings (and in the original procedure)

+1 on the silicon grease and not RTV on the O-rings for coolant.

 

[mdisher]

I wouldn't use RTV either. Too messy to clean up later. But silicone grease is a good idea for seating those o-rings (and in the original procedure)

+1 on the silicon grease and not RTV on the O-rings for coolant.

For the record... (I know it was said earlier but I want to echo it). Even though your o-rings look good, even real good, they are not originally squared off. Change them unless you want the thrill of watching coolant bubble out the top of your nice clean valve cover and have a burning desire to drain the coolant and do it all over a 2nd time.

I picked up the closest match from a local hardware store. Took the pipe with me to be certain I had the right size. But in the end I didn't use the new ones.

And that was a stupid move. I was unable to find Silicon grease at either of the hardware stores, so I used a Silicon spray lubricant/conditioner. It seemed to work just dandy.

 

[TomInPA]

Fred, I suggest you add this note done by RH HERE into your thread, just in case some idiot goes ahead and removes the timing cover like I just did. I got the pin to realign, and the chain has been tight AFAIK

Also, I notice that when I have the intake valves in position to check clearance, that it takes about 12-degrees of movement to put any exhaust valve into the adjustment position. The two indents in the intake/exhaust cams line up TDC. As far as I know, this is the first time the valve cover has been off and the bike has been running great. So far clearances are in spec, but like I said, you can't do the checks of intake and exhaust without moving the crank and I thought that should be the case. Could this be skipped-tooth problem?

Edit: using an inspection mirror the marks on the cam chain sprockets are aligned. Those things are tough to see with the frame in the way.

The dowel pin that locates the left-side chain slipper will probably come out with the cover. It's a very tight fit in the cover and oil on the pin will create a vacuum to "lock" it to the cover. Since this pin positively controls the position of the slipper, it is imperative that you do NOT rotate the motor until you pull the pin from the cover and replace it in the engine block to anchor the slipper. It's the one the CCT presses against to tighten the chain and WILL slip if you move the chain in any direction. DO NOT rotate the motor until that pin is back through the bottom of the slipper, in the block.

 

[Fred W]

Thanks Tom.

In my original post I specifically mentioned NOT removing the timing cover unless you need to make an adjustment. So I highlighted that phrase and added a link to your note in case someone decides they want to remove the cover.

When I replaced my CCT with the newer version I remember being concerned with that dowel as I slowly removed the cover, but mine stayed in place and didn't stick in the cover.

When I've done my valve checks I've always been able to check both the exhaust and intake at the same crankshaft position. When they are in the correct position the cam lobes are not pointing directly away from the valve. They will be pointed equally forward (exhaust) and back (intake) like this picture:

 

[TomInPA]

Thanks Tom.

In my original post I specifically mentioned NOT removing the timing cover unless you need to make an adjustment. So I highlighted that phrase and added a link to your note in case someone decides they want to remove the cover.

When I replaced my CCT with the newer version I remember being concerned with that dowel as I slowly removed the cover, but mine stayed in place and didn't stick in the cover.

When I've done my valve checks I've always been able to check both the exhaust and intake at the same crankshaft position. When they are in the correct position the cam lobes are not pointing directly away from the valve. They will be pointed equally forward (exhaust) and back (intake) like this picture:

Thanks again Fred. Big help and really appreciate all the tech advise you have posted here. The CCT is also on the agenda today.

All valve checks show proper clearance. :clapping: .15-.18mm on intake and .18-.20mm on exhaust.

 

[Fred W]

Thanks again Fred. Big help and really appreciate all the tech advise you have posted here. The CCT is also on the agenda today.

You are most welcome. If you have not already seen my notes on the CCT replacement, they are here

 

[SkooterG]

You raise a valid concern about the o-rings. One that I considered before I went ahead with the generic o-rings from "The Despot". In my line of work we do use a lot of Teflon and Viton o-rings, both in high vacuum areas and also in junctions subject to extreme <i>cold </i>temperatures. But we really never have any applications where the <i>maximum </i>temperature is the issue, like on the head of our engines. So, naturally, I Googled up a <a href="https://www.sisweb.com/vacuum/o-rings/oring.htm" target="_blank">reference</a> that indicates the conventional rubber o-rings (Buna-N actually) are good for apps up to 300F. The engine should never be above ~250F, so that seems a comfortable margin.
I'm betting that if one was able to find the source of Yamaha's p/n 93210-18417-00 o-rings, you'd find that they are Buna-N. At least the ones I took out sure looked like it to me.

And, hey, Mom... all the other kids are doing it! Lots of other folks have used the generics with nary a problem.

Just a note here Fred. According to my trusted tech, the OEM Yamaha O-rings are made of Viton - a superior material than the Buna-N. Though as you have pointed out, so far it seems no issues using the cheaper ones.

 

[Fred W]

I wasn't ignoring you, Greg. I just never saw your reply before.

Viton is superior and the difference in expense is negligible. If you can score some locally you should definitely go for them. If not, be assured that the lower grade Buta-N rings work for at least 26k miles.