how often to check valve clearance

I just bought my XJ750 1982 this year and it now runs great. I had to do a few small things to get it running good. It start right up and gives no problems. I remember eading tha some people check there valves every year. How critical is this and do you all only check them when there is a problem? I dont want to mess with anything because it is running good.

 

check every 5k miles. you most likely won't need new shims that often.
The first time checking shims is the nasty one since you have to measure the gap AND fish them out to measure and/or read the labels. Every time after that you already have written down somewhere safe, what size your shims are and what valves they are on.
Don't worry, doing the valves won't make it run worse but NOT doing it WILL eventually damage your valves and then it WILL run worse.

I used the zip tie method and had never done this style of valve adjustment before.(replaced lots of hydraulic lifters in cars so I knew roughly what I was looking at) It took me about 2.5 hours to measure and record the first time. Then when I got new shims it took about 45 minutes (had gotten lots of practice) to put them in and shuffle them around.

*Begin broken record* You did check the rear brake pads for delamination, yeah?

 

You don't have to 'fish' the shims out to check to clearance, the first time or any time.

 

yeah true but if you don't already have records of what ones are in there you might as well do it while you're at it. You for sure have to if they measure too tight and need replacing.

 

If you wait to check you valves when you have a problem then its too late, possible engine dammage. Check every 5000 miles or so. It should be part of the regular maintenance you do, just like oil changes. Depending on how much you ride it might be once a year or once every two years. I do mine in the winter every two years.

 

Initial period was 3000 miles, then every 5000 thereafter.

As everyone mentioned above, the best practice is to keep a log book, and record the installed shims. Then when you discover an out of spec valve, you already know what size shim is in there and therefore what size you will need.

 

just to clear this up, Fitz, are you suggesting that you should pull the shims & record the sizes, even if the valves are in spec'.

 

I will have to make time for it but that sounds like an ounce of prevention

 

I'm not saying should, although I do/did. You can certainly wait for your "cumulative record" to catch up with all eight; in my case one of the 550s needed 7 of 8 so I recorded them all; on the '81 I didn't when I first got the bike but then I got them all the next time I was in there.

Think about it-- you will eventually pull a particular shim to read it and then put it back, and pull it again to replace it, unless you have one of the desired size on hand. The "extra" remove-to-read cyle will occur once, then if records are kept, it becomes a one-step process from then on. I just get it out of the way ahead of time.

A little extra effort on the first adjustment cycle makes the subsequent ones quicker is all.

 

If you check the valves and if they are in spec. I would save the shim recording until this winter.

Becides thats a good time to go over all the little things that you never have time to look at when its riding weather.

MN

 

Like I said the bike runs great so I will wait till the winter. I have not check much other then regular things like the brakes actually function ,tire pressure and plug quality. Right now it runs good and stops good so I am happy but I should check the things that could break or save my life ( like rear brakes etc.) I think I will run it for the rest of the riding season and then mess with it in the winter. I am also looking at buying an 87` virago anybody got any heads up on this bike. The pictures look good and the guy only wants $350 for it. If I pick it up I might make a bobber out of the Maxim.

 

Check to see if the Virago had the starter clutch issue worked out. I don't remember the specifics but there is a design flaw that causes the starter/clutch to sound like rocks in a coffee can when you turn the starter. There are a few home grown rememdies to try to fix it, my buddy is still trying different ones after a few months since getting one. Do some internet research.

 

the problem is greatly exaggerated if one cylinder doesn't want to light off right away. One cylinder fires, the starter clutch disengages and the other cylinder doesn't fire, the crank doesn't have enough momentum to get a good run at the first cylinder again. Your thumb is still on the button and the starter is grinding away, catching, trying to re-engage, skipping off the corners of it's engagement. THAT is the rocks in a coffee can sound.

The one mod I helped do had to do with getting it to re-engage more enthusiastically.

 

I would take the time to at least check the clearances right away, if the bike has 9K miles and they've never been done, there's going to be at least a couple that are tight, probably all of them. No sense burning a valve, it doesn't take a lot to check them.

 

Mine ran like a sumbitch with NO clearance (ok so .05mm when stone cold) and boy am I glad I made the time to do it when I did. The valves themselves look ok but I suspect the seats are a little cajun style (haven't pulled the head, just looked through the plug hole.)

The more I dig into and maintain this bike the less happy I am with the Previous owners. From here on out, for the rest of my used bike buying days, I'm assuming the PO hasn't done a single thing other than flog it since it came from the factory unless I see service receipts.

Following that logic your's is approaching it's second valve check/adjust interval. Check 'em now, it'll take an hour or less, then decide if you need shims or not and do that service when you care to (if it can wait)