New member here, just bought an xs1100 special

[TheNannerpus]

cajun31

This thread is the latest news on my progress. The other thread (https://xs11.club/forum/idle-talk-fo...ing-from-carbs) is earlier.

Which means I'm pulling the carbs and parking the bike for the winter. 🙁

[cajun31]

So I've had several successful starts and idles and revs over the past couple of weeks without issue. Bike sounded great since I carbtuned.

I went ahead and ordered a Colortune from eBay, which arrived a few days ago. I had to get the 10mm version and an adapter off Amazon to make it work. But this was my last step before I put her back together and take it for a ride.

So I went to start up the bike on Monday and guess what? Gas leaking out of airbox. Again. I thought the colder temps here in eastern WI got a float needle stuck, so I tried tapping the bowls lightly with a wrench. I decided to keep it running and see what happens and eventually it stopped leaking. I'm pretty sure it's not float height since I set them all at 23.5mm.

Once it warmed up, I still couldn't take it off choke without it dying, and every time I restarted, gas leak again. I got a little (a lot) worried when the gas was leaking on the warmed up tailpipes. Shop towels and an extinguisher on standby kept my sanity.

And man, was it running rich! I couldn't believe how much gas was used up just from idling for a bit. There was a haze in the garage and I smelled of gas the rest of the night.

Just for fun, I hooked the Colortune up to #1 and it looked all right. But #2 was yellow even after turning the mixture screw all the way in. I wasn't sure if this was because I was still on half-choke, or the gas issue. Either way, I knew I had to pull the carbs again.

Super-bummed about it. I felt confident I'd get a ride on it before winter. I am not sure it will happen now.

From what I've read here, I should check if my new gaskets interfere with the floats at all. I also wonder if I should switch #2 and #3 main jets from 120 to 110. Any thoughts on that?

Also, is there supposed to be a drain tube out of the airbox? It's seems like a bad design for overflow in the airbox to drip onto a hot exhaust.

I have three Midnight Specials which basically are the same as your bike other then the color scheme. With that said... I run 110 main jets and 42.5 pilot jets in all of them. I also set the floats to exactly 23mm. One other thing I always do when I clean carbs is to manually take a drill bit about the size of the float pin and use that to clean the float where the float pin resides. That and carb cleaner to be sure the floats are not hanging on the pins. Doing away with the Octi is your decision but might help alleviate some of the flooding. Of course if the floats are set right, and the needle valve and seat are working correctly the gas should still not flood at the level you are experiencing. One other .. maybe stupid question... You do have the bike on the centerstand while you are doing all of the tuning etc..? As for the bike only running on choke indicates to me that you are still having a problem with the pilot circuit. Are all your parts genuine Mikuni? As for the Colortune if you had the choke fully engage all readings should be in the yellow range with all the extra fuel the choke is providing. You will not be able to tune them properly until you get the bike running normally on idle. Keep us posted.

[TheNannerpus]

So I've had several successful starts and idles and revs over the past couple of weeks without issue. Bike sounded great since I carbtuned.

I went ahead and ordered a Colortune from eBay, which arrived a few days ago. I had to get the 10mm version and an adapter off Amazon to make it work. But this was my last step before I put her back together and take it for a ride.

So I went to start up the bike on Monday and guess what? Gas leaking out of airbox. Again. I thought the colder temps here in eastern WI got a float needle stuck, so I tried tapping the bowls lightly with a wrench. I decided to keep it running and see what happens and eventually it stopped leaking. I'm pretty sure it's not float height since I set them all at 23.5mm.

Once it warmed up, I still couldn't take it off choke without it dying, and every time I restarted, gas leak again. I got a little (a lot) worried when the gas was leaking on the warmed up tailpipes. Shop towels and an extinguisher on standby kept my sanity.

And man, was it running rich! I couldn't believe how much gas was used up just from idling for a bit. There was a haze in the garage and I smelled of gas the rest of the night.

Just for fun, I hooked the Colortune up to #1 and it looked all right. But #2 was yellow even after turning the mixture screw all the way in. I wasn't sure if this was because I was still on half-choke, or the gas issue. Either way, I knew I had to pull the carbs again.

Super-bummed about it. I felt confident I'd get a ride on it before winter. I am not sure it will happen now.

From what I've read here, I should check if my new gaskets interfere with the floats at all. I also wonder if I should switch #2 and #3 main jets from 120 to 110. Any thoughts on that?

Also, is there supposed to be a drain tube out of the airbox? It's seems like a bad design for overflow in the airbox to drip onto a hot exhaust.

[wbw750]

Here's the Youtube Link to the Aussie fella Steptoe.. site is Steptoexs11

https://www.youtube.com/watch?v=tsJ3xWA4V7g&ab_channel=Steptoexs11

He makes the carbs off/on job look easy!

[TheNannerpus]

Thanks for sharing this. I like the crossover setup, to avoid starving fuel from one side of the carb. I'm going to incorporate that in my setup.

I have those exact same shutoffs that I was contemplating using. Which end do you have running into the carb? I like the idea of putting that valve as close to the carb as possible, to minimize the amount of fuel that could potentially leak.

[Aches n Pains]

This worked great for me. Removed octy. Set up with a T to feed from both sides of the tank to all four carbs. Added a shutoff on each side so I don't need to sweat the petcock leaking into the carbs. Always shut off the fuel line and ran the carbs dry if I wasn't going to be riding for a couple of weeks.

[Aches n Pains]

This worked great for me. Removed octy. Set up with a T to feed from both sides of the tank to all four carbs. Added a shutoff on each side so I don't need to sweat the petcock leaking into the carbs. Always shut off the fuel line and ran the carbs dry if I wasn't going to be riding for a couple of weeks.

[cajun31]

The MNS NEEDS to be stock!! I miss the one I had, but it went to someone who knew what it was, and wanted another after a long break. My '79 was worked on by Bob Jones, and it does have a bit more than a stock bike. 175psi readings on my gauge. I still need to get the '78 engine back together and see what it will do.

My thoughts exactly Ray. That was quite a gesture on your part to sell the MNS. I know I could never sell the one I bought brand new, however I do have 2 others that don't hold the sentimental value the original does. I am in the process of completing my barn find I picked up last October. Finally got everything sprayed and am now wet sanding and buffing the main body parts. I was slowed a bit by an accident I suffered in late September. Trimming tree limbs and took a fall on my right shoulder. Makes doing things like sanding and wrenching a bit more painful. Amazing how slowly you heal when you get to your mid 60s.

[DiverRay]

The MNS NEEDS to be stock!! I miss the one I had, but it went to someone who knew what it was, and wanted another after a long break. My '79 was worked on by Bob Jones, and it does have a bit more than a stock bike. 175psi readings on my gauge. I still need to get the '78 engine back together and see what it will do.

[cajun31]

cajun31
I can't seem to find a colortune available that fits, unfortunately. Seems to be backordered.

Even if I won't use this info now, I may need it down the road. Or, perhaps more importantly, our posterity will find this useful. I know I've come across many old posts that have been valuable because there was some nugget of info I needed. I recently read a post on here from a member that has passed on, which made me sad, but grateful.

This supply chain problem and people staying at home is really limiting what you can buy. I have noticed that they are hit and miss on Ebay.

[DiverRay]

If you can hear the difference in idle speed, you can adjust by ear. You can also use the tach, but it is NOT that accurate at low RPM's.
1. From your start point, turn #4 clockwise SLOWLY until the idle seems to slow.
2. Turn 1/8 turn counterclockwise.
3. Rev engine slightly and let settle.
4. move to #3 and repeat steps 1-3. continue until done with all 4 carbs.
5. RESYNC the carbs, or at least check to make sure they have not gone out of sync. I use a set of 4 gauges, and check all 4 before each use. They WILL move now and then!
You may need to turn the idle up or down, depending on how close the carbs are.

[TheNannerpus]

cajun31
I can't seem to find a colortune available that fits, unfortunately. Seems to be backordered.

Even if I won't use this info now, I may need it down the road. Or, perhaps more importantly, our posterity will find this useful. I know I've come across many old posts that have been valuable because there was some nugget of info I needed. I recently read a post on here from a member that has passed on, which made me sad, but grateful.

[cajun31]

After pulling the carbs yet again, I got the floats where I think they're pretty good, mainly because gas isn't leaking anymore. See this thread for more.

Carbs were synched with carbtune. I tried the colortune by ear, but I couldn't hear the revs change, so the pilot screws are set at 2 turns out until I get me one of those tools.



My octy is on vacation until further notice (per this thread), replaced with these. Coincidentally, also an octy (once I put the final section of tubing after the filters). Go figure. I still have to test fit to get the best tube lengths.

I plan on putting stuff back together between now and the weekend and see if this thing is road worthy. I'd like to get even a short ride on it before winter.

you probably won't have to deal with it again but another trick to drill that stuck pilot screw out would have been to simply reinstall the drilled brass plug into the top of the tower to use as a guide to drill the screw. It would ha ve prevented you from getting off center and at a angle to begin with. The screws are brass as well and drill like butter with a good sharp drill bit. As I have stated... I have had to do this several times and once properly drilled then it is generally no problem to employ penetrating oil and a quality extractor to get the screw out without damaging the tower or the the threads that hold the screw in.
If I read correctly ... you ordered a color tune tool? If so then when you get it in .. tune each cylinder to just the hint of a yellowish orange. Makes things a tad rich and is where these bike run best. Actually will let them idle a bit cooler. To tune them by ear takes a bit of practice. Best I can explain it is you will be turning the screw counter clockwise until you start to hear the bike stall or stumble. I always hear that and the bike may even begin to pop or backfire a tad. Once you hear that then slowly begin to turn the screw back in until that clears up. At that point you are where you want to be.
Also.... and I find this helps everything else is to make sure the carbs are synched before doing the final pilot screw adjustments. You will want to re synch a final time once you are finished too and periodically as you keep and ride the bike.

[TheNannerpus]

After pulling the carbs yet again, I got the floats where I think they're pretty good, mainly because gas isn't leaking anymore. See this thread for more.

Carbs were synched with carbtune. I tried the colortune by ear, but I couldn't hear the revs change, so the pilot screws are set at 2 turns out until I get me one of those tools.



My octy is on vacation until further notice (per this thread), replaced with these. Coincidentally, also an octy (once I put the final section of tubing after the filters). Go figure. I still have to test fit to get the best tube lengths.

I plan on putting stuff back together between now and the weekend and see if this thing is road worthy. I'd like to get even a short ride on it before winter.

[cajun31]

Instead of the 4mm tap just screw a pointy sheet metal screw in the small hole you drilled and grab it with your small vicegrips and pull it out of your way. This way you avoid damaging the heads of the idle mixture screw. Speaking of those, they may be difficult to get out. Soak them in PB blaster and custom grind a screw driver to fit the screw slots. They are soft and you can create a drill it out situation if not careful.

I have seen many broken pilot screw towers due to the sheet metal screw approach. Not that it is the culprit .. just some folks act like a gorilla doing that method.