update on my project

[GLoweVA]

DG, I pulled the plugs and checked the gaps and none were way off, I made sure they were about .75mm each before I put them back in.
Here's how they looked: (Left to Right, #1 thru #4) (oh and there are brand new NGKs BP6ES)

Sorry the pic is a little dark, All I had was the porch light in the carport last night.
#3 & 4 were the sootiest, while #1 was a little lean looking.

Motoman, I know you want to tell me 'I told you so', but I'm not ready to totally give up yet.
As for getting 'replacement' jets, I can now 'steal/borrow' the mikuni's out of my G, seeing as he's not going anywhere at the moment.

I think with a proper sync and dialing in the idle mix screws, I can get these plugs less sooty and bring up my MPGs.

Here's a current pic:


I put the WJ5 on last night and I'll get a pic up this afternoon.

[GLoweVA]

I forgot to mention that when I filled up this morning,

58.8 miles, 2.25 gals = 26 MPG

So, the numbers are getting better. (up from 23)
Now I've got about 120 miles on her since her resurection.

I'll fill up again Thurs morning and check it again, maybe the fairing may help or hinder the mileage.

[DGXSER]

George, one thing you could do to prove out it is in the carbs is swap carbs with your G.

As to the plugs, yes, one looks maybe lean. The other three are obviously very rich. something that happened to me a few years ago, I rebuilt my first set of carbs. I even pulled apart the slide to be sure and clean the needle jet well. However, when I reassembled them, I got the spring in the wrong spot on no 1 carb. That thing ran rich like Donald Trump no matter what I did to the mix screw or anything else. I finally figured it out and put it back in the right order, ran like a top from then on. Just something else to think about.

[GLoweVA]

George, one thing you could do to prove out it is in the carbs is swap carbs with your G.

As to the plugs, yes, one looks maybe lean. The other three are obviously very rich. something that happened to me a few years ago, I rebuilt my first set of carbs. I even pulled apart the slide to be sure and clean the needle jet well. However, when I reassembled them, I got the spring in the wrong spot on no 1 carb. That thing ran rich like Donald Trump no matter what I did to the mix screw or anything else. I finally figured it out and put it back in the right order, ran like a top from then on. Just something else to think about.

Are you talking about the little spring that sits under the plate that's inside the slide that keeps the needle tight?
I did pull all 4 of those apart to clean the gunk outta there and they were a bugger to get back together, so maybe.... (I don't think that mine had position clip/settings)

Yeah swapping the whole carb bank might be a little easier. At least I know the G's carbs were working fairly okay. I was getting about 32-34 MPG with that bike. I could put the bank in, sync and check the idle screws and go from there.

[DGXSER]

You are correct, the little spring that sits on top of the needle and pushes it down against the slide. It is under the metal plate held down wiht two small screws. I installed the spring UNDER the needle in the no 1 carb slide. So it held it up, which made the main jet slightly open more than it should be at idle and low load.

Now, on mine, I could rev it up to 3k or so and things would clear up, run smooth and no black plug. Sitting at a stop light no 1 would load up so bad it would start fouling out, black as the ace of spades. But rev it back up and it would clean the plug up and run nice.

[motoman]

You are correct, the little spring that sits on top of the needle and pushes it down against the slide. It is under the metal plate held down wiht two small screws. I installed the spring UNDER the needle in the no 1 carb slide. So it held it up, which made the main jet slightly open more than it should be at idle and low load.

Now, on mine, I could rev it up to 3k or so and things would clear up, run smooth and no black plug. Sitting at a stop light no 1 would load up so bad it would start fouling out, black as the ace of spades. But rev it back up and it would clean the plug up and run nice.

May wanna pull them and check spring location. Figure by time your done you should have removing the carbs down to bout ten-twelve minutes. Least that's all it takes me including removing the fairing lowers, seat and tank after chasing my tail a couple yrs. back.

[TopCatGr58]

Hey George,

Did you first test the pipes to see if all 4 sizzle when warmed up? Wondering if #1 is actually getting much/any fuel at all, and that you might be running on 3 cylinders??? Also could have a vacuum leak....ie. synch port cap, or intake boot to engine, exhaust gasket leak....need to check and rule that out also!

Also, I know you like to run at low rpms, but with the cooler temps you're riding in, would suggest you keep the rpms up a bit more to help keep the engine in the warmer/sweeter power band zone. JAT/IMHO!

T.C.

PS, nice looking Special!!

[GLoweVA]

Here she is with the fairing on.

[GLoweVA]

Hey George,

Did you first test the pipes to see if all 4 sizzle when warmed up? Wondering if #1 is actually getting much/any fuel at all, and that you might be running on 3 cylinders??? Also could have a vacuum leak....ie. synch port cap, or intake boot to engine, exhaust gasket leak....need to check and rule that out also!

Also, I know you like to run at low rpms, but with the cooler temps you're riding in, would suggest you keep the rpms up a bit more to help keep the engine in the warmer/sweeter power band zone. JAT/IMHO!

T.C.

PS, nice looking Special!!

Thanks TC.

When I was testing last weekend, (and found my bad coil), #1 & 4 were getting plenty hot (while 2 & 3 weren't due to bad coil) I haven't checked them since though.
I put 4 new caps on the sync ports and the vac advance hose seems pretty intact too.
Intake boots looked okay on the inside last time I had the carbs off.
When I had the head off to replace the #3 valve, the exhaust gaskets were still in there and I torqued the header bolts back on good and tight.
I'm running between 4 & 5K rpms at about 65-75mph for most of my commute.
She seems to like that power band and with the fairing now, I seem to like it too.

This morning's fill up was 59miles @ 2.3 gals, so the fairing hasn't affected the MPG, still holding at 26.

So, the plan is this weekend to swap in the G's carb rack and sync then ride.
I'll then get a chance to pull the SG carbs apart and check everything.
It sure is nice to have an 'extra' bike around to borrow parts off of when you need them. I just wish I had a garage instead of a carport. It gets a little cold and dark.

[skids]

Keep in mind that your other set of carbs are probably synched and pilot screws tweaked to that other bike. If both bikes have even compression it shouldnt matter asumming all possible air leaks are tight.

[GLoweVA]

Update

Sat morning, I swapped carb banks with the G's. Put the sync rig on and balanced the carbs. (only 1&2 needed tweaking). (mains in the G carbs were 110/115/115/110)
I shut it off and had gas running out the airbox!
I tapped the bowls with a rubber hammer and that seemed to free things up.
I guess with the carbs fully drained 1 or more of the floats got hung up open.

I had a short run around town and pulled the plugs.
I'd say they look a whole lot better than before!


Tomorrow, I'll fill up the tank and check the mileage, but if those plugs are any indication, then it should be in the 30's at least.

Sunday I also did a few other things like new foot rubber, fixed my front running lights, and adjusted the right mirror.
I pulled the heat shields off the mufflers and this is what I found on the right side:


OMG! that 'crack' is almost clean thru! I tried to get the best camera angle so you can see the light thru the crack. Crappy PO weld! Not having a welder handy, I had a patch kit for exhuast pipes lying around, so I wrapped it in that funny metal tape and plastic stuff that came in the kit. Says to run it for 15 mins to let it 'cure' then it should be good to go. I figured it'd be under the heat shield anyway, so nobody will see it.
Maybe one weekend, I can get TC to fire up his welder again.

So, I go to fire it up and turn the key and I get nothing. I got 12V at the battery, but no voltage at the fuse block, so I figure the key switch is bad, so off with it and clean it. That wasn't it. Looks like I've got a loose wire/bad connection between the battery and the main fuse. With the key on, and no oil lights ie. open wire/connection, I wiggled stuff and the oil light came on.
I tightend down on the lead for the starter and the battery post leads and the gremlin hasn't reared it head again, so maybe that was it.

ps. Motoman, I'm gonna order a new pilot jet to replace that stripped out one and get rid of those 'new' ones that came in that kit. Then, I can get the SG carbs back on this bike.
I know... You told me so....

[DGXSER]

I am not saying your wrong, but I know for a fact I have had two SH that I rebuilt the carbs with those K&L kits. Run beautifully. So try it to see what happens, but do not freak out if it is not the solution.

[GLoweVA]

They weren't K&L kits, but kits I got from PartsnMore.
From their site:

Carb Rebuild Kit
#48-1955 | Yamaha XS1100 (1980)
Carb Rebuild Kit Includes Items Pictured High Quality - Made In Japan 1 Kit Needed Per Carb

ANYhow, I'm not totally giving up, but just kinda postponing anymore tinkering right now. I'd like to get her running pretty decently first before I go pulling the carbs back out again.
At least I did the quick seat mod, and the fuel lines are a little long, so It's getting easier to get TO the carbs.
I think I might do that airbox mod that someone posted about the top bracket to make it easier to get the airbox lowered to ease the carb removal.

[DGXSER]

George, I did that on my SH, cut the bracket off the top of the airbox, and shotened the snorkel down to maybe two inches or so. ALOT easier to get the airbox out of the way to pull the carbs.

[motoman]

George, I did that on my SH, cut the bracket off the top of the airbox, and shotened the snorkel down to maybe two inches or so. ALOT easier to get the airbox out of the way to pull the carbs.

If one removes the lower portion of air box and filter, no need to remove rest of airbox to remove carbs. Pull it off the carb bells and lower front of it down resting on engine case, giving more than enough room to remove carbs.