Still not running right.....Valves?

Well I finally got around to putting everything back together and firing the bike. I was working on my XJ last week and an old friend stopped by with a guy he works with. He works at a repair shop in the area, and took one listen to my bike and was convinced the carbs were still dirty after 2 rounds of canned carb cleaning. They use ultrasonic cleaning at his shop, and he said for $10 a carb, he would get them cleaned up, set floats, adjustments, etc, and inspect for issues.

He handed me my carbs yesterday, and said he had to replace a 2 jets as well. I put everything back together this morning, and prime it to fill the bowls, and some fuel came out of #1 carb. Im not sure if the float stuck from transport or what, but it didnt happen again. I wiped up the gas, and attached the airbox to start it. It started, and does run better than it did, but theres still some issues. It starts, will warm up with choke, and once warm, the choke can be removed. Sometimes the bike will sit idle at about 1000 and seem okay, and sometimes it will sputter and stall.

The only thing I havent done is check the valve clearances. I plan on getting on that this weekend, but I just wanted to see if I would notice any problems because of tight valves? It seems to me that it should still run fine, and then just end up doing damage when it got tight enough. Correct?

Could this all just be due to the fact that it needs a proper tune?

I know I absolutely have to get those 10 year old shims checked, and will get on that before I possibly do some damage, but does anyone have any ideas?


-Kaya

 

valve shims were one of the first things i did, just from what i read it's just another thing that you don't have to rule out if you get it done and over with. If you have an old motorcycle salvage yard around, check them for shims. I got 4 shims, headlight, and taillight for 40 bucks. The shims are rather easy to do, not a big deal. Replacing the valve cover donuts was the only hard thing about it (if they need replacing)

 

-You do need to get the valves in spec first. The shims don't wear appreciably; the valves pound themselves into their seats, decreasing the clearances. You don't replace shims because they're worn; you replace them to bring the valve clearances into spec.

-You also need to ensure the float levels were set accurately; this is very important. They need to be verified individually using fuel and clear tubing. The folks that "did" the carbs may not have been aware of how fine and critical this adjustment is.

-Then you'll need to do a running vacuum sync with YICS blocked.

There are fine carb adjustments that need to be made "to" the bike (sync, final mixture adjustemnts) that simply can't be done on the bench.

They symptoms you're describing are of uneven float levels and/or out-of-sync carbs.

 

Yeah I had the valve cover off. The donut gaskets were in good shape still. I was all set to do my check and I find out that my feeler gauge doesnt go small enough.... About an hour later, my carbs got dropped off. I almost felt a need to get the carbs installed and give it a shot.

Still, tight valves would just chatter until they are bad enough to do damage right?

If so, then I still have other problems.



Thanks,

-Kaya

 

Again, valve clearance adjustment is NOT a "get it done and over with" proposition.

It needs to be done every 5000 miles; and any time you change a shim you'll generally need to re-sync.

 

Got it. The floats seem fine after the initial leak. I would be more willing to do a simple check but...... My screws are stripped, and Im not super excited about easy outing them. I suppose your right though. Ill do what it takes.

Ill get the valves in spec, manometer, and do a YICS is you think I need it. Ive just read that lots of people do without.


Thanks guys, helpful as usual.


-Kaya

 

No, tight valves are quiet. What happens is they open too soon, stay open too long, and close too late. This decreases the all-important amount of time they spend in heat-dissipating contact with their seats.

The tighter valves run, the worse the motor runs, and if you let them go long enough you can burn a valve and/or damage its seat.

And because nobody seems to want to believe the importance of setting the valve clearances; again I present the following from the factory service manual:

 

I appreciate the help. But let me point out.

2 times in my initial post and 1 time in my follow up I say I do understand the importance of it, and the need to get it done. In fact, I talk about having the valve covers off to do the work in my 2nd post.

This :

"The tighter valves run, the worse the motor runs, and if you let them go long enough you can burn a valve and/or damage its seat."

Is the answer I was looking for.


Thank you sir,


-Kaya

 

Anytime.

Sorry, I'm used to the folks who will try anything else, rather than actually adjust their valves, set their floats or sync their carbs.

You're on the right track.

Hopefully you found this: http://xjbikes.com/Forums/viewtopic/t=14827.html

 

Fitzs isn't use to not having to bang his head against a brick wall trying to get some owners to understand that ALL the checks have to be done or the bike will run like apiece of sh*t!

 

I got ya.

With your post count I suppose you kinda skim posts like those speed reader people do, and sorta automatically reply.

I Got a new feeler and a long needed set of easy-outs. Measurements will take place tomorrow. Im gonna reshim the valves and I suppose easy out my drains to check my float levels tomorrow.

Oh, and that post is, in fact, better than the CD. You are quite literally an XJ-Guru.

I just have one more question for you. How do you keep your aluminum fins on your engine so clean and nice looking? It almost looks new or freshly painted nickel or some metalic color.



-Kaya

 

I think Fitz sits in his garage cleaning/polishing when hes not riding or working!

 

Its just rediculous how clean that bike is. Thats gotta be it.



-Kaya

 

Thanks, but that's not it at all. I spend a LOT more time working on the photo articles.

Once the bike is clean, if you use the right products, it will stay clean and only need the occasional touch up cleaning and polishing now and then.

The other part of the equation is when you DO wash it, use "Car Wash" soap and NOT dish soap to clean it with.

Car washing soap is formulated to NOT strip wax and protectants; dish washing soap will wash away all the protective coatings left behind by chrome and metal polishes as well as strip your wax.

 

Well I finally got the time to get a reliable gauge on the bike.
Compression is dead even and good 150PSI.

Valves all checked out semi reasonably, compression checks good, sparks good, and carbs are clean.

The only thing that I havent done now is set the floats. I suppose that would be the proper thing to get checked out. Ill get the easy out I need tomorrow and give it a shot.

I thought I remember reading about specific screws that are needed for the drains. Has anyone found a local source so I dont need to get it mailed?


-Kaya

 

What, is that like "semi pregnant?" They're either in spec, or they aren't. If they aren't in spec, they need to be.

This is that beating my head against the wall thing that was mentioned previously...

 

Dood....


You told me my valves were okay.....



Remember?


-Kaya

 

Compression checked out also......


-Kaya

 

He's saying that the #'s won't throw off your compression but you still need to replace the three tight ones

 

Valve clearance specs.

650 all x. Turbo:
Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")

1 .007" .005"
2 .006" .005"
3 .007" .004"
4 .006" .005"


Unless Im not looking at this right...Those check out in spec. Given they are not dead set at .005 intake, and .007 on the exhaust. Still in spec from my understanding. Hence the semi reasonably. Am I missing something?


-Kaya

 

Hey a Wisconsinite. Madison area here.


-Kaya

 

the thing I've found about shim clearances is to work in metric. these bikes were made with almost all metric measurements, nuts, & bolts so try to do the measurements using metric feelers. even if you have a cheapo feeler gauge, it should have conversion(s) on each feeler.

look up .004" conversion to mm using google. then you'll see why that #3 intake is pushing to be tight. look up .006" conversion to mm using google again & you'll see that #2 & #4 exhaust(s) are tight.

Oh btw, "tight" means they are not okay...they are outta spec just like bigfitz52 told ya in the first place

 

I got ya.

While they check out as far as the conversion into inches. The actual metric measurements leave me out of spec.

Conversions are what the problem is here. .004" is in fact .10mm which is tight.

The .006" converts to .15mm which is also out of spec.


Thanks guys. Being American I find myself often wondering why we use our system of measurements.

Metric FTW.

-Kaya

 

Not a bad idea to measure the shims with a micrometer too. I found several shims to be a tad thinner than the specified number. This could throw off your calculations slightly

 

Good point.

I was under the assumption that I was still all in spec. Barely, but at spec. Turns out I was wrong.

Im gonna get the valves done this week, but I seriously doubt that the just barely out of spec valves are what is causing my problem.


Thanks fellas,

Kaya