82 xj 650 startng problem - surpise!

Giving you grief about checking your valve clearances is NOT suppose to annoy.

It IS supposed to be taken as good advice; if it was me (as Pat mentioned) I would heed the good advice.

What don't you understand about free advice? People here have integrity behind their words. They want everyone who comes here to have a safe, reliable ride. . . this isn't a cyber-bullying site; it's an XJ Bikes site. A lot of people reply because they actually know a thing or two (me? I just like to see my dog's picture on the world wide web). I have learned things here that are priceless and have served me well.

Because the truth of the advice may come across as cold and hard doesn't mean you should take it personally. Embrace the XJ love!

 

You're giving us grief by not doing the NUMBER ONE maintenance item in any XJ manual you'll find...valve clearances.

So, the valves are all within the specs that were posted, but NO ONE posted any valve clearance specs.

You get replies from the same people, because some of us are on here way more than others. Another reason to heed their advice.

Please don't ever check the valves. We need more decent parts bikes with blown motors.

 

Unless you've got a 2-stroke, or hydraulic lifters, the valves need to be checked. The bike is new to you, and may have never had the initial valve check done.
Fitz has the tagline "Technical Writer" for a reason; he knows of what he speaks.
Take the advice you've been given so you don't spend a week chasing your own tail around trying to solve the hanging idle issue.

If you've checked them and they are in spec according to the Haynes manual then they aren't in spec. Haynes made several errors in the published manual, as did Yamaha (which is why your air jets got moved to the wrong positions). The correct valve clearances are printed on the inside of one of the sidecovers (I forget which ATM).

http://xjbikes.com/Forums/viewtopic/t=14827/postdays=0/postorder=asc/start=0.html

If the valves truly are in spec then we can move on to checking for vacuum leaks and other possible causes.

 

It could be a number of things. But the first step is the get the valves in spec.

You can't sync the carbs without it done.

Sounds like it could be any number of problems... Start a list check off the valves and go from there.



A pic I got from fitz when I first started here.

Heres how to do it...

http://xjbikes.com/Forums/viewtopic/t=1 ... xj550.html




Thanks to fitz.

If it hasn't been done yet.

 

1. Check check check check Valves valves valves valves..... Better yet don't check them .... When your engines seizes pull the shims that never needed to be checked and send the to me so I can throw them out since they will most likely be damaged beyond use.

2. Amazing....bigpiss, huh?!?!. A Gear Grinder rank and he's calling people names.... Especially after asking for advice, advice given....... And duly refuted. Did anyone

3. Funny, you only posted 9 things.... Two on May 8--within 9 minutes, 5 on May 22--some pretty close together, And then two today. Now, your gonna complain when people try to help by answering QUICKLY? Heck, ask another question--- I'll be willing to wait to answer it next year if it will help you feel better.

3. Women will HEAR what someone said

4 . Bye....... Ok, see ya.... Don't let the door hit ya

Good luck to you.

D

 

FYI - Those compression numbers are in spec for the 6000 ft in altitude where he lives. For altitude we have to do compression conversion, The conversion factor for those of us at this altitude is 0.83.

Make sure your throttle cable is sitting correctly in the bracket. It make be sitting high on the bracket.

 

Not one to be a killjoy and interrupt this Thread-Of-Happiness, but I feel that, for clarification purposes and---in tribute to the immortal words spoken in the classic, epic, pre-salad-dressing days of yore in "Cool Hand Luke" by Mr. Paul Newman---it should be said that in assisting in "Getting your mind right" I should gently point out that an oft-repeated statement expressed 'round these parts isn't quite the truth, the whole truth, and nothing-but-the-truth, and that statement is this:

And yes, I know that this gospel comes straight from the red-circled horse's mouth, Yamaha Motor Company.

But it ain't true, and it begins with the reality that you ain't "synching" the carbs, at all, no, nein, nyet, nope.

You're synching the engine via the adjustment (of the throttle shaft openings) of the carbs.

And I'm not just trying to nit-pick words; words have meaning, or, as a former president of Ford Motor Company used to say, "When I speak, each word weighs a ton". Words convey an understanding of what is going on, and the wrong words give a person the wrong understanding, the wrong visual, the wrong (in modern hipster slang) "optics" in their minds, and a wrong understanding of what is going on (and what you need to do to correct it) could easily turn a mind into that dreaded "terrible thing that's been wasted".


Synchronize: to cause to go on, move, operate, work, etc., at the same rate and exactly together: They synchronized their steps and walked on together.

http://dictionary.reference.com/browse/synchronize?s=t


Does setting all the carb openings to differing amounts mean that they "move, operate, work, etc. at the same rate and exactly together"?

Well golly-gee no, it doesn't. In fact, the process of "synching" does EXACTLY THE OPPOSITE, in regards to the carbs........it sets them up to "operate" slightly differently from each other. On purpose.


For what purpose, you may ask? For a good purpose, of course! So that you can equalize the power output of the cylinders, so that you can "synchronize" the horsepower/torque output of each cylinder, so that each cylinder will, in fact, "work, etc. at the same rate" (or power output).

And by the way, for you guys that are over-edumacated, you'll immediately recognize that the word "work", in this context, is really close to the physics definition of "work", that being of energy output over a unit of time. But I digress.......


Having each cylinder output 20 horsepower (20-20-20-20), rather than a cylinder output map that looks like this: 16-23-24-17 ----- and please notice that in both cases, the total engine output is 80 horsepower ---- but in the 2nd example, since each cylinder outputs a different amount of power, the engine will "fight itself" and run rough, perhaps misfire, beat itself to death, etc. Definitely not that "sewing machine smoothness" that we all adore and aspire to.

And beat itself to death, over time, it surely will. Having grossly mis-matched power outputs in each cylinder puts incredible stresses on the crank, rods, and bearings. If that thought doesn't bother you much, then do the following:

a) carefully remove your valve cover. Set all the bolts aside, labeling as necessary so you can re-assemble properly.

b) remove the camshaft bearing caps, just one or two of them. Again, put aside and label.

c) get your ball-peen or claw hammer out, and start hammering away, as hard and as fast as you can, on the cam journals. Try to do this at least 3000 - 6000 times a minute to closely duplicate what an unbalanced engine does to its rod and main bearings.

d) re-assemble everything and go ride your bike in traffic, or on a long-distance ride. It's all okay. These engines are built tough.


Now, why would an engine have a power output map of something kooky like 16-23-24-17, or even 19-21-22-18 (note this last one is a lot closer to being equal across each cylinder). Well, it could be that the pistons/rings in each cylinder aren't EXACTLY equal in condition to each other. Maybe one cylinder has a bore that is .02mm larger than the others, or maybe a larger ring gap on the top ring. Or another cylinder has a valve that isn't seating/sealing as well as the others.

Or, hey, how about this: the valves ARE in spec, but since spec is .11-.15mm clearance (on the intakes), suppose cylinder #2 intake valve is at .11mm clearance and cylinder #4 is at .15mm.....both within spec......but the different clearances results in different valve timing (when the valve opens and closes within the cycle) and thus a different power output from each cylinder.


What you want is a power output of 20-20-20-20, or at least as close to that ideal as possible.....and note that it MAY NOT BE POSSIBLE. Cylinder #1 has a slightly.....which is well within tolerance, mind you.....larger bore than all the others. It has a little bit more ring blow-by. It won't/can't develop as much compression pressure as the other three. So you get compression numbers like this: 131 133 139 137

Again, well within "spec". But cylinder #1 isn't going to EVER make as much power as the others, and short of taking the engine apart and "blueprinting" it, that "little #1 cylinder that could" well, in reality it couldn't, wouldn't, and it won't ever make as much power as the other cylinders.


So note that the "synch" process forces you ---- via adjustment of the carb throttle shaft openings, setting them all a little bit differently from each other ---- TO DE-TUNE THE POWER OUTPUT OF EACH CYLINDER DOWN TO THE LOWEST COMMON DENOMINATOR.......it's the educational system equivalent of "dumbing down" the students so that everyone gets a gold star.....

So in this engine: 16-23-24-17

you're going to have to "de-tune" each cylinder to 16hp, so that it ends up looking like this: 16-16-16-16


But in this engine: 19-21-22-18

you'll be able to achieve this output map: 18-18-18-18


Hey, that's an extra 8hp, which is nothing to sneeze at in an engine of this size, and truly a difference that you can feel.....


So why do you adjust the valves before you "synch" (really, un-synch) the carbs? Because out-of-spec valve clearances will typically get you this engine:

16-24-24-17 (which you can then "synch" to 16-16-16-16)

while valve clearances in-spec will allow you to get this result:

19-21-19-21 (which you can then "synch" to 19-19-19-19).


Look, you can't do anything about cylinder bores, ring clearances, valve seat seal, carbon build-up, etc. as part of any normal maintenance procedure (well, you could, but 99.99% of people aren't going to do a top-end job every 5000 miles). But you can adjust your valve clearances pretty easy. And doing so will allow you to flash a big toothy grin with "19's" all across the board, rather than a set of 16's on all cylinders, and unlike what you read on the internets, the "size" of numbers does matter, and bigger really is better-er.


So in conclusion: Yes, Virginia, you can "synch" even if your valves are not in spec ---- you can synch your engine to 16-16-16-16 instead of 20-20-20-20 ---- and negate lots of the fine engineering that Yamaha did for you and piss away 16 horsepower the fast and easy way.

Like they say on TV, it's your dime, Boss............

 

I think maybe it is a case of deflated ego
you buy a bike and you get all kinds of ideas of what
you want to do to it
then you come on here.. and get told you have to
do this that and the other thing before you can even think
about the other thing
it is like yeah yeah yeah.. I know what I wanna do.. but
when it comes to it.. Bigfitz and others stressing
to check the valves is no damned joke
the bike will not run properly without it being done
you can't run without walking
and when it comes to valves in Spec, that is barely crawling
this forum is the most amazing place on the internet
when it comes to knowledge and care for your bike
it is also sometimes the most comforting place on the internet
my bike runs great, because of the help I got from everyone
also this place can be the most entertaining out there
and I am going to go on the record to say it is a once a day
must go to site
you can buy a repair manual for 20 bux and you should
but the advice, and help on here is the best bar none
same goes for Len and his parts
or Hogfiddles and his shim pool

so spend the time, check your valves.. or have a bike that
will not run properly and no matter how clean your carbs are
you still will not get it to purr like a Main Coone kitten

 

i got my bike and it had about 25k on it. i thought hell maybe the valves are in spec. but i got more weary and weary and reading posts on this site to check them. and they were wacked out. i for one am glad i listened to guys like hogfiddles and bigpiss... sorry i couldnt resist chuckling there bigfitz

 

If ever there was a case for a "sticky" nomination, Chacal gets my vote!

 

I checked mine a few months ago and even I am weary and
want to recheck them
when the bike runs perfect

my favorite part is when BigFitz gets sarcastic and starts mocking
it is in this thread and the awesome
"I am done with this XJ" thread

 

Nice post Len, very interesting to read. I knew there is some latitude for adjustment, I could feel it and understand it, but not explain it. That sums it up.

Dave

 

So, just as starting a bike is important, we must also realize that stopping a bike is important.

SO......maybe it might be a prudent thing to mention that you should take a moment to check your rear brakes for delamination signs.

Well, that would be a moot point, of course, if one feels that the brakes are not an issue because it stopped perfectly fine last summer......

 

It was Wisconsin sand not delaminated brakes!