What am I missing??

[XJ Rob]

I can throw a set together and send them to you for diagnostic purposes.

I would settle for a set of stock needles. Everything else in the carbs are already stock.

I know the needles are not stock but again, this is the way I got the bike. Only the mains and needles were changed by the PO.

When my dad went to look at this bike, the guy couldn't even get it started. The price went from 1000 to 300 and he loaded it up in the truck knowing that I bought my XJ after sitting for a number of years and put it back on the road. There is only 14000 miles on this 81 special.

[3Phase]

I am working on an 81 Special. ...

Oops. I should know better than to read/write anything before 'noon on any Sunday.

The Y80 needles are wrong. Someone may have drilled the air bleed holes in the carburetor slides too, so when you find the needles the slides themselves will not work correctly.

Before you do the jetting you need to check the carburetor slides for tamp^H^H^Herformance modifications, then find four Yamaha# 360-14116-07-00/Mikuni# 5GL16 jet needles unless you want to subsume your bike and most of what remains of your life in Mikuni CV carburetorolgy and tuning.

.

[mack]

Air Box

Did you say you have the stock air box on it. If you have the 78/79 carbs they need to be vented to the air box. The stock air box on an 81 has the nipples plugged at the factory. You need to check and make sure the PO drilled those holes out so the carb bowls can breath and allow the fuel to syphon through the circuits. Quick check is to just pull the two black hoses off the air box nipples.

[XJ Rob]

Getting closer..Maybe???

I was going through my original thread ( What size Jets) And I found something that (dbeardslee) had posted. It was a measurement of the needle from the bottom of the slide to the tip of the needle. His measurement was 1.672in.
I measured these needles and they are WAY short. The white spacer/washer at the bottom of the slide down in the hole where needle goes...... IS THAT a necessary part to these carbs?? Sorry.. It's been a while and I cant remember how to post pics to the forum thread.

The piece I'm asking about is the one next to the needle in the second pic that TopCat posted on the first page.

[natemoen]

He did later correct that to 1.572

[motoman]

Hi XJ Rob,
Just for grins, since being incorrect metering rods, to short,etc., drop them all the way down to the last top clippy notch and see if that leans things a bit. Since it's not running good enough to acually adjust idle mixtures, bench set them bout 2 1/3-3 turns out from lightly seated.
At this point just kinda throwin' ideas out and see what 'sticks' since having what it sounds like a hodgepod of mis-macthed carb internals, least definitely metering rods and main jets.
Magnify those pilots on the side looking for the Mikuni logo. Those ARE the correct size, if Mikuni and BS30/96 having six patterened holes on sides of pilot jets(toothpic those tiny sideholes and make sure teeny-tiny atomizing hole in bottom can be seen thru).

Don't be too surprised that you likely may have to locate some 80-81Special metering rods using corresponding 110mains as a baseline, 80-81Standard metering rods with corresponding 115mains outer two cyls./120mains center two cyls.(115's across all four works too), or 82(84Canadian) XJ metering rods with corresponding 112.5 main jetting as a baseline.

Obviously rich enough I'm sure it fires right up when cold......likely without using enricher either.

[XJ Rob]

Nope..

I pulled the spacers out of the slide holes and lifted the needles to accomplish a 1.56 in length on the needle. Still cant rev the motor at all without stalling. Also it doesn't idle as smooth as it use to. Sounds like it needs to be synced but Carbtune says different. Its real close to perfect. Although the vacuum is lower than it was before.
When the carbs are at rest (No throttle) do the needles go into the main jet at all?? The needles I have won't even come close to going into the hole of the 115 I took out. I have 110s across the board now.

[motoman]

I pulled the spacers out of the slide holes and lifted the needles to accomplish a 1.56 in length on the needle. Still cant rev the motor at all without stalling. Also it doesn't idle as smooth as it use to. Sounds like it needs to be synced but Carbtune says different. Its real close to perfect. Although the vacuum is lower than it was before.
When the carbs are at rest (No throttle) do the needles go into the main jet at all?? The needles I have won't even come close to going into the hole of the 115 I took out. I have 110s across the board now.

Lifted?..........being shorter....and configured a bit different on the taper I previously suggested DROPPING them all the way. IMO that length measurement is in material for comparison to stock since rest of metering rod is tapered different........and no, they do not go down into jet.

Also, its gotta meter fuel correctly at an idle, or at least close before any accurate carb sync can be done. Too much fuel, vacuum drops......to less fuel vacuum drops....and at this point is likely varying between cyls., so all your doin' is syncing to already improperly fuel ed cyls.

[XJ Rob]

After 10 hours of R&Ring carbs. checking for any plugged circuits and Re-checking float levels, moving needles up and down, I gave up for the day. I'll lower the needles all way tomorrow after work. I am curious to know if that spacers belongs in there with the aftermarket needles. Does anyone know??

[XJ Rob]

Good News

I came home today and pulled the carbs again in record time I think. I lowered the needles as far as they would go. The bike runs and revs great but still runs TOO Rich. Fouled out a new set of plugs. Now I need to find a set of stock needles and I should be good. If someone has a set they are willing to part with please let me know.
Thanks for all the input and suggestions. It is very much appreciated.

[mack]

5GL 16 jet needles

There is a set on EBay right now for 11 bucks. Jump on them or I will. Just go to Ebay and type in "5GL16 jet needles" comes right up.

[XJ Rob]

Missed them.

I see a set of 3 for 10.00 a piece. Are those the ones you saw or did you scoop them up already?? I had some important things to take care of yesterday.

http://www.ebay.com/itm/Yamaha-1980-...fc0df8&vxp=mtr

[mack]

Yes

sorry I was in a hurry as well and didn't read through the whole advert. But at this point, buy the three. It will get you three steps closer to where you need to be. In the future it will be easier to scrounge one from a member who has a trashed float post or something then finding someone who is willing to part with all four.

[XJ Rob]

Scooped those needles up. Now I just need 1 more. Thanks for the heads up. If ANYONE has a 5GL16 jet needle for an 81 special, in usable condition please let me know.

[XJ Rob]

Update..

Just thought I would update the progress. I found 4 stock needles and installed them. The carbs are completely stock and the bike runs great. I took it for a short ride yesterday and it seemed to be a little swirly in the front end. I'll check it out more when time is available. For now I'm happy it runs as well as it does.