Do I need to check valve clearance

Bought a 82 XJ550 Maxim with 8100 miles, sat for 10 years in a heated garage. Excellent shape but carbs were in need of help. It did run enough to drive around but no top end and rough idle. Cleaned & rebuilt carbs, new o-rings etc. Bench tuned, ready to go back in and then sync them. Question is, should I, do I need to pull the valve cover and check valve clearances with only 8100 mile on bike?? How critical is it?

 

Critical? Very.

Initial adjustment was to have been at 3000 miles, and every 5000 thereafter. If it was never touched (a good possibility) then you are right at the mileage where you could start to cause serious issues if you leave them untouched.

My 7100-mile 550 had never been touched; all 8 were tight, seven of them critically so.

Do the valve adjustment before you try to sync, or drive yourself nuts.

 

And it's easy-> http://xjbikes.com/Forums/viewtopic/t=14827/
written by bigfitz52 of course!

Why spend time troubleshooting what you can check and correct now?

 

chadnolt

while you got the cover off. Check the cam chain for looseness. It is very easy to adjust now.

 

Thanks fellows, I removed the valve cover over lunch, easy enough. Will check clearances and adjust the cam tonight. Also thanks for the great link ManBot13 to bigfritz52's excellent tutorial. (nice)

Do not have the specialty tool so I quickly tried the tie-strap trick on #1 intake valve before I came back to work just in case I need to change shims, it works well so will not purchase tool. I tried to raise the shim and it is set tightly into the lifter. Small screwdriver, o-ring pick etc, I can lift it slightly at the lifter slot but it just wedges in tighter. Again did not play with it long. Any special trick or just patience and determination?

Love this sight, used all last winter when I rebuild the carbs etc.

 

My personal favorite is the forceps as illustrated in my article.

Although this may create a bit of a firestorm, don't use a magnet to get the shims out.

When you replace the valve cover gasket, replace the rubber/metal 'donuts' on the bolts too. They do the work of pushing the cover down, as the bolts have stop collars.

Be sure everything is nice and clean and you have a well lit area to work in; relax and take notes. It's actually fun...

One tip I should have included: it's a good idea to cram a rag or shop towel into the camchain gallery so in case a shim gets away from you it won't go down into the motor.

 

Great tip. My heart sank just thinking about that happening!

 

Cam adjusted and valve clearances checked. Here are the results

Intakes (.004-.006)
-1&4 = loose .005 tight .006.
-2&3 = right on at .005

Exhaust (.006-.008)
-1&4 = loose .006 tight .007
-3 = right on at .006
-2 = was a .005 and tight .006

I don't understand this but on #2 exhaust if I rotated the crank counterclockwise and stopped with the gear lash and timing chain tight I could not get the .006 gauge in but if I rocked the crank slightly clockwise (basically just reversed the backlash) I could fit the .006 in snug.

So intakes are good and exhaust as well except #2 seemed to be a half to one thousandths tight depending on how I rotated the shaft.

Is #2 okay?? I know I would not have worried about it when rebuilding and adjusting V-twins and 3 cylinders in lawn & garden and compact tractors but not as familiar with these bikes.

I need to order a gasket and donuts, where the best place? I assume Chacal has these items correct?

 

I would replace #2 and #3 exhaust with the next smaller shim. Re-measure and you should be at .008 for both #2 and #3 exhaust. I would leave everything else alone.

 

Just as a little tip. If you have metric feeler gauges, use them, as the shims are labeled in metric units

 

From what I've read in other posts I now understand why the clearances tighten up over time (valves pounding the seats)

Clarification - Can I assume that it is best to adjust to the higher end of the spec? (Example: Set exhaust valves at .008 for a .006-.008 spec rather than let them at .006)

Gauges also have metric readings (just got get my head thinkin metrics again, haven't done that much lately) I will record the mm so I know where I'm at before I remove the shims.

 

The clearances do get tighter with wear.

I consider being at the minimum to be barely in spec. You KNOW that a clearance at minimum is going to get tighter and be TOO TIGHT some time soon.

Since you have cover off go ahead and replace the shims that are barely in spec.

Be aware that getting the shims out can be a breeze or a total pain. I have one shim that took days to get out. I broke a screwdriver getting it out. All the other shims were no problem. I recommend buying the bucket hold down tool.

 

Re: Minimum being too tight: Especially if you're using the "American" (Imperial) equivalents.

Here's why: .006" is actually 0.15240mm, quite tight compared to the true specification of 0.16mm.

When you convert .004" it comes out to 0.10160mm, a lot less than 0.11mm. "Tight" side of the Imperial equivalents is too tight.

The above is also another reason to invest in a set of metric feeler gauges.

Do everything in metric and there is no guesswork, and only one shim that will put you truly in spec for any given valve.

 

Ok, fitz, the feelers are only a couple of bucks. I will go get a set as I am planning to check my clearances soon. Thanks

 

You are not just sync'in the carbs, but the whole motor, the general idea is to pull all four cylinders inline with each other for the most power output threw out the rpm range.

I have yet to purchace my shims, but if i manage to put the wrong shim in somewhare, i'll just get more untill i get it right. Just take your time and do it right the first time. Good Luck