Come on ride the train, the valve train!

[87handmedown]

Meh, so it's not my best title. I know someone out there laughed.

Checked the clearance on my valves tonight as the bike has been sporatically running out of power. My results are as follows


Cylinder________#1 ______ #2 ________ #3 _______ #4

Inlet__________0.13 _____ 0.12 _______ 0.16 _____ 0.10

Exhaust_______0.17 ______ 0.20 ______ 0.18 _____ 0.18



So it's not what I expected at all. Only one valve is out of spec, three are close, and the rest are all fine. It's just wierd, some times the bike will run fine, other times it acts like it's running out of power. Example, Sunday afternoon I had the throttle wide open and in fifth gear, it wouldnt' pull itself past 7000rpm. However, Wednesday on the ride home from work, I ran 90mph (again around) 7000rpm and I was only at 3/4 throttle and it had plenty more in it. Weather conditions were extremely similar in both cases as was the road/terrain.

I guess I just expected it to be farther out of spec than it is. Sporatic problems are the WORST to try and solve. But I'll worry about the big picture later. Right now I'm just looking for any advice or direction to take as far as bringing the valve train back into adjustment.

[StarGate]

What are the specs for intake and exhaust on your bike?

[87handmedown]

Oh sorry, I thought they were all the same. 0.08-0.18mm is what the book says.



And here it is in my 100% uncertified 'feshional mechanics shop. The "pro" is dropped off because I don't get paid. lol



Nate was right. It really isn't that hard at all to do, and all my rubber gaskets have gotten hard so they do need replaced.

[Ronmac1118]

Gas Man, nothing but high test premium, gas now is rotten, trashy, weak

[87handmedown]

I'm curious as to how switching to a higher octane gas is going to solve my problem. All I would be doing is going to a fuel that is less likely to autoignite.

[87handmedown]

Should I bother messing with the 0.16 valve on the intake side? Anyone have any tips for doing this? It seems pretty straightforward but I was just wondering.

[A2rider]

Valves only get tighter as time goes on.

[A2rider]

I'm curious as to how switching to a higher octane gas is going to solve my problem. All I would be doing is going to a fuel that is less likely to autoignite.

Most owners of these only run 87 octane. Not because they're cheap, but because the bike runs better on it. Mine runs like doo doo on anything except 87.

[87handmedown]

Ok, so I removed the cam, buckets, and shims and then looked at what was stamped on the shims. The numbers on the exhaust are 250, 245, 245, and 250. I assume this means 2.50mm, 2.45mm ect... correct?

So if I take the two outside shims and put them on the two inside valves, that will bring the clearance in on them from .20 and .18 to .15 and .13 respectively right?

And then I should order the 2.55mm shims from Z1 to bring the other two within tolerance?

Just trying to make sure that I don't do this wrong.

[87handmedown]

Most owners of these only run 87 octane. Not because they're cheap, but because the bike runs better on it. Mine runs like doo doo on anything except 87.

That's exactly what I thought. No difference in flame speed or energy released.

[StarGate]

I wouldn't touch the exhaust side. They are all at the loose side of tolerance now or just above it which is the preferred setting.

I would go with a .05 smaller shim on #1, #2, and .10 smaller on #4 inlets then button it back up and ride it.

[87handmedown]

I wouldn't touch the exhaust side. They are all at the loose side of tolerance now or just above it which is the preferred setting.

I would go with a .05 smaller shim on #1, #2, and .10 smaller on #4 inlets then button it back up and ride it.

Valves only get tighter as time goes on.

Wait a sec, I'm extremely confused now. I thought everything got loose as time went on... thus I would have to put bigger and bigger shims in the valvetrain to take up the slack. Meaning as time goes on, a .18 gap turns into a .22 gap and a .12 gap will grow to a .15 but you guys are saying that it's the other way around.

Am I reading this correctly?

[StarGate]

Yes you are reading correctly. With more wear the valve will sink farther into the head which closes the gap between the cam and valve thus making the gap smaller. If you adjust it for maximum gap then ride the poo out of it, the gap will only get smaller meaning that your adjustment to max will be within spec for a longer period of time.

[87handmedown]

Ah! Thank you for explaining that too me. I had it all backwards. In addition to this being my first bike, it is also the first overhead cam engine I have worked on so thanks for setting me straight!

I'll order the correct parts tonight and then get to taking the intake apart tomorrow!

[Nate]

That looks familiar, Orry!

In my estimation, increasing the clearance on 1, 2, & 4 intakes won't hurt anything.

As for it running poorly, are you 100% certain the fuel tank cap vent passage is clean? I spent about a half a can of carb cleaner on my SR cap making sure it was clear and pulled the cap assembly apart to clean the 650B's vent.

Beyond a fuel blockage, the only other thing would be electrical. A coil could be breaking down or a condenser getting weak and not allowing the coil to charge to full strength thus weakening the spark.

Once you get it back together warm it up and do a compression test. You should see about 150 PSI on all four cylinders.

As to why a bike will run better on "premium" gas may well be that the gas is indeed better or more stable than the cheap stuff from a given company. Many companies claim various blends and it would stand to reason that they may treat the "premium" gas with a bit more care than just adding more octane to it. Doing so also allows people to believe that a higher octane rating equals higher performance gasoline, when actually a higher octane rating is required for a higher performance (compression) engine. People have come to believe that the tail wags the dog.

[87handmedown]

It's actually spelled Orrie, but the fact that you tried is all I really care about anyways.

Please elaborate on this fuel tank cap vent. I was unaware that there was anythign to clean. How do I clean/disassemble it? To be honest, it does act a lot like a fuel problem.

[Nate]

Orry, Orrie, Nate, Nat, it's all the same to an old guy!

There is a small passage that allows air into the tank as the fuel level drops. Likewise, as the fuel expands on a warm day or contracts when it cools, air is forced out or drawn in respectively. That's how moisture gets into an otherwise "sealed" tank and rust forms. Rust and dirt can also collect through that passage partially clogging it.

Now, your bike being an '82 has a different style cap than I'm familiar with. I'd bet that Andy has a good idea on how to clean it. All I can say is remove the gasket and look for a tiny hole or series of tiny holes (maybe three) and shoot carb cleaner into them followed by shots of compressed air. Also, a new cap gasket maybe the answer as a new one won't deform and perhaps block the vent(s) (that's just a theory of mine as I have no proof that could happen). Finally, when you look at the underside of the cap, you may find it assembled with screws (650B) or as a padlock (SR). I'm no locksmith so I didn't attempt to disassemble the SR cap, but the 650B cap was taken apart with ease and cleaned. Yes, there was gunk in each.

One telltale sign that it's plugged is that right after a ride of some distance you open the cap and you hear air rushing into the tank. Also, on the day it was sluggish, had you ridden farther than on the day it ran fine? At some point the fuel flow will stop completely until some air can be let into the tank and it can return to atmospheric pressure.

[87handmedown]

Well, I think I really ****ed myself this time. I was taking the intake cam off when I dropped one of these little guys down into the slot where the timing chain runs.



Please tell me that it went straight to the oil pan and that it's not stuck halfway in the block going to cause me problems later. Do these bikes have magnetic plugs that it'll stick to at the bottom? I probably need to remove the exhaust and then drop the pan to find out where it is don't I?

Taking any and all possible suggestions on how to solve this one.


Back to the original problem, the shims on the intake valves going from left to right, which is #1-#4 cylinders right?( don't want to **** anything else up) are 2.50, 2.55, 2.50, and 2.45.

So if I take the 2.45 shim and put it on the #1 intake valve inplace of the 2.50 shim, and then take that 2.50 shim and put it on the #2 intake valve, I'll only need to buy a 2.35 valve for the #4 intake valve correct?

[StarGate]

Correct and before you pull the oil pan. I've dropped a bolt in mine before and was able to fish it out with a magnet. You can use a magnet thats attached to one of those telescoping rods. You might just get lucky and snag it if you have a lot of patience.

[87handmedown]

Well good news! I was playing with my little magnet on a stick tool and managed to grab the bushing as it was resting on top of the crankshaft gear. I had already drained the oil but that's ok... bike needed an oil change anyways. So now I'm back to square one!

Only question I've got right now is, on the timing chain tensioner, there are two bolts that hold it on. One of these, the top bolt, had a washer, the bottom bolt did not, or at least it didn't when I took it off. Should both bolts have a washer, or just the top one?