question about valve adjustment

I have been trying to check the clearances but the feeler gauges I have wont cover all the sizes that are for the specs. My question is if I have .11 that is too loose and a .14 that is too tight can I assume that it is with in specs?

 

Get a full set of metric feelers for C.... sake.

 

You will be glad you invested in the full set of metric guages once you get them. No more headaches.

 

That Wizard guy gets right to the point

 

& the heart of the wallet.....

 

I have been trying to find a full set of metric have tried napa, autozone, and sears with no luck. guess I will have to order a set from on line.

 

U can stack 2 together if you wipe them off real good

 

You can always use an imperial set and convert the sizes to metric by multiplying by 25.4.

 

Check Harbor Freight

http://www.harborfreight.com/32-piece-s ... 32214.html

 

That harbor freight one is actually SAE with metric conversions. you actually need metric feeler guages like this:

http://www.bikebandit.com/bikemaster-20 ... 4godWG4APg

 

K-D Tools' #2274 is widely available, most O'Reilly's have them in stock:

 

Well I got a set today and checked all of the the valves. Turned out that the 123 exhaust valves were tight. got 3 new shims today and installed them. I also pulled the carbs off to go through them also. I found some crud in the air jets and also found one of my fuel mix screw the o ring was broken. I went ahead and replace the o rings on all 4 fuel mix screws. Seams to be running a lot better now. Thanks for all your help.

I am finally a lot more comfortable taking the carbs a part and cleaning them. Just counted the turns on the fuel mix screws and put them back to the same settings. They are all at 3 turns out, does this sound right for a 900R?

 

Check Spark Plug coloration.
Paper Bag brown is sweet.

Judge how it "Gets-out-of-the-hole"

If you're too Lean it will hesitate.
A 900r should get-up and GO.

Tweak:
Adjust the Mixture Screws about the width of a Dime when you are close.

 

You skipped a step.

Three turns out is a fine baseline setting. However, before proceeding with the mixture fine-tuning as described by Rick;

you need to do a running vacuum sync with the YICS blocked.

If the bike seems to be running well, then you're probably only looking at "touching up" the sync.

Once it's been sync'ed, then twiddle mixtures if needed.

 

I had the carbs rebuilt at a shop a couple of years ago and they synced them then. I didn't disassemble the rack thinking that the sync would be the same. Does it change after adjusting the valves?

The plugs were all light tan but not as dark as a paper bag. The bike starts and runs better than it ever has. doesn't seam to have any hesitation off idle or snapping the throttle open in say 3rd gear. I just went out to the garage and hit the starter button and it fired right up with out the choke. After start up needed to give it a little choke for 30sec to get it to idle.

 

Adjusting the valves does affect the sync. Since you said it's quite responsive and seems to run fine, like I said, it probably only needs "touching up." Fuel economy will improve, as will performance believe it or not.

If the shop didn't sync the carbs ON THE BIKE, then all you're running on is a bench sync. Save me some typing, and read this, it explains what a "carb" sync really does: http://xjbikes.com/Forums/viewtopic/t=14608.html

When you had your carbs apart, did you wet-set or at least wet-verify the float levels? I ask because you should need the "choke" for cold-starting. It's not a choke, it's an enrichment circuit; my concern is that you may have a float or two set too high.

Don't start twiddling mixtures yet. From the sound of things, those are really close.

 

Thanks Fitz I will read up on the sync. I did check the float height and they all seemed fine. believe they were all at 22mm which was in spec with my manual. It fires off but have to add the choke right away to keep it warming up.

 

Sounds like your work paid-off.
When it fires-right-up; you know you're pretty close to dialed-in.

These Bikes just love to run great when the Mixture is too Lean.
Keep an eye on things for a couple weeks.

If the Plugs look too Clean; bring the Pilot Mix Screws OUT the width of a Dime or Nickel.

 

Thanks for every ones help with this. I think I know where to start on my XJ750 now. It very hard to start also going to get it out and start checking valves and compression. Then give the carbs a good cleaning. I will have it running right soon.

 

That's a "dry" setting, with the bowls off and the floats measured against the carb bodies?

That's only the starting point. To get the float levels truly dialed, you need to "wet-set" them, using fuel and clear tubing. Give this a read: http://www.xj4ever.com/setting%20fuel%20levels.pdf

 

When I service Carbs, if a Clear Tube reading shows that the Floats require adjustment, ... I use any one correct (or close to correct and set right) as the Baseline for adjusting the others.

I measure the correct one DRY and set the other to that Height.
Once the Floats are all the same Height ... DRY ... I re-wet test and make any slight adjustments.

To measure Heights DRY, I epoxyed a Toothpick to a Mechanics Pocket Ruler and Measure the Highest Point of the Float elements. (BOTH)!

From there, back to Clear Tube Method.
More often than not, ... the Fuel Levels are corrected.