84 FJ1100 Starting /Idle probs

[Brian]

G'day , this my 1st  email i hope I'm using the correct way of sending my message to the club , i see that Andy seems to be the Guru & would like to ask something so here goes. The bike was running /starting basically well enough & would start 1st time with full choke & idle up to temp but would idle very erratically though & had alot of top end noise. So i did the valve clearances & got them all in spec , balanced the carbs ,seemed like it was alot quieter, but after doing that it wouldn't start & idle using the choke any more so i have to  hold the throttle open a touch. The pilot screws are at 2 turns the plugs look a nice grey & it runs really well once warmed up but even after 10 Min's riding it will only just idle on 1000 approx ,and if i turn the idle screw up a touch it will idle at 12-1300 but sounds like I'm forcing it to run ( if that makes sense ) with still alot of engine noise but not the top end noise i had before  Would a stretched cam chain give me hard starting now that the valves are in spec because they all needed 5 & 10 thou shims,it just seems very coincidental to go from easy starting to this, any ideas please  ?

[andyb]

First, no not really.  More a librarian than anything

Idle should be set  at 1050 -/- 50.  Or higher, just not lower.

Much of the noise is likely cam chain and starter chain slap.  That said, it's also a pretty noisy motor, particularly at low rpm/idle.  Not having water passageways to quiet things down, y`see.

It's possible that the cam chain is stretched (likely, really), but that should functionally just retard the cams somewhat, and doing the shims shouldn't change the length of the camchain.  More tellingly, I'm assuming you pulled the cams to swap shims around?  What odds you didn't get things lined up properly when you put them back?  If the cam timing is out it will move the power around quite significantly.... someplace someone did the math and being a tooth off on the cam sprockets was something big like 12 degrees, a very massive change.  If the cams were moved in that manner in the right direction, you could easily get piston/valve interference (read, you'd smash the hell out of the valves).

I'd start with a compressino check, first and foremost.  That'll give you an idea of if the cams are miles out, as you'll be quite low all accross.  If that nets you a set of good numbers but you still suspect the cam chain is longer than it oughta be, you can pull the valve cover again and doublecheck the timing marks--the camchain length can be off, but if all the dots align, you're fine.

With all that done, you can breathe a bit easier and not worry about the top end.  I would be absolutely unsurprised to find that changing the valve clearances changed the airflow through the motor somewhat, and that will screw with your jettinng, nevermind possible reassembly errors. 

Start with the compression and get the valvetrain crossed off the list of things that  can be wrong.  If you end up pulling things apart again and can't seem to get the cams aligned where the markings say they should go, you can always get slotted camsprockets (or slot your own) and put the cams exactly on the mark.  There's a spec for the chain, but it's pretty major surgery to replace, so unless you've got other reasons for  going in there (i.e., fixing a wonky transmission), you probably will want to explore all the other options first.

And if you don't have a shop manual, get one.  Priceless for getting things set up properly.

[Brian]

 compression checked  after doing the shims to make sure cams wern't riding  & had 130,115,130,120 &  replaced the shims using the bucket tool so no cams out ,& have a workshop manual ,so maybe engine noise is something to live with . I just don't get how it used to start full choke & idle up , & then no & all I changed was the shims . I guess coincidence could play a part here , & pulling carbs checking idle /start  circiuts for blockage is next ? I know the choke is working because pulling choke on while engine is running just about stalls the engine , would that be right ?

[oldktmdude]

  G'day Brian, try pulling your clutch lever in at idle, sometimes you can have alot of clutch rattle at low revs and this can make you think that you have a camchain problem. This however, does not explain why it's starting differently, compared to the way it started before you adjusted the clearances.
  Welcome to the forum mate, you've come to the best place to get info on the great FJ and  meet a great bunch of blokes.  Regards, Pete.
P.S head to the intro section and introduce yourself, tell us a bit about your bike and your riding history. I've noticed lately that there have been a few comments posted about new members posting questions without an intro and have received some wrath. (as they should)