3 questions on valve adjustment

82 Seca 650. Original / mint. 9000 miles

In a previous post, someone (can't recall) said to do the valves before I bother with a YICS balancing. Forum member KVB_650 is gracious enough to offer to help with the balancing - he also said to get the valves done first. I'm all for doing things properly of course. I don't want to do anything half-assed on this bike. I'm hoping that no one considered the low mileage on the bike.

Question 1) With only 9000 miles, is it likely that I should have the valves done? It runs smooth & silent.

I'm not mechanically inclined but I read a post by rickomatic that if there are any valve issues, the compression would be off in the affected cylinder.

Question 2) can a compression check give the valve train a clean bill of health? Or should I bite the bullet (more delays.... sniff!), pay someone to do it? Wait, that's 2 questions

Question 3) from what I've read, you need to have 'the right' shims to correct any 'off' valves. So doesn't this mean any shop I bring it to will need to have a whole assortment of these, to get the right one? IE: isn't it unlikely these days that any shop has the whole range? Or are these shims from the 80s standard fare in any garage these days?

I just want to get out & ride this thing but I won't until it's ship-shape.

thanks in advance

 

I did my valves the other day for the first time. Bigfitz has a write up in the FAQ section. Pretty easy.

I believe they're supposed to be done every 6,000 miles. So if you haven't done yours you should.

Open it up, check them all, record the numbers from the bottom side of the shims and then order new ones. you may only need a few or you may need 8. I needed 4 as I could reposition some to fix the clearance on a different valve.

I believe these shims were/are used on more than just these bikes and a good shop should have a pile of them in all sizes. I ordered my replacements from Chacal (Len) along with some other stuff I needed.

 

1--Yes... running silent isn't necessarily a good thing, there should be a little valve clatter, its due.
1a--True.
2a--Not always, could be rings.
2b--Bite th bullet
3--Yes you need th right shims, can get th shims from many places--th net--
chacal
Yeah I just wanted to just ride it but I waited till it was bike-shaped :->
Bigfitz' how to http://xjbikes.com/Forums/viewtopic/t=14827.html

 

1: Unless you've done them yourself, yes they need to be done. Initial adjustment is at 3000 miles and thereafter every 5000. Valves get tighter as they wear not looser, so silent running is not necessarily a good thing.

2: A compression test can tell you that you don't have a burnt valve right now, it won't tell you you're in the process of burning one because it's way too tight. I would not put it off, but it's not something you should have to pay to get done, it's not all that complicated you just need to pay attention.

3: Correct. The existing shims on any out of spec valve need to be "read" and the appropriate replacement determined. While there was some commonality of shims between the XJ and some other Jap bikes of the era, a shop may or may not have the correct shims. It's basically a two-step process: tear it down, see what you need, order your shims, then replace them. Another argument for doing it yourself.

You did find this, right? http://xjbikes.com/Forums/viewtopic/t=14827.html

 

What are the odds of the gasket being re-usable? Or should I just order one in advance?

Thanks for the answers. I will add yet another stop on the road to just driving it.

Damn... I got it over a month ago and so far, I've had to content myself with a couple of 10-15 minute rides around the neighborhood. grrrrrr

but when I bring it to KVB_650 for the balancing, at least it will be top-shape.

 

They should be reuseable but you never know. On the plus side you'll know if it tears or is brittle when you take the cover off to check the clearance. If it's bad you can order one with the shims.

 

hey, your post (fitz) came-in while I was typing my other response.

Yeah, I had previously read your pictorial how-to. Great job btw.

It doesn't look terribly complicated but I'm dreading to find bad news (more delays from having to order replacement shims). But I guess I should pull my head out of my a** and do it properly. If a shop has the shims in stock, it would be nicer to just get it done. I guess I'll take a whack at it.

If Ken (KVB_650) is nice enough to offer helping out with the carb balancing, I should at least prep the bike properly beforehand.

 

+1. On a non-YICS motor, chances of being able to re-use the gasket are slim; pick up a set of the rubber "half moons" to go with it.

You're right, it doesn't make any sense to balance the carbs on a bike that needs a valve adjustment.

 

my feelers smallest strip is .05mm so that's why there are values such as <.05 below


Cylinder 1 2 3 4
Intake: <.05 .07 <.05 <.05
Exhaust: .13 .15 .15 .13

I don't understand how they actually get tighter with age but....

The intakes are all tighter than spec. So does this mean I now have to pull them all out, then look at that chart and get the replacements?

Damn, now I have to locate a bucket / shim tool

 

You can use a zip tie for the tool. It slips through the spark plug hole and above the valve. Then gets caught when the valve closes holding the bucket down. I found this easier than the tool.

They get tighter because the cam bearings and the cams themselves wear. The bearings get thinner moving the cam closer to the engine.

 

whoa, really?

if I understand correctly, rotate crank until desired valve is fully down, shove a zip tie in there, then rotate the crank again?

THANKS!!! I'm sure it'll still be a pain (for the first time) but thank you so very very much

I had no idea when I woke up this morning that I'd be learning how to do my own valves!

what a resource - thanks to everyone out here!

 

sounds like you understand it. Cyl's 1 & 2 are easy because you're there with the wrench to turn the crank in one hand and the zip tie in the other. 3&4 are harder. Watch out for the handle bars. I smacked my head on them a couple times leaning over then standing back up.

Also, bend your zip tie into a J shape it'll be easier to slip the bent end in.

 

clearences get tighter mainly because the valve keeps smashing against the seat which crushes the seat. So the valve actually comes up into the head further. the wear of the cam I never heard of. This is why high mileage bikes get new valve seats, becuase the shape changes over time w/ the constant smashing. sometimes you'll actually have to order shorter valves after a seat job

 

Precisely. It has nothing to do with cam wear, the valves pound themselves into the head, plain and simple.

The only potential drawback with the "zip tie method" is the possibility of shearing off the zip tie and spending hours fishing the piece back out of the cylinder.

"The tool" is cheap, readily available, and frustrating as hell to use until you get the hang of it. Once you do, it works fine and you aren't shoving foreign objects down your cylinders.

I love mine now that I know how to use it.

(An alternative to the zip tie is a hunk of #12 insulated electrical wire bent to shape.) But I didn't tell you that.

 

What Fitz said, gameover is mistaken, yamahaman is correct.

Valve seats get hammered into the head by the valves allowing the valve stem, with the buckets on them, to move closer to the cams.

that's the selling point for the redline break in method where you run through all the gears several times at say a quarter throttle, then again at half throttle, again and again at incremental RPM ranges all the way up to redline. The seats get seated, you adjust them and they're not going to move any further henceforth.

The breakin methods of keeping the RPM's low until rings mate to cylinders and all that are somewhat outdated and get more and more so as manufacturing processes advance. It's not like RUNNING the bike is responsible for deburring tranny gears anymore and now-a-days cylinders are much closer to true round than they once were. It's not going to gall straight from the factory like it may have in days of yore. The dealer just has to cover their ass. That's why breakin info is so hard to find detailed specifics on from the factory.

 

So the Valve in the down position is where you check the clearance for the shim. I am a little confused also. Then what does the tool difficulty come in? Does it not seat right or move while hand cranking the engine over? 8O

 

No. You check the shim-to-cam-lobe clearance when the valve is in its "up" position, fully closed against its valve seat.

However, if your clearances are out of spec, then the only way that you'll know what new size shim to use (in order to get the clearance back into spec), you'll have to first extract the currently-installed shim to determine what "size" (thickness) shim is in there.

In order to extract the currently-installed shim (or install a new shim), THEN the valve has to be held "open", away from it's seat, in order to be able to pop the shim out of its lifter bucket.