Jump to content

Having trouble adjusting valves, I think.


johnsnownw
This post is 5024 days old and we'd rather you create a new post instead of adding to this one. You can't reply in this post.

Recommended Posts

Alright, so I ordered a set of new adjusting screws to replace the old ones, because when I adjusted the valves before it didn't seem to work. So here are some questions.

I know I'm supposed to adjust the left side valves when on the "LT" mark. However, when I reach the "LF" mark, and continue on to the "LT" mark, the left intake begins to move slightly downward, and continues to do so until I'm at the "LT" mark. When I tried this with the right side valves, the right intake did not move downward as I neared the "RT" mark. Anyone know if this is supposed to occur?

Also, if I line up to the "LF" mark, there is free play in both rocker arms, after I've adjusted the valves on the "LT" mark. Is this supposed to happen?

Hopefully my questions are not confusing.

Edit: I should also mention that the Left intake adjuster screw seems quite a bit higher, that is there is more screw above the lock nut, than on the Right intake.

Link to comment
Share on other sites

Do you want an ad-free experience? Join today and help support the Yamaha Owners Club.

Update:

So, I decided to fool around with it. When turned to "LF" the rockers had more play in them than when it was on "LT" (Even after I adjusted them on "LT") This doesn't seem like it should happen, as there should never be more play than in TDC or "LT". I'm assuming here so feel free to tell me I'm wrong and am an idiot! So, I decided to adjust the left side on "LF" Now the screw adjusters for the right and left piston look to be at the same height. Meaning that the distance between the lock-nut and adjuster screw top seems to be equal, for both the right and the left valves.

I'm going to wait until tomorrow to start her up, but if anyone has any comments on whether I'm about to destroy the engine or not, feel free to post them!

Link to comment
Share on other sites

I'm going to do it, I swear! I will start this thing up, unless someone stops me. If I've done something wrong and no one tells me, I'm going to blame you all!

Not really. I mean I'm going to start her up, but I won't blame anyone B)

Link to comment
Share on other sites

Although you set the valves with the LT or RT marks lined up with the pointer you must make sure you are on the compression stroke when you set the valves. When setting the LH cyliner turn the crank until the LT mark lines up with the pointer and watch the rockers.If they are moving you are on the wrong stroke so turn the crank another 360 degrees and you should find when the LT mark lines up again the rockers don't move. This is where you set the valve clearances at TDC on the compression stroke. The same for the RH side. Tony.

Link to comment
Share on other sites

Although you set the valves with the LT or RT marks lined up with the pointer you must make sure you are on the compression stroke when you set the valves. When setting the LH cyliner turn the crank until the LT mark lines up with the pointer and watch the rockers.If they are moving you are on the wrong stroke so turn the crank another 360 degrees and you should find when the LT mark lines up again the rockers don't move. This is where you set the valve clearances at TDC on the compression stroke. The same for the RH side. Tony.

Tried that already. Every single time I come up to the LT mark after the LF mark, the intake rocker moves down. It does not do this for the RH side when nearing RT. So I simply turned it to the LF, where the rocker doesn't start to move down and adjusted there. I think somehow, in the 30 years of use, something has come amiss. I mean there is really only an inch between the LF mark and the LT, if that.

Thanks for the reply though.

Link to comment
Share on other sites

All I can say to you is "good luck". On mine, I adjusted the valves on the LT mark (and RT, respectively). To tell the truth, I did not pay that much attention to checking if it was still going up or down or not. Even with the plugs out, I have to wedge the wrench holding the alternator nut against the footpeg or else the engine would "flop" past the LT mark. Same on the RT. When exactly on the LT mark, I could feel play on both intake and exhaust which is what the manual says I should be able to do when it is at TDC. Following this procedure and setting the adjusters in the middle of the range, I can hear them, but the sound is light and not at all loud. Perhaps you are correct that someone has modified something over the years. I wish I had more info for you.

Link to comment
Share on other sites

All I can say to you is "good luck". On mine, I adjusted the valves on the LT mark (and RT, respectively). To tell the truth, I did not pay that much attention to checking if it was still going up or down or not. Even with the plugs out, I have to wedge the wrench holding the alternator nut against the footpeg or else the engine would "flop" past the LT mark. Same on the RT. When exactly on the LT mark, I could feel play on both intake and exhaust which is what the manual says I should be able to do when it is at TDC. Following this procedure and setting the adjusters in the middle of the range, I can hear them, but the sound is light and not at all loud. Perhaps you are correct that someone has modified something over the years. I wish I had more info for you.

No worries. When I originally tried to adjust them I had to unscrew the LH side a lot to bring it in spec when on LT. So, the fact that TDC is now slightly before LT, kind of makes sense. I still don't understand why though. *shrugs*

Link to comment
Share on other sites

Can you take out the LH spark plug and either shine a torch down the plug hole to confirm that when the piston is at TDC the LT mark lines up with the pointer. The only other thing I can think of is have you had the cyinder head off and got the camchain/valve timing out ? Tony.

Link to comment
Share on other sites

  • Moderator

the easiest wsay to check your at TDC is put your thumb over the spark hole and listen for compression. Thats' turning the crank anti-clockwise on the left hand side

the LT nearest that compression stroke is the one you use.

LF is the firing mark and is in advance of TDC as it takes a millisencond for the fuel to ignite and the flame front to expand and send the piston down.

Link to comment
Share on other sites

Well, I believe I have the valves figured out. After adjusting them on the LF mark, leaving them a bit loose, the bike sounds great. Well, it did after it didn't. I finished putting in the new spark plug cables, caps, and plugs, and starter her up. However, now there was a loud sound coming from the engine on the left side, almost as though exhaust was escaping. Well, it was, the left header had lost a nut and was quite loose. I was worried before I found the problem because I had just traded a clicking for a much louder pounding sound. So, I bought a new nut and tightened both headers. Problem fixed, and she runs beautifully. Hopefully that's the last of the major repairs/adjustments I will have to do this year (knocks on wood).

Thanks for the suggestions everyone.

Link to comment
Share on other sites

  • Moderator

Well, I believe I have the valves figured out. After adjusting them on the LF mark, leaving them a bit loose, the bike sounds great.

should be LT mark john, but if your happy, I'm not one to p*ss on your party!!

Link to comment
Share on other sites

should be LT mark john, but if your happy, I'm not one to p*ss on your party!!

Thanks Drewps, I know it's supposed to be LT. However, when moving from LF to LT the intake valve begins to move downward. This is why the adjuster screw on the left side had to be loosened so much more than the right side. I don't know what is causing this issue, but TDC seems to be at "LF" or slightly after. Got me, all I know is after only adjusting the left side differently the whole engine sounds better, and seems to run quite well. I was afraid that adjusting it on LF could cause the valves to be too tight, which is why I adjusted them slightly more loose than spec.

Link to comment
Share on other sites

×
×
  • Create New...