newcomer..possible a/f screw plugged off???

Hello all, new here and i just recently bought an 82 xj650 maxim. yay. fairly clean bike but, as i dig in the more i find not 100% to my liking. typical. my main question is about the air/fuel ratio screw, i believe it is plugged off with a brass plug. i have the Hitachi hsc32 carbs. i believe the screw sits right next to the choke slide?? not really sure. if that is the right location, why would this be plugged off? i did fire it up before i tore it apart and couldn't get it to run under 3k with choke on. also would like to know if i were to remove the plug, would the screw threads be in the bottom of hole? so i would be able to stick a new a/f needle screw in or should i just start looking for new carbs?

I found this forum after i bought the bike and man am i glad. an amazing resource. I've been reading through the site and you guys are awesome. i hope i can contribute. I thank you all for your responses ahead of time. your time is very much appreciated!

 

Drill a small hole in the plug.....only JUST through.
The mixture screw is located JUST under the plug.
Use a self tapping screw to screw the plug out.
The mixture screws were set at the factory & sealed so they wouldn't be tampered with & thus still meet emmission levels.
Screw the mixture screw in making sure you count & record how many turns till the screw bottoms out.
Repeat this for each carb as they may all be different.
After cleaning (search "church of clean") 2.5 turns out is a good starting point.

Good luck & keep posting your progress.

Cheers

Tim

 

Wow that was quick...
Thank you for the good news.
yep read "church of clean" and catching up on other reading
gonna order the rest of the parts i need now and let you know how it turns out.

Thanks alot!

 

As xjlenordski said, the screw is right under the plug, and the plug is only roughly 1/8 inch thick or so. Drill carefully! The screw is also very possibly brass (read soft) and will damage easily. This is what one on my newly acquired Max looked like:



It was a pain to get out and fortunately I have a spare rack of carbs so I was able to steal a different screw. New ones are available but they're not exactly cheap.

 

Also do yourself a favor and after you replace the tiny o-rings (you will do this, right? ) dab a bit of anti-seize on the screw when you put it back in.

 

I didn't have much time today, but got 1 plug removed and their she was. i barely damaged the head.
Thanks for the advice, it will be carried through

 

After you get all the little caps out if the screws don't turn freely apply some Kroil or other penetrating oil and let it soak for a while.

 

carbs are back together!. Thanks Chacal for the parts. ill put a pic up tomorrow

 

Float levels individually WET-SET to spec?

Valves in spec?

Now comes the fun part-- vacuum sync, (with YICS blocked.)

 

yup floats are set, valves are way too tight. it does run now fairly well, running lean at bottom end. gonna colortune and vacuum sync next week i hope. still need to buy lifter bucket tool and go through the rear-end. should i just keep the yics blocked?

 

here's that before and after...so pretty....oh, i need to re-size.

 

Don't leave the YICS blocked; and don't bother trying to sync until the valves are in spec.

From the factory book:

 

Yes, i will do valves first i just wrote everything upside down. lol
where do you guys get your shims from?
and what if i cant even fit a .006 feeler in there, which is the smallest
i have at hand. what size shim should i start with?
or do i just downsize till i can stick a feeler gauge in there?

Thanks again

 

xj4ever has them. Click on the XJ Engine on the top of this page. Get yourself a metric feeler gauge set from the auto parts store or Sears.

MN

 

That's a Nightmare.
Drilling it out might be a fight.
Although many have had success with reverse drills and EZ-Outs.

 

I would consider those zero. On the intakes go two smaller shims sizes and three on the exhaust.

 

Drilling?!? no i was talking about the valve shims. i have a .006
feeler gauge and it wont fit between the lifter shim and cam lobe.
i guess ill take .010 off of the shim that is in there and see what i come up with and go from there?

what causes valves to get tighter? does the valve seat get pushed into the head?
or does the valve stretch? you'd think it would loosen up

i just saw biggs500's post, Ill try that.

 

Opps, I just noticed you said .006 (I read that on my phone :? , hard to see somethings). That would be thousandths I would assume. Six one thousandths equals .15 mm. Intake spec is .11mm to .15mm and exhaust is .16mm to .20mm.

And yes to your question as to why the clearances decrease. The seats and faces wear.